floem_editor_core/

editor.rs

use std::{collections::HashSet, iter, ops::Range};

use itertools::Itertools;
use lapce_xi_rope::{DeltaElement, Rope, RopeDelta};

use crate::{
    buffer::{Buffer, InvalLines, rope_text::RopeText},
    command::EditCommand,
    cursor::{Cursor, CursorAffinity, CursorMode, get_first_selection_after},
    mode::{Mode, MotionMode, VisualMode},
    register::{Clipboard, Register, RegisterData, RegisterKind},
    selection::{InsertDrift, SelRegion, Selection},
    util::{
        has_unmatched_pair, matching_char, matching_pair_direction, str_is_pair_left,
        str_matching_pair,
    },
    word::{CharClassification, get_char_property},
};

fn format_start_end(
    buffer: &Buffer,
    range: Range<usize>,
    is_vertical: bool,
    first_non_blank: bool,
    count: usize,
) -> Range<usize> {
    let start = range.start;
    let end = range.end;

    if is_vertical {
        let start_line = buffer.line_of_offset(start.min(end));
        let end_line = buffer.line_of_offset(end.max(start));
        let start = if first_non_blank {
            buffer.first_non_blank_character_on_line(start_line)
        } else {
            buffer.offset_of_line(start_line)
        };
        let end = buffer.offset_of_line(end_line + count);
        start..end
    } else {
        let s = start.min(end);
        let e = start.max(end);
        s..e
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum EditType {
    InsertChars,
    Delete,
    DeleteSelection,
    InsertNewline,
    Cut,
    Paste,
    Indent,
    Outdent,
    ToggleComment,
    MoveLine,
    Completion,
    DeleteWord,
    DeleteToBeginningOfLine,
    DeleteToEndOfLine,
    DeleteToEndOfLineAndInsert,
    MotionDelete,
    NormalizeLineEndings,
    Undo,
    Redo,
    Other,
}

impl EditType {
    /// Checks whether a new undo group should be created between two edits.
    pub fn breaks_undo_group(self, previous: EditType) -> bool {
        !((self == EditType::InsertChars || self == EditType::Delete) && self == previous)
    }
}

pub struct EditConf<'a> {
    pub comment_token: &'a str,
    pub modal: bool,
    pub smart_tab: bool,
    pub keep_indent: bool,
    pub auto_indent: bool,
}

pub struct Action {}

impl Action {
    pub fn insert(
        cursor: &mut Cursor,
        buffer: &mut Buffer,
        s: &str,
        prev_unmatched: &dyn Fn(&Buffer, char, usize) -> Option<usize>,
        auto_closing_matching_pairs: bool,
        auto_surround: bool,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        let mut deltas = Vec::new();
        if let CursorMode::Insert(selection) = &cursor.mode {
            if s.chars().count() != 1 {
                let (text, delta, inval_lines) =
                    buffer.edit([(selection, s)], EditType::InsertChars);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                deltas.push((text, delta, inval_lines));
                cursor.mode = CursorMode::Insert(selection);
            } else {
                let c = s.chars().next().unwrap();
                let matching_pair_type = matching_pair_direction(c);

                // The main edit operations
                let mut edits = vec![];

                // "Late edits" - characters to be inserted after particular regions
                let mut edits_after = vec![];

                let mut selection = selection.clone();
                for (idx, region) in selection.regions_mut().iter_mut().enumerate() {
                    let offset = region.end;
                    let cursor_char = buffer.char_at_offset(offset);
                    let prev_offset = buffer.move_left(offset, Mode::Normal, 1);
                    let prev_cursor_char = if prev_offset < offset {
                        buffer.char_at_offset(prev_offset)
                    } else {
                        None
                    };

                    // when text is selected, and [,{,(,'," is inserted
                    // wrap the text with that char and its corresponding closing pair
                    if region.start != region.end
                        && auto_surround
                        && (matching_pair_type == Some(true) || c == '"' || c == '\'' || c == '`')
                    {
                        edits.push((Selection::imaginary_caret(region.min()), c.to_string()));
                        edits_after.push((
                            idx,
                            match c {
                                '"' => '"',
                                '\'' => '\'',
                                '`' => '`',
                                _ => matching_char(c).unwrap(),
                            },
                        ));
                        continue;
                    }

                    if auto_closing_matching_pairs {
                        if (c == '"' || c == '\'' || c == '`') && cursor_char == Some(c) {
                            // Skip the closing character
                            let new_offset = buffer.next_grapheme_offset(offset, 1, buffer.len());

                            *region = SelRegion::caret(new_offset, CursorAffinity::Backward);
                            continue;
                        }

                        if matching_pair_type == Some(false) {
                            if cursor_char == Some(c) {
                                // Skip the closing character
                                let new_offset =
                                    buffer.next_grapheme_offset(offset, 1, buffer.len());

                                *region = SelRegion::caret(new_offset, CursorAffinity::Backward);
                                continue;
                            }

                            let line = buffer.line_of_offset(offset);
                            let line_start = buffer.offset_of_line(line);
                            if buffer.slice_to_cow(line_start..offset).trim() == "" {
                                let opening_character = matching_char(c).unwrap();
                                if let Some(previous_offset) =
                                    prev_unmatched(buffer, opening_character, offset)
                                {
                                    // Auto-indent closing character to the same level as the opening.
                                    let previous_line = buffer.line_of_offset(previous_offset);
                                    let line_indent = buffer.indent_on_line(previous_line);

                                    let current_selection = Selection::region(
                                        line_start,
                                        offset,
                                        CursorAffinity::Backward,
                                    );

                                    edits.push((current_selection, format!("{line_indent}{c}")));
                                    continue;
                                }
                            }
                        }

                        if matching_pair_type == Some(true) || c == '"' || c == '\'' || c == '`' {
                            // Create a late edit to insert the closing pair, if allowed.
                            let is_whitespace_or_punct = cursor_char
                                .map(|c| {
                                    let prop = get_char_property(c);
                                    prop == CharClassification::Lf
                                        || prop == CharClassification::Cr
                                        || prop == CharClassification::Space
                                        || prop == CharClassification::Punctuation
                                })
                                .unwrap_or(true);

                            let should_insert_pair = match c {
                                '"' | '\'' | '`' => {
                                    is_whitespace_or_punct
                                        && prev_cursor_char
                                            .map(|c| {
                                                let prop = get_char_property(c);
                                                prop == CharClassification::Lf
                                                    || prop == CharClassification::Cr
                                                    || prop == CharClassification::Space
                                                    || prop == CharClassification::Punctuation
                                            })
                                            .unwrap_or(true)
                                }
                                _ => is_whitespace_or_punct,
                            };

