use eframe::egui;
use egui::{Sense, vec2};

use crate::font::BitmapFont;
use crate::font_dialog::{FontDialogState, show as show_font_dialog};
use crate::render::{PALETTE_PANEL_W, glyph_preview_button, paint_glyph};
use kiln_core::game::{ALL_ARCHETYPES, Archetype, Board, Glyph};

/// Which tab is active in the editor side panel.
#[derive(Copy, Clone, PartialEq, Eq)]
pub(crate) enum EditorTab {
    /// Archetype + glyph palette for painting cells.
    Palette,
    /// Object placement and script assignment.
    Objects,
    /// Board-level properties (font, board script).
    Board,
    /// Named script library for this board.
    Scripts,
    /// World-level properties (placeholder).
    World,
}

/// Palette-tab state: what gets stamped when painting cells.
pub(crate) struct PaletteState {
    /// The archetype that will be stamped when the user clicks a cell.
    pub(crate) selected: Archetype,
    /// The glyph (tile index + colors) to stamp. Independent of the archetype's default.
    pub(crate) glyph: Glyph,
    /// Whether the glyph picker dialog is currently open (Palette tab).
    pub(crate) picker_open: bool,
}

/// Font-dialog state: the floating font picker and its in-progress edit.
pub(crate) struct FontDialog {
    /// Whether the font picker dialog is currently open.
    pub(crate) open: bool,
    /// In-progress state for the font dialog while it is open.
    pub(crate) state: FontDialogState,
}

/// Objects-tab state: selection, placement, and the glyph being edited.
pub(crate) struct ObjectEdit {
    /// Index into `board.objects` of the currently selected object, or `None`.
    pub(crate) selected: Option<usize>,
    /// Whether the glyph picker is open for editing the selected object's glyph.
    pub(crate) picker_open: bool,
    /// Local copy of the selected object's glyph for the picker to edit.
    ///
    /// Kept separate from `board.objects` to avoid a borrow conflict while the
    /// glyph picker holds `&mut Glyph` and the board is also borrowed. Written
    /// back to `board.objects[i].glyph` each frame while an object is selected.
    pub(crate) editing_glyph: Glyph,
    /// When `true`, the next board click in the Objects tab places a new object.
    /// Set by the "Add Object" button; cleared after placement or on tab switch.
    pub(crate) placing: bool,
}

/// Scripts-tab state: the script open in the code editor and the new-script draft.
pub(crate) struct ScriptEdit {
    /// Name of the script currently open in the code editor, or `None` if closed.
    pub(crate) editing: Option<String>,
    /// Working copy of the script body while the code editor is open.
    /// Written back to `board.scripts` when the user clicks "Back".
    pub(crate) content: String,
    /// Draft name typed into the "new script" text field in the Scripts tab.
    pub(crate) new_name: String,
}

/// Transient editor state. Only meaningful when the app is in Edit mode.
///
/// Fields are grouped by concern into sub-structs so each editor tab can take
/// the narrow borrow it needs rather than all of `EditorState`.
pub(crate) struct EditorState {
    /// Which side-panel tab is currently shown.
    pub(crate) tab: EditorTab,
    /// Palette tab: archetype + glyph being painted.
    pub(crate) palette: PaletteState,
    /// The font picker dialog and its edit buffer.
    pub(crate) font_dialog: FontDialog,
    /// Objects tab: selection, placement, and object glyph editing.
    pub(crate) objects: ObjectEdit,
    /// Scripts tab: the open script and new-script draft.
    pub(crate) scripts: ScriptEdit,
}

impl EditorState {
    /// Creates editor state with `Wall` selected and all dialogs closed.
    pub(crate) fn new() -> Self {
        Self {
            tab: EditorTab::Palette,
            palette: PaletteState {
                selected: Archetype::Wall,
                glyph: Archetype::Wall.default_glyph(),
                picker_open: false,
            },
            font_dialog: FontDialog {
                open: false,
                state: FontDialogState::from_spec(None),
            },
            objects: ObjectEdit {
                selected: None,
                picker_open: false,
                editing_glyph: Glyph::player(), // overwritten on first selection
                placing: false,
            },
            scripts: ScriptEdit {
                editing: None,
                content: String::new(),
                new_name: String::new(),
            },
        }
    }
}

