use bevy::prelude::*;
use bevy::ecs::system::ParamSet;
use std::time::Duration;

use crate::components::{Bullet, Captured, Enemy, Invincible, Player};
use crate::constants::{
    BULLET_SIZE, PLAYER_ENEMY_COLLISION_THRESHOLD, PLAYER_INVINCIBILITY_DURATION, PLAYER_SIZE,
    PLAYER_SPEED, WINDOW_HEIGHT, WINDOW_WIDTH,
};
use crate::game_state::AppState;
use crate::resources::{PlayerLives, PlayerRespawnTimer};
use crate::systems::spawn_explosion;

// Helper to spawn player (used in setup and respawn)
pub fn spawn_player_ship(commands: &mut Commands) {
    commands.spawn((
        Sprite {
            color: Color::srgb(0.0, 0.5, 1.0),
            custom_size: Some(PLAYER_SIZE),
            ..default()
        },
        Transform::from_translation(Vec3::new(
            0.0,
            -WINDOW_HEIGHT / 2.0 + PLAYER_SIZE.y / 2.0 + 20.0,
            0.0,
        )),
        Player {
            speed: PLAYER_SPEED,
            shoot_cooldown: Timer::new(Duration::from_secs_f32(0.3), TimerMode::Once),
        },
        // Player starts invincible for a short time
        Invincible {
            timer: Timer::new(
                Duration::from_secs_f32(PLAYER_INVINCIBILITY_DURATION),
                TimerMode::Once,
            ),
        },
    ));
    println!("Player spawned!");
}

pub fn move_player(
    keyboard_input: Res<ButtonInput<KeyCode>>,
    mut query: Query<(&mut Transform, &Player), Without<Captured>>, // Don't move captured players with controls
    time: Res<Time>,
) {
    // Using get_single_mut handles the case where player might not exist yet (or was just destroyed)
    if let Ok((mut transform, player)) = query.single_mut() {
        let mut direction = 0.0;

        if keyboard_input.pressed(KeyCode::KeyA) || keyboard_input.pressed(KeyCode::ArrowLeft) {
            direction -= 1.0;
        }

        if keyboard_input.pressed(KeyCode::KeyD) || keyboard_input.pressed(KeyCode::ArrowRight) {
            direction += 1.0;
        }

        transform.translation.x += direction * player.speed * time.delta_secs();
        let half_player_width = PLAYER_SIZE.x / 2.0;
        transform.translation.x = transform.translation.x.clamp(
            -WINDOW_WIDTH / 2.0 + half_player_width,
            WINDOW_WIDTH / 2.0 - half_player_width,
        );
    }
}

// New system to handle captured player movement
pub fn handle_captured_player(
    mut commands: Commands,
    time: Res<Time>,
    mut set: ParamSet<(
        Query<(Entity, &mut Transform, &mut Captured)>,
        Query<&Transform, (With<Enemy>, Without<Player>)>,
    )>,
    mut lives: ResMut<PlayerLives>,
    mut respawn_timer: ResMut<PlayerRespawnTimer>,
    mut next_state: ResMut<NextState<AppState>>,
) {
    // First, collect data about captured players and their bosses
    let mut captured_data = Vec::new();
    
    // Get player data
    for (entity, transform, captured) in set.p0().iter() {
        captured_data.push((entity, transform.translation, captured.boss_entity, captured.timer.clone()));
    }
    
    // Process each captured player
    for (player_entity, _player_pos, boss_entity, mut timer) in captured_data {
        // Check if the boss exists and get its position
        let boss_pos = set.p1().get(boss_entity).map(|t| t.translation).ok();
        
        // Tick the timer
        timer.tick(time.delta());
        
        // Update the player
        if let Ok((entity, mut transform, mut captured)) = set.p0().get_mut(player_entity) {
            // Update the actual timer
            captured.timer.tick(time.delta());
            
            match boss_pos {
                Some(boss_pos) => {
                    // Boss exists, update player position
                    let target_pos = boss_pos - Vec3::new(0.0, PLAYER_SIZE.y + 10.0, 0.0);
                    transform.translation = transform.translation.lerp(target_pos, 0.2);
                }
                None => {
                    // Boss is gone, release player but lose a life
                    println!("Boss is gone, releasing captured player!");
                    commands.entity(entity).remove::<Captured>();
                    lose_life_and_respawn(
                        &mut commands,
                        &mut lives,
                        &mut respawn_timer,
                        &mut next_state,
                        entity,
                        _player_pos,
                    );
                    continue; // Skip the rest of processing for this player
                }
            }
            
            // If capture duration expires, player escapes but loses a life
            if captured.timer.is_finished() {
                println!("Player escaped from capture after timer expired!");
                commands.entity(entity).remove::<Captured>();
                lose_life_and_respawn(
                    &mut commands,
                    &mut lives,
                    &mut respawn_timer,
                    &mut next_state,
                    entity,
                    transform.translation,
                );
            }
        }
    }
}

