ghast-tools/tools/src/main/java/ghast/assets/AssetsManager.java

package ghast.assets;

import ghast.GhastTools;
import lombok.experimental.UtilityClass;
import org.bukkit.plugin.Plugin;

import java.io.*;
import java.net.URL;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Scanner;

import static java.text.MessageFormat.format;

@UtilityClass
@SuppressWarnings("unused")
public class AssetsManager {

	private static final String ERROR_NOT_FOUND = "Asset \"{0}\" not found";
	private static final String ERROR_OPEN = "Error open asset \"{0}\": {1}";

	//region getAsInputStream methods
	public InputStream getAsInputStream(String resourceName, String defaultResourceName, boolean saveDefault) {
		Plugin plugin = GhastTools.getPlugin();
		InputStream inputStream;

		Path pathToResource = plugin.getDataFolder().toPath().resolve(resourceName);
		if (Files.exists(pathToResource)) {
			inputStream = openResource(pathToResource);
		} else if (defaultResourceName != null) {
			URL resourceUrl = getResourceUrl(defaultResourceName);

			if (saveDefault) {
				doSaveTo(resourceUrl, pathToResource);
				inputStream = openResource(pathToResource);
			} else {
				inputStream = openResource(resourceUrl);
			}
		} else {
			throw new AssetsException(format(ERROR_NOT_FOUND, resourceName));
		}

		return inputStream;
	}

	public InputStream getAsInputStream(String resourceName, String defaultResourceName) {
		return getAsInputStream(resourceName, defaultResourceName, true);
	}

	public InputStream getAsInputStream(String resourceName, boolean saveDefault) {
		return getAsInputStream(resourceName, resourceName, saveDefault);
	}

	public InputStream getAsInputStream(String resourceName) {
		return getAsInputStream(resourceName, resourceName, true);
	}
	//endregion

	//region getAsReader methods
	public Reader getAsReader(String resourceName, String defaultResourceName, boolean saveDefault) {
		return new InputStreamReader(getAsInputStream(resourceName, defaultResourceName, saveDefault));
	}

	public Reader getAsReader(String resourceName, String defaultResourceName) {
		return new InputStreamReader(getAsInputStream(resourceName, defaultResourceName, true));
	}

	public Reader getAsReader(String resourceName, boolean saveDefault) {
		return new InputStreamReader(getAsInputStream(resourceName, resourceName, saveDefault));
	}

	public Reader getAsReader(String resourceName) {
		return new InputStreamReader(getAsInputStream(resourceName, resourceName, true));
	}
	//endregion

	//region getAsString methods
	public String getAsString(String resourceName, String defaultResourceName, Charset charset, boolean saveDefault) {
		try (InputStream inputStream = getAsInputStream(resourceName, defaultResourceName, saveDefault);
			 Scanner scanner = new Scanner(inputStream, charset.name()).useDelimiter("\\A")) {

			return scanner.next();
		} catch (IOException e) {
			throw new AssetsException(format(ERROR_OPEN, resourceName, e.getMessage()), e);
		}
	}

	public String getAsString(String resourceName, String defaultResourceName, Charset charset) {
		return getAsString(resourceName, defaultResourceName, charset, true);
	}

	public String getAsString(String resourceName, String defaultResourceName, boolean saveDefault) {
		return getAsString(resourceName, defaultResourceName, StandardCharsets.UTF_8, saveDefault);
	}

	public String getAsString(String resourceName, String defaultResourceName) {
		return getAsString(resourceName, defaultResourceName, StandardCharsets.UTF_8, true);
	}

	public String getAsString(String resourceName, Charset charset, boolean saveDefault) {
		return getAsString(resourceName, resourceName, charset, saveDefault);
	}

	public String getAsString(String resourceName, Charset charset) {
		return getAsString(resourceName, resourceName, charset, true);
	}

	public String getAsString(String resourceName, boolean saveDefault) {
		return getAsString(resourceName, resourceName, StandardCharsets.UTF_8, saveDefault);
	}

	public String getAsString(String resourceName) {
		return getAsString(resourceName, resourceName, StandardCharsets.UTF_8, true);
	}
	//endregion
	
	private URL getResourceUrl(String resourceName) {
		URL resourceUrl = AssetsManager.class.getClassLoader().getResource(resourceName);
		if (resourceUrl == null) {
			throw new AssetsException(format(ERROR_NOT_FOUND, resourceName));
		}

		return resourceUrl;
	}

	private void doSaveTo(URL resourceUrl, Path saveToPath) {
		try {
			Files.createDirectories(saveToPath.getParent());

			try (InputStream inputStream = resourceUrl.openStream();
				 OutputStream outputStream = Files.newOutputStream(saveToPath)) {

				byte[] buffer = new byte[8192];
				int count;
				while ((count = inputStream.read(buffer)) != -1) {
					outputStream.write(buffer, 0, count);
				}
				outputStream.flush();
			}
		} catch (IOException e) {
			throw new AssetsException(format("Error save asset \"{0}\" to \"{1}\": {2}",
					resourceUrl, saveToPath, e.getMessage()), e);
		}
	}

	private InputStream openResource(Path pathToResource) {
		try {
			return Files.newInputStream(pathToResource);
		} catch (IOException e) {
			throw new AssetsException(format(ERROR_OPEN, pathToResource, e.getMessage()), e);
		}
	}

	private InputStream openResource(URL resourceUrl) {
		try {
			return resourceUrl.openStream();
		} catch (IOException e) {
			throw new AssetsException(format(ERROR_OPEN, resourceUrl, e.getMessage()), e);
		}
	}
}