import Player from '../entities/Player.js';
import Asteroid from '../entities/Asteroid.js';
import AlienShip from '../entities/AlienShip.js';
import Bullet from '../entities/Bullet.js';

const STARTING_LIVES = 3;

export default class GameScene extends Phaser.Scene {
    constructor() {
        super({ key: 'GameScene' });
    }

    create() {
        this.createTextures();

        // State
        this.level = 1;
        this.score = 0;
        this.lives = STARTING_LIVES;
        this.gameOver = false;
        this.levelComplete = false;

        // Physics groups (used for overlap detection)
        this.asteroidsGroup     = this.physics.add.group();
        this.aliensGroup        = this.physics.add.group();
        this.playerBulletsGroup = this.physics.add.group();
        this.alienBulletsGroup  = this.physics.add.group();

        // Entity arrays for custom update logic
        this.asteroids     = [];
        this.aliens        = [];
        this.playerBullets = [];
        this.alienBullets  = [];

        this.player = new Player(this, 800, 450);

        this.setupCollisions();
        this.createUI();
        this.startLevel();

        this.alienTimer = this.time.addEvent({
            delay: this.alienSpawnDelay(),
            callback: this.spawnAlien,
            callbackScope: this,
            loop: true
        });
    }

    // ─── Texture Generation ───────────────────────────────────────────────────

    createTextures() {
        // Player ship – texture 64×32, nose points right (angle 0)
        // Nose: (56,16)  left-wing: (12,4)  right-wing: (12,28)
        let g = this.make.graphics({ add: false });
        g.lineStyle(2, 0x00ff44, 1);
        g.strokeTriangle(56, 16, 12, 4, 12, 28);
        g.generateTexture('player', 64, 32);
        g.destroy();

        // Player ship with thruster flame
        g = this.make.graphics({ add: false });
        g.lineStyle(2, 0x00ff44, 1);
        g.strokeTriangle(56, 16, 12, 4, 12, 28);
        g.lineStyle(2, 0xff6600, 1);
        // Flame behind the ship: (12,11),(12,21) -> (0,16)
        g.strokeTriangle(12, 11, 12, 21, 0, 16);
        g.generateTexture('player_thrust', 64, 32);
        g.destroy();

        // Large asteroid – 120×120 texture, radius 50, 12-sided irregular polygon
        g = this.make.graphics({ add: false });
        g.lineStyle(2, 0xcccccc, 1);
        g.strokePoints(this.asteroidPoints(60, 60, 50, 12,
            [1.0, 0.82, 1.08, 0.88, 1.0, 0.78, 1.1, 0.9, 0.94, 1.0, 0.84, 1.06]
        ), true);
        g.generateTexture('asteroid_large', 120, 120);
        g.destroy();

        // Medium asteroid – 64×64, radius 26, 10-sided
        g = this.make.graphics({ add: false });
        g.lineStyle(2, 0xcccccc, 1);
        g.strokePoints(this.asteroidPoints(32, 32, 26, 10,
            [1.0, 0.78, 1.1, 0.88, 1.0, 0.82, 1.0, 0.92, 1.06, 0.80]
        ), true);
        g.generateTexture('asteroid_medium', 64, 64);
        g.destroy();

        // Small asteroid – 32×32, radius 12, 8-sided
        g = this.make.graphics({ add: false });
        g.lineStyle(2, 0xcccccc, 1);
        g.strokePoints(this.asteroidPoints(16, 16, 12, 8,
            [1.0, 0.78, 1.12, 0.84, 1.0, 0.9, 0.80, 1.04]
        ), true);
        g.generateTexture('asteroid_small', 32, 32);
        g.destroy();

        // Alien saucer – 64×48, drawn as two stacked ellipses
        g = this.make.graphics({ add: false });
        g.lineStyle(2, 0x00ffff, 1);
        g.strokeEllipse(32, 30, 52, 20); // main body
        g.strokeEllipse(32, 22, 30, 18); // dome
        g.generateTexture('alien', 64, 48);
        g.destroy();

        // Player bullet – 8×8 yellow circle
        g = this.make.graphics({ add: false });
        g.fillStyle(0xffff00, 1);
        g.fillCircle(4, 4, 4);
        g.generateTexture('bullet', 8, 8);
        g.destroy();

        // Alien bullet – 8×8 red circle
        g = this.make.graphics({ add: false });
        g.fillStyle(0xff4444, 1);
        g.fillCircle(4, 4, 4);
        g.generateTexture('alien_bullet', 8, 8);
        g.destroy();
    }

    // Returns array of {x,y} points forming an irregular polygon
    asteroidPoints(cx, cy, radius, numPoints, offsets) {
        return offsets.map((scale, i) => {
            const angle = (i / numPoints) * Math.PI * 2;
            return {
                x: cx + Math.cos(angle) * radius * scale,
                y: cy + Math.sin(angle) * radius * scale
            };
        });
    }

