use bevy::prelude::*;

use crate::state::AppState;

// ── Markers ─────────────────────────────────────────────────────────────────

#[derive(Component)]
pub struct MainMenuUi;

#[derive(Component)]
pub enum MenuButton {
    ContinueGame, //Needed for later once save game functionality is implemented, should have a check to see if a save game exists and only show this button if it does
    NewGame,
    Options,
    Exit,
}

// ── Main Menu ───────────────────────────────────────────────────────────────

pub fn setup_main_menu(mut commands: Commands) {
    let button_style = Node {
        width: Val::Px(280.0),
        height: Val::Px(64.0),
        justify_content: JustifyContent::Center,
        align_items: AlignItems::Center,
        ..default()
    };

    let button_text_font = TextFont {
        font_size: 28.0,
        ..default()
    };

    commands
        .spawn((
            Node {
                width: Val::Percent(100.0),
                height: Val::Percent(100.0),
                display: Display::Flex,
                flex_direction: FlexDirection::Column,
                justify_content: JustifyContent::Center,
                align_items: AlignItems::Center,
                row_gap: Val::Px(24.0),
                ..default()
            },
            BackgroundColor(Color::srgb(0.02, 0.02, 0.06)),
            MainMenuUi,
        ))
        .with_children(|parent| {
            // Title
            parent.spawn((
                Text::new("VOID::NAV"),
                TextFont {
                    font_size: 72.0,
                    ..default()
                },
                TextColor(Color::srgb(0.7, 0.85, 1.0)),
                Node {
                    margin: UiRect::bottom(Val::Px(48.0)),
                    ..default()
                },
            ));

            // Subtitle
            parent.spawn((
                Text::new("A space exploration RPG"),
                TextFont {
                    font_size: 18.0,
                    ..default()
                },
                TextColor(Color::srgb(0.4, 0.5, 0.6)),
                Node {
                    margin: UiRect::bottom(Val::Px(32.0)),
                    ..default()
                },
            ));

            // Start Game button
            spawn_menu_button(
                &mut parent.spawn_empty(),
                "Start Game",
                MenuButton::NewGame,
                &button_style,
                &button_text_font,
            );

            // Options button
            spawn_menu_button(
                &mut parent.spawn_empty(),
                "Options",
                MenuButton::Options,
                &button_style,
                &button_text_font,
            );

            // Exit button
            spawn_menu_button(
                &mut parent.spawn_empty(),
                "Exit",
                MenuButton::Exit,
                &button_style,
                &button_text_font,
            );
        });
}

fn spawn_menu_button(
    cmd: &mut EntityCommands,
    label: &str,
    marker: MenuButton,
    style: &Node,
    text_font: &TextFont,
) {
    cmd.insert((
        Button,
        style.clone(),
        BackgroundColor(Color::srgb(0.08, 0.1, 0.18)),
        BorderColor(Color::srgb(0.3, 0.45, 0.7)),
        BorderRadius::all(Val::Px(8.0)),
        marker,
    ))
    .with_children(|btn| {
        btn.spawn((
            Text::new(label),
            text_font.clone(),
            TextColor(Color::srgb(0.75, 0.85, 1.0)),
        ));
    });
}

pub fn despawn_main_menu(mut commands: Commands, query: Query<Entity, With<MainMenuUi>>) {
    for entity in &query {
        commands.entity(entity).despawn();
    }
}

// ── Button Interaction ──────────────────────────────────────────────────────

pub fn main_menu_buttons(
    mut next_state: ResMut<NextState<AppState>>,
    mut exit: EventWriter<AppExit>,
    interaction_query: Query<(&Interaction, &MenuButton), Changed<Interaction>>,
) {
    for (interaction, button) in &interaction_query {
        if *interaction == Interaction::Pressed {
            match button {
                MenuButton::ContinueGame => next_state.set(AppState::InGame), // Placeholder for now
                MenuButton::NewGame => next_state.set(AppState::Galaxy),
                MenuButton::Options => next_state.set(AppState::Options),
                MenuButton::Exit => {
                    exit.write(AppExit::Success);
                }
            }
        }
    }
}