package org.fox.ttrss.offline;

import java.lang.reflect.Type;
import java.util.HashMap;
import java.util.List;

import org.fox.ttrss.ApiRequest;
import org.fox.ttrss.MainActivity;
import org.fox.ttrss.R;
import org.fox.ttrss.R.drawable;
import org.fox.ttrss.R.string;
import org.fox.ttrss.types.Article;
import org.fox.ttrss.types.Feed;
import org.fox.ttrss.types.FeedCategory;
import org.fox.ttrss.util.DatabaseHelper;
import org.fox.ttrss.util.ImageCacheService;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Element;
import org.jsoup.select.Elements;

import android.app.ActivityManager;
import android.app.ActivityManager.RunningServiceInfo;
import android.app.IntentService;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteStatement;
import android.os.Binder;
import android.os.Bundle;
import android.os.Environment;
import android.os.IBinder;
import android.preference.PreferenceManager;
import android.provider.BaseColumns;
import android.util.Log;

import com.google.gson.Gson;
import com.google.gson.JsonElement;
import com.google.gson.reflect.TypeToken;

public class OfflineDownloadService extends Service {

	private final String TAG = this.getClass().getSimpleName();

	public static final int NOTIFY_DOWNLOADING = 1;
	public static final String INTENT_ACTION_SUCCESS = "org.fox.ttrss.intent.action.DownloadComplete";
	public static final String INTENT_ACTION_CANCEL = "org.fox.ttrss.intent.action.Cancel";

	private static final int OFFLINE_SYNC_SEQ = 40;
	private static final int OFFLINE_SYNC_MAX = 500;
	
	private SQLiteDatabase m_writableDb;
	private SQLiteDatabase m_readableDb;
	private int m_articleOffset = 0;
	private String m_sessionId;
	private NotificationManager m_nmgr;
	
	private boolean m_downloadInProgress = false;
	private boolean m_downloadImages = false;
	private int m_syncMax;
	private SharedPreferences m_prefs;
	private boolean m_canProceed = true;
	
	private final IBinder m_binder = new LocalBinder();
	
    public class LocalBinder extends Binder {
        OfflineDownloadService getService() {
            return OfflineDownloadService.this;
        }
    }
	
    @Override
    public IBinder onBind(Intent intent) {
        return m_binder;
    }
    
	@Override
	public void onCreate() {
		super.onCreate();
		m_nmgr = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
		m_prefs = PreferenceManager
						.getDefaultSharedPreferences(getApplicationContext());
 
		m_downloadImages = m_prefs.getBoolean("offline_image_cache_enabled", false);
		m_syncMax = m_prefs.getInt("offline_sync_max", OFFLINE_SYNC_MAX);
		
		initDatabase();
	}
	
	private void updateNotification(String msg) {
		Notification notification = new Notification(R.drawable.icon, 
				getString(R.string.notify_downloading_title), System.currentTimeMillis());
		
		Intent intent = new Intent(this, MainActivity.class);
		intent.setAction(INTENT_ACTION_CANCEL);
		
		PendingIntent contentIntent = PendingIntent.getActivity(this, 0,
                intent, 0);
		
		notification.flags |= Notification.FLAG_ONGOING_EVENT;
		notification.flags |= Notification.FLAG_ONLY_ALERT_ONCE;
		
        notification.setLatestEventInfo(this, getString(R.string.notify_downloading_title), msg, contentIntent);
                       
        m_nmgr.notify(NOTIFY_DOWNLOADING, notification);
	}

	private void updateNotification(int msgResId) {
		updateNotification(getString(msgResId));
	}

	private void downloadFailed() {
        m_readableDb.close();
        m_writableDb.close();

        m_nmgr.cancel(NOTIFY_DOWNLOADING);
        
        // TODO send notification to activity?
        
        m_downloadInProgress = false;
        stopSelf();
	}
	
	private boolean isCacheServiceRunning() {
	    ActivityManager manager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);
	    for (RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
	        if ("org.fox.ttrss.ImageCacheService".equals(service.service.getClassName())) {
	            return true;
	        }
	    }
	    return false;
	}
	
	public void downloadComplete() {
		m_downloadInProgress = false;
		
        // if cache service is running, it will send a finished intent on its own
        if (!isCacheServiceRunning()) {
            m_nmgr.cancel(NOTIFY_DOWNLOADING);

