// ============= Enemy System =============
const blueShades = [
    'rgb(0, 0, 255)',    // Bright blue
    'rgb(0, 0, 200)',    // Medium blue
    'rgb(0, 0, 150)',    // Darker blue
    'rgb(0, 0, 100)',    // Even darker blue
    'rgb(0, 0, 50)'      // Very dark blue
];

const generateEnemies = (villagers, collisionMap) => {
    const enemies = [];
    const gridSize = CONFIG.display.grid.size;
    const occupiedCells = new Set([...collisionMap.keys()]);
    
    villagers.forEach(villager => {
        if (villager.status === 'rescued') return;
        
        // Generate 2-5 enemies per villager
        const numEnemies = 2 + Math.floor(Math.random() * 4);
        
        for (let i = 0; i < numEnemies; i++) {
            // Place within 2-3 cells of villager
            const radius = 2 + Math.floor(Math.random());
            const angle = Math.random() * Math.PI * 2;
            
            const cellX = villager.cellX + Math.floor(Math.cos(angle) * radius);
            const cellY = villager.cellY + Math.floor(Math.sin(angle) * radius);
            const cellKey = `${cellX},${cellY}`;
            
            // Skip if cell is occupied
            if (occupiedCells.has(cellKey)) {
                continue;
            }
            
            // Generate random color between orange and dark red
            const red = 150 + Math.floor(Math.random() * 105);  // 150-255
            const green = Math.floor(Math.random() * 100);      // 0-100
            const blue = 0;
            
            enemies.push({
                x: (cellX * gridSize) + (gridSize / 2),
                y: (cellY * gridSize) + (gridSize / 2),
                color: `rgb(${red}, ${green}, ${blue})`,
                size: CONFIG.enemies.size.min + Math.random() * (CONFIG.enemies.size.max - CONFIG.enemies.size.min),
                targetVillager: villager,
                patrolAngle: Math.random() * Math.PI * 2,
                isChasing: false,
                hp: 2 + Math.floor(Math.random() * 9),
                stunned: false,
                stunEndTime: 0,
                attacking: false,
                attackCooldown: false,
                attackCooldownUntil: 0,
                knockback: {
                    active: false,
                    startX: 0,
                    startY: 0,
                    targetX: 0,
                    targetY: 0,
                    startTime: 0,
                    duration: 300
                }
            });
            
            occupiedCells.add(cellKey);
        }
    });
    
    return enemies;
};

const handleEnemyDamage = (enemy, damage, knockbackForce = 0, angle = 0) => {
    const gridSize = CONFIG.display.grid.size;
    enemy.hp -= damage;
    
    if (damage > 0 && enemy.hp <= 0) {
        // Create death particles
        const numParticles = 15 + Math.floor(Math.random() * 10);
        for (let i = 0; i < numParticles; i++) {
            const angle = (i / numParticles) * Math.PI * 2;
            const speed = 2 + Math.random() * 3;
            state.particles.push({
                x: enemy.x,
                y: enemy.y,
                dx: Math.cos(angle) * speed,
                dy: Math.sin(angle) * speed,
                size: enemy.size * (0.1 + Math.random() * 0.2),
                color: enemy.color,
                lifetime: 1000,
                createdAt: animationTime
            });
        }

        // Generate diamonds when enemy is defeated
        const diamondCount = Math.floor(Math.random() * 5); // 0 to 4 diamonds
        for (let i = 0; i < diamondCount; i++) {
            state.diamonds.push({
                x: enemy.x + (Math.random() - 0.5) * 20,
                y: enemy.y + (Math.random() - 0.5) * 20,
                size: 6, // Smaller size (was 10)
                collected: false
            });
        }
    }
    
    return damage > 0 && enemy.hp <= 0;
};

const updateEnemies = (enemies, deltaTime) => {
    const gridSize = CONFIG.display.grid.size;
    const aggroRange = gridSize * CONFIG.enemies.chase.range;

    // Check for weapon collisions
    enemies.forEach(enemy => {
        // Check bubble collisions
        state.player.bubbles.forEach((bubble, bubbleIndex) => {
            const dx = enemy.x - bubble.x;
            const dy = enemy.y - bubble.y;
            const distance = Math.sqrt(dx * dx + dy * dy);
            
            if (distance < enemy.size + CONFIG.bubble.size) {
                // Remove the bubble
                state.player.bubbles.splice(bubbleIndex, 1);
                