                            if should_insert_pair {
                                let insert_after = match c {
                                    '"' => '"',
                                    '\'' => '\'',
                                    '`' => '`',
                                    _ => matching_char(c).unwrap(),
                                };
                                edits_after.push((idx, insert_after));
                            }
                        };
                    }

                    let current_selection = Selection::imaginary_region(region.start, region.end);

                    edits.push((current_selection, c.to_string()));
                }

                // Apply edits to current selection
                let edits = edits
                    .iter()
                    .map(|(selection, content)| (selection, content.as_str()))
                    .collect::<Vec<_>>();

                let (text, delta, inval_lines) = buffer.edit(&edits, EditType::InsertChars);

                buffer.set_cursor_before(CursorMode::Insert(selection.clone()));

                // Update selection
                let mut selection = selection.apply_delta(&delta, true, InsertDrift::Default);

                buffer.set_cursor_after(CursorMode::Insert(selection.clone()));

                deltas.push((text, delta, inval_lines));
                // Apply late edits
                let edits_after = edits_after
                    .iter()
                    .map(|(idx, content)| {
                        let region = &selection.regions()[*idx];
                        (
                            Selection::imaginary_caret(region.max()),
                            content.to_string(),
                        )
                    })
                    .collect::<Vec<_>>();

                let edits_after = edits_after
                    .iter()
                    .map(|(selection, content)| (selection, content.as_str()))
                    .collect::<Vec<_>>();

                if !edits_after.is_empty() {
                    let (text, delta, inval_lines) =
                        buffer.edit(&edits_after, EditType::InsertChars);
                    deltas.push((text, delta, inval_lines));
                }

                // Adjust selection according to previous late edits
                let mut adjustment = 0;
                for region in selection
                    .regions_mut()
                    .iter_mut()
                    .sorted_by(|region_a, region_b| region_a.start.cmp(&region_b.start))
                {
                    let new_region = SelRegion::new(
                        region.start + adjustment,
                        region.end + adjustment,
                        CursorAffinity::Backward,
                        None,
                    );

                    if let Some(inserted) = edits_after.iter().find_map(|(selection, str)| {
                        if selection.last_inserted().map(|r| r.start) == Some(region.start) {
                            Some(str)
                        } else {
                            None
                        }
                    }) {
                        adjustment += inserted.len();
                    }

                    *region = new_region;
                }

                cursor.mode = CursorMode::Insert(selection);
            }
        }
        deltas
    }

    fn toggle_visual(cursor: &mut Cursor, visual_mode: VisualMode, modal: bool) {
        if !modal {
            return;
        }

        match &cursor.mode {
            CursorMode::Visual {
                start,
                end,
                mode,
                affinity,
            } => {
                if mode != &visual_mode {
                    cursor.mode = CursorMode::Visual {
                        start: *start,
                        end: *end,
                        mode: visual_mode,
                        affinity: *affinity,
                    };
                } else {
                    let affinity = cursor.affinity();
                    cursor.mode = CursorMode::Normal {
                        offset: *end,
                        affinity,
                    };
                };
            }
            _ => {
                let offset = cursor.offset();
                let affinity = cursor.affinity();
                cursor.mode = CursorMode::Visual {
                    start: offset,
                    end: offset,
                    mode: visual_mode,
                    affinity,
                };
            }
        }
    }

    fn insert_new_line(
        buffer: &mut Buffer,
        cursor: &mut Cursor,
        selection: Selection,
        keep_indent: bool,
        auto_indent: bool,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        let mut edits = Vec::with_capacity(selection.regions().len());
        let mut extra_edits = Vec::new();
        let mut shift = 0i32;
        let line_ending = buffer.line_ending().get_chars();
        for region in selection.regions() {
            let offset = region.max();
            let line = buffer.line_of_offset(offset);
            let line_start = buffer.offset_of_line(line);
            let line_end = buffer.line_end_offset(line, true);
            let line_indent = buffer.indent_on_line(line);
            let first_half = buffer.slice_to_cow(line_start..offset);
            let second_half = buffer.slice_to_cow(offset..line_end);
            let second_half_trim = second_half.trim();

            // TODO: this could be done with 1 string
            let new_line_content = {
                let indent_storage;
                let indent = if auto_indent && has_unmatched_pair(&first_half) {
                    indent_storage = format!("{}{}", line_indent, buffer.indent_unit());
                    &indent_storage
                } else if keep_indent
                    && (second_half_trim.is_empty() || !second_half.starts_with(&line_indent))
                {
                    &line_indent
                } else {
                    indent_storage = String::new();
                    &indent_storage
                };
                format!("{line_ending}{indent}")
            };

            let selection = Selection::imaginary_region(region.min(), region.max());

            shift -= (region.max() - region.min()) as i32;
            shift += new_line_content.len() as i32;

            edits.push((selection, new_line_content));

            if let Some(c) = first_half.chars().rev().find(|&c| c != ' ')
                && let Some(true) = matching_pair_direction(c)
                && let Some(c) = matching_char(c)
                && second_half_trim.starts_with(c)
            {
                let selection = Selection::imaginary_caret((region.max() as i32 + shift) as usize);
                let content = format!("{line_ending}{line_indent}",);
                extra_edits.push((selection, content));
            }
        }

        let edits = edits
            .iter()
            .map(|(selection, s)| (selection, s.as_str()))
            .collect::<Vec<_>>();
        let (text, delta, inval_lines) = buffer.edit(&edits, EditType::InsertNewline);
        let mut selection = selection.apply_delta(&delta, true, InsertDrift::Default);

        let mut deltas = vec![(text, delta, inval_lines)];

        if !extra_edits.is_empty() {
            let edits = extra_edits
                .iter()
                .map(|(selection, s)| (selection, s.as_str()))
                .collect::<Vec<_>>();
            let (text, delta, inval_lines) = buffer.edit(&edits, EditType::InsertNewline);
            selection = selection.apply_delta(&delta, false, InsertDrift::Default);
            deltas.push((text, delta, inval_lines));
        }

        cursor.mode = CursorMode::Insert(selection);

        deltas
    }

    pub fn execute_motion_mode(
        cursor: &mut Cursor,
        buffer: &mut Buffer,
        motion_mode: MotionMode,
        range: Range<usize>,
        is_vertical: bool,
        register: &mut Register,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        let mut deltas = Vec::new();
        match motion_mode {
            MotionMode::Delete { .. } => {
                let range = format_start_end(buffer, range, is_vertical, false, 1);
                register.add(
                    RegisterKind::Delete,
                    RegisterData {
                        content: buffer.slice_to_cow(range.clone()).to_string(),
                        mode: if is_vertical {
                            VisualMode::Linewise
                        } else {
                            VisualMode::Normal
                        },
                    },
                );
                let selection = Selection::region(range.start, range.end, CursorAffinity::Forward);
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::MotionDelete);
                cursor.apply_delta(&delta);
                deltas.push((text, delta, inval_lines));
            }
            MotionMode::Yank { .. } => {
                let range = format_start_end(buffer, range, is_vertical, false, 1);
                register.add(
                    RegisterKind::Yank,
                    RegisterData {
                        content: buffer.slice_to_cow(range).to_string(),
                        mode: if is_vertical {
                            VisualMode::Linewise
                        } else {
                            VisualMode::Normal
                        },
                    },
                );
            }
            MotionMode::Indent => {
                let selection = Selection::region(range.start, range.end, CursorAffinity::Backward);
                let (text, delta, inval_lines) = Self::do_indent(buffer, selection);
                deltas.push((text, delta, inval_lines));
            }
            MotionMode::Outdent => {
                let selection = Selection::region(range.start, range.end, CursorAffinity::Forward);
                let (text, delta, inval_lines) = Self::do_outdent(buffer, selection);
                deltas.push((text, delta, inval_lines));
            }
        }
        deltas
    }

