using System;
using System.Collections;
using System.Collections.Generic;
using Unity.Collections;
using Unity.Jobs;
using UnityEngine;
using UnityEngine.Tilemaps;

//[Serializable]
//public class Ore
//{
//    public string name;
//    /// <summary>
//    /// The lower the numer the higher the amount of ores that will spawn
//    /// Higher number means less ore
//    /// </summary>
//    [Tooltip("The lower the numer the higher the amount of ores that will spawn. Higher number means less ore.")]
//    [Range(1, 100000)]
//    public int weight;
//    /// <summary>
//    /// The lower the number the more dense the ore will spawn (big clusters
//    /// Higher number means little clusters (more spread)
//    /// </summary>
//    [Tooltip("The lower the number the more dense the ore will spawn (big clusters. Higher number means little clusters (more spread).")]
//    [Range(10, 100000)]
//    public int clusterWeight;
//    public CustomRuleTile tile;
//    public int maxSpawnHeight;
//    public int minSpawnHeight;
//}

public class GenerateTileMap : MonoBehaviour
{
    public int? seed;
    public static int maxWidth = 256;
    public static int maxDepth = 384;
    public static int groundDepth = 256;
    private float scale;
    private float offsetX;
    private float offsetY;
    Tilemap tilemap;
    public CustomRuleTile forestRuleTile;
    public TileBase borderTile;
    private List<Generateable> generateables;

    //public List<TileBase> tiles;
    public const int CHUNK_SIZE = 16; // Size of each chunk
    public int LOAD_DISTANCE = 2; // Number of chunks to load around player

    private Dictionary<Vector2Int, bool> loadedChunks = new Dictionary<Vector2Int, bool>();
    private Transform playerTransform; // Reference to player/camera
    private Vector2Int lastLoadedChunk;
    private GameManager gameManager;

    private void Awake()
    {
        gameManager = FindObjectOfType<GameManager>();
        tilemap = GetComponent<Tilemap>();
        playerTransform = GameObject.FindGameObjectWithTag("Player").transform; // Make sure your player has the "Player" tag
#if DEBUG
        seed = 0123456789;
#endif
        if (seed == null)
        {
            seed = GenerateSeed(9);
        }

        SetSettingsFromSeed(seed.Value);

        // Position adjusted to center horizontally, but align top at y=0
        transform.position = new Vector3((maxWidth / 2) * -1, -1, transform.position.z);

        LoadGenerateablesFromResources();
    }
    private void Update()
    {
        if (playerTransform == null) return;
        //Debug.Log($"Player Position: {playerTransform.position}");
        Vector2Int currentChunk = GetChunkPosition(playerTransform.position);
        //Debug.Log($"Current Chunk: {currentChunk}");
        if (currentChunk != lastLoadedChunk)
        {
            StartCoroutine(UpdateLoadedChunks(currentChunk));
            lastLoadedChunk = currentChunk;
        }
    }
    // When a tile is destroyed in a chunk, update GameManager's list
    private void AddDestroyedTile(Vector3Int tilePos)
    {
        if (!gameManager.destroyedTiles.Contains(tilePos))
        {
            gameManager.destroyedTiles.Add(tilePos);
        }
    }

    // When checking if a tile is destroyed, use GameManager's list
    private bool IsTileDestroyed(Vector3Int tilePos)
    {
        return gameManager.destroyedTiles.Contains(tilePos);
    }
    private IEnumerator UpdateLoadedChunks(Vector2Int currentChunk)
    {
        // Unload distant chunks
        List<Vector2Int> chunksToUnload = new List<Vector2Int>();
        foreach (var chunk in loadedChunks.Keys)
        {
            if (Mathf.Abs(chunk.x - currentChunk.x) > LOAD_DISTANCE ||
                Mathf.Abs(chunk.y - currentChunk.y) > LOAD_DISTANCE)
            {
                chunksToUnload.Add(chunk);
                UnloadChunk(chunk);
            }
        }
        foreach (var chunk in chunksToUnload)
        {
            loadedChunks.Remove(chunk);
        }

        // Load new chunks
        yield return LoadChunksAroundPosition(currentChunk, new List<Vector3Int>());
    }

    private void UnloadChunk(Vector2Int chunk)
    {
        int startX = chunk.x * CHUNK_SIZE;
        int startY = (chunk.y * CHUNK_SIZE)-1;

        for (int x = startX; x < startX + CHUNK_SIZE; x++)
        {
            for (int y = startY; y > startY - CHUNK_SIZE; y--)
            {
                tilemap.SetTile(new Vector3Int(x, y), null);
            }
        }
    }
    private void LoadGenerateablesFromResources()
    {
        // Clear existing siblings
        forestRuleTile.siblings.Clear();