                // Normalize the direction vector
                const length = Math.sqrt(dx * dx + dy * dy);
                const dirX = dx / length;
                const dirY = dy / length;
                
                // Set up knockback animation
                enemy.knockback = {
                    active: true,
                    startX: enemy.x,
                    startY: enemy.y,
                    targetX: enemy.x + dirX * CONFIG.display.grid.size,
                    targetY: enemy.y + dirY * CONFIG.display.grid.size,
                    startTime: animationTime,
                    duration: 300
                };
                
                // Stun the enemy
                enemy.stunned = true;
                enemy.stunEndTime = animationTime + 500; // Stun for 500ms
            }
        });
        
        // Check sword collision
        if (state.player.isSwinging && state.player.equipment === 'sword') {
            const swordTip = {
                x: state.player.x + Math.cos(state.player.swordAngle) * CONFIG.sword.length,
                y: state.player.y + Math.sin(state.player.swordAngle) * CONFIG.sword.length
            };
            
            const dx = enemy.x - swordTip.x;
            const dy = enemy.y - swordTip.y;
            const distance = Math.sqrt(dx * dx + dy * dy);
            
            if (distance < enemy.size + 10) { // 10px sword hit tolerance
                handleEnemyDamage(enemy, 1);
                enemy.stunned = true;
                enemy.stunEndTime = animationTime + 300; // Stun for 300ms
            }
        }
    });

    return enemies.filter(enemy => enemy.hp > 0).map(enemy => {
        const baseSpeed = CONFIG.enemies.patrol.speed.base * deltaTime / 1000;  // Convert to pixels per frame

        // Handle knockback animation
        if (enemy.knockback.active) {
            const progress = (animationTime - enemy.knockback.startTime) / enemy.knockback.duration;
            
            if (progress >= 1) {
                enemy.knockback.active = false;
                enemy.x = enemy.knockback.targetX;
                enemy.y = enemy.knockback.targetY;
                
                // Calculate distance from villager after knockback
                const dvx = enemy.x - enemy.targetVillager.x;
                const dvy = enemy.y - enemy.targetVillager.y;
                const distanceToVillager = Math.sqrt(dvx * dvx + dvy * dvy);
                
                // If too far from villager, set returning state
                if (distanceToVillager > gridSize * 3) {
                    return {
                        ...enemy,
                        x: enemy.x,
                        y: enemy.y,
                        isChasing: false,
                        isReturning: true
                    };
                }
            } else {
                // Smooth easing function (ease-out)
                const t = 1 - Math.pow(1 - progress, 3);
                enemy.x = enemy.knockback.startX + (enemy.knockback.targetX - enemy.knockback.startX) * t;
                enemy.y = enemy.knockback.startY + (enemy.knockback.targetY - enemy.knockback.startY) * t;
            }
            
            return {
                ...enemy,
                x: enemy.x,
                y: enemy.y,
                isChasing: false
            };
        }
        
        // If enemy is returning to villager
        if (enemy.isReturning) {
            const dvx = enemy.targetVillager.x - enemy.x;
            const dvy = enemy.targetVillager.y - enemy.y;
            const distanceToVillager = Math.sqrt(dvx * dvx + dvy * dvy);
            
            // If back within range, resume normal behavior
            if (distanceToVillager <= gridSize * 2) {
                enemy.isReturning = false;
            } else {
                // Move towards villager
                const angle = Math.atan2(dvy, dvx);
                const returnSpeed = baseSpeed * CONFIG.enemies.return.speedMultiplier;
                
                return {
                    ...enemy,
                    x: enemy.x + Math.cos(angle) * returnSpeed,
                    y: enemy.y + Math.sin(angle) * returnSpeed,
                    isChasing: false,
                    isReturning: true
                };
            }
        }
        
        // Check if stun has worn off
        if (enemy.stunned && animationTime >= enemy.stunEndTime) {
            enemy.stunned = false;
        }
        
        if (enemy.targetVillager.status === 'rescued') {
            return {
                ...enemy,
                color: CONFIG.enemies.colors.defeated
            };
        }
        