    /// Compute the result of pasting `content` into `selection`.
    /// If the number of lines to be pasted is divisible by the number of [`SelRegion`]s in
    /// `selection`, partition the content to be pasted into groups of equal numbers of lines and
    /// paste one group at each [`SelRegion`].
    /// The way lines are counted and `content` is partitioned depends on `mode`.
    fn compute_paste_edit(
        buffer: &mut Buffer,
        selection: &Selection,
        content: &str,
        mode: VisualMode,
    ) -> (Rope, RopeDelta, InvalLines) {
        if selection.len() > 1 {
            let line_ends: Vec<_> = content.match_indices('\n').map(|(idx, _)| idx).collect();

            match mode {
                // Consider lines to be separated by the line terminator.
                // The number of lines == number of line terminators + 1.
                // The final line in each group does not include the line terminator.
                VisualMode::Normal if (line_ends.len() + 1) % selection.len() == 0 => {
                    let lines_per_group = (line_ends.len() + 1) / selection.len();
                    let mut start_idx = 0;
                    let last_line_start = line_ends
                        .len()
                        .checked_sub(lines_per_group)
                        .and_then(|line_idx| line_ends.get(line_idx))
                        .map(|line_end| line_end + 1)
                        .unwrap_or(0);

                    let groups = line_ends
                        .iter()
                        .skip(lines_per_group - 1)
                        .step_by(lines_per_group)
                        .map(|&end_idx| {
                            let group = &content[start_idx..end_idx];
                            let group = group.strip_suffix('\r').unwrap_or(group);
                            start_idx = end_idx + 1;

                            group
                        })
                        .chain(iter::once(&content[last_line_start..]));

                    let edits = selection
                        .regions()
                        .iter()
                        .copied()
                        .map(Selection::sel_region)
                        .zip(groups);

                    buffer.edit(edits, EditType::Paste)
                }
                // Consider lines to be terminated by the line terminator.
                // The number of lines == number of line terminators.
                // The final line in each group includes the line terminator.
                VisualMode::Linewise | VisualMode::Blockwise
                    if line_ends.len() % selection.len() == 0 =>
                {
                    let lines_per_group = line_ends.len() / selection.len();
                    let mut start_idx = 0;

                    let groups = line_ends
                        .iter()
                        .skip(lines_per_group - 1)
                        .step_by(lines_per_group)
                        .map(|&end_idx| {
                            let group = &content[start_idx..=end_idx];
                            start_idx = end_idx + 1;

                            group
                        });

                    let edits = selection
                        .regions()
                        .iter()
                        .copied()
                        .map(Selection::sel_region)
                        .zip(groups);

                    buffer.edit(edits, EditType::Paste)
                }
                _ => buffer.edit([(&selection, content)], EditType::Paste),
            }
        } else {
            buffer.edit([(&selection, content)], EditType::Paste)
        }
    }

    pub fn do_paste(
        cursor: &mut Cursor,
        buffer: &mut Buffer,
        data: &RegisterData,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        let mut deltas = Vec::new();
        match data.mode {
            VisualMode::Normal => {
                let selection = match cursor.mode {
                    CursorMode::Normal { offset, affinity } => {
                        let line_end = buffer.offset_line_end(offset, true);
                        let offset = (offset + 1).min(line_end);
                        Selection::caret(offset, affinity)
                    }
                    CursorMode::Insert { .. } | CursorMode::Visual { .. } => {
                        cursor.edit_selection(buffer)
                    }
                };
                let after = cursor.is_insert() || !data.content.contains('\n');
                let (text, delta, inval_lines) =
                    Self::compute_paste_edit(buffer, &selection, &data.content, data.mode);
                let selection = selection.apply_delta(&delta, after, InsertDrift::Default);
                deltas.push((text, delta, inval_lines));
                if !after {
                    cursor.update_selection(buffer, selection);
                } else {
                    match cursor.mode {
                        CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                            let offset = buffer.prev_grapheme_offset(selection.min_offset(), 1, 0);
                            cursor.mode = CursorMode::Normal {
                                offset,
                                affinity: selection.get_cursor_affinity(),
                            };
                        }
                        CursorMode::Insert { .. } => {
                            cursor.mode = CursorMode::Insert(selection);
                        }
                    }
                }
            }
            VisualMode::Linewise | VisualMode::Blockwise => {
                let (selection, content) = match &cursor.mode {
                    CursorMode::Normal { offset, .. } => {
                        let line = buffer.line_of_offset(*offset);
                        let offset = buffer.offset_of_line(line + 1);
                        (
                            Selection::caret(offset, CursorAffinity::Backward),
                            data.content.clone(),
                        )
                    }
                    CursorMode::Insert(selection) => {
                        let mut selection = selection.clone();
                        for region in selection.regions_mut() {
                            if region.is_caret() {
                                let line = buffer.line_of_offset(region.start);
                                let start = buffer.offset_of_line(line);
                                region.start = start;
                                region.end = start;
                            }
                        }
                        (selection, data.content.clone())
                    }
                    CursorMode::Visual { mode, .. } => {
                        let selection = cursor.edit_selection(buffer);
                        let data = match mode {
                            VisualMode::Linewise => data.content.clone(),
                            _ => "\n".to_string() + &data.content,
                        };
                        (selection, data)
                    }
                };
                let (text, delta, inval_lines) =
                    Self::compute_paste_edit(buffer, &selection, &content, data.mode);
                let selection =
                    selection.apply_delta(&delta, cursor.is_insert(), InsertDrift::Default);
                deltas.push((text, delta, inval_lines));
                match cursor.mode {
                    CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                        let offset = selection.min_offset();
                        let offset = if cursor.is_visual() {
                            offset + 1
                        } else {
                            offset
                        };
                        let line = buffer.line_of_offset(offset);
                        let offset = buffer.first_non_blank_character_on_line(line);
                        cursor.mode = CursorMode::Normal {
                            offset,
                            affinity: selection.get_cursor_affinity(),
                        };
                    }
                    CursorMode::Insert(_) => {
                        cursor.mode = CursorMode::Insert(selection);
                    }
                }
            }
        }
        deltas
    }

    fn do_indent(buffer: &mut Buffer, selection: Selection) -> (Rope, RopeDelta, InvalLines) {
        let indent = buffer.indent_unit();
        let mut edits = Vec::new();