        // Load all Item prefabs from the "Resources/Items" folder
        GameObject[] generateablePrefabs = Resources.LoadAll<GameObject>("Generateable");
        generateables = new List<Generateable>();
        foreach (GameObject prefab in generateablePrefabs)
        {
            Generateable generateable = prefab.GetComponent<Generateable>();
            if (generateable != null)
            {
                generateable.tile = ScriptableObject.CreateInstance<CustomRuleTile>();
                generateable.tile.m_DefaultGameObject = prefab;
                generateable.tile.m_DefaultSprite = generateable.sprite;
                generateables.Add(generateable);
                forestRuleTile.siblings.Add(generateable.tile);
            }
            else
            {
                Debug.LogWarning($"Prefab {prefab.name} does not have an Item component");
            }
        }

        GenerateableDatabase.Instance.InitializeFromGenerateables(generateables);

        if (generateables.Count == 0)
        {
            Debug.LogWarning("No items found in Resources/Items folder");
        }
    }

    public void SetSettingsFromSeed(int seed)
    {
        UnityEngine.Random.State randomState = UnityEngine.Random.state;

        UnityEngine.Random.InitState(seed);
        scale = UnityEngine.Random.Range(17f, 23f);
        offsetX = UnityEngine.Random.Range(-10000f, 10000f);
        offsetY = UnityEngine.Random.Range(-10000f, 10000f);

        UnityEngine.Random.state = randomState;

    }

    private int GenerateSeed(int size)
    {
        System.Random rand = new System.Random();
        string seedNumbers = "0123456789";
        char[] chars = new char[size];
        for (int i = 0; i < size; i++)
        {
            chars[i] = seedNumbers[rand.Next(seedNumbers.Length)];
        }
        return int.Parse(new string(chars));
    }

    public IEnumerator GenerateTiles(Action finishedCallback, List<Vector3Int> destroyedTiles)
    {
        // Get initial player chunk position
        Vector2Int currentChunk = GetChunkPosition(playerTransform.position);
        lastLoadedChunk = currentChunk;

        // Generate initial chunks around player
        yield return LoadChunksAroundPosition(currentChunk, destroyedTiles);

        finishedCallback();
    }
    private Vector2Int GetChunkPosition(Vector3 worldPosition)
    {
        // Adjust for tilemap offset
        float adjustedX = worldPosition.x - transform.position.x;
        float adjustedY = (worldPosition.y - transform.position.y) + CHUNK_SIZE;

        return new Vector2Int(
            Mathf.FloorToInt(adjustedX / CHUNK_SIZE),
            Mathf.FloorToInt(adjustedY / CHUNK_SIZE)
        );
    }
    private IEnumerator LoadChunksAroundPosition(Vector2Int centerChunk, List<Vector3Int> destroyedTiles)
    {
        for (int x = -LOAD_DISTANCE; x <= LOAD_DISTANCE; x++)
        {
            for (int y = -LOAD_DISTANCE; y <= LOAD_DISTANCE; y++)
            {
                Vector2Int chunkPos = new Vector2Int(centerChunk.x + x, centerChunk.y + y);
                if (!loadedChunks.ContainsKey(chunkPos))
                {
                    yield return GenerateChunk(chunkPos, destroyedTiles);
                    loadedChunks[chunkPos] = true;
                }
            }
        }
    }
    private IEnumerator GenerateChunk(Vector2Int chunk, List<Vector3Int> destroyedTiles)
    {
        int startX = chunk.x * CHUNK_SIZE;
        int startY = (chunk.y * CHUNK_SIZE) - 1;

        // Create job data
        var groundJob = new GenerateGroundJob
        {
            chunkStartX = startX,
            chunkStartY = startY,
            chunkSize = CHUNK_SIZE,
            maxWidth = maxWidth,
            groundDepth = groundDepth,
            scale = scale,
            offsetX = offsetX,
            offsetY = offsetY,
            groundTiles = new NativeArray<bool>(CHUNK_SIZE * CHUNK_SIZE, Allocator.TempJob)
        };

        // Schedule the job
        JobHandle groundJobHandle = groundJob.Schedule(CHUNK_SIZE * CHUNK_SIZE, 64);

        // Wait for the job to complete
        groundJobHandle.Complete();

        // Apply the results
        for (int i = 0; i < CHUNK_SIZE * CHUNK_SIZE; i++)
        {
            if (groundJob.groundTiles[i])
            {
                int x = startX + (i % CHUNK_SIZE);
                int y = startY - (i / CHUNK_SIZE);
                Vector3Int tilePos = new Vector3Int(x, y);

                if (!IsTileDestroyed(tilePos))
                {
                    tilemap.SetTile(tilePos, forestRuleTile);
                }
            }
        }