        // Calculate distance to player
        const dx = state.player.x - enemy.x;
        const dy = state.player.y - enemy.y;
        const distanceToPlayer = Math.sqrt(dx * dx + dy * dy);
        
        if (distanceToPlayer <= aggroRange) {
            // Check if in attack range (half grid cell)
            const attackRange = gridSize * 0.5;
            
            // If on attack cooldown, keep distance
            if (enemy.attackCooldown) {
                if (animationTime >= enemy.attackCooldownUntil) {
                    enemy.attackCooldown = false;
                } else if (distanceToPlayer < gridSize) {
                    // Retreat if too close during cooldown
                    const retreatAngle = Math.atan2(dy, dx) + Math.PI; // Opposite direction
                    const retreatSpeed = baseSpeed * CONFIG.enemies.chase.speedMultiplier;
                    return {
                        ...enemy,
                        x: enemy.x + Math.cos(retreatAngle) * retreatSpeed,
                        y: enemy.y + Math.sin(retreatAngle) * retreatSpeed,
                        isChasing: true
                    };
                }
            }
            
            // If in attack range and not on cooldown, initiate attack
            if (distanceToPlayer <= attackRange && !enemy.attacking && !enemy.attackCooldown) {
                enemy.attacking = true;
                enemy.attackStartPosition = { x: enemy.x, y: enemy.y };
                enemy.attackTargetPosition = {
                    x: state.player.x,
                    y: state.player.y
                };
                enemy.attackStartTime = animationTime;

                // Change enemy color to a random blue shade
                enemy.color = blueShades[Math.floor(Math.random() * blueShades.length)];
            }
            
            // Handle attack animation and damage
            if (enemy.attacking) {
                const attackDuration = 200; // 200ms attack
                const progress = (animationTime - enemy.attackStartTime) / attackDuration;
                
                if (progress >= 1) {
                    enemy.attacking = false;
                    enemy.attackCooldown = true;
                    enemy.attackCooldownUntil = animationTime + 1000; // 1 second cooldown
                    
                    // Check if attack hit the player
                    const finalDx = state.player.x - enemy.x;
                    const finalDy = state.player.y - enemy.y;
                    const finalDistance = Math.sqrt(finalDx * finalDx + finalDy * finalDy);
                    
                    if (finalDistance < enemy.size + CONFIG.player.size && 
                        !state.player.isInvulnerable && 
                        !state.player.isDefending && 
                        !state.player.isSwinging && 
                        state.player.bubbles.length === 0) {
                        state.player.hp -= 1;
                        state.player.isInvulnerable = true;
                        state.player.invulnerableUntil = animationTime + 1000;
                    }
                    
                    return {
                        ...enemy,
                        isChasing: true
                    };
                }
                
                // Fast lunge animation with ease-in
                const t = progress * progress; // Quadratic ease-in
                return {
                    ...enemy,
                    x: enemy.attackStartPosition.x + (enemy.attackTargetPosition.x - enemy.attackStartPosition.x) * t,
                    y: enemy.attackStartPosition.y + (enemy.attackTargetPosition.y - enemy.attackStartPosition.y) * t,
                    isChasing: true,
                    attacking: true
                };
            }
            
            // Normal chase behavior if not attacking
            const angle = Math.atan2(dy, dx);
            const chaseSpeed = baseSpeed * CONFIG.enemies.chase.speedMultiplier;
            
            return {
                ...enemy,
                x: enemy.x + Math.cos(angle) * chaseSpeed,
                y: enemy.y + Math.sin(angle) * chaseSpeed,
                isChasing: true
            };
        } else {
            // Get current distance from villager
            const dvx = enemy.x - enemy.targetVillager.x;
            const dvy = enemy.y - enemy.targetVillager.y;
            const distanceToVillager = Math.sqrt(dvx * dvx + dvy * dvy);
            
            // If too far from villager, start returning
            if (distanceToVillager > gridSize * 3) {
                return {
                    ...enemy,
                    isReturning: true,
                    isChasing: false
                };
            }
            
