using System;
using Core;
using Core.Lifecycle;
using Input;
using UnityEngine;

namespace Common.Input
{
    /// <summary>
    /// Cached launch parameters calculated during drag.
    /// Avoids recalculating force/direction multiple times.
    /// </summary>
    public struct LaunchParameters
    {
        public Vector2 Direction;
        public float Force;
        public float DragDistance;
        public float DragRatio;
        public float Mass;
        
        public bool IsValid => Force > 0f && DragDistance > 0f;
    }
    
    /// <summary>
    /// Base class for drag-to-launch mechanics (Angry Birds style).
    /// Provides core drag logic, force calculation, and input handling.
    /// Uses SlingshotConfig for all settings - fully configuration-driven.
    /// Subclasses implement visual feedback and specific launch behavior.
    /// </summary>
    public abstract class DragLaunchController : ManagedBehaviour, ITouchInputConsumer
    {
        #region Events
        
        /// <summary>
        /// Fired when drag starts. Parameters: (Vector2 startPosition)
        /// </summary>
        public event Action<Vector2> OnDragStart;
        
        /// <summary>
        /// Fired during drag update. Parameters: (Vector2 currentPosition, Vector2 direction, float force)
        /// </summary>
        public event Action<Vector2, Vector2, float> OnDragUpdate;
        
        /// <summary>
        /// Fired when drag ends. Parameters: (Vector2 endPosition, Vector2 direction, float force)
        /// </summary>
        public event Action<Vector2, Vector2, float> OnDragEnd;
        
        /// <summary>
        /// Fired when launch occurs. Parameters: (Vector2 direction, float force)
        /// </summary>
        public event Action<Vector2, float> OnLaunch;
        
        #endregion

        #region Settings
        
        private SlingshotConfig _config;
        
        protected SlingshotConfig Config
        {
            get
            {
                if (_config == null)
                {
                    _config = GetSlingshotConfig();
                }
                return _config;
            }
        }
        
        /// <summary>
        /// Subclasses implement to return their slingshot configuration
        /// from their specific settings object
        /// </summary>
        protected abstract SlingshotConfig GetSlingshotConfig();
        
        /// <summary>
        /// Subclasses implement to return the projectile prefab that will be launched.
        /// Used for reading Rigidbody2D properties (mass, gravityScale) for trajectory calculations.
        /// </summary>
        protected abstract GameObject GetProjectilePrefab();
        
        #endregion

        #region Inspector Properties
        
        [Header("Launch Settings Overrides (leave 0 to use config)")]
        [Tooltip("Override max drag distance (0 = use config)")]
        [SerializeField] protected float maxDragDistanceOverride = 0f;
        
        [Tooltip("Override max force (0 = use config)")]
        [SerializeField] protected float maxForceOverride = 0f;
        
        [Header("References")]
        [Tooltip("Launch anchor point (spawn/slingshot position)")]
        [SerializeField] protected Transform launchAnchor;
        
        [Tooltip("Trajectory preview component (auto-found if not assigned)")]
        [SerializeField] protected Common.Visual.TrajectoryPreview trajectoryPreview;
        
        [Header("Debug")]
        [SerializeField] protected bool showDebugLogs;
        
        #endregion
        
        #region Computed Properties
        
        protected float MaxDragDistance => maxDragDistanceOverride > 0 ? maxDragDistanceOverride : Config?.maxDragDistance ?? 5f;
        protected float MaxForce => maxForceOverride > 0 ? maxForceOverride : Config?.baseLaunchForce ?? 20f;
        
        #endregion

        #region State
        
        private bool _isDragging;
        private Vector2 _dragStartPosition;
        private bool _isEnabled = false;
        private bool _isRegisteredForInput = false;
        
        // Cached launch parameters - calculated once during drag, used for both preview and launch
        private LaunchParameters _cachedLaunchParams;
        
        public bool IsDragging => _isDragging;
        public bool IsEnabled => _isEnabled;
        
        #endregion

        #region Lifecycle
        
        internal override void OnManagedAwake()
        {
            base.OnManagedAwake();
            
            if (launchAnchor == null)
            {
                launchAnchor = transform;
            }
            