        let mut lines = HashSet::new();
        for region in selection.regions() {
            let start_line = buffer.line_of_offset(region.min());
            let mut end_line = buffer.line_of_offset(region.max());
            if end_line > start_line {
                let end_line_start = buffer.offset_of_line(end_line);
                if end_line_start == region.max() {
                    end_line -= 1;
                }
            }
            for line in start_line..=end_line {
                if lines.insert(line) {
                    let line_content = buffer.line_content(line);
                    if line_content == "\n" || line_content == "\r\n" {
                        continue;
                    }
                    let nonblank = buffer.first_non_blank_character_on_line(line);
                    let edit = crate::indent::create_edit(buffer, nonblank, indent);
                    edits.push(edit);
                }
            }
        }

        buffer.edit(&edits, EditType::Indent)
    }

    fn do_outdent(buffer: &mut Buffer, selection: Selection) -> (Rope, RopeDelta, InvalLines) {
        let indent = buffer.indent_unit();
        let mut edits = Vec::new();

        let mut lines = HashSet::new();
        for region in selection.regions() {
            let start_line = buffer.line_of_offset(region.min());
            let mut end_line = buffer.line_of_offset(region.max());
            if end_line > start_line {
                let end_line_start = buffer.offset_of_line(end_line);
                if end_line_start == region.max() {
                    end_line -= 1;
                }
            }
            for line in start_line..=end_line {
                if lines.insert(line) {
                    let line_content = buffer.line_content(line);
                    if line_content == "\n" || line_content == "\r\n" {
                        continue;
                    }
                    let nonblank = buffer.first_non_blank_character_on_line(line);
                    if let Some(edit) = crate::indent::create_outdent(buffer, nonblank, indent) {
                        edits.push(edit);
                    }
                }
            }
        }

        buffer.edit(&edits, EditType::Outdent)
    }

    fn duplicate_line(
        cursor: &mut Cursor,
        buffer: &mut Buffer,
        direction: DuplicateDirection,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        // TODO other modes
        let selection = match cursor.mode {
            CursorMode::Insert(ref mut sel) => sel,
            _ => return vec![],
        };

        let mut line_ranges = HashSet::new();
        for region in selection.regions_mut() {
            let start_line = buffer.line_of_offset(region.start);
            let end_line = buffer.line_of_offset(region.end) + 1;

            line_ranges.insert(start_line..end_line);
        }

        let mut edits = vec![];
        for range in line_ranges {
            let start = buffer.offset_of_line(range.start);
            let end = buffer.offset_of_line(range.end);

            let content = buffer.slice_to_cow(start..end).into_owned();
            edits.push((
                match direction {
                    DuplicateDirection::Up => Selection::caret(end, CursorAffinity::Backward),
                    DuplicateDirection::Down => Selection::caret(start, CursorAffinity::Backward),
                },
                content,
            ));
        }

        let edits = edits
            .iter()
            .map(|(sel, content)| (sel, content.as_str()))
            .collect::<Vec<_>>();

        let (text, delta, inval_lines) = buffer.edit(&edits, EditType::InsertChars);

        *selection = selection.apply_delta(&delta, true, InsertDrift::Default);

        vec![(text, delta, inval_lines)]
    }

    #[allow(clippy::too_many_arguments)]
    pub fn do_edit<T: Clipboard>(
        cursor: &mut Cursor,
        buffer: &mut Buffer,
        cmd: &EditCommand,
        clipboard: &mut T,
        register: &mut Register,
        EditConf {
            comment_token,
            modal,
            smart_tab,
            keep_indent,
            auto_indent,
        }: EditConf,
    ) -> Vec<(Rope, RopeDelta, InvalLines)> {
        use crate::command::EditCommand::*;
        match cmd {
            MoveLineUp => {
                let mut deltas = Vec::new();
                if let CursorMode::Insert(mut selection) = cursor.mode.clone() {
                    for region in selection.regions_mut() {
                        let start_line = buffer.line_of_offset(region.min());
                        if start_line > 0 {
                            let previous_line_len = buffer.line_content(start_line - 1).len();

                            let end_line = buffer.line_of_offset(region.max());
                            let start = buffer.offset_of_line(start_line);
                            let end = buffer.offset_of_line(end_line + 1);
                            let content = buffer.slice_to_cow(start..end).to_string();
                            let (text, delta, inval_lines) = buffer.edit(
                                [
                                    (&Selection::region(start, end, region.affinity), ""),
                                    (
                                        &Selection::caret(
                                            buffer.offset_of_line(start_line - 1),
                                            region.affinity,
                                        ),
                                        &content,
                                    ),
                                ],
                                EditType::MoveLine,
                            );
                            deltas.push((text, delta, inval_lines));
                            region.start -= previous_line_len;
                            region.end -= previous_line_len;
                        }
                    }
                    cursor.mode = CursorMode::Insert(selection);
                }
                deltas
            }
            MoveLineDown => {
                let mut deltas = Vec::new();
                if let CursorMode::Insert(mut selection) = cursor.mode.clone() {
                    for region in selection.regions_mut().iter_mut().rev() {
                        let last_line = buffer.last_line();
                        let start_line = buffer.line_of_offset(region.min());
                        let end_line = buffer.line_of_offset(region.max());
                        if end_line < last_line {
                            let next_line_len = buffer.line_content(end_line + 1).len();

                            let start = buffer.offset_of_line(start_line);
                            let end = buffer.offset_of_line(end_line + 1);
                            let content = buffer.slice_to_cow(start..end).to_string();
                            let (text, delta, inval_lines) = buffer.edit(
                                [
                                    (
                                        &Selection::caret(
                                            buffer.offset_of_line(end_line + 2),
                                            region.affinity,
                                        ),
                                        content.as_str(),
                                    ),
                                    (&Selection::region(start, end, region.affinity), ""),
                                ],
                                EditType::MoveLine,
                            );
                            deltas.push((text, delta, inval_lines));
                            region.start += next_line_len;
                            region.end += next_line_len;
                        }
                    }
                    cursor.mode = CursorMode::Insert(selection);
                }
                deltas
            }
            InsertNewLine => match cursor.mode.clone() {
                CursorMode::Normal { offset, .. } => Self::insert_new_line(
                    buffer,
                    cursor,
                    Selection::imaginary_caret(offset),
                    keep_indent,
                    auto_indent,
                ),
                CursorMode::Insert(selection) => {
                    Self::insert_new_line(buffer, cursor, selection, keep_indent, auto_indent)
                }
                CursorMode::Visual { .. } => {
                    vec![]
                }
            },
            InsertTab => {
                let mut deltas = Vec::new();
                if let CursorMode::Insert(selection) = &cursor.mode {
                    if smart_tab {
                        let indent = buffer.indent_unit();
                        let mut edits = Vec::new();