        // Clean up native array
        groundJob.groundTiles.Dispose();

        // Generate ores
        if (generateables != null)
        {
            yield return GenerateOresInChunk(chunk, destroyedTiles);
        }

        // Generate borders when needed
        if (startX == 0 || startX + CHUNK_SIZE >= maxWidth ||
            startY == 0 || startY - CHUNK_SIZE <= -groundDepth)
        {
            yield return GenerateBorders();
        }
    }

    //private IEnumerator CreateGroundLayer(List<Vector3Int> destroyedTiles)
    //{
    //    for (int x = 1; x < maxWidth; x++)
    //    {
    //        for (int y = -1; y > -groundDepth; y--)
    //        {
    //            float xPerlin = ((float)x / maxWidth) * scale + offsetX;
    //            float yPerlin = ((float)Mathf.Abs(y) / maxDepth) * scale + offsetY;
    //            float perlinNoise = Mathf.PerlinNoise(xPerlin, yPerlin);

    //            if (perlinNoise <= 0.7f)
    //            {
    //                Vector3Int tileSpawnCoord = new Vector3Int(x, y);
    //                if (!destroyedTiles.Contains(tileSpawnCoord))
    //                {
    //                    tilemap.SetTile(tileSpawnCoord, forestRuleTile);
    //                }
    //            }

    //        }

    //        // Update UI every 8 lines
    //        if ((x % 8) == 0)
    //        {
    //            yield return null;
    //        }
    //    }
    //}
    private IEnumerator GenerateOresInChunk(Vector2Int chunk, List<Vector3Int> destroyedTiles)
    {
        int startX = chunk.x * CHUNK_SIZE;
        int startY = chunk.y * CHUNK_SIZE;

        foreach (Generateable generateable in generateables)
        {
            // Convert spawn heights to negative values if they aren't already
            int maxY = -Mathf.Abs(generateable.maxSpawnHeight);
            int minY = -Mathf.Abs(generateable.minSpawnHeight);
            // Changed condition: Check if the chunk's Y range overlaps with ore spawn range
            int chunkMaxY = startY;
            int chunkMinY = startY - CHUNK_SIZE;

            // Only process this chunk if it's within the ore's spawn height range
            if (chunkMinY <= maxY && chunkMaxY >= minY)
            {
                for (int x = startX; x < startX + CHUNK_SIZE; x++)
                {
                    if (x >= maxWidth) continue;

                    // Adjusted Y range calculation
                    int rangeStart = Mathf.Max(chunkMinY, minY);
                    int rangeEnd = Mathf.Min(chunkMaxY, maxY);

                    for (int y = rangeStart; y <= rangeEnd; y++)
                    {
                        float xPerlin = ((float)x / maxWidth) * (float)generateable.clusterWeight + offsetX;
                        float yPerlin = ((float)Mathf.Abs(y) / maxDepth) * (float)generateable.clusterWeight + offsetY;
                        float perlinNoise = Mathf.PerlinNoise(xPerlin, yPerlin);

                        if (perlinNoise <= (1f / (float)generateable.weight))
                        {
                            Vector3Int tileSpawnCoord = new Vector3Int(x, y);
                            if (!destroyedTiles.Contains(tileSpawnCoord) && tilemap.HasTile(tileSpawnCoord))
                            {
                                int clusterSize = CountPotentialClusterSize(x, y, generateable.weight, generateable.clusterWeight);
                                if (clusterSize >= generateable.minClusterSize)
                                {
                                    tilemap.SetTile(tileSpawnCoord, generateable.tile);
                                }
                            }
                        }
                    }
                }

                // Update every few rows to maintain performance
                if (generateables.Count > 3)
                {
                    yield return null;
                }
            }
        }
    }

    //private IEnumerator GenerateOreClusters(List<Vector3Int> destroyedTiles)
    //{
    //    foreach (Generateable generateable in generateables)
    //    {
    //        // Convert spawn heights to negative values if they aren't already
    //        int maxY = -Mathf.Abs(generateable.maxSpawnHeight);
    //        int minY = -Mathf.Abs(generateable.minSpawnHeight);
    //        Debug.Log($"Generating {generateable.name} between Y: {minY} - {maxY}");
    //        for (int x = 0; x < maxWidth; x++)
    //        {
    //            for (int y = maxY; y > minY; y--)
    //            {
    //                float xPerlin = ((float)x / maxWidth) * (float)generateable.clusterWeight + offsetX;
    //                float yPerlin = ((float)Mathf.Abs(y) / maxDepth) * (float)generateable.clusterWeight + offsetY;
    //                float perlinNoise = Mathf.PerlinNoise(xPerlin, yPerlin);

