// Import Three.js library (already included in index.html)
// const THREE = window.THREE;

class Background {
    constructor() {
        // Initialize core Three.js components
        this.scene = new THREE.Scene();
        this.camera = new THREE.PerspectiveCamera(
            75, // Field of view
            window.innerWidth / window.innerHeight, // Aspect ratio
            0.1, // Near plane
            1000 // Far plane
        );
        
        // Setup renderer with transparency and anti-aliasing
        this.renderer = new THREE.WebGLRenderer({
            canvas: document.querySelector('#webgl-background'),
            alpha: true,
            antialias: true
        });
        this.renderer.setSize(window.innerWidth, window.innerHeight);
        this.renderer.setClearColor(0x0a0a0a, 1); // Dark background color

        // Initialize particle system properties
        this.particles = [];
        this.particleCount = 100;
        this.particleGeometry = new THREE.BufferGeometry();
        this.particleMaterial = new THREE.PointsMaterial({
            size: 2,
            color: 0xffffff,
            transparent: true,
            opacity: 0.5,
            blending: THREE.AdditiveBlending
        });

        // Set up camera position
        this.camera.position.z = 100;

        // Initialize the background
        this.init();

        // Bind event listeners
        this.bindEvents();
    }

    init() {
        // Create particle positions array
        const positions = new Float32Array(this.particleCount * 3);
        
        // Generate random positions for particles
        for (let i = 0; i < this.particleCount; i++) {
            const i3 = i * 3; // Index for x, y, z coordinates
            positions[i3] = (Math.random() - 0.5) * window.innerWidth;     // X coordinate
            positions[i3 + 1] = (Math.random() - 0.5) * window.innerHeight; // Y coordinate
            positions[i3 + 2] = (Math.random() - 0.5) * 500;               // Z coordinate
            
            // Store particle data for animation
            this.particles.push({
                velocity: (Math.random() - 0.5) * 0.2,
                baseX: positions[i3],
                baseY: positions[i3 + 1]
            });
        }

        // Set particle positions in geometry
        this.particleGeometry.setAttribute(
            'position',
            new THREE.BufferAttribute(positions, 3)
        );

        // Create particle system and add to scene
        this.particleSystem = new THREE.Points(
            this.particleGeometry,
            this.particleMaterial
        );
        this.scene.add(this.particleSystem);

        // Start animation loop
        this.animate();
    }

    // Handle window resize events
    bindEvents() {
        window.addEventListener('resize', () => {
            // Update camera aspect ratio and projection matrix
            this.camera.aspect = window.innerWidth / window.innerHeight;
            this.camera.updateProjectionMatrix();
            
            // Update renderer size
            this.renderer.setSize(window.innerWidth, window.innerHeight);
        });
    }

    // Animation loop for particle movement
    animate() {
        requestAnimationFrame(() => this.animate());

        const positions = this.particleGeometry.attributes.position.array;
        const time = Date.now() * 0.0005;

        // Update particle positions with wave-like motion
        for (let i = 0; i < this.particleCount; i++) {
            const i3 = i * 3;
            const particle = this.particles[i];

            // Create wave-like motion using sine waves
            positions[i3] = particle.baseX + Math.sin(time + i) * 2;
            positions[i3 + 1] = particle.baseY + Math.cos(time + i) * 2;
            
            // Add slight drift to z-position
            positions[i3 + 2] += particle.velocity;

            // Reset particles that drift too far
            if (Math.abs(positions[i3 + 2]) > 250) {
                positions[i3 + 2] = -250;
            }
        }

        // Mark particle positions for update
        this.particleGeometry.attributes.position.needsUpdate = true;

        // Add subtle camera movement
        this.camera.position.x = Math.sin(time) * 10;
        this.camera.position.y = Math.cos(time) * 10;
        this.camera.lookAt(this.scene.position);

        // Render the scene
        this.renderer.render(this.scene, this.camera);
    }

    // Method to add dramatic effects during game events
    addDramaticEffect(type) {
        switch(type) {
            case 'impostor_reveal':
                // Create a dramatic red flash effect
                this.particleMaterial.color.setHex(0xff0000);
                setTimeout(() => {
                    this.particleMaterial.color.setHex(0xffffff);
                }, 1000);
                break;
            
            case 'round_start':
                // Increase particle movement temporarily
                const originalVelocities = this.particles.map(p => p.velocity);
                this.particles.forEach(p => p.velocity *= 2);
                setTimeout(() => {
                    this.particles.forEach((p, i) => p.velocity = originalVelocities[i]);
                }, 2000);
                break;
            
            case 'voting':
                // Create a pulsing effect
                const pulseAnimation = () => {
                    this.particleMaterial.size = 2 + Math.sin(Date.now() * 0.005) * 1;
                };
                const pulseInterval = setInterval(pulseAnimation, 16);
                setTimeout(() => {
                    clearInterval(pulseInterval);
                    this.particleMaterial.size = 2;
                }, 3000);
                break;
        }
    }
}

// Initialize the background when the DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
    const background = new Background();

    // Expose background instance for game events
    window.gameBackground = background;
});

// Export the Background class for potential module usage
export default Background;