package com.demo.loading;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.Comparator;
import org.apache.commons.lang.StringUtils;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;
import android.os.StatFs;

public class ImageFileCache {
	private static final String WHOLESALE_CONV = ".cach";
	/** 過期時間3天 **/
	private static final long mTimeDiff = 3 * 24 * 60 * 60 * 1000;
	private String cardType = null;

	public ImageFileCache() {
		// 清理檔案快取
		removeCache(getDirectory());
	}

	/**
	 * 通過URL獲取圖片
	 * 
	 * @param url
	 * @return Bitmap
	 */
	public Bitmap getImage(final String url) {
		final String path = getDirectory() + "/" + convertUrlToFileName(url);
		File file = new File(path);
		if (file.exists()) {
			Bitmap bmp = BitmapFactory.decodeFile(path);
			if (bmp == null) {
				file.delete();
			} else {
				updateFileTime(path);
				return bmp;
			}
		}
		return null;
	}

	/**
	 * 判斷圖片是否存在
	 * 
	 * @param url
	 */
	public Boolean exists(String url) {
		String path = getDirectory() + "/" + convertUrlToFileName(url);
		File file = new File(path);
		return file.exists();
	}

	/**
	 * 刪除快取檔案
	 * 
	 * @param url
	 */
	public void deleteFile(String url) {
		try {
			if (StringUtils.isNotBlank(url)) {
				final String path = getDirectory() + "/"
						+ convertUrlToFileName(url);
				File file = new File(path);
				if (file != null && file.exists()) {
					file.delete();
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/*** 快取空間大小 ****/
	private static final int FREE_SD_SPACE_NEEDED_TO_CACHE = 10;

	/**
	 * 儲存圖片到SD卡
	 * 
	 * @param bm
	 * @param url
	 */
	public void saveBmpToSd(Bitmap bm, String url) {
		if (bm == null) {
			// 需要儲存的是一個空值
			return;
		}

		// 判斷sdcard上的空間
		if (FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
			// SD空間不足
			return;
		}

		String filename = convertUrlToFileName(url);
		String dir = getDirectory();
		File fileDir = new File(dir);
		if (!fileDir.exists()) {
			fileDir.mkdirs();
		}
		File file = new File(dir + "/" + filename);
		try {
			file.createNewFile();
			OutputStream outStream = new FileOutputStream(file);
			bm.compress(Bitmap.CompressFormat.PNG, 10, outStream);
			outStream.flush();
			outStream.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 儲存圖片到SD卡
	 * 
	 * @param bData
	 * @param url
	 */
	public void saveBmpToSd(byte[] bData, String url, String cardType) {
		this.cardType = cardType;
		if (bData == null) {
			// 需要儲存的是一個空值
			return;
		}

		// 判斷sdcard上的空間
		if (FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
			// SD空間不足
			return;
		}

		String filename = convertUrlToFileName(url);
		String dir = getDirectory();
		File fileDir = new File(dir);
		if (!fileDir.exists()) {
			fileDir.mkdirs();
		}
		File file = new File(dir + "/" + filename);
		FileOutputStream fos = null;
		try {
			file.createNewFile();
			fos = new FileOutputStream(file);
			fos.write(bData);
		} catch (Exception e) {
			file.delete();
			e.printStackTrace();
		} finally {
			try {
				fos.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

	private static final int CACHE_SIZE = 10;

	/**
	 * 清理快取 計算儲存目錄下的檔案大小，
	 * 當檔案總大小大於規定的CACHE_SIZE或者sdcard剩餘空間小於FREE_SD_SPACE_NEEDED_TO_CACHE的規定
	 * 那麼刪除40%最近沒有被使用的檔案
	 * 
	 * @param dirPath
	 */
	private boolean removeCache(String dirPath) {
		File dir = new File(dirPath);
		File[] files = dir.listFiles();
		if (files == null) {
			return true;
		}

		if (!android.os.Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED)) {
			return false;
		}
		int dirSize = 0;

		for (int i = 0; i < files.length; i++) {
			if (files[i].getName().contains(WHOLESALE_CONV)) {
				dirSize += files[i].length();
			}
		}

		if (dirSize > CACHE_SIZE * MB
				|| FREE_SD_SPACE_NEEDED_TO_CACHE > freeSpaceOnSd()) {
			int removeFactor = (int) ((0.4 * files.length) + 1);
			Arrays.sort(files, new FileLastModifSort());
			for (int i = 0; i < removeFactor; i++) {
				if (files[i].getName().contains(WHOLESALE_CONV)) {
					files[i].delete();
				}
			}
		}

		if (freeSpaceOnSd() <= CACHE_SIZE) {
			return false;
		}
		return true;
	}

	/**
	 * 根據檔案的最後修改時間進行排序*
	 */
	private class FileLastModifSort implements Comparator<File> {
		public int compare(File arg0, File arg1) {
			if (arg0.lastModified() > arg1.lastModified()) {
				return 1;
			} else if (arg0.lastModified() == arg1.lastModified()) {
				return 0;
			} else {
				return -1;
			}
		}
	}

	/**
	 * 刪除過期檔案
	 * 
	 * @param dirPath
	 * @param filename
	 */
	public void removeExpiredCache(String dirPath, String filename) {
		File file = new File(dirPath, filename);
		if (System.currentTimeMillis() - file.lastModified() > mTimeDiff) {
			file.delete();
		}
	}

	/**
	 * 修改檔案的最後修改時間 這裡需要考慮,是否將使用的圖片日期改為當前日期
	 * 
	 * @param path
	 */
	public void updateFileTime(String path) {
		File file = new File(path);
		long newModifiedTime = System.currentTimeMillis();
		file.setLastModified(newModifiedTime);
	}

	/**
	 * 計算sdcard上的剩餘空間
	 * 
	 * @return
	 */
	private int MB = 1024 * 1024;

	/**
	 * 計算sdcard上的剩餘空間
	 * 
	 * @return
	 */
	private int freeSpaceOnSd() {
		StatFs stat = new StatFs(Environment.getExternalStorageDirectory()
				.getPath());
		double sdFreeMB = ((double) stat.getAvailableBlocks() * (double) stat
				.getBlockSize()) / MB;
		return (int) sdFreeMB;
	}

	/** 將url轉成檔名 **/
	private String convertUrlToFileName(String url) {
		// String[] strs = url.split("/");
		String fileName = "";
		if (url.contains(".jpg"))
			fileName = cardType + ".jpg";// + WHOLESALE_CONV;
		else if (url.contains(".png"))
			fileName = cardType + ".png";
		return fileName.replaceAll("[?]", "_");
	}

	/** 獲得快取目錄 **/
	private String getDirectory() {
		String dir = getSDPath() + "/" + ConstantUtils.IMAGECACHDIR;
		String substr = dir.substring(0, 4);
		if (substr.equals("/mnt")) {
			dir = dir.replace("/mnt", "");
		}
		return dir;
	}

	/**** 取SD卡路徑不帶/ ****/
	public String getSDPath() {
		File sdDir = null;
		boolean sdCardExist = Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED); // 判斷sd卡是否存在
		if (sdCardExist) {
			sdDir = Environment.getExternalStorageDirectory();// 獲取跟目錄
		}

		if (sdDir != null) {
			return sdDir.toString();
		} else {
			return "";
		}
	}
	/**
	 * http://www.cnblogs.com/TerryBlog/archive/2012/01/08/2316482.html
	 */
}