mod editor;
mod find_highlight;
mod line_numbers;

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

use self::editor::editor_view_ui;
use self::line_numbers::{get_visual_line_mapping, render_line_numbers};

pub(crate) fn central_panel(app: &mut TextEditor, ctx: &egui::Context) {
    let show_line_numbers = app.show_line_numbers;
    let word_wrap = app.word_wrap;
    let line_side = app.line_side;
    let font_size = app.font_size;

    egui::CentralPanel::default()
        .frame(egui::Frame::NONE)
        .show(ctx, |ui| {
            let bg_color = ui.visuals().extreme_bg_color;
            let panel_rect = ui.available_rect_before_wrap();
            ui.painter().rect_filled(panel_rect, 0.0, bg_color);
            let editor_height = panel_rect.height();

            if !show_line_numbers || app.get_active_tab().is_none() {
                egui::ScrollArea::vertical()
                    .auto_shrink([false; 2])
                    .show(ui, |ui| {
                        editor_view_ui(ui, app);
                    });
                return;
            }

            let line_count = app.get_text_processing_result().line_count;
            let editor_dimensions = app.calculate_editor_dimensions(ui);
            let line_number_width = editor_dimensions.line_number_width;

            let visual_line_mapping = if word_wrap {
                let available_text_width = editor_dimensions.text_width;
                if let Some(active_tab) = app.get_active_tab() {
                    get_visual_line_mapping(
                        ui,
                        &active_tab.content,
                        available_text_width,
                        font_size,
                    )
                } else {
                    vec![]
                }
            } else {
                vec![]
            };

            let line_numbers_widget = |ui: &mut egui::Ui| {
                render_line_numbers(
                    ui,
                    line_count,
                    &visual_line_mapping,
                    line_number_width,
                    word_wrap,
                    font_size,
                );
            };

            let separator_widget = |ui: &mut egui::Ui| {
                ui.add_space(3.0);
                let separator_x = ui.cursor().left();
                let mut y_range = ui.available_rect_before_wrap().y_range();
                y_range.max += 2.0 * font_size; // Extend separator to cover more vertical space
                ui.painter()
                    .vline(separator_x, y_range, ui.visuals().window_stroke);
                ui.add_space(4.0);
            };

            egui::ScrollArea::vertical()
                .auto_shrink([false; 2])
                .show(ui, |ui| {
                    if line_side {
                        // Line numbers on the right
                        let text_editor_width = editor_dimensions.text_width + editor_dimensions.total_reserved_width;
                        ui.allocate_ui_with_layout(
                            egui::vec2(text_editor_width, editor_height),
                            egui::Layout::left_to_right(egui::Align::TOP),
                            |ui| {
                                // Constrain editor to specific width to leave space for line numbers
                                ui.allocate_ui_with_layout(
                                    egui::vec2(editor_dimensions.text_width, editor_height),
                                    egui::Layout::left_to_right(egui::Align::TOP),
                                    |ui| {
                                        editor_view_ui(ui, app);
                                    },
                                );
                                separator_widget(ui);
                                line_numbers_widget(ui);
                            },
                        );
                    } else {
                        // Line numbers on the left
                        let text_editor_width = editor_dimensions.text_width + editor_dimensions.total_reserved_width;
                        ui.allocate_ui_with_layout(
                            egui::vec2(text_editor_width, editor_height),
                            egui::Layout::left_to_right(egui::Align::TOP),
                            |ui| {
                                line_numbers_widget(ui);
                                separator_widget(ui);
                                editor_view_ui(ui, app);
                            },
                        );
                    }
                });
        });
}