                        for region in selection.regions() {
                            if region.is_caret() {
                                edits.push(crate::indent::create_edit(buffer, region.start, indent))
                            } else {
                                let start_line = buffer.line_of_offset(region.min());
                                let end_line = buffer.line_of_offset(region.max());
                                for line in start_line..=end_line {
                                    let offset = buffer.first_non_blank_character_on_line(line);
                                    edits.push(crate::indent::create_edit(buffer, offset, indent))
                                }
                            }
                        }

                        let (text, delta, inval_lines) = buffer.edit(&edits, EditType::InsertChars);
                        let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                        deltas.push((text, delta, inval_lines));
                        cursor.mode = CursorMode::Insert(selection);
                    } else {
                        let (text, delta, inval_lines) =
                            buffer.edit([(&selection, "\t")], EditType::InsertChars);
                        let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                        deltas.push((text, delta, inval_lines));
                        cursor.mode = CursorMode::Insert(selection);
                    }
                }
                deltas
            }
            IndentLine => {
                let selection = cursor.edit_selection(buffer);
                let (text, delta, inval_lines) = Self::do_indent(buffer, selection);
                cursor.apply_delta(&delta);
                vec![(text, delta, inval_lines)]
            }
            JoinLines => {
                let offset = cursor.offset();
                let (line, _col) = buffer.offset_to_line_col(offset);
                if line < buffer.last_line() {
                    let start = buffer.line_end_offset(line, true);
                    let end = buffer.first_non_blank_character_on_line(line + 1);
                    vec![buffer.edit(
                        [(&Selection::imaginary_region(start, end), " ")],
                        EditType::Other,
                    )]
                } else {
                    vec![]
                }
            }
            OutdentLine => {
                let selection = cursor.edit_selection(buffer);
                let (text, delta, inval_lines) = Self::do_outdent(buffer, selection);
                cursor.apply_delta(&delta);
                vec![(text, delta, inval_lines)]
            }
            ToggleLineComment => {
                let mut lines = HashSet::new();
                let selection = cursor.edit_selection(buffer);
                let mut had_comment = true;
                let mut smallest_indent = usize::MAX;
                for region in selection.regions() {
                    let mut line = buffer.line_of_offset(region.min());
                    let end_line = buffer.line_of_offset(region.max());
                    let end_line_offset = buffer.offset_of_line(end_line);
                    let end = if end_line > line && region.max() == end_line_offset {
                        end_line_offset
                    } else {
                        buffer.offset_of_line(end_line + 1)
                    };
                    let start = buffer.offset_of_line(line);
                    for content in buffer.text().lines(start..end) {
                        let trimmed_content = content.trim_start();
                        if trimmed_content.is_empty() {
                            line += 1;
                            continue;
                        }
                        let indent = content.len() - trimmed_content.len();
                        if indent < smallest_indent {
                            smallest_indent = indent;
                        }
                        if !trimmed_content.starts_with(comment_token) {
                            had_comment = false;
                            lines.insert((line, indent, 0));
                        } else {
                            let had_space_after_comment =
                                trimmed_content.chars().nth(comment_token.len()) == Some(' ');
                            lines.insert((
                                line,
                                indent,
                                comment_token.len() + usize::from(had_space_after_comment),
                            ));
                        }
                        line += 1;
                    }
                }

                let (text, delta, inval_lines) = if had_comment {
                    let mut selection = Selection::new();
                    for (line, indent, len) in lines.iter() {
                        let start = buffer.offset_of_line(*line) + indent;
                        selection.add_region(SelRegion::imaginary_region(start, start + len))
                    }
                    buffer.edit([(&selection, "")], EditType::ToggleComment)
                } else {
                    let mut selection = Selection::new();
                    for (line, _, _) in lines.iter() {
                        let start = buffer.offset_of_line(*line) + smallest_indent;
                        selection.add_region(SelRegion::imaginary_caret(start))
                    }
                    buffer.edit(
                        [(&selection, format!("{comment_token} ").as_str())],
                        EditType::ToggleComment,
                    )
                };
                cursor.apply_delta(&delta);
                vec![(text, delta, inval_lines)]
            }
            Undo => {
                if let Some((text, delta, inval_lines, cursor_mode)) = buffer.do_undo() {
                    apply_undo_redo(cursor, buffer, modal, text, delta, inval_lines, cursor_mode)
                } else {
                    vec![]
                }
            }
            Redo => {
                if let Some((text, delta, inval_lines, cursor_mode)) = buffer.do_redo() {
                    apply_undo_redo(cursor, buffer, modal, text, delta, inval_lines, cursor_mode)
                } else {
                    vec![]
                }
            }
            ClipboardCopy => {
                let data = cursor.yank(buffer);
                clipboard.put_string(data.content);

                match &cursor.mode {
                    CursorMode::Visual { start, end, .. } => {
                        let offset = *start.min(end);
                        let offset = buffer.offset_line_end(offset, false).min(offset);
                        cursor.mode = CursorMode::Normal {
                            offset,
                            affinity: CursorAffinity::Forward,
                        };
                    }
                    CursorMode::Normal { .. } | CursorMode::Insert(_) => {}
                }
                vec![]
            }
            ClipboardCut => {
                let data = cursor.yank(buffer);
                clipboard.put_string(data.content);

                let selection = if let CursorMode::Insert(mut selection) = cursor.mode.clone() {
                    for region in selection.regions_mut() {
                        if region.is_caret() {
                            let line = buffer.line_of_offset(region.start);
                            let start = buffer.offset_of_line(line);
                            let end = buffer.offset_of_line(line + 1);
                            region.start = start;
                            region.end = end;
                        }
                    }
                    selection
                } else {
                    cursor.edit_selection(buffer)
                };

                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], EditType::Cut);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            ClipboardPaste => {
                if let Some(s) = clipboard.get_string() {
                    let mode = if s.ends_with('\n') {
                        VisualMode::Linewise
                    } else {
                        VisualMode::Normal
                    };
                    let data = RegisterData { content: s, mode };
                    Self::do_paste(cursor, buffer, &data)
                } else {
                    vec![]
                }
            }
            Yank => {
                match &cursor.mode {
                    CursorMode::Visual { start, end, .. } => {
                        let data = cursor.yank(buffer);
                        register.add_yank(data);