// Helper function for player life loss and respawn logic
fn lose_life_and_respawn(
    commands: &mut Commands,
    lives: &mut ResMut<PlayerLives>,
    respawn_timer: &mut ResMut<PlayerRespawnTimer>,
    next_state: &mut ResMut<NextState<AppState>>,
    player_entity: Entity,
    player_position: Vec3,
) {
    // Lose a life
    lives.count = lives.count.saturating_sub(1);
    println!("Lives remaining: {}", lives.count);

    // Spawn explosion at player position before destroying
    spawn_explosion(commands, player_position);

    // Destroy player
    commands.entity(player_entity).despawn();

    if lives.count > 0 {
        respawn_timer.timer.reset();
        respawn_timer.timer.unpause();
        println!("Respawn timer started.");
    } else {
        println!("GAME OVER!");
        next_state.set(AppState::GameOver);
    }
}

pub fn player_shoot(
    keyboard_input: Res<ButtonInput<KeyCode>>,
    mut query: Query<(&Transform, &mut Player), Without<Captured>>, // Only non-captured players can shoot
    mut commands: Commands,
    time: Res<Time>,
) {
    if let Ok((player_transform, mut player)) = query.single_mut() {
        player.shoot_cooldown.tick(time.delta());

        if (keyboard_input.just_pressed(KeyCode::Space)
            || keyboard_input.just_pressed(KeyCode::ArrowUp))
            && player.shoot_cooldown.is_finished()
        {
            player.shoot_cooldown.reset();

            let bullet_start_pos = player_transform.translation
                + Vec3::Y * (PLAYER_SIZE.y / 2.0 + BULLET_SIZE.y / 2.0);

            commands.spawn((
                Sprite {
                    color: Color::srgb(1.0, 1.0, 1.0),
                    custom_size: Some(BULLET_SIZE),
                    ..default()
                },
                Transform::from_translation(bullet_start_pos),
                Bullet,
            ));
        }
    }
}

// Modified Collision Check for Player vs Enemy
pub fn check_player_enemy_collisions(
    mut commands: Commands,
    mut lives: ResMut<PlayerLives>,
    mut respawn_timer: ResMut<PlayerRespawnTimer>,
    mut next_state: ResMut<NextState<AppState>>, // Resource to change state
    // Query player without Invincible component - relies on run_if condition too
    player_query: Query<
        (Entity, &Transform),
        (With<Player>, Without<Invincible>, Without<Captured>),
    >, // Don't check collisions for captured players
    enemy_query: Query<(Entity, &Transform), With<Enemy>>,
) {
    // This system only runs if player exists and is not invincible, due to run_if
    if let Ok((player_entity, player_transform)) = player_query.single() {
        for (enemy_entity, enemy_transform) in enemy_query.iter() {
            let distance = player_transform
                .translation
                .distance(enemy_transform.translation);

            if distance < PLAYER_ENEMY_COLLISION_THRESHOLD {
                println!("Player hit by enemy!");
                spawn_explosion(&mut commands, enemy_transform.translation);
                commands.entity(enemy_entity).despawn(); // Despawn enemy

                lives.count = lives.count.saturating_sub(1); // Decrement lives safely
                println!("Lives remaining: {}", lives.count);

                spawn_explosion(&mut commands, player_transform.translation);
                commands.entity(player_entity).despawn(); // Despawn player

                if lives.count > 0 {
                    // Start the respawn timer
                    respawn_timer.timer.reset();
                    respawn_timer.timer.unpause();
                    println!("Respawn timer started.");
                } else {
                    println!("GAME OVER!");
                    next_state.set(AppState::GameOver); // Updated for newer Bevy states API
                }
                // Important: Break after handling one collision per frame for the player
                break;
            }
        }
    }
}

// New System: Respawn Player
pub fn respawn_player(
    mut commands: Commands,
    time: Res<Time>,
    mut respawn_timer: ResMut<PlayerRespawnTimer>,
    // No player query needed here due to run_if condition
) {
    // Tick the timer only if it's actually running
    if respawn_timer.timer.tick(time.delta()).just_finished() {
        println!("Respawn timer finished. Spawning player.");
        spawn_player_ship(&mut commands);
        respawn_timer.timer.pause(); // Pause timer until next death
    }
}

// New System: Manage Invincibility
pub fn manage_invincibility(
    mut commands: Commands,
    time: Res<Time>,
    mut query: Query<(Entity, &mut Invincible, Option<&mut Visibility>), With<Player>>,
) {
    for (entity, mut invincible, mut visibility) in query.iter_mut() {
        invincible.timer.tick(time.delta());

        // Blinking effect (optional)
        if let Some(ref mut vis) = visibility {
            // Blink roughly 5 times per second
            let elapsed_secs = invincible.timer.elapsed_secs();
            **vis = if (elapsed_secs * 10.0).floor() % 2.0 == 0.0 {
                Visibility::Visible
            } else {
                Visibility::Hidden
            };
        }

        if invincible.timer.is_finished() {
            println!("Invincibility finished.");
            commands.entity(entity).remove::<Invincible>();
            // Ensure player is visible when invincibility ends
            if let Some(ref mut vis) = visibility {
                **vis = Visibility::Visible;
            }
        }
    }
}