			Intent intent = new Intent();
			intent.setAction(INTENT_ACTION_SUCCESS);
			intent.addCategory(Intent.CATEGORY_DEFAULT);
			sendBroadcast(intent);
        } else {
        	updateNotification(getString(R.string.notify_downloading_images, 0));
        }
        
        m_readableDb.close();
        m_writableDb.close();
        
        stopSelf();
	}
	
	private void initDatabase() {
		DatabaseHelper dh = new DatabaseHelper(getApplicationContext());
		m_writableDb = dh.getWritableDatabase();
		m_readableDb = dh.getReadableDatabase();
	}
	
	private synchronized SQLiteDatabase getReadableDb() {
		return m_readableDb;
	}
	
	private synchronized SQLiteDatabase getWritableDb() {
		return m_writableDb;
	}
	
	@SuppressWarnings("unchecked")
	private void downloadArticles() {
		Log.d(TAG, "offline: downloading articles... offset=" + m_articleOffset);
		
		updateNotification(getString(R.string.notify_downloading_articles, m_articleOffset));
		
		OfflineArticlesRequest req = new OfflineArticlesRequest(this);
		
		@SuppressWarnings("serial")
		HashMap<String,String> map = new HashMap<String,String>() {
			{
				put("op", "getHeadlines");
				put("sid", m_sessionId);
				put("feed_id", "-4");
				put("view_mode", "unread");
				put("show_content", "true");
				put("skip", String.valueOf(m_articleOffset));
				put("limit", String.valueOf(OFFLINE_SYNC_SEQ));
			}			 
		};
		
		req.execute(map);
	}
	
	private void downloadFeeds() {

		updateNotification(R.string.notify_downloading_feeds);
		
		getWritableDb().execSQL("DELETE FROM feeds;");
		
		ApiRequest req = new ApiRequest(getApplicationContext()) {
			@Override
			protected void onPostExecute(JsonElement content) {
				if (content != null) {
					
					try {
						Type listType = new TypeToken<List<Feed>>() {}.getType();
						List<Feed> feeds = new Gson().fromJson(content, listType);
						
						SQLiteStatement stmtInsert = getWritableDb().compileStatement("INSERT INTO feeds " +
								"("+BaseColumns._ID+", title, feed_url, has_icon, cat_id) " +
						"VALUES (?, ?, ?, ?, ?);");
						
						for (Feed feed : feeds) {
							stmtInsert.bindLong(1, feed.id);
							stmtInsert.bindString(2, feed.title);
							stmtInsert.bindString(3, feed.feed_url);
							stmtInsert.bindLong(4, feed.has_icon ? 1 : 0);
							stmtInsert.bindLong(5, feed.cat_id);

							stmtInsert.execute();
						}

						stmtInsert.close();

						Log.d(TAG, "offline: done downloading feeds");
						
						m_articleOffset = 0;
						
						getWritableDb().execSQL("DELETE FROM articles;");
						
						if (m_canProceed) { 
							downloadArticles();
						} else {
							downloadFailed();
						}
					} catch (Exception e) {
						e.printStackTrace();
						updateNotification(R.string.offline_switch_error);
						downloadFailed();
					}
				
				} else {
					updateNotification(getErrorMessage());
					downloadFailed();
				}
			}

		};
		
		@SuppressWarnings("serial")
		HashMap<String,String> map = new HashMap<String,String>() {
			{
				put("op", "getFeeds");
				put("sid", m_sessionId);
				put("cat_id", "-3");
				put("unread_only", "true");
			}			 
		};
		
		req.execute(map);
	}

	private void downloadCategories() {

		updateNotification(R.string.notify_downloading_feeds);
		
		getWritableDb().execSQL("DELETE FROM categories;");
		
		ApiRequest req = new ApiRequest(getApplicationContext()) {
			@Override
			protected void onPostExecute(JsonElement content) {
				if (content != null) {
					
					try {
						Type listType = new TypeToken<List<FeedCategory>>() {}.getType();
						List<FeedCategory> cats = new Gson().fromJson(content, listType);
						
						SQLiteStatement stmtInsert = getWritableDb().compileStatement("INSERT INTO categories " +
								"("+BaseColumns._ID+", title) " +
						"VALUES (?, ?);");
						
						for (FeedCategory cat : cats) {
							stmtInsert.bindLong(1, cat.id);
							stmtInsert.bindString(2, cat.title);

							stmtInsert.execute();
						}

						stmtInsert.close();