/// Renders the editor side panel (must be called before `CentralPanel`).
///
/// Shows tab bar (Palette / Objects / Board / Scripts / World) and the content
/// for the active tab. `board` is the current board, used by the Objects and
/// Scripts tabs and to read/write the board font. `active_font` is the resolved
/// font currently in use for rendering.
pub(crate) fn show_editor_panel(
    ctx: &egui::Context,
    editor: &mut EditorState,
    board: &mut Board,
    active_font: &BitmapFont,
) {
    egui::SidePanel::right("palette_panel")
        .resizable(true)
        .default_width(PALETTE_PANEL_W)
        .show(ctx, |ui| {
            // Tab bar — wraps automatically if the panel is narrow.
            ui.horizontal_wrapped(|ui| {
                ui.selectable_value(&mut editor.tab, EditorTab::Palette, "Palette");
                ui.selectable_value(&mut editor.tab, EditorTab::Objects, "Objects");
                ui.selectable_value(&mut editor.tab, EditorTab::Board, "Board");
                ui.selectable_value(&mut editor.tab, EditorTab::Scripts, "Scripts");
                ui.selectable_value(&mut editor.tab, EditorTab::World, "World");
            });
            ui.separator();

            // Dispatch to the active tab's renderer, passing only the sub-struct each
            // tab needs. World is an empty placeholder.
            match editor.tab {
                EditorTab::Palette => palette_tab(ui, &mut editor.palette, active_font),
                EditorTab::Objects => objects_tab(
                    ui,
                    &mut editor.objects,
                    &mut editor.scripts,
                    board,
                    active_font,
                ),
                EditorTab::Board => board_tab(ui, &mut editor.font_dialog, board),
                EditorTab::Scripts => scripts_tab(ui, &mut editor.scripts, board),
                EditorTab::World => {}
            }
        });

    // Font dialog floats outside the side panel; show it here so it renders on top.
    if editor.font_dialog.open {
        show_font_dialog(
            ctx,
            &mut editor.font_dialog.open,
            &mut editor.font_dialog.state,
            &mut board.font,
        );
    }
}

/// Palette tab: scrollable archetype list plus the current-glyph preview button.
fn palette_tab(ui: &mut egui::Ui, palette: &mut PaletteState, active_font: &BitmapFont) {
    let tw = active_font.tile_w as f32;
    let th = active_font.tile_h as f32;

    ui.label("Element");

    // Scrollable archetype list; shows at most 5 rows before scrolling.
    let row_h = th + ui.spacing().item_spacing.y;
    egui::ScrollArea::vertical()
        .max_height(row_h * 5.0)
        .id_salt("arch_list")
        .show(ui, |ui| {
            for &archetype in ALL_ARCHETYPES {
                let is_selected = palette.selected == archetype;
                let glyph = archetype.default_glyph();
                ui.horizontal(|ui| {
                    let (r, cell_resp) = ui.allocate_exact_size(vec2(tw, th), Sense::click());
                    paint_glyph(ui.painter(), r, &glyph, active_font);
                    let label_resp = ui.selectable_label(is_selected, archetype.name());
                    if cell_resp.clicked() || label_resp.clicked() {
                        palette.selected = archetype;
                        palette.glyph = archetype.default_glyph();
                    }
                });
            }
        });

    ui.separator();

    ui.label("Glyph");
    // Preview swatch for the current glyph; clicking opens the glyph picker.
    if glyph_preview_button(ui, &palette.glyph, active_font).clicked() {
        palette.picker_open = true;
    }
}

