/*
 * Copyright 2011 gitblit.com.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.gitblit;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.charset.Charset;
import java.text.MessageFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.beust.jcommander.JCommander;
import com.beust.jcommander.Parameter;
import com.beust.jcommander.ParameterException;
import com.beust.jcommander.Parameters;
import com.gitblit.utils.MarkdownUtils;

public class BuildSite {

	public static void main(String... args) {
		Params params = new Params();
		JCommander jc = new JCommander(params);
		try {
			jc.parse(args);
		} catch (ParameterException t) {
			usage(jc, t);
		}

		File sourceFolder = new File(params.sourceFolder);
		File destinationFolder = new File(params.outputFolder);
		File[] markdownFiles = sourceFolder.listFiles(new FilenameFilter() {

			@Override
			public boolean accept(File dir, String name) {
				return name.toLowerCase().endsWith(".mkd");
			}
		});
		Arrays.sort(markdownFiles);

		Map<String, String> aliasMap = new HashMap<String, String>();
		for (String alias : params.aliases) {
			String[] values = alias.split("=");
			aliasMap.put(values[0], values[1]);
		}

		System.out.println(MessageFormat.format("Generating site from {0} Markdown Docs in {1} ", markdownFiles.length, sourceFolder.getAbsolutePath()));
		String linkPattern = "<a href=''{0}''>{1}</a>";
		StringBuilder sb = new StringBuilder();
		for (File file : markdownFiles) {
			String documentName = getDocumentName(file);
			String displayName = documentName;
			if (aliasMap.containsKey(documentName)) {
				displayName = aliasMap.get(documentName);
			}
			String fileName = documentName + ".html";
			sb.append(MessageFormat.format(linkPattern, fileName, displayName));
			sb.append(" | ");
		}
		sb.setLength(sb.length() - 3);
		sb.trimToSize();

		String html_header = readContent(new File(params.pageHeader));
		String html_footer = readContent(new File(params.pageFooter));
		final String links = sb.toString();
		final String header = MessageFormat.format(html_header, Constants.FULL_NAME, links);
		final String date = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
		final String footer = MessageFormat.format(html_footer, "generated " + date);
		for (File file : markdownFiles) {
			try {
				String documentName = getDocumentName(file);
				String fileName = documentName + ".html";
				System.out.println(MessageFormat.format("  {0} => {1}", file.getName(), fileName));
				InputStreamReader reader = new InputStreamReader(new FileInputStream(file), Charset.forName("UTF-8"));
				String content = MarkdownUtils.transformMarkdown(reader);
				for (String token : params.substitutions) {
					String [] kv = token.split("=");
					content = content.replace(kv[0], kv[1]);
				}
				OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(new File(destinationFolder, fileName)), Charset.forName("UTF-8"));
				writer.write(header);
				writer.write(content);
				writer.write(footer);
				reader.close();
				writer.close();
			} catch (Throwable t) {
				System.err.println("Failed to transform " + file.getName());
				t.printStackTrace();
			}
		}
	}

	private static String readContent(File file) {
		StringBuilder sb = new StringBuilder();
		try {
			InputStreamReader is = new InputStreamReader(new FileInputStream(file), Charset.forName("UTF-8"));
			BufferedReader reader = new BufferedReader(is);
			String line = null;
			while ((line = reader.readLine()) != null) {
				sb.append(line);
			}
			reader.close();
		} catch (Throwable t) {
			System.err.println("Failed to read content of " + file.getAbsolutePath());
			t.printStackTrace();
		}
		return sb.toString();
	}

	private static String getDocumentName(File file) {
		String displayName = file.getName().substring(0, file.getName().lastIndexOf('.')).toLowerCase();
		// trim leading ##_ which is to control display order
		return displayName.substring(3);
	}

	private static void usage(JCommander jc, ParameterException t) {
		System.out.println(Constants.getRunningVersion());
		System.out.println();
		if (t != null) {
			System.out.println(t.getMessage());
			System.out.println();
		}
		if (jc != null) {
			jc.usage();
		}
		System.exit(0);
	}

	@Parameters(separators = " ")
	private static class Params {

		@Parameter(names = { "--sourceFolder" }, description = "Markdown Source Folder", required = true)
		public String sourceFolder;

		@Parameter(names = { "--outputFolder" }, description = "HTML Ouptut Folder", required = true)
		public String outputFolder;

		@Parameter(names = { "--pageHeader" }, description = "Page Header HTML Snippet", required = true)
		public String pageHeader;

		@Parameter(names = { "--pageFooter" }, description = "Page Footer HTML Snippet", required = true)
		public String pageFooter;

		@Parameter(names = { "--alias" }, description = "Filename=Linkname aliases", required = false)
		public List<String> aliases = new ArrayList<String>();

		@Parameter(names = { "--substitute" }, description = "@TOKEN@=value", required = false)
		public List<String> substitutions = new ArrayList<String>();

	}
}