                        let offset = *start.min(end);
                        let offset = buffer.offset_line_end(offset, false).min(offset);
                        cursor.mode = CursorMode::Normal {
                            offset,
                            affinity: CursorAffinity::Forward,
                        };
                    }
                    CursorMode::Normal { .. } => {}
                    CursorMode::Insert(_) => {}
                }
                vec![]
            }
            Paste => {
                let data = register.unnamed.clone();
                Self::do_paste(cursor, buffer, &data)
            }
            PasteBefore => {
                let offset = cursor.offset();
                let data = register.unnamed.clone();
                let mut local_cursor =
                    Cursor::new(CursorMode::Insert(Selection::new()), None, None);
                local_cursor.set_offset(offset, CursorAffinity::Forward, false, false);
                Self::do_paste(&mut local_cursor, buffer, &data)
            }
            NewLineAbove => {
                let offset = cursor.offset();
                let line = buffer.line_of_offset(offset);
                let offset = if line > 0 {
                    buffer.line_end_offset(line - 1, true)
                } else {
                    buffer.first_non_blank_character_on_line(line)
                };
                let delta = Self::insert_new_line(
                    buffer,
                    cursor,
                    Selection::imaginary_caret(offset),
                    keep_indent,
                    auto_indent,
                );
                if line == 0 {
                    cursor.mode =
                        CursorMode::Insert(Selection::caret(offset, CursorAffinity::Backward));
                }
                delta
            }
            NewLineBelow => {
                let offset = cursor.offset();
                let offset = buffer.offset_line_end(offset, true);
                Self::insert_new_line(
                    buffer,
                    cursor,
                    Selection::imaginary_caret(offset),
                    keep_indent,
                    auto_indent,
                )
            }
            DeleteBackward => {
                let (selection, edit_type) = match cursor.mode {
                    CursorMode::Normal { .. } => (cursor.edit_selection(buffer), EditType::Delete),
                    CursorMode::Visual { .. } => {
                        (cursor.edit_selection(buffer), EditType::DeleteSelection)
                    }
                    CursorMode::Insert(_) => {
                        let selection = cursor.edit_selection(buffer);
                        let edit_type = if selection.is_caret() {
                            EditType::Delete
                        } else {
                            EditType::DeleteSelection
                        };
                        let indent = buffer.indent_unit();
                        let mut new_selection = Selection::new();
                        for region in selection.regions() {
                            let new_region = if region.is_caret() {
                                if indent.starts_with('\t') {
                                    let new_end = buffer.move_left(region.end, Mode::Insert, 1);
                                    SelRegion::new(region.start, new_end, region.affinity, None)
                                } else {
                                    let line = buffer.line_of_offset(region.start);
                                    let nonblank = buffer.first_non_blank_character_on_line(line);
                                    let (_, col) = buffer.offset_to_line_col(region.start);
                                    let count = if region.start <= nonblank && col > 0 {
                                        let r = col % indent.len();
                                        if r == 0 { indent.len() } else { r }
                                    } else {
                                        1
                                    };
                                    let new_end = buffer.move_left(region.end, Mode::Insert, count);
                                    SelRegion::new(region.start, new_end, region.affinity, None)
                                }
                            } else {
                                *region
                            };
                            new_selection.add_region(new_region);
                        }

                        let mut selection = new_selection;
                        if selection.regions().len() == 1 {
                            let delete_str = buffer
                                .slice_to_cow(selection.min_offset()..selection.max_offset())
                                .to_string();
                            if str_is_pair_left(&delete_str)
                                || delete_str == "\""
                                || delete_str == "'"
                                || delete_str == "`"
                            {
                                let matching_char = match delete_str.as_str() {
                                    "\"" => Some('"'),
                                    "'" => Some('\''),
                                    "`" => Some('`'),
                                    _ => str_matching_pair(&delete_str),
                                };
                                if let Some(c) = matching_char {
                                    let offset = selection.max_offset();
                                    let line = buffer.line_of_offset(offset);
                                    let line_end = buffer.line_end_offset(line, true);
                                    let content = buffer.slice_to_cow(offset..line_end).to_string();
                                    if content.trim().starts_with(&c.to_string()) {
                                        let index = content.match_indices(c).next().unwrap().0;
                                        let affinity = selection.get_cursor_affinity();
                                        selection = Selection::region(
                                            selection.min_offset(),
                                            offset + index + 1,
                                            affinity,
                                        );
                                    }
                                }
                            }
                        }
                        (selection, edit_type)
                    }
                };
                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], edit_type);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteForward => {
                let (selection, edit_type) = match cursor.mode {
                    CursorMode::Normal { .. } => (cursor.edit_selection(buffer), EditType::Delete),
                    CursorMode::Visual { .. } => {
                        (cursor.edit_selection(buffer), EditType::DeleteSelection)
                    }
                    CursorMode::Insert(_) => {
                        let selection = cursor.edit_selection(buffer);
                        let edit_type = if selection.is_caret() {
                            EditType::Delete
                        } else {
                            EditType::DeleteSelection
                        };
                        let mut new_selection = Selection::new();
                        for region in selection.regions() {
                            let new_region = if region.is_caret() {
                                let new_end = buffer.move_right(region.end, Mode::Insert, 1);
                                SelRegion::new(region.start, new_end, region.affinity, None)
                            } else {
                                *region
                            };
                            new_selection.add_region(new_region);
                        }
                        (new_selection, edit_type)
                    }
                };
                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], edit_type);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteSelection => {
                let selection = match cursor.mode {
                    CursorMode::Normal { .. } => cursor.edit_selection(buffer),
                    CursorMode::Visual { .. } => cursor.edit_selection(buffer),
                    CursorMode::Insert(_) => cursor.edit_selection(buffer),
                };

                if selection.regions().iter().all(|r| r.is_caret()) {
                    return vec![];
                }

                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteSelection);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteLine => {
                let selection = cursor.edit_selection(buffer);
                let range = format_start_end(
                    buffer,
                    selection.min_offset()..selection.max_offset(),
                    true,
                    false,
                    1,
                );
                let selection = Selection::region(range.start, range.end, CursorAffinity::Forward);
                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], EditType::Delete);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.mode = CursorMode::Insert(selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteWordForward => {
                let selection = match cursor.mode {
                    CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                        cursor.edit_selection(buffer)
                    }
                    CursorMode::Insert(_) => {
                        let mut new_selection = Selection::new();
                        let selection = cursor.edit_selection(buffer);

                        for region in selection.regions() {
                            let end = buffer.move_word_forward(region.end);
                            let new_region =
                                SelRegion::new(region.start, end, region.affinity, None);
                            new_selection.add_region(new_region);
                        }

                        new_selection
                    }
                };
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteWord);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteWordBackward => {
                let selection = match cursor.mode {
                    CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                        cursor.edit_selection(buffer)
                    }
                    CursorMode::Insert(_) => {
                        let mut new_selection = Selection::new();
                        let selection = cursor.edit_selection(buffer);

                        for region in selection.regions() {
                            let end = buffer.move_word_backward_deletion(region.end);
                            let new_region =
                                SelRegion::new(region.start, end, region.affinity, None);
                            new_selection.add_region(new_region);
                        }

                        new_selection
                    }
                };
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteWord);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteToBeginningOfLine => {
                let selection = match cursor.mode {
                    CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                        cursor.edit_selection(buffer)
                    }
                    CursorMode::Insert(_) => {
                        let selection = cursor.edit_selection(buffer);