/// Objects tab: add/select objects and edit the selected object's glyph, flags, and script.
fn objects_tab(
    ui: &mut egui::Ui,
    objects: &mut ObjectEdit,
    scripts: &mut ScriptEdit,
    board: &mut Board,
    active_font: &BitmapFont,
) {
    // "Add Object" toggles placement mode; next board click places a new object.
    let add_label = if objects.placing {
        "Cancel Add"
    } else {
        "Add Object"
    };
    if ui.button(add_label).clicked() {
        objects.placing = !objects.placing;
        objects.selected = None;
    }
    if objects.placing {
        ui.label("Click on the board to place.");
    }

    ui.separator();

    let Some(i) = objects.selected else {
        if !objects.placing {
            ui.label("Click an object on the board to select it.");
        }
        return;
    };

    // Collect sorted script names before taking a mutable borrow on board.objects.
    let mut script_names: Vec<String> = board.scripts.keys().cloned().collect();
    script_names.sort();

    ui.label("Glyph");
    // Preview swatch for the object's glyph; clicking opens the glyph picker.
    if glyph_preview_button(ui, &objects.editing_glyph, active_font).clicked() {
        objects.picker_open = true;
    }

    let obj = &mut board.objects[i];

    ui.checkbox(&mut obj.passable, "Passable");
    ui.checkbox(&mut obj.opaque, "Opaque");

    let current = obj.script_name.as_deref().unwrap_or("(none)").to_string();

    ui.label("Script");
    egui::ComboBox::from_id_salt("obj_script")
        .selected_text(&current)
        .show_ui(ui, |ui| {
            // "(none)" clears the script assignment.
            if ui
                .selectable_label(obj.script_name.is_none(), "(none)")
                .clicked()
            {
                obj.script_name = None;
            }
            for name in &script_names {
                let is_sel = obj.script_name.as_deref() == Some(name.as_str());
                if ui.selectable_label(is_sel, name.as_str()).clicked() {
                    obj.script_name = Some(name.clone());
                }
            }
            // Placeholder for future "create and edit a new script" flow.
            let _ = ui.selectable_label(false, "(create new...)");
        });

    if ui.button("Edit Script").clicked()
        && let Some(ref script_name) = obj.script_name.clone()
    {
        scripts.content = board.scripts.get(script_name).cloned().unwrap_or_default();
        scripts.editing = Some(script_name.clone());
    }
}

/// Board tab: board-level font selection and zoom.
fn board_tab(ui: &mut egui::Ui, font_dialog: &mut FontDialog, board: &mut Board) {
    let font_label = match &board.font {
        Some(s) => s.path.clone(),
        None => "(default)".to_owned(),
    };
    ui.label(format!("Font: {font_label}"));
    if ui.button("Font…").clicked() {
        font_dialog.state = FontDialogState::from_spec(board.font.as_ref());
        font_dialog.open = true;
    }

    ui.separator();
    ui.label("Zoom");
    ui.add(egui::Slider::new(&mut board.zoom, 1..=8).text("×"));
}

/// Scripts tab: create a named script and edit existing ones.
fn scripts_tab(ui: &mut egui::Ui, scripts: &mut ScriptEdit, board: &mut Board) {
    // New script: text field + Create button.
    ui.horizontal(|ui| {
        ui.text_edit_singleline(&mut scripts.new_name);
        let can_create =
            !scripts.new_name.is_empty() && !board.scripts.contains_key(&scripts.new_name);
        if ui
            .add_enabled(can_create, egui::Button::new("Create"))
            .clicked()
        {
            let name = scripts.new_name.clone();
            board.scripts.insert(name.clone(), String::new());
            scripts.new_name.clear();
            scripts.content = String::new();
            scripts.editing = Some(name);
        }
    });

    ui.separator();

    if board.scripts.is_empty() {
        ui.label("No scripts yet.");
        return;
    }

    let mut names: Vec<String> = board.scripts.keys().cloned().collect();
    names.sort();
    egui::ScrollArea::vertical()
        .id_salt("scripts_list")
        .show(ui, |ui| {
            for name in &names {
                ui.horizontal(|ui| {
                    ui.label(name);
                    if ui.button("Edit").clicked() {
                        scripts.content = board.scripts.get(name).cloned().unwrap_or_default();
                        scripts.editing = Some(name.clone());
                    }
                });
            }
        });
}