/**
 * Copyright (C) 2024, 2025 Adrien Hopkins
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
package sevenUnits.unit;

import java.nio.file.Path;
import java.util.Optional;

/**
 * An exception that occurred when loading a file. This wrapper class adds more
 * info about the error.
 * 
 * @author Adrien Hopkins
 * @since 2024-08-22
 */
public final class LoadingException extends RuntimeException {
	/** The type of file that was being loaded. */
	public static enum FileType {
		@SuppressWarnings("javadoc") UNIT, @SuppressWarnings("javadoc") DIMENSION
	}

	private static final long serialVersionUID = -8167971828216907607L;

	private final long lineNumber;
	private final String line;
	private final Optional<Path> file;

	private final FileType fileType;

	private final RuntimeException problem;

	/**
	 * Create a LoadingException from some information, without a file.
	 * 
	 * @param lineNumber line number error happened on
	 * @param line       text of invalid line
	 * @param fileType   type of file
	 * @param problem    problem, as an Exception
	 */
	public LoadingException(long lineNumber, String line, FileType fileType,
			RuntimeException problem) {
		super(problem);
		this.lineNumber = lineNumber;
		this.line = line;
		this.file = Optional.empty();
		this.fileType = fileType;
		this.problem = problem;
	}

	/**
	 * Create a LoadingException from some information, with a file.
	 * 
	 * @param lineNumber line number error happened on
	 * @param line       text of invalid line
	 * @param file       file error happened on
	 * @param fileType   type of file
	 * @param problem    problem, as an Exception
	 */
	public LoadingException(long lineNumber, String line, Path file,
			FileType fileType, RuntimeException problem) {
		super(problem);
		this.lineNumber = lineNumber;
		this.line = line;
		this.file = Optional.of(file);
		this.fileType = fileType;
		this.problem = problem;
	}

	/**
	 * @return the file this error happened in, if there is one
	 */
	public Optional<Path> file() {
		return this.file;
	}

	/**
	 * @return type of file that this error happened in
	 */
	public FileType fileType() {
		return this.fileType;
	}

	@Override
	public String getMessage() {
		return this.file
				.map(f -> String.format(
						"Error parsing line %d of %s file '%s' (\"%s\"): %s",
						this.lineNumber, this.fileType.toString().toLowerCase(), f,
						this.line, this.problem))
				.orElse(String.format(
						"Error parsing line %d of %s stream (\"%s\"): %s",
						this.lineNumber, this.fileType.toString().toLowerCase(),
						this.line, this.problem));
	}

	/**
	 * @return text of line that caused this error
	 */
	public String line() {
		return this.line;
	}

	/**
	 * @return number of line that caused this error
	 */
	public long lineNumber() {
		return this.lineNumber;
	}

	/**
	 * @return the error, as an exception
	 */
	public RuntimeException problem() {
		return this.problem;
	}
}