            // Auto-find trajectory preview if not assigned
            if (trajectoryPreview == null)
            {
                trajectoryPreview = GetComponent<Common.Visual.TrajectoryPreview>();
            }
        }
        
        #endregion

        #region Enable/Disable
        
        /// <summary>
        /// Enable the launch controller and register with InputManager
        /// </summary>
        public virtual void Enable()
        {
            _isEnabled = true;
            
            // Register with InputManager as override consumer
            if (InputManager.Instance != null && !_isRegisteredForInput)
            {
                InputManager.Instance.RegisterOverrideConsumer(this);
                _isRegisteredForInput = true;
                if (showDebugLogs) Logging.Debug($"[{GetType().Name}] Registered with InputManager");
            }
            
            // Show preview visuals
            ShowPreview();
            
            if (showDebugLogs) Logging.Debug($"[{GetType().Name}] Enabled");
        }
        
        /// <summary>
        /// Disable the launch controller and unregister from InputManager
        /// </summary>
        public virtual void Disable()
        {
            _isEnabled = false;
            _isDragging = false;
            
            // Unregister from InputManager
            if (InputManager.Instance != null && _isRegisteredForInput)
            {
                InputManager.Instance.UnregisterOverrideConsumer(this);
                _isRegisteredForInput = false;
                if (showDebugLogs) Logging.Debug($"[{GetType().Name}] Unregistered from InputManager");
            }
            
            // Hide preview visuals
            HidePreview();
            
            if (showDebugLogs) Logging.Debug($"[{GetType().Name}] Disabled");
        }
        
        #endregion

        #region ITouchInputConsumer Implementation
        
        public void OnTap(Vector2 worldPosition)
        {
            // Drag-to-launch uses hold/drag, not tap
        }
        
        public void OnHoldStart(Vector2 worldPosition)
        {
            if (!_isEnabled) return;
            StartDrag(worldPosition);
        }
        
        public void OnHoldMove(Vector2 worldPosition)
        {
            if (!_isEnabled || !_isDragging) return;
            UpdateDrag(worldPosition);
        }
        
        public void OnHoldEnd(Vector2 worldPosition)
        {
            if (!_isEnabled || !_isDragging) return;
            EndDrag(worldPosition);
        }
        
        #endregion

        #region Drag Handling
        
        /// <summary>
        /// Start drag operation
        /// </summary>
        protected virtual void StartDrag(Vector2 worldPosition)
        {
            _isDragging = true;
            // Use launch anchor as the reference point (like Angry Birds)
            _dragStartPosition = launchAnchor.position;
            
            if (showDebugLogs) Logging.Debug($"[{GetType().Name}] Started drag at {worldPosition}, anchor at {_dragStartPosition}");
            
            OnDragStart?.Invoke(worldPosition);
        }
        
        /// <summary>
        /// Update drag operation
        /// </summary>
        protected virtual void UpdateDrag(Vector2 currentWorldPosition)
        {
            // Calculate launch parameters once and cache
            _cachedLaunchParams = CalculateLaunchParameters(currentWorldPosition);
            
            // Warn if mass is zero or invalid
            if (_cachedLaunchParams.Mass <= 0f && showDebugLogs)
            {
                Logging.Warning($"[{GetType().Name}] Projectile mass is {_cachedLaunchParams.Mass}! Trajectory calculation will be inaccurate. Override GetProjectileMass().");
            }
            
            // Update visuals with cached parameters
            UpdateVisuals(currentWorldPosition, _cachedLaunchParams);
            
            OnDragUpdate?.Invoke(currentWorldPosition, _cachedLaunchParams.Direction, _cachedLaunchParams.Force);
        }
        
        /// <summary>
        /// End drag operation and potentially launch
        /// </summary>
        protected virtual void EndDrag(Vector2 currentWorldPosition)
        {
            _isDragging = false;
            
            // Hide preview
            HidePreview();
            
            // Recalculate final parameters (position may have changed since last UpdateDrag)
            _cachedLaunchParams = CalculateLaunchParameters(currentWorldPosition);

