package helpers;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import javax.imageio.ImageIO;

import models.Image;
import play.Logger;

public class FileHelper {
	public final static String FILE_DIRECTORY = "data" + File.separator + "pictures";
	public final static String THUMBS_DIRECTORY = "data" + File.separator + "thumbnails";
	public final static String REFS_DIRECTORY = "data" + File.separator + "refs";
	public final static String SOBEL_DIRECTORY = "data" + File.separator + "sobel";
	public final static String COLORS_DIRECTORY = "data" + File.separator + "colors";
	private FileHelper() {

	}

	public static Image save(final String filename, final File file, final String contentType) {
		checkFolders();
		String checksum = null;
		try {
			checksum = getChecksum(MessageDigest.getInstance("SHA-256"), file);
		} catch (NoSuchAlgorithmException e) {
			Logger.error(e.getLocalizedMessage(), e);
		} catch (IOException e) {
			Logger.error(e.getLocalizedMessage(), e);
		}
		if (checksum != null && file != null && contentType.contains("image")) {
			String ext = contentType.replace("image/", "").trim();
			File newFile = new File(FILE_DIRECTORY + File.separator + checksum + "." + ext);
			try {
				Files.copy(file.toPath(), newFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
			} catch (IOException e) {
				Logger.error(e.getLocalizedMessage(), e);
			}
			Image img = Image.findOrCreate(checksum);
			img.extension = ext;
			img.imagePath =  newFile.getAbsolutePath();
			img.name = filename;
			File thumbnail = ImageHelper.thumbnail(img);
			if(thumbnail != null) {
				img.thumbnailPath = thumbnail.getAbsolutePath();
			}
			File sobel = ImageHelper.edgeImage(img);
			if(sobel != null) {
				img.sobelImagePath = sobel.getAbsolutePath();
			}
			try {
				Set<Integer> dims = getDims(newFile);
				if(dims.size() == 2) {
					Iterator<Integer> dimIter = dims.iterator();
					img.imageHeight = dimIter.next();
					img.imageWidth = dimIter.next();
				}
				dims = getDims(thumbnail);
				if(dims.size() == 2) {
					Iterator<Integer> dimIter = dims.iterator();
					img.thumbnailHeight = dimIter.next();
					img.thumbnailWidth = dimIter.next();
				}
				File refImage = ImageHelper.referenceImage(img);
				if(refImage != null) {
					img.refImagePath = refImage.getAbsolutePath();	
					Color[][] signature = ImageHelper.createSignature(img);
					img.setSignature(signature);
				}
			} catch (IOException e) {
				Logger.error(e.getLocalizedMessage(), e);
			}
			img.save();
			ImageHelper.countColors(img);
			return img;
		}
		return null;
	}

	private static Set<Integer> getDims(final File file) throws IOException {
		Set<Integer> dims = new HashSet<>();
		if(file == null || !file.exists()) {
			return dims;
		}
		BufferedImage bimg = ImageIO.read(file);
		dims.add(bimg.getHeight());
		dims.add(bimg.getWidth());
		return dims;
	}
	
	private static String getChecksum(final MessageDigest digest, final File file) throws IOException {
		// Get file input stream for reading the file content
		FileInputStream fis = new FileInputStream(file);

		// Create byte array to read data in chunks
		byte[] byteArray = new byte[1024];
		int bytesCount = 0;

		// Read file data and update in message digest
		while ((bytesCount = fis.read(byteArray)) != -1) {
			digest.update(byteArray, 0, bytesCount);
		}

		// close the stream; We don't need it now.
		fis.close();

		// Get the hash's bytes
		byte[] bytes = digest.digest();

		// This bytes[] has bytes in decimal format;
		// Convert it to hexadecimal format
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < bytes.length; i++) {
			sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
		}

		// return complete hash
		return sb.toString();
	}

	private static void checkFolders() {
		final String[] folders = { FILE_DIRECTORY, THUMBS_DIRECTORY, COLORS_DIRECTORY, REFS_DIRECTORY, SOBEL_DIRECTORY };
		for (String folder : folders) {
			File f = new File(folder);
			if (!f.exists()) {
				f.mkdirs();
			}
		}
	}
}