package goblincave.gitea.nes;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import org.apache.commons.io.FilenameUtils;

import io.github.jacksonbrienen.jwfd.JWindowsFileDialog;

public class AT3merge {

	public static void main(String[] args) throws IOException {
		
		String[] selection = JWindowsFileDialog.showMultiDialog(null, "Select AT3 files to merge");
		boolean[] merged = new boolean[selection.length];
				
		// identify AT3 part files: name_01.at3, name_02.at3
		for(int a = 0; a < selection.length; a++) {
			
			if(merged[a])
				continue;
			
			File fileA = new File(selection[a]);
			String filenameA = FilenameUtils.removeExtension(fileA.getName());
			String partnameA = filenameA.substring(filenameA.length() - 3);
			filenameA = filenameA.substring(0, filenameA.length() - 3);
			
			if(partnameA.equals("_01")) {
				
				for(int b = 0; b < selection.length; b++) {
	
					if(merged[b] || selection[a].equals(selection[b]))
						continue;
					
					File fileB = new File(selection[b]);
					
					String filenameB = FilenameUtils.removeExtension(fileB.getName());
					String partnameB = filenameB.substring(filenameB.length() - 3);
					filenameB = filenameB.substring(0, filenameB.length() - 3);
					
					if(filenameA.equals(filenameB) && partnameB.equals("_02")) {
						
						// MERGE parts into one file
						System.out.println("Merging " + fileA.getName() + " and " + fileB.getName());
						
						merge(fileA, fileB);
						
						merged[b] = true;
						break;
						
					}
					
				}
				
				// REMOVE suffix from processed file
				System.out.println("Renaming to " + filenameA + ".at3");
				
				if(fileA.renameTo(new File(fileA.getParent(), filenameA + ".at3")));
				else System.out.println("Failed to rename " + fileA);
				
				merged[a] = true;
				
			} else continue;
			
		}
		
		// merge matching parts into a single file
		// remove part suffixes from files
		
	}

	/**
	 * Appends fileB to the end of fileA. FileB is then deleted.
	 * 
	 * @param fileA
	 * @param fileB
	 * @throws IOException 
	 */
	private static void merge(File fileA, File fileB) throws IOException {

		try (
			FileInputStream input = new FileInputStream(fileB);
			FileOutputStream output = new FileOutputStream(fileA, true);
		) {
			// append fileB
			byte[] buffer = new byte[1024];
			int bytesRead;
			while((bytesRead = input.read(buffer)) != -1) {
				output.write(buffer, 0, bytesRead);
			}
			
		}
		
		// delete fileB
		if(fileB.delete());
		else System.out.println("Failed to delete " + fileB);
		
	}
	
}