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/*
 * Copyright (c) 2017 simplity.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package org.simplity.tp;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;

import org.simplity.kernel.ApplicationError;
import org.simplity.kernel.comp.ComponentManager;
import org.simplity.kernel.data.FlatFileRowType;
import org.simplity.kernel.dm.Record;
import org.simplity.kernel.expr.Expression;
import org.simplity.kernel.expr.InvalidOperationException;
import org.simplity.kernel.util.TextUtil;
import org.simplity.kernel.value.Value;
import org.simplity.service.ServiceContext;

/**
 * Data structure that keeps meta data about a flat-file
 *
 * @author simplity.org
 *
 */
public class OutputFile {
	/**
	 *
	 * This is expressed using {name} and and
	 * {ext} that stand for file name and extension of primary input file.
	 * example if input file name is a.txt, then {name}.{ext}.out will translate to a.txt.out and {fileName}.out will
	 * translate to a.out.
	 *
	 * Of course if it is not dependent on the input file, then it can be plain file name, or $fieldName
	 *
	 */
	String fileName;
	/**
	 * record that describes fields/columns in this file
	 */
	String recordName;
	/**
	 * how columns/fields are organized in each row
	 */
	FlatFileRowType dataFormat;
	/**
	 * in case the row may be written conditionally. Defaults to write always.
	 */
	Expression conditionToOutput;


	/**
	 * @param service
	 */
	void getReady(Service service) {
		if(this.fileName == null){
			throw new ApplicationError("file name is required for outputFile");
		}
	}

	/**
	 *
	 * @return worker to read from this file
	 */
	public Worker getWorker() {
		return new Worker();
	}

	/**
	 * mutable class to take care of run-time requirements of this component
	 * @author simplity.org
	 *
	 */
	class Worker implements BatchOutput{
		protected Record record;
		protected File realFile;
		private BufferedWriter writer;

		String getFileName() {
			return this.realFile.getName();
		}

		void setFileName(String rootFolder, String refFileName, ServiceContext ctx){
			this.realFile = new File(rootFolder + TextUtil.getFileName(OutputFile.this.fileName, refFileName, ctx));
		}

		@Override
		public void openShop(ServiceContext ctx) throws IOException {
			this.record = ComponentManager.getRecord(OutputFile.this.recordName);
			this.writer = new BufferedWriter(new FileWriter(this.realFile));
		}

		@Override
		public boolean outputARow(ServiceContext ctx) throws IOException {
			Expression expr = OutputFile.this.conditionToOutput;
			try {
				if (expr == null || Value.intepretAsBoolean(expr.evaluate(ctx))) {
					this.writer.write((this.record.formatFlatRow(OutputFile.this.dataFormat, ctx)));
					this.writer.newLine();
					return true;
				}
				return false;
			} catch (InvalidOperationException e) {
				throw new ApplicationError(e, "Error while evaluating expresssion " + expr);
			}
		}

		@Override
		public void closeShop(ServiceContext ctx) {
			try {
				this.writer.close();
			} catch (Exception ignore) {
				//
			}
		}
	}
}