package zero1hd.wavedecoder;

import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.InvalidParameterException;

import com.badlogic.gdx.Gdx;

public class WavInfo {
	private int channels;
	private double sampleRate;
	private int dataSize;
	private int byteRate;
	private FileInputStream audioFile;
	private DataInputStream readStream;
	private String fileName;
	
	public WavInfo(File file) throws InvalidParameterException {
		try {
			fileName = file.getName();
			audioFile = new FileInputStream(file);
			initDataStream();
			getHeaderInfo();
			closeStreams();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	protected void getHeaderInfo() throws IOException {
		if (!readBytesToString(4).equals("RIFF")) { //4 for RIFF tag
			throw new InvalidParameterException("RIFF tag not found in header.");
		}
		dataSize = littleEndianIntBytes(); //4 for Chunk size

		if (!readBytesToString(4).equals("WAVE")) { //4 for WAVE tag
			throw new InvalidParameterException("WAVE format tag not found.");
		}
		
		if (!readBytesToString(4).equals("fmt ")) { //4 for 'fmt '
			throw new InvalidParameterException("fmt header not found.");
		}
		
		if (littleEndianIntBytes() != 16) { //subchunk1size (4 bytes)
			throw new InvalidParameterException("Data not pcm?");
		}
		
		if (readStream.readByte() != 1) { //1 pcm
			throw new InvalidParameterException("Data not pcm?");
		}
		readStream.skip(1); //1

		channels = readStream.readByte(); //1  channel count
		readStream.skip(1); //1 

		sampleRate = littleEndianIntBytes(); //4 sample rate
		
		byteRate = littleEndianIntBytes(); //4
		
		readStream.skip(4); //38
		
//		System.out.println(readBytesToString(4).equals("data"));
		
		if (!readBytesToString(4).equals("data")) { // 4
			Gdx.app.debug("Audio", "sample rate: " + sampleRate);
			Gdx.app.debug("Audio", "Data chunk size: " + dataSize);
			Gdx.app.debug("Audio", "Channel count: " + channels);
			
			throw new InvalidParameterException("initial data section tag not found on wav: " + fileName);
		}
		
		readStream.skip(4);
	}
	
	protected void initDataStream() {
		readStream = new DataInputStream(audioFile);
	}
	
	protected void closeStreams() throws IOException {
		readStream.close();
		audioFile.close();
	}
	
	private String readBytesToString(int bytesToRead) throws IOException {
		byte byteString[] = new byte[bytesToRead];
		readStream.read(byteString);
		return new String(byteString);
	}

	private int littleEndianIntBytes() throws IOException {
		int data = readStream.readInt();
		return Integer.reverseBytes(data);
	}
	
	protected short readLittleEndianShort() throws IOException {
		short data = readStream.readShort();
		return Short.reverseBytes(data);
	}
	
	protected DataInputStream getReadStream() {
		return readStream;
	}
	
	public int getChannels() {
		return channels;
	}
	
	public int getByteRate() {
		return byteRate;
	}
	
	public int getDataSize() {
		return dataSize;
	}
	
	public double getSampleRate() {
		return sampleRate;
	}
	
	public long getDurationInSeconds() {
		return (long) (dataSize/byteRate);
	}
}