            // Patrol behavior - move in small circles around current position
            if (!enemy.patrolAngle) {
                enemy.patrolAngle = Math.random() * Math.PI * 2;
            }
            
            enemy.patrolAngle += baseSpeed * 0.02; // Small angle change for circular movement
            
            return {
                ...enemy,
                x: enemy.x + Math.cos(enemy.patrolAngle) * baseSpeed,
                y: enemy.y + Math.sin(enemy.patrolAngle) * baseSpeed,
                patrolAngle: enemy.patrolAngle,
                isChasing: false
            };
        }
    });
};

const renderEnemies = (ctx, enemies) => {
    // Pre-create the health circle gradient once
    const healthGradient = ctx.createRadialGradient(0, 0, 0, 0, 0, 2);
    healthGradient.addColorStop(0, 'rgba(255, 0, 0, 0.8)');
    healthGradient.addColorStop(0.7, 'rgba(200, 0, 0, 0.6)');
    healthGradient.addColorStop(1, 'rgba(150, 0, 0, 0.4)');

    enemies.forEach(enemy => {
        // Draw enemy body
        ctx.beginPath();
        ctx.arc(enemy.x, enemy.y, enemy.size, 0, Math.PI * 2);
        ctx.fillStyle = enemy.stunned ? 'rgb(150, 150, 150)' : enemy.color;
        ctx.fill();
        
        // Add a glowing effect
        const glowSize = enemy.stunned ? 1.1 : (enemy.attacking ? 1.6 : enemy.isChasing ? 1.4 : 1.2);
        const glowIntensity = enemy.stunned ? 0.1 : (enemy.attacking ? 0.5 : enemy.isChasing ? 0.3 : 0.2);
        
        // Create glow gradient only once per enemy
        const glowGradient = ctx.createRadialGradient(
            enemy.x, enemy.y, enemy.size * 0.5,
            enemy.x, enemy.y, enemy.size * glowSize
        );
        glowGradient.addColorStop(0, `rgba(255, 0, 0, ${glowIntensity})`);
        glowGradient.addColorStop(1, 'rgba(255, 0, 0, 0)');
        
        ctx.beginPath();
        ctx.arc(enemy.x, enemy.y, enemy.size * glowSize, 0, Math.PI * 2);
        ctx.fillStyle = glowGradient;
        ctx.fill();
        
        // Draw HP circles
        if (enemy.hp > 0) {
            const circleRadius = 3;
            const circleSpacing = 8;
            const totalCircles = enemy.hp;
            const startX = enemy.x - ((totalCircles - 1) * circleSpacing) / 2;
            const circleY = enemy.y - enemy.size - 15;
            
            // Batch draw the circle borders
            ctx.beginPath();
            for (let i = 0; i < totalCircles; i++) {
                const circleX = startX + (i * circleSpacing);
                ctx.moveTo(circleX + circleRadius, circleY);
                ctx.arc(circleX, circleY, circleRadius, 0, Math.PI * 2);
            }
            ctx.strokeStyle = 'rgba(255, 255, 255, 0.3)';
            ctx.lineWidth = 1;
            ctx.stroke();
            
            // Batch draw the filled circles
            ctx.beginPath();
            for (let i = 0; i < totalCircles; i++) {
                const circleX = startX + (i * circleSpacing);
                ctx.moveTo(circleX + circleRadius - 1, circleY);
                ctx.arc(circleX, circleY, circleRadius - 1, 0, Math.PI * 2);
            }
            ctx.fillStyle = 'rgba(255, 0, 0, 0.6)';
            ctx.fill();
        }
    });
};

const generateDiamonds = () => {
    const diamondCount = Math.floor(Math.random() * 5); // 0 to 4 diamonds
    const diamonds = [];
    
    for (let i = 0; i < diamondCount; i++) {
        diamonds.push({
            x: enemy.x + (Math.random() - 0.5) * 20, // Random position around the enemy
            y: enemy.y + (Math.random() - 0.5) * 20,
            size: 10, // Size of the diamond
            collected: false // Track if collected
        });
    }
    
    return diamonds;
};

// Export the functions
window.enemySystem = {
    generateEnemies,
    updateEnemies,
    renderEnemies
};