package com.anyun.exam.lib;

import android.app.DownloadManager;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.database.Cursor;
import android.net.Uri;
import android.os.Environment;
import android.util.Log;

import java.io.File;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class DownloadManagerUtil {
    public static final String TAG = DownloadManagerUtil.class.getCanonicalName();
    private Context context;
    private DownloadManager downloadManager = null;
    private static DownloadManagerUtil instance = null;
    private DownloadManagerCallback callback = null;

    class DownloadItem {
        long id;
        String fileName;
        String url;

        public DownloadItem (long id, String fileName, String url) {
            this.id = id;
            this.fileName = fileName;
            this.url = url;
        }
    }

    public static DownloadManagerUtil getInstance(Context context) {
        if (instance == null) {
            synchronized (DownloadManagerUtil.class) {
                if (instance == null) {
                    instance = new DownloadManagerUtil(context);
                }
            }
        }
        return instance;
    }

    private DownloadManagerUtil(Context context) {
        this.context = context;
        if (downloadManager == null) {
            downloadManager = (DownloadManager) context.getSystemService(Context.DOWNLOAD_SERVICE);
        }

        RegisterDownload();
    }

    public void RegisterDownload() {
        IntentFilter filter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
        context.registerReceiver(mReceiver, filter);
    }

    public void SetDMCallback(final DownloadManagerCallback cb) {
        callback = cb;
    }

    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (action.equals(DownloadManager.ACTION_DOWNLOAD_COMPLETE)) {
                long id = intent.getLongExtra(DownloadManager.EXTRA_DOWNLOAD_ID, -1);
                DownloadManager.Query query = new DownloadManager.Query();
                Cursor cursor = downloadManager.query(query);

                while (cursor != null && cursor.moveToFirst()) {
                    int cid = cursor.getInt( cursor.getColumnIndex(DownloadManager.COLUMN_ID) );
                    int status = cursor.getInt( cursor.getColumnIndex(DownloadManager.COLUMN_STATUS) );

                    if (id == cid && status == DownloadManager.STATUS_SUCCESSFUL) {
                        String title = cursor.getString( cursor.getColumnIndex(DownloadManager.COLUMN_TITLE) );
                        String fileUri = cursor.getString(cursor.getColumnIndexOrThrow(DownloadManager.COLUMN_LOCAL_URI));
                        Log.d(TAG, "下载完毕 " + fileUri);

                        if (callback != null) {
                            callback.DownloadComplete(title, Uri.parse(fileUri).getPath());
                        }
                        break;
                    }
                }
            }
        }
    };

    public void DownloadFile(String url, String saveFileName, String title, String desc) {
        Log.d(TAG, "下载文件 " + url);
        // 跳过已经在下载的
        if (CheckAndClear(title) == 1) {
            Log.d(TAG, "跳过已经在下载的 " + title);
            return;
        }

        DownloadManager.Request request = new DownloadManager.Request(Uri.parse(url));

        File file = new File(context.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS), saveFileName);
        request.setDestinationUri(Uri.fromFile(file));

        request.setTitle(title);
        request.setDescription(desc);

        if (downloadManager != null) {
            long idx = downloadManager.enqueue(request);
            Log.d(TAG, "新建下载任务 id = " + idx);
        }
    }

    public int CheckAndClear(String title) {
        DownloadManager.Query query = new DownloadManager.Query();
        Cursor cursor = downloadManager.query(query);
        while (cursor != null && cursor.moveToNext()) {
            String theTitle = cursor.getString(cursor.getColumnIndex(DownloadManager.COLUMN_TITLE));
            if (theTitle.equals(title)) {
                int status = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));
                long id = cursor.getLong(cursor.getColumnIndex(DownloadManager.COLUMN_ID));
                Log.d(TAG, "当前该文件下载状态 " + status);

                if (status == DownloadManager.STATUS_FAILED || status == DownloadManager.STATUS_SUCCESSFUL) {
                    downloadManager.remove(id);
                    return 0;
                } else if (status != DownloadManager.STATUS_RUNNING) {
                    // 如果是多次处于暂停\挂起状态，还是删除
                    downloadManager.remove(id);
                    return 0;
                }
                return 1;
            }
        }
        return 0;
    }

    public int CheckDownloadStatus(int id) {
        DownloadManager.Query query = new DownloadManager.Query();
        Cursor cursor = downloadManager.query(query);

        while (cursor != null && cursor.moveToNext()) {
            int status = cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_STATUS));

            if (id == cursor.getInt(cursor.getColumnIndex(DownloadManager.COLUMN_ID))) {
                return status;
            }
        }
        return -1;
    }
}