use crate::app::TextEditor;
use eframe::egui;

use super::find_highlight::draw_find_highlight;

pub(super) fn editor_view(
    ui: &mut egui::Ui,
    app: &mut TextEditor,
) -> (egui::Response, Option<egui::Rect>) {
    let current_match_position = app.get_current_match_position();
    let show_find = app.show_find;
    let prev_show_find = app.prev_show_find;
    let show_preferences = app.show_preferences;
    let show_about = app.show_about;
    let show_shortcuts = app.show_shortcuts;
    let word_wrap = app.word_wrap;
    let font_size = app.font_size;

    // Check if reset zoom was requested in previous frame
    let reset_zoom_key = egui::Id::new("editor_reset_zoom");
    let should_reset_zoom = ui.ctx().memory_mut(|mem| {
        mem.data.get_temp::<bool>(reset_zoom_key).unwrap_or(false)
    });
    
    // Reset zoom if requested
    if should_reset_zoom {
        app.zoom_factor = 1.0;
        ui.ctx().set_zoom_factor(1.0);
        ui.ctx().memory_mut(|mem| {
            mem.data.insert_temp(reset_zoom_key, false);
        });
    }

    if let Some(active_tab) = app.get_active_tab_mut() {
        let bg_color = ui.visuals().extreme_bg_color;
        let editor_rect = ui.available_rect_before_wrap();
        ui.painter().rect_filled(editor_rect, 0.0, bg_color);

        let desired_width = if word_wrap {
            ui.available_width()
        } else {
            f32::INFINITY
        };

        let text_edit = egui::TextEdit::multiline(&mut active_tab.content)
            .frame(false)
            .font(egui::TextStyle::Monospace)
            .code_editor()
            .desired_width(desired_width)
            .desired_rows(0)
            .lock_focus(true)
            .cursor_at_end(false)
            .id(egui::Id::new("main_text_editor"));

        let output = text_edit.show(ui);
        
        // Store text length for context menu
        let text_len = active_tab.content.len();

        // Right-click context menu
        output.response.context_menu(|ui| {
            if ui.button("Cut").clicked() {
                ui.ctx().input_mut(|i| i.events.push(egui::Event::Cut));
                ui.close_menu();
            }
            if ui.button("Copy").clicked() {
                ui.ctx().input_mut(|i| i.events.push(egui::Event::Copy));
                ui.close_menu();
            }
            if ui.button("Paste").clicked() {
                ui.ctx()
                    .send_viewport_cmd(egui::ViewportCommand::RequestPaste);
                ui.close_menu();
            }
            if ui.button("Delete").clicked() {
                ui.ctx().input_mut(|i| {
                    i.events.push(egui::Event::Key {
                        key: egui::Key::Delete,
                        physical_key: None,
                        pressed: true,
                        repeat: false,
                        modifiers: egui::Modifiers::NONE,
                    })
                });
                ui.close_menu();
            }
            if ui.button("Select All").clicked() {
                let text_edit_id = egui::Id::new("main_text_editor");
                if let Some(mut state) = egui::TextEdit::load_state(ui.ctx(), text_edit_id) {
                    let select_all_range = egui::text::CCursorRange::two(
                        egui::text::CCursor::new(0),
                        egui::text::CCursor::new(text_len),
                    );
                    state.cursor.set_char_range(Some(select_all_range));
                    egui::TextEdit::store_state(ui.ctx(), text_edit_id, state);
                }
                ui.close_menu();
            }
            ui.separator();
            if ui.button("Reset Zoom").clicked() {
                ui.ctx().memory_mut(|mem| {
                    mem.data.insert_temp(reset_zoom_key, true);
                });
                ui.close_menu();
            }
        });

        let cursor_rect = if let Some(cursor_range) = output.state.cursor.char_range() {
            let cursor_pos = cursor_range.primary.index;
            let content = &active_tab.content;

            // Count newlines up to cursor position using char_indices to avoid char boundary issues
            let cursor_line = content
                .char_indices()
                .take_while(|(byte_pos, _)| *byte_pos < cursor_pos)
                .filter(|(_, ch)| *ch == '\n')
                .count();

            let font_id = ui
                .style()
                .text_styles
                .get(&egui::TextStyle::Monospace)
                .unwrap_or(&egui::FontId::monospace(font_size))
                .clone();
            let line_height = ui.fonts(|fonts| fonts.row_height(&font_id));

            let y_pos = output.response.rect.top() + (cursor_line as f32 * line_height);
            let cursor_rect = egui::Rect::from_min_size(
                egui::pos2(output.response.rect.left(), y_pos),
                egui::vec2(2.0, line_height),
            );
            Some(cursor_rect)
        } else {
            None
        };

        if !show_find && prev_show_find {
            if let Some((start_pos, end_pos)) = current_match_position {
                let text_edit_id = egui::Id::new("main_text_editor");
                if let Some(mut state) = egui::TextEdit::load_state(ui.ctx(), text_edit_id) {
                    let cursor_range = egui::text::CCursorRange::two(
                        egui::text::CCursor::new(start_pos),
                        egui::text::CCursor::new(end_pos),
                    );
                    state.cursor.set_char_range(Some(cursor_range));
                    egui::TextEdit::store_state(ui.ctx(), text_edit_id, state);
                }
            }
        }

        if show_find {
            if let Some((start_pos, end_pos)) = current_match_position {
                draw_find_highlight(
                    ui,
                    &active_tab.content,
                    start_pos,
                    end_pos,
                    output.response.rect,
                    font_size,
                );
            }
        }

        if output.response.changed() {
            active_tab.update_modified_state();
            app.find_matches.clear();
            app.current_match_index = None;
        }

        if !output.response.has_focus()
            && !show_preferences
            && !show_about
            && !show_shortcuts
            && !show_find
        {
            output.response.request_focus();
        }
        (output.response, cursor_rect)
    } else {
        (ui.label("No file open, how did you get here?"), None)
    }
}

pub(super) fn editor_view_ui(ui: &mut egui::Ui, app: &mut TextEditor) {
    let word_wrap = app.word_wrap;

    if word_wrap {
        let (_response, _cursor_rect) = editor_view(ui, app);
    } else {
        let estimated_width = app.calculate_content_based_width(ui);
        let output = egui::ScrollArea::horizontal()
            .auto_shrink([false; 2])
            .show(ui, |ui| {
                ui.allocate_ui_with_layout(
                    egui::Vec2::new(estimated_width, ui.available_height()),
                    egui::Layout::left_to_right(egui::Align::TOP),
                    |ui| editor_view(ui, app),
                )
            });

        let editor_response = &output.inner.inner.0;
        if let Some(cursor_rect) = output.inner.inner.1 {
            let text_edit_id = egui::Id::new("main_text_editor");
            let current_cursor_pos =
                if let Some(state) = egui::TextEdit::load_state(ui.ctx(), text_edit_id) {
                    state.cursor.char_range().map(|range| range.primary.index)
                } else {
                    None
                };

            let cursor_moved = current_cursor_pos != app.previous_cursor_position;
            let text_changed = editor_response.changed();
            let should_scroll = (cursor_moved || text_changed)
                && {
                    let visible_area = ui.clip_rect();
                    !visible_area.intersects(cursor_rect)
                };

            if should_scroll {
                ui.scroll_to_rect(cursor_rect, Some(egui::Align::Center));
            }

            app.previous_cursor_position = current_cursor_pos;
        }
    }
}