						Log.d(TAG, "offline: done downloading categories");
						
						if (m_canProceed) { 
							downloadFeeds();
						} else {
							downloadFailed();
						}
					} catch (Exception e) {
						e.printStackTrace();
						updateNotification(R.string.offline_switch_error);
						downloadFailed();
					}
				
				} else {
					updateNotification(getErrorMessage());
					downloadFailed();
				}
			}

		};
		
		@SuppressWarnings("serial")
		HashMap<String,String> map = new HashMap<String,String>() {
			{
				put("op", "getCategories");
				put("sid", m_sessionId);
				//put("cat_id", "-3");
				put("unread_only", "true");
			}			 
		};
		
		req.execute(map);
	}

	
	@Override
	public void onDestroy() {
		super.onDestroy();
		m_nmgr.cancel(NOTIFY_DOWNLOADING);

		m_canProceed = false;
		Log.d(TAG, "onDestroy");
		
		//m_readableDb.close();
		//m_writableDb.close();
	}

	public class OfflineArticlesRequest extends ApiRequest {
		public OfflineArticlesRequest(Context context) {
			super(context);
		}

		@Override
		protected void onPostExecute(JsonElement content) {
			if (content != null) {
				try {
					Type listType = new TypeToken<List<Article>>() {}.getType();
					List<Article> articles = new Gson().fromJson(content, listType);
	
					SQLiteStatement stmtInsert = getWritableDb().compileStatement("INSERT INTO articles " +
							"("+BaseColumns._ID+", unread, marked, published, updated, is_updated, title, link, feed_id, tags, content) " +
					"VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);");
	
					for (Article article : articles) {
	
						String tagsString = "";
						
						for (String t : article.tags) {
							tagsString += t + ", ";
						}
						
						tagsString = tagsString.replaceAll(", $", "");
						
						stmtInsert.bindLong(1, article.id);
						stmtInsert.bindLong(2, article.unread ? 1 : 0);
						stmtInsert.bindLong(3, article.marked ? 1 : 0);
						stmtInsert.bindLong(4, article.published ? 1 : 0);
						stmtInsert.bindLong(5, article.updated);
						stmtInsert.bindLong(6, article.is_updated ? 1 : 0);
						stmtInsert.bindString(7, article.title);
						stmtInsert.bindString(8, article.link);
						stmtInsert.bindLong(9, article.feed_id);
						stmtInsert.bindString(10, tagsString); // comma-separated tags
						stmtInsert.bindString(11, article.content);
						
						if (m_downloadImages) {
							Document doc = Jsoup.parse(article.content);
							
							if (doc != null) {
								Elements images = doc.select("img");
								
								for (Element img : images) {
									String url = img.attr("src");
									
									if (url.indexOf("://") != -1) {
										if (!ImageCacheService.isUrlCached(url)) {										
											Intent intent = new Intent(OfflineDownloadService.this,
													ImageCacheService.class);
										
											intent.putExtra("url", url);
											startService(intent);
										}
									}
								}
							}
						}
						
						try {
							stmtInsert.execute();
						} catch (Exception e) {
							e.printStackTrace();
						}
	
					}

					stmtInsert.close();

					//m_canGetMoreArticles = articles.size() == 30;
					m_articleOffset += articles.size();
	
					Log.d(TAG, "offline: received " + articles.size() + " articles; canProc=" + m_canProceed);
					
					if (m_canProceed) {
						if (articles.size() == OFFLINE_SYNC_SEQ && m_articleOffset < m_syncMax) {
							downloadArticles();
						} else {
							downloadComplete();
						}
					} else {
						downloadFailed();
					}
					
					return;
					
				} catch (Exception e) {
					updateNotification(R.string.offline_switch_error);
					Log.d(TAG, "offline: failed: exception when loading articles");
					e.printStackTrace();
					downloadFailed();
				}
				
			} else {
				Log.d(TAG, "offline: failed: " + getErrorMessage());
				updateNotification(getErrorMessage());
				downloadFailed();
			}
		}
	}

	@Override
	public void onStart(Intent intent, int startId) {
		m_sessionId = intent.getStringExtra("sessionId");
		
		if (!m_downloadInProgress) {
			if (m_downloadImages) ImageCacheService.cleanupCache(false);
			
			updateNotification(R.string.notify_downloading_init);
			m_downloadInProgress = true;
		
			downloadCategories();
		}
	}
}