    // ─── Collision Setup ─────────────────────────────────────────────────────

    setupCollisions() {
        this.physics.add.overlap(
            this.playerBulletsGroup, this.asteroidsGroup,
            this.onPlayerBulletHitAsteroid, null, this
        );
        this.physics.add.overlap(
            this.playerBulletsGroup, this.aliensGroup,
            this.onPlayerBulletHitAlien, null, this
        );
        this.physics.add.overlap(
            this.alienBulletsGroup, this.player.sprite,
            this.onAlienBulletHitPlayer, null, this
        );
        this.physics.add.overlap(
            this.player.sprite, this.asteroidsGroup,
            this.onPlayerHitAsteroid, null, this
        );
        this.physics.add.overlap(
            this.player.sprite, this.aliensGroup,
            this.onPlayerHitAlien, null, this
        );
    }

    // ─── UI ──────────────────────────────────────────────────────────────────

    createUI() {
        const mono = { fontFamily: 'monospace', fill: '#ffffff' };
        this.scoreText = this.add.text(16, 16, 'SCORE: 0',  { ...mono, fontSize: '20px' }).setDepth(10);
        this.livesText = this.add.text(16, 44, 'LIVES: 3',  { ...mono, fontSize: '20px' }).setDepth(10);
        this.levelText = this.add.text(800, 16, 'LEVEL 1',  { ...mono, fontSize: '24px' })
            .setOrigin(0.5, 0).setDepth(10);
        this.msgText   = this.add.text(800, 420, '', { ...mono, fontSize: '52px', align: 'center' })
            .setOrigin(0.5).setDepth(10).setVisible(false);
    }

    updateUI() {
        this.scoreText.setText(`SCORE: ${this.score}`);
        this.livesText.setText(`LIVES: ${this.lives}`);
        this.levelText.setText(`LEVEL ${this.level}`);
    }

    showMessage(text, autohideMs = 0) {
        if (!text) { this.msgText.setVisible(false); return; }
        this.msgText.setText(text).setVisible(true);
        if (autohideMs > 0) {
            this.time.delayedCall(autohideMs, () => this.msgText.setVisible(false));
        }
    }

    // ─── Level Management ────────────────────────────────────────────────────

    startLevel() {
        this.levelComplete = false;

        // Clear all entities
        this.asteroids.forEach(a => a.destroy());     this.asteroids = [];
        this.aliens.forEach(a => a.destroy());        this.aliens = [];
        this.playerBullets.forEach(b => b.destroy()); this.playerBullets = [];
        this.alienBullets.forEach(b => b.destroy());  this.alienBullets = [];

        // Respawn player at center
        this.player.respawn(800, 450);

        // Spawn large asteroids – more per level
        const count = 3 + this.level;
        for (let i = 0; i < count; i++) {
            const { x, y } = this.edgePosition();
            this.asteroids.push(new Asteroid(this, x, y, 'large', this.asteroidsGroup));
        }

        this.updateUI();
        this.showMessage(`LEVEL ${this.level}`, 2000);
    }

    // Random position along any screen edge, away from center
    edgePosition() {
        const W = 1600, H = 900;
        let x, y;
        do {
            const edge = Phaser.Math.Between(0, 3);
            switch (edge) {
                case 0: x = Phaser.Math.Between(0, W); y = 0;   break;
                case 1: x = Phaser.Math.Between(0, W); y = H;   break;
                case 2: x = 0;                          y = Phaser.Math.Between(0, H); break;
                default: x = W;                         y = Phaser.Math.Between(0, H); break;
            }
        } while (Phaser.Math.Distance.Between(x, y, 800, 450) < 200);
        return { x, y };
    }

    alienSpawnDelay() {
        return Math.max(8000, 22000 - this.level * 1500);
    }

    // ─── Spawning ────────────────────────────────────────────────────────────

    spawnAlien() {
        if (this.gameOver || this.levelComplete) return;
        if (this.aliens.length >= 2) return;
        const { x, y } = this.edgePosition();
        this.aliens.push(new AlienShip(this, x, y, this.aliensGroup));
    }

    spawnPlayerBullet(x, y, angle) {
        this.playerBullets.push(
            new Bullet(this, x, y, angle, 'player', this.playerBulletsGroup)
        );
    }

    spawnAlienBullet(x, y, angle) {
        this.alienBullets.push(
            new Bullet(this, x, y, angle, 'alien', this.alienBulletsGroup)
        );
    }