                        let mut new_selection = Selection::new();
                        for region in selection.regions() {
                            let line = buffer.line_of_offset(region.end);
                            let end = buffer.offset_of_line(line);
                            let new_region =
                                SelRegion::new(region.start, end, region.affinity, None);
                            new_selection.add_region(new_region);
                        }

                        new_selection
                    }
                };
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteToBeginningOfLine);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteToEndOfLine => {
                let selection = match cursor.mode {
                    CursorMode::Normal { .. } | CursorMode::Visual { .. } => {
                        cursor.edit_selection(buffer)
                    }
                    CursorMode::Insert(_) => {
                        let mut selection = cursor.edit_selection(buffer);

                        let cursor_offset = cursor.offset();
                        let line = buffer.line_of_offset(cursor_offset);
                        let end_of_line_offset = buffer.line_end_offset(line, true);
                        let new_region = SelRegion::new(
                            cursor_offset,
                            end_of_line_offset,
                            CursorAffinity::Backward,
                            None,
                        );
                        selection.add_region(new_region);

                        selection
                    }
                };
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteToEndOfLine);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.update_selection(buffer, selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteForwardAndInsert => {
                let selection = cursor.edit_selection(buffer);
                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], EditType::Delete);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.mode = CursorMode::Insert(selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteWordAndInsert => {
                let selection = {
                    let mut new_selection = Selection::new();
                    let selection = cursor.edit_selection(buffer);

                    for region in selection.regions() {
                        let end = buffer.move_word_forward(region.end);
                        let new_region =
                            SelRegion::new(region.start, end, CursorAffinity::Backward, None);
                        new_selection.add_region(new_region);
                    }

                    new_selection
                };
                let (text, delta, inval_lines) =
                    buffer.edit([(&selection, "")], EditType::DeleteWord);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.mode = CursorMode::Insert(selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteLineAndInsert => {
                let selection = cursor.edit_selection(buffer);
                let range = format_start_end(
                    buffer,
                    selection.min_offset()..selection.max_offset(),
                    true,
                    true,
                    1,
                );
                let selection =
                    Selection::region(range.start, range.end - 1, CursorAffinity::Backward); // -1 because we want to keep the line itself
                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], EditType::Delete);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.mode = CursorMode::Insert(selection);
                vec![(text, delta, inval_lines)]
            }
            DeleteToEndOfLineAndInsert => {
                let mut selection = cursor.edit_selection(buffer);

                let cursor_offset = cursor.offset();
                let line = buffer.line_of_offset(cursor_offset);
                let end_of_line_offset = buffer.line_end_offset(line, true);

                let new_region = SelRegion::new(
                    cursor_offset,
                    end_of_line_offset,
                    CursorAffinity::Backward,
                    None,
                );
                selection.add_region(new_region);

                let (text, delta, inval_lines) = buffer.edit([(&selection, "")], EditType::Delete);
                let selection = selection.apply_delta(&delta, true, InsertDrift::Default);
                cursor.mode = CursorMode::Insert(selection);
                vec![(text, delta, inval_lines)]
            }
            NormalMode => {
                if !modal {
                    if let CursorMode::Insert(selection) = &cursor.mode {
                        match selection.regions().len() {
                            i if i > 1 => {
                                if let Some(region) = selection.last_inserted() {
                                    let new_selection = Selection::region(
                                        region.start,
                                        region.end,
                                        region.affinity,
                                    );
                                    cursor.mode = CursorMode::Insert(new_selection);
                                    return vec![];
                                }
                            }
                            1 => {
                                let region = selection.regions()[0];
                                if !region.is_caret() {
                                    let new_selection =
                                        Selection::caret(region.end, region.affinity);
                                    cursor.mode = CursorMode::Insert(new_selection);
                                    return vec![];
                                }
                            }
                            _ => (),
                        }
                    }

                    return vec![];
                }

                let offset = match &cursor.mode {
                    CursorMode::Insert(selection) => {
                        let offset = selection.min_offset();
                        buffer.prev_grapheme_offset(
                            offset,
                            1,
                            buffer.offset_of_line(buffer.line_of_offset(offset)),
                        )
                    }
                    CursorMode::Visual { end, .. } => buffer.offset_line_end(*end, false).min(*end),
                    CursorMode::Normal { offset, .. } => *offset,
                };
                let affinity = cursor.affinity();

                buffer.reset_edit_type();
                cursor.mode = CursorMode::Normal { offset, affinity };
                cursor.horiz = None;
                vec![]
            }
            InsertMode => {
                cursor.mode =
                    CursorMode::Insert(Selection::caret(cursor.offset(), cursor.affinity()));
                vec![]
            }
            InsertFirstNonBlank => {
                match &cursor.mode {
                    CursorMode::Normal { offset, .. } => {
                        let line = buffer.line_of_offset(*offset);
                        let offset = buffer.first_non_blank_character_on_line(line);
                        cursor.mode =
                            CursorMode::Insert(Selection::caret(offset, CursorAffinity::Forward));
                    }
                    CursorMode::Visual { .. } => {
                        let mut selection = Selection::new();
                        for region in cursor.edit_selection(buffer).regions() {
                            selection.add_region(SelRegion::caret(region.min(), region.affinity));
                        }
                        cursor.mode = CursorMode::Insert(selection);
                    }
                    CursorMode::Insert(_) => {}
                };
                vec![]
            }
            Append => {
                let offset = cursor.offset();
                let line = buffer.line_of_offset(offset);
                let line_len = buffer.line_len(line);
                let count = (line_len > 1 || (buffer.last_line() == line && line_len > 0)) as usize;
                let offset = buffer.move_right(cursor.offset(), Mode::Insert, count);
                cursor.mode =
                    CursorMode::Insert(Selection::caret(offset, CursorAffinity::Backward));
                vec![]
            }
            AppendEndOfLine => {
                let offset = cursor.offset();
                let line = buffer.line_of_offset(offset);
                let offset = buffer.line_end_offset(line, true);
                cursor.mode =
                    CursorMode::Insert(Selection::caret(offset, CursorAffinity::Backward));
                vec![]
            }
            ToggleVisualMode => {
                Self::toggle_visual(cursor, VisualMode::Normal, modal);
                vec![]
            }
            ToggleLinewiseVisualMode => {
                Self::toggle_visual(cursor, VisualMode::Linewise, modal);
                vec![]
            }
            ToggleBlockwiseVisualMode => {
                Self::toggle_visual(cursor, VisualMode::Blockwise, modal);
                vec![]
            }
            DuplicateLineUp => Self::duplicate_line(cursor, buffer, DuplicateDirection::Up),
            DuplicateLineDown => Self::duplicate_line(cursor, buffer, DuplicateDirection::Down),
            NormalizeLineEndings => {
                let Some((text, delta, inval)) = buffer.normalize_line_endings() else {
                    return vec![];
                };

                cursor.apply_delta(&delta);