    //                if (perlinNoise <= (1f / (float)generateable.weight))
    //                {
    //                    Vector3Int tileSpawnCoord = new Vector3Int(x, y);
    //                    if (!destroyedTiles.Contains(tileSpawnCoord) && tilemap.HasTile(tileSpawnCoord))
    //                    {
    //                        // Check potential cluster size before placing
    //                        int clusterSize = CountPotentialClusterSize(x, y, generateable.weight, generateable.clusterWeight);
    //                        if (clusterSize >= generateable.minClusterSize)
    //                        {
    //                            tilemap.SetTile(tileSpawnCoord, generateable.tile);
    //                        }
    //                        //tilemap.SetTile(tileSpawnCoord, generateable.tile);
    //                    }
    //                }

    //            }

    //            // Update UI every 8 lines
    //            if ((x % 8) == 0)
    //            {
    //                yield return null;
    //            }
    //        }
    //    }
    //}

    private IEnumerator GenerateBorders()
    {
        // Vertical borders (going up from underground to sky)
        for (int x = 0; x <= maxWidth; x += maxWidth)
        {
            for (int y = -groundDepth; y <= maxDepth - groundDepth; y++)
            {
                tilemap.SetTile(new Vector3Int(x, y), borderTile);
            }
        }
        yield return null;

        // Horizontal borders (at bottom and sky level)
        for (int y = -groundDepth; y <= maxDepth - groundDepth; y += maxDepth)
        {
            for (int x = 1; x <= maxWidth; x++)
            {
                tilemap.SetTile(new Vector3Int(x, y), borderTile);
            }
        }
        yield return null;
    }

    private int CountPotentialClusterSize(int startX, int startY, int weight, int clusterWeight)
    {
        int size = 0;
        Queue<Vector2Int> toCheck = new Queue<Vector2Int>();
        HashSet<Vector2Int> checked_positions = new HashSet<Vector2Int>();

        toCheck.Enqueue(new Vector2Int(startX, startY));
        checked_positions.Add(new Vector2Int(startX, startY));

        while (toCheck.Count > 0)
        {
            Vector2Int current = toCheck.Dequeue();
            size++;

            // Check all 8 neighboring tiles
            for (int dx = -1; dx <= 1; dx++)
            {
                for (int dy = -1; dy <= 1; dy++)
                {
                    if (dx == 0 && dy == 0) continue;

                    Vector2Int neighbor = new Vector2Int(current.x + dx, current.y + dy);
                    if (checked_positions.Contains(neighbor)) continue;

                    float xPerlin = ((float)neighbor.x / maxWidth) * clusterWeight + offsetX;
                    float yPerlin = ((float)Mathf.Abs(neighbor.y) / maxDepth) * clusterWeight + offsetY;
                    float perlinNoise = Mathf.PerlinNoise(xPerlin, yPerlin);

                    if (perlinNoise <= (1f / (float)weight))
                    {
                        toCheck.Enqueue(neighbor);
                        checked_positions.Add(neighbor);
                    }
                }
            }
        }

        return size;
    }
#if UNITY_EDITOR
    private void OnDrawGizmos()
    {
        if (!Application.isPlaying) return;

        // Draw current chunk boundaries
        if (playerTransform != null)
        {
            Vector2Int currentChunk = GetChunkPosition(playerTransform.position);
            Gizmos.color = Color.yellow;

            for (int x = -LOAD_DISTANCE; x <= LOAD_DISTANCE; x++)
            {
                for (int y = -LOAD_DISTANCE; y <= LOAD_DISTANCE; y++)
                {
                    Vector2Int chunk = new Vector2Int(currentChunk.x + x, currentChunk.y + y);
                    Vector3 worldPos = new Vector3(
                        chunk.x * CHUNK_SIZE + transform.position.x,
                        chunk.y * CHUNK_SIZE + transform.position.y,
                        0
                    );

                    // Draw chunk boundary
                    Gizmos.DrawWireCube(
                        worldPos + new Vector3(CHUNK_SIZE / 2f, -CHUNK_SIZE / 2f, 0),
                        new Vector3(CHUNK_SIZE, CHUNK_SIZE, 0)
                    );

                    // Draw chunk coordinates
                    UnityEditor.Handles.Label(
                        worldPos + new Vector3(CHUNK_SIZE / 2f, -CHUNK_SIZE / 2f, 0),
                        $"({chunk.x}, {chunk.y})"
                    );
                }
            }
        }
    }
#endif
}