    // ─── Collision Callbacks ─────────────────────────────────────────────────

    onPlayerBulletHitAsteroid(bulletSprite, asteroidSprite) {
        if (!bulletSprite.active || !asteroidSprite.active) return;
        const bullet   = bulletSprite.gameEntity;
        const asteroid = asteroidSprite.gameEntity;
        if (!bullet || !asteroid || !bullet.alive || !asteroid.alive) return;

        const scoreTable = { large: 20, medium: 50, small: 100 };
        this.addScore(scoreTable[asteroid.size] || 20);

        this.splitAsteroid(asteroid);

        bullet.destroy();
        this.playerBullets = this.playerBullets.filter(b => b !== bullet);
    }

    onPlayerBulletHitAlien(bulletSprite, alienSprite) {
        if (!bulletSprite.active || !alienSprite.active) return;
        const bullet = bulletSprite.gameEntity;
        const alien  = alienSprite.gameEntity;
        if (!bullet || !alien || !bullet.alive || !alien.alive) return;

        this.addScore(200);
        alien.destroy();
        this.aliens = this.aliens.filter(a => a !== alien);

        bullet.destroy();
        this.playerBullets = this.playerBullets.filter(b => b !== bullet);
    }

    onAlienBulletHitPlayer(alienBulletSprite, playerSprite) {
        if (!alienBulletSprite.active) return;
        const bullet = alienBulletSprite.gameEntity;
        if (!bullet || !bullet.alive) return;

        bullet.destroy();
        this.alienBullets = this.alienBullets.filter(b => b !== bullet);
        this.handlePlayerHit();
    }

    onPlayerHitAsteroid(playerSprite, asteroidSprite) {
        if (!asteroidSprite.active) return;
        const asteroid = asteroidSprite.gameEntity;
        if (!asteroid || !asteroid.alive) return;
        this.handlePlayerHit();
    }

    onPlayerHitAlien(playerSprite, alienSprite) {
        if (!alienSprite.active) return;
        const alien = alienSprite.gameEntity;
        if (!alien || !alien.alive) return;
        this.handlePlayerHit();
    }

    handlePlayerHit() {
        if (!this.player.hit()) return; // invincible – ignore

        this.player.die(); // hide ship and go invincible immediately
        this.lives--;
        this.updateUI();

        if (this.lives <= 0) {
            this.triggerGameOver();
        } else {
            // Brief pause so the destruction is visible before respawning
            this.time.delayedCall(1500, () => {
                if (!this.gameOver) this.player.respawn(800, 450);
            });
        }
    }

    // ─── Asteroid Splitting ───────────────────────────────────────────────────

    splitAsteroid(asteroid) {
        const { x, y } = asteroid.sprite;
        asteroid.destroy();
        this.asteroids = this.asteroids.filter(a => a !== asteroid);

        if (asteroid.size === 'large') {
            const count = Phaser.Math.Between(1, 3);
            for (let i = 0; i < count; i++) {
                const size = Math.random() < 0.5 ? 'medium' : 'small';
                this.asteroids.push(new Asteroid(this, x, y, size, this.asteroidsGroup));
            }
        } else if (asteroid.size === 'medium') {
            for (let i = 0; i < 2; i++) {
                this.asteroids.push(new Asteroid(this, x, y, 'small', this.asteroidsGroup));
            }
        }
        // small: fully destroyed – no fragments
    }

    // ─── Score / Game Over ────────────────────────────────────────────────────

    addScore(pts) {
        this.score += pts;
        this.scoreText.setText(`SCORE: ${this.score}`);
    }

    triggerGameOver() {
        this.gameOver = true;
        this.player.alive = false;
        this.player.sprite.setVisible(false);
        this.showMessage(`GAME OVER\n\nSCORE: ${this.score}\n\nPress R to restart`);
        this.input.keyboard.once('keydown-R', () => this.scene.restart());
    }

    // ─── Level Completion Check ───────────────────────────────────────────────

    checkLevelComplete() {
        if (this.levelComplete) return;
        if (this.asteroids.length > 0 || this.aliens.length > 0) return;

        this.levelComplete = true;
        this.showMessage('LEVEL COMPLETE!', 2000);

        this.time.delayedCall(2500, () => {
            this.level++;
            this.changeBgColor();
            this.startLevel();
            // Reset alien spawn timer for new level
            this.alienTimer.remove();
            this.alienTimer = this.time.addEvent({
                delay: this.alienSpawnDelay(),
                callback: this.spawnAlien,
                callbackScope: this,
                loop: true
            });
        });
    }

    // ─── Background Color ─────────────────────────────────────────────────────

    changeBgColor() {
        // Pick dim, randomised tint – one channel slightly brighter for variety
        const rgb = [
            Phaser.Math.Between(0, 35),
            Phaser.Math.Between(0, 35),
            Phaser.Math.Between(0, 35)
        ];
        const boost = Phaser.Math.Between(0, 2);
        rgb[boost] = Phaser.Math.Between(45, 80);
        this.cameras.main.setBackgroundColor(
            Phaser.Display.Color.GetColor(rgb[0], rgb[1], rgb[2])
        );
    }

    // ─── Main Update Loop ────────────────────────────────────────────────────

    update(time, delta) {
        if (this.gameOver) return;

        this.player.update(time, delta);

        this.asteroids.forEach(a => a.update());

        this.aliens.forEach(a => a.update(time, this.player));

        // Update bullets; keep only still-alive ones
        this.playerBullets = this.playerBullets.filter(b => b.update(time));
        this.alienBullets  = this.alienBullets.filter(b => b.update(time));

        this.checkLevelComplete();
    }
}