using Core;
using Core.Lifecycle;
using Core.Settings;
using UnityEngine;

namespace Minigames.BirdPooper
{
    /// <summary>
    /// Poop projectile that falls straight down with manual gravity.
    /// Destroys when off-screen or hitting targets (Phase 5).
    /// </summary>
    [RequireComponent(typeof(Rigidbody2D))]
    [RequireComponent(typeof(Collider2D))]
    public class PoopProjectile : ManagedBehaviour
    {
        private IBirdPooperSettings settings;
        private float verticalVelocity; // Current downward velocity
        private const float GravityAcceleration = 20f; // Gravity acceleration (units/s²)
        
        internal override void OnManagedAwake()
        {
            base.OnManagedAwake();
            
            // Load settings
            settings = GameManager.GetSettingsObject<IBirdPooperSettings>();
            if (settings == null)
            {
                Debug.LogError("[PoopProjectile] BirdPooperSettings not found!");
                Destroy(gameObject);
                return;
            }
            
            // Initialize velocity with settings speed as starting velocity
            verticalVelocity = settings.PoopFallSpeed;
            
            // Verify Rigidbody2D configuration
            Rigidbody2D rb = GetComponent<Rigidbody2D>();
            if (rb != null)
            {
                rb.bodyType = RigidbodyType2D.Dynamic;
                rb.gravityScale = 0f; // Manual gravity
                rb.collisionDetectionMode = CollisionDetectionMode2D.Continuous;
            }
            
            // Verify collider is trigger (for target detection in Phase 5)
            Collider2D col = GetComponent<Collider2D>();
            if (col != null && !col.isTrigger)
            {
                Debug.LogWarning("[PoopProjectile] Collider should be set as Trigger for target detection!");
            }
        }
        
        private void Update()
        {
            if (settings != null)
            {
                ApplyGravity();
                FallDown();
                CheckBounds();
            }
        }
        
        /// <summary>
        /// Apply gravity acceleration to velocity.
        /// </summary>
        private void ApplyGravity()
        {
            // Increase downward velocity over time (gravity acceleration)
            verticalVelocity += GravityAcceleration * Time.deltaTime;
        }
        
        /// <summary>
        /// Manual downward movement using current velocity.
        /// </summary>
        private void FallDown()
        {
            // Move straight down at current velocity
            transform.position += Vector3.down * verticalVelocity * Time.deltaTime;
        }
        
        /// <summary>
        /// Check if projectile is off-screen and should be destroyed.
        /// </summary>
        private void CheckBounds()
        {
            if (transform.position.y < settings.PoopDestroyYPosition)
            {
                Destroy(gameObject);
            }
        }
        
        /// <summary>
        /// Trigger collision detection for targets (Phase 5).
        /// TODO: Uncomment when Target.cs is implemented in Phase 5
        /// </summary>
        private void OnTriggerEnter2D(Collider2D other)
        {
            // Phase 5 integration - currently commented out
            /*
            if (other.CompareTag("Target"))
            {
                // Notify target it was hit
                Target target = other.GetComponent<Target>();
                if (target != null)
                {
                    target.OnHitByProjectile();
                }
                
                Destroy(gameObject);
            }
            */
        }
    }
}