package mp4parser;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;

// For parsing frames from an mp4 file.
public class mp4parser {

	public static void main(String[] args) throws IOException {

		// Holds the size of the box in bytes
		long size;
		// Temporary holder for bit shifting
		long size2;
		// Holds the type of the box as ASCII characters
		long type = 0;
		// Temporary holder for bit shifting
		long type2;
		// Signifies end of file when -1
		int eof = 0;
		// Signifies 64 bit size when 1
		int largesize = 0;
		// Counter for reading whole box
		int j = 0;
		// Input stream for file
		FileInputStream fis = new FileInputStream("C:\\Test\\57.mp4");
		// Array for the media data
		ArrayList<Integer> mdat = new ArrayList<Integer>();

		// Read through whole file
		while(eof != -1) {

			// Read size
			size = (fis.read() << 24);
			size2 = size;
			size = ((size2)) | (fis.read() << 16 );
			size2 = size;
			size = ((size2)) | (fis.read() << 8 );
			size2 = size;
			size = ((size2)) | (fis.read() );
			j+=4;

			// Print size
			System.out.println(String.format("%d", size));

			// Means there is an 8 byte size
			if (size == 1) {
				largesize = 1;
			}
			// Means the box goes to the end of the file
			// TODO Top level boxes don't appear to follow this logic
			else if (size == 0) {
				eof = -1;
			}
			// Means size is accurate
			else {
				largesize = 0;
			}

			// Read in the 8 byte size
			if(largesize == 1) {
				size = (fis.read() << 56);
				size2 = size;
				size = ((size2)) | (fis.read() << 48 );
				size2 = size;
				size = ((size2)) | (fis.read() << 40 );
				size2 = size;
				size = ((size2)) | (fis.read() << 32);
				size2 = size;
				size = size | (fis.read() << 24);
				size2 = size;
				size = ((size2)) | (fis.read() << 16 );
				size2 = size;
				size = ((size2)) | (fis.read() << 8 );
				size2 = size;
				size = ((size2)) | (fis.read() );
				j+=8;
				// Print size
				System.out.println(String.format("%d", size));
			}

			// Read through the whole box
			while (j < (size)) {

				// Read type
				if(j == 4) {
					type = fis.read();
					type2 = type;
					type = (type2) | (fis.read() << 8);
					type2 = type;
					type = (type2) | (fis.read() << 16);
					type2 = type;
					type = (type2) | (fis.read() << 24);
					j+=4;
					System.out.println(toASCII(type));
				}
				// Read and print file type info
				else if(toASCII((bytesToLong("ftyp".getBytes()))).equals(toASCII(type))) {
					// Read through whole box
					while (j < (size)) {
						if(j == 12) {
							type = (fis.read() << 24);
							type2 = type;
							type = ((type2)) | (fis.read() << 16 );
							type2 = type;
							type = ((type2)) | (fis.read() << 8 );
							type2 = type;
							type = ((type2)) | (fis.read() );
							j+=4;
							// Print size
							System.out.println(String.format("%d", size));
						} else {
						type = fis.read();
						type2 = type;
						type = (type2) | (fis.read() << 8);
						type2 = type;
						type = (type2) | (fis.read() << 16);
						type2 = type;
						type = (type2) | (fis.read() << 24);
						j+=4;
						// Print file type info
						System.out.println(toASCII(type));
						}
					}
				}
				// Skip free space
				else if(toASCII((bytesToLong("free".getBytes()))).equals(toASCII(type))) {
					fis.read();
				}
				// Read media data
				else if(toASCII((bytesToLong("mdat".getBytes()))).equals(toASCII(type))) {
				}
				// Read movie data
				else if(toASCII((bytesToLong("moov".getBytes()))).equals(toASCII(type))) {

				}
			}
			// Reset to read next box
			j = 0;
		}
	}

	// Converts long into ASCII string
	private static String toASCII(long type) {
		// Types are 4 bytes long
		int length = 4;
		// Counter for converting each character
		int i = 0;
		// For building 4 character string
		StringBuilder builder = new StringBuilder(length);
		// Add all characters to string
		while (i < length) {
			builder.append((char) ((type >> (8 * i)) & 0xFF));
			i++;
		}
		return builder.toString();
	}

	public static long bytesToLong(byte[] b) {
	    long type = 0;
	    long type2;
	    int i = 0;
	    while(i < 4){
	    	type2 = type;
			type = (type2) | (b[i] << (8*i));
			i++;
	    }
	    return type;
	}
}