using UnityEngine;
using System.IO;
using System.Collections.Generic;
using System;
using System.Threading;
using System.Collections;
using UnityEngine.Events;

public class ImageFileWatcher : MonoBehaviour
{
    //public string originFolder;
    public static ImageFileWatcher instance;

    [Serializable]
    public class TextureDataHandler : UnityEvent<TextureData> { };
    public TextureDataHandler TextureAddedEvent = new TextureDataHandler();
    public TextureDataHandler TextureRemovedEvent = new TextureDataHandler();

    public int photoSize = 0;
    public float photoCheckingPeriod = 0.2f;
    public int maxNum = 20;
    [Tooltip("the root path is unity project path")]
    public string rootPath = "Scan";
    public Texture2D[] texListForDebugging;
    public bool clearAfterLoaded = false;
    private string todayFolder = DateTime.Now.ToString("yyyy-MM-dd");
    private Queue<TextureData> waiting_queue = new Queue<TextureData>();
    private Queue<TextureData> ready_queue = new Queue<TextureData>();
    private Queue<TextureData> texturePool   = new Queue<TextureData>();
    
    private Thread loadingThread;
    private bool isThreadRunning = true;
    private FileSystemWatcher watcher;
    public Dictionary<string, GameObject> type_map = new Dictionary<string, GameObject>();
    [SerializeField]
    private bool search_last_file = false;
    [SerializeField]
    private bool dailyFolder = true;
    [SerializeField]
    private bool isRelative = false;
    void Awake()
    {
        instance = this;
        //rootPath = Application.dataPath + "/"+rootPath;
    }
    void Start()
    {
        DateTime date = DateTime.Now;

        if (isRelative)
            rootPath = Application.dataPath + "\\" + rootPath;

        if (search_last_file)
        {
            List<string> historic_files = find_last_files();
            foreach (string file in historic_files)
            {
                lock (waiting_queue)
                {
                    waiting_queue.Enqueue(new TextureData(file));
                }
            }
        }

     

        //string[] dir_list = {"2013.02.21","2010.06.20","1985.08.27","3820.01.02" };
        if (!Directory.Exists(rootPath))
        {
            Directory.CreateDirectory(rootPath);
        }
        string watch_path = rootPath;
        if (dailyFolder)
        {
            watch_path = rootPath + "/" + todayFolder;
            if (!Directory.Exists(watch_path))
            {
                Directory.CreateDirectory(watch_path);
            }
        }
        watcher = new FileSystemWatcher(watch_path);
        watcher.Created += onFileChanged;

        watcher.EnableRaisingEvents = true;

        loadingThread = new Thread(new ThreadStart(resizing_to_memory_service));
        loadingThread.Start();
        StartCoroutine(loadTextureFromMemory());
        /*
        TextureAddedEvent += (TextureData t) =>
        {
            //Debug.Log("Add " + t);
        };
        TextureRemovedEvent += (TextureData t) =>
        {
            //Debug.Log("Remove " + t);
        };*/
    }
    void OnDestroy()
    {
        isThreadRunning = false;
        while (loadingThread.IsAlive)
        {
            Thread.Sleep(1);
        }
        loadingThread.Abort();
    }
    IEnumerator loadTextureFromMemory()
    {
        while (true)
        {
            if (ready_queue.Count > 0)
            {
                TextureData newData = null;
                lock (ready_queue)
                {
                    newData = ready_queue.Dequeue();
                }
                
                if(newData.createTextureFromMemory())
                {
                    yield return null;
                    texturePool.Enqueue(newData);
                    TextureAddedEvent.Invoke(newData);

                    if (clearAfterLoaded)
                    {
                        File.Delete(newData.filePath);
                    }


                    yield return null;
                    while (texturePool.Count > maxNum)
                    {
                        TextureData removalData = texturePool.Dequeue();
                        TextureRemovedEvent.Invoke(removalData);
                        removalData.destroyTexture();
                    }

                    texListForDebugging = new Texture2D[texturePool.Count];
                    int i = 0;
                    foreach(TextureData data in texturePool)
                    {
                        texListForDebugging[i++] = data.texture;
                    }                    
                }
            }
            yield return new WaitForSeconds(photoCheckingPeriod);
        }
    }
    private List<string> find_last_files()
    {
        List<string> result = new List<string>();
        string[] dir_list = Directory.GetDirectories(rootPath);
        Array.Sort<string>(dir_list);
        bool ok = false;
        for (int i = dir_list.Length - 1; i >= 0; --i)
        {
            var png_files = Directory.GetFiles(dir_list[i], "*.png");
            var jpg_files = Directory.GetFiles(dir_list[i], "*.jpg");
            var files_list = new List<string>();
            files_list.AddRange(png_files);
            files_list.AddRange(jpg_files);
            string[] file_list = files_list.ToArray();

            //string[] file_list = Directory.GetFiles(dir_list[i], "*.png");
            Array.Sort<string>(file_list);

            for (int j = file_list.Length - 1; j >= 0; --j)
            {
                result.Add(file_list[j]);
                if (ok = (result.Count >= maxNum))
                    break;
            }
            if (ok)
                break;
        }
        result.Reverse();
        return result;
    }
    private void onFileChanged(object sender, FileSystemEventArgs e)
    {        
        TextureData data = new TextureData(e.FullPath);
        lock (waiting_queue)
        {
            waiting_queue.Enqueue(data);
        }
        Debug.Log("onFileChanged()  "+ e.FullPath);
    }
   
    private void resizing_to_memory_service()
    {
        while (isThreadRunning)
        {
            if (waiting_queue.Count > 0)
            {
                TextureData data = null;
                lock (waiting_queue)
                {
                    data = waiting_queue.Dequeue();
                }
                string str = data.ToString();

                if (data.loadToMemory(photoSize))
                {
                    lock (ready_queue)
                    {
                        ready_queue.Enqueue(data);
                    }
                    str = "[ OK ]" + str;
                }
                else
                {
                    str = "[FAIL]" + str;
                }
                Debug.Log(str);
            }
            else
            {
                Thread.Sleep((int)(photoCheckingPeriod * 1000));
            }
        }
    }

}