                vec![(text, delta, inval)]
            }
        }
    }
}

fn apply_undo_redo(
    cursor: &mut Cursor,
    buffer: &mut Buffer,
    modal: bool,
    text: Rope,
    delta: RopeDelta,
    inval_lines: InvalLines,
    cursor_mode: Option<CursorMode>,
) -> Vec<(Rope, RopeDelta, InvalLines)> {
    if let Some(cursor_mode) = cursor_mode {
        cursor.mode = if modal {
            CursorMode::Normal {
                offset: cursor_mode.offset(),
                affinity: cursor_mode.affinity(),
            }
        } else if cursor.is_insert() {
            cursor_mode
        } else {
            CursorMode::Insert(Selection::caret(
                cursor_mode.offset(),
                cursor_mode.affinity(),
            ))
        };
    } else if let Some(new_cursor) = get_first_selection_after(cursor, buffer, &delta) {
        *cursor = new_cursor
    } else if !delta
        .els
        .iter()
        .any(|el| matches!(el, DeltaElement::Copy(_, _)))
    {
        // if there's no copy that means the whole document was swapped
        // we'd better not moving the cursor
    } else {
        cursor.apply_delta(&delta);
    }
    vec![(text, delta, inval_lines)]
}

enum DuplicateDirection {
    Up,
    Down,
}

#[cfg(test)]
mod test {
    use crate::{
        buffer::{Buffer, rope_text::RopeText},
        cursor::{Cursor, CursorAffinity, CursorMode},
        editor::{Action, DuplicateDirection},
        selection::{SelRegion, Selection},
        word::WordCursor,
    };

    fn prev_unmatched(buffer: &Buffer, c: char, offset: usize) -> Option<usize> {
        WordCursor::new(buffer.text(), offset).previous_unmatched(c)
    }

    #[test]
    fn test_insert_simple() {
        let mut buffer = Buffer::new("abc");
        let mut cursor = Cursor::new(
            CursorMode::Insert(Selection::caret(1, CursorAffinity::Backward)),
            None,
            None,
        );

        Action::insert(&mut cursor, &mut buffer, "e", &prev_unmatched, true, true);
        assert_eq!("aebc", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn test_insert_multiple_cursor() {
        let mut buffer = Buffer::new("abc\nefg\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(5, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::insert(&mut cursor, &mut buffer, "i", &prev_unmatched, true, true);
        assert_eq!("aibc\neifg\n", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn test_insert_complex() {
        let mut buffer = Buffer::new("abc\nefg\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(5, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::insert(&mut cursor, &mut buffer, "i", &prev_unmatched, true, true);
        assert_eq!("aibc\neifg\n", buffer.slice_to_cow(0..buffer.len()));
        Action::insert(&mut cursor, &mut buffer, "j", &prev_unmatched, true, true);
        assert_eq!("aijbc\neijfg\n", buffer.slice_to_cow(0..buffer.len()));
        Action::insert(&mut cursor, &mut buffer, "{", &prev_unmatched, true, true);
        assert_eq!("aij{bc\neij{fg\n", buffer.slice_to_cow(0..buffer.len()));
        Action::insert(&mut cursor, &mut buffer, " ", &prev_unmatched, true, true);
        assert_eq!("aij{ bc\neij{ fg\n", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn test_insert_pair() {
        let mut buffer = Buffer::new("a bc\ne fg\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(6, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::insert(&mut cursor, &mut buffer, "{", &prev_unmatched, true, true);
        assert_eq!("a{} bc\ne{} fg\n", buffer.slice_to_cow(0..buffer.len()));
        Action::insert(&mut cursor, &mut buffer, "}", &prev_unmatched, true, true);
        assert_eq!("a{} bc\ne{} fg\n", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn test_insert_pair_with_selection() {
        let mut buffer = Buffer::new("a bc\ne fg\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::new(0, 4, CursorAffinity::Backward, None));
        selection.add_region(SelRegion::new(5, 9, CursorAffinity::Backward, None));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);
        Action::insert(&mut cursor, &mut buffer, "{", &prev_unmatched, true, true);
        assert_eq!("{a bc}\n{e fg}\n", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn test_insert_pair_without_auto_closing() {
        let mut buffer = Buffer::new("a bc\ne fg\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(6, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::insert(&mut cursor, &mut buffer, "{", &prev_unmatched, false, false);
        assert_eq!("a{ bc\ne{ fg\n", buffer.slice_to_cow(0..buffer.len()));
        Action::insert(&mut cursor, &mut buffer, "}", &prev_unmatched, false, false);
        assert_eq!("a{} bc\ne{} fg\n", buffer.slice_to_cow(0..buffer.len()));
    }

    #[test]
    fn duplicate_down_simple() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Down);

        assert_ne!(cursor.offset(), 0);
        assert_eq!(
            "first line\nfirst line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_up_simple() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Up);

        assert_eq!(cursor.offset(), 0);
        assert_eq!(
            "first line\nfirst line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_down_multiple_cursors_in_same_line() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Down);

        assert_eq!(
            "first line\nfirst line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_up_multiple_cursors_in_same_line() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Up);

        assert_eq!(
            "first line\nfirst line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_down_multiple() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(15, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Down);

        assert_eq!(
            "first line\nfirst line\nsecond line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_up_multiple() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(15, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Up);

        assert_eq!(
            "first line\nfirst line\nsecond line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_down_multiple_with_swapped_cursor_order() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(15, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Down);

        assert_eq!(
            "first line\nfirst line\nsecond line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn duplicate_up_multiple_with_swapped_cursor_order() {
        let mut buffer = Buffer::new("first line\nsecond line\n");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(15, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::duplicate_line(&mut cursor, &mut buffer, DuplicateDirection::Up);

        assert_eq!(
            "first line\nfirst line\nsecond line\nsecond line\n",
            buffer.slice_to_cow(0..buffer.len())
        );
    }

    #[test]
    fn check_multiple_cursor_match_insertion() {
        let mut buffer = Buffer::new(" 123 567 9ab def");
        let mut selection = Selection::new();
        selection.add_region(SelRegion::caret(0, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(4, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(8, CursorAffinity::Backward));
        selection.add_region(SelRegion::caret(12, CursorAffinity::Backward));
        let mut cursor = Cursor::new(CursorMode::Insert(selection), None, None);

        Action::insert(&mut cursor, &mut buffer, "(", &prev_unmatched, true, true);

        assert_eq!(
            "() 123() 567() 9ab() def",
            buffer.slice_to_cow(0..buffer.len())
        );

        let mut end_selection = Selection::new();
        end_selection.add_region(SelRegion::caret(1, CursorAffinity::Backward));
        end_selection.add_region(SelRegion::caret(7, CursorAffinity::Backward));
        end_selection.add_region(SelRegion::caret(13, CursorAffinity::Backward));
        end_selection.add_region(SelRegion::caret(19, CursorAffinity::Backward));
        assert_eq!(cursor.mode, CursorMode::Insert(end_selection));
    }

    // TODO(dbuga): add tests duplicating selections (multiple line blocks)
}