            OnDragEnd?.Invoke(currentWorldPosition, _cachedLaunchParams.Direction, _cachedLaunchParams.Force);

            if (showDebugLogs) 
                Logging.Debug($"[{GetType().Name}] Launching with force {_cachedLaunchParams.Force:F2}");
            PerformLaunch(_cachedLaunchParams.Direction, _cachedLaunchParams.Force);
            OnLaunch?.Invoke(_cachedLaunchParams.Direction, _cachedLaunchParams.Force);
        }
        
        /// <summary>
        /// Calculate launch parameters from current drag position.
        /// Caches results to avoid recalculating force multiple times.
        /// </summary>
        private LaunchParameters CalculateLaunchParameters(Vector2 currentWorldPosition)
        {
            // Calculate drag vector from anchor to current drag position
            // Pull back (away from anchor) = launch forward (toward anchor direction)
            Vector2 dragVector = _dragStartPosition - currentWorldPosition;
            
            // Calculate distance and ratio
            float dragDistance = dragVector.magnitude;
            float dragRatio = Mathf.Clamp01(dragDistance / MaxDragDistance);
            
            // Calculate force using config
            float force = Config?.CalculateForce(dragDistance, dragRatio) ?? (dragRatio * MaxForce);
            
            // Normalize direction
            Vector2 direction = dragDistance > 0.01f ? dragVector.normalized : Vector2.zero;
            
            // Get mass from projectile
            float mass = GetProjectileMass();
            
            return new LaunchParameters
            {
                Direction = direction,
                Force = force,
                DragDistance = dragDistance,
                DragRatio = dragRatio,
                Mass = mass
            };
        }
        
        #endregion

        #region Abstract Methods - Subclass Implementation
        
        /// <summary>
        /// Perform the actual launch (spawn projectile/airplane, apply force, etc.)
        /// </summary>
        protected abstract void PerformLaunch(Vector2 direction, float force);
        
        #endregion
        
        #region Virtual Methods - Visual Feedback (Override if needed)
        
        /// <summary>
        /// Update visual feedback during drag (trajectory preview, rubber band, etc.)
        /// Default: Updates trajectory preview using prefab's physics properties.
        /// Override for custom visuals.
        /// </summary>
        /// <param name="currentPosition">Current drag position</param>
        /// <param name="launchParams">Cached launch parameters (direction, force, etc.)</param>
        protected virtual void UpdateVisuals(Vector2 currentPosition, LaunchParameters launchParams)
        {
            if (trajectoryPreview != null && launchParams.DragDistance > 0.1f)
            {
                GameObject prefab = GetProjectilePrefab();
                if (prefab == null) return;
                
                // Get gravity from prefab's Rigidbody2D gravityScale
                var rb = prefab.GetComponent<Rigidbody2D>();
                float gravityScale = rb != null ? rb.gravityScale : 1f;
                float gravity = Physics2D.gravity.magnitude * gravityScale;
                
                // Use mass from settings (already in launchParams)
                trajectoryPreview.UpdateTrajectory(launchAnchor.position, launchParams.Direction, 
                    launchParams.Force, launchParams.Mass, gravity);
            }
        }
        
        /// <summary>
        /// Show preview visuals when controller is enabled.
        /// Default: Shows trajectory preview.
        /// Override for custom visuals.
        /// </summary>
        protected virtual void ShowPreview()
        {
            trajectoryPreview?.Show();
        }
        
        /// <summary>
        /// Hide preview visuals when controller is disabled.
        /// Default: Hides trajectory preview.
        /// Override for custom visuals.
        /// </summary>
        protected virtual void HidePreview()
        {
            trajectoryPreview?.Hide();
        }
        
        public Transform GetLaunchAnchorTransform()
        {
            return launchAnchor;
        }
        
        #endregion
        
        #region Abstract Methods - Physics Configuration
        
        /// <summary>
        /// Get projectile mass for trajectory calculation.
        /// MUST read from settings - the same source that Initialize() uses.
        /// Subclasses implement to return the actual runtime mass.
        /// </summary>
        protected abstract float GetProjectileMass();
        
        #endregion

        #region Cleanup
        
        internal override void OnManagedDestroy()
        {
            base.OnManagedDestroy();
            
            // Ensure we unregister from InputManager
            if (_isRegisteredForInput && InputManager.Instance != null)
            {
                InputManager.Instance.UnregisterOverrideConsumer(this);
            }
        }
        
        #endregion
    }
}