/*
 * Copyright (c) 2013 TMate Software Ltd
 *  
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * 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 General Public License for more details.
 *
 * For information on how to redistribute this software under
 * the terms of a license other than GNU General Public License
 * contact TMate Software at support@hg4j.com
 */
package org.tmatesoft.hg.test;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.tmatesoft.hg.core.HgIterateDirection.NewToOld;
import static org.tmatesoft.hg.core.HgIterateDirection.OldToNew;
import static org.tmatesoft.hg.repo.HgRepository.NO_REVISION;
import static org.tmatesoft.hg.repo.HgRepository.TIP;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.junit.Assert;
import org.junit.Rule;
import org.junit.Test;
import org.tmatesoft.hg.core.HgAnnotateCommand;
import org.tmatesoft.hg.core.HgAnnotateCommand.LineInfo;
import org.tmatesoft.hg.core.HgCallbackTargetException;
import org.tmatesoft.hg.core.HgIterateDirection;
import org.tmatesoft.hg.core.HgRepoFacade;
import org.tmatesoft.hg.internal.FileAnnotation;
import org.tmatesoft.hg.internal.FileAnnotation.LineDescriptor;
import org.tmatesoft.hg.internal.FileAnnotation.LineInspector;
import org.tmatesoft.hg.internal.IntVector;
import org.tmatesoft.hg.repo.HgBlameFacility;
import org.tmatesoft.hg.repo.HgBlameFacility.AddBlock;
import org.tmatesoft.hg.repo.HgBlameFacility.Block;
import org.tmatesoft.hg.repo.HgBlameFacility.BlockData;
import org.tmatesoft.hg.repo.HgBlameFacility.ChangeBlock;
import org.tmatesoft.hg.repo.HgBlameFacility.DeleteBlock;
import org.tmatesoft.hg.repo.HgBlameFacility.EqualBlock;
import org.tmatesoft.hg.repo.HgDataFile;
import org.tmatesoft.hg.repo.HgLookup;
import org.tmatesoft.hg.repo.HgRepository;
import org.tmatesoft.hg.util.Path;

/**
 * 
 * @author Artem Tikhomirov
 * @author TMate Software Ltd.
 */
public class TestBlame {

	@Rule
	public ErrorCollectorExt errorCollector = new ErrorCollectorExt();

	
	@Test
	public void testSingleParentBlame() throws Exception {
		HgRepository repo = new HgLookup().detectFromWorkingDir();
		final String fname = "src/org/tmatesoft/hg/internal/PatchGenerator.java";
		final int checkChangeset = 539;
		HgDataFile df = repo.getFileNode(fname);
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		new HgBlameFacility(df).annotateSingleRevision(checkChangeset, new DiffOutInspector(new PrintStream(bos)));
		LineGrepOutputParser gp = new LineGrepOutputParser("^@@.+");
		ExecHelper eh = new ExecHelper(gp, null);
		eh.run("hg", "diff", "-c", String.valueOf(checkChangeset), "-U", "0", fname);
		//
		String[] apiResult = splitLines(bos.toString());
		String[] expected = splitLines(gp.result());
		Assert.assertArrayEquals(expected, apiResult);
	}
	
	@Test
	public void testFileLineAnnotate1() throws Exception {
		HgRepository repo = new HgLookup().detectFromWorkingDir();
		final String fname = "src/org/tmatesoft/hg/internal/PatchGenerator.java";
		HgDataFile df = repo.getFileNode(fname);
		AnnotateRunner ar = new AnnotateRunner(df.getPath(), null);

		for (int cs : new int[] { 539, 541 /*, TIP */}) {
			ar.run(cs, false);
			FileAnnotateInspector fa = new FileAnnotateInspector();
			FileAnnotation.annotate(df, cs, fa);
			doAnnotateLineCheck(cs, ar.getLines(), Arrays.asList(fa.lineRevisions), Arrays.asList(fa.lines));
		}
	}
	
	@Test
	public void testFileLineAnnotate2() throws Exception {
		HgRepository repo = Configuration.get().find("test-annotate");
		HgDataFile df = repo.getFileNode("file1");
		AnnotateRunner ar = new AnnotateRunner(df.getPath(), repo.getWorkingDir());

		for (int cs : new int[] { 4, 6 /*, 8 see below*/, TIP}) {
			ar.run(cs, false);
			FileAnnotateInspector fa = new FileAnnotateInspector();
			FileAnnotation.annotate(df, cs, fa);
			doAnnotateLineCheck(cs, ar.getLines(), Arrays.asList(fa.lineRevisions), Arrays.asList(fa.lines));
		}
		/*`hg annotate -r 8` and HgBlameFacility give different result
		 * for "r0, line 5" line, which was deleted in rev2 and restored back in
		 * rev4 (both in default branch), while branch with r3 and r6 kept the line intact.
		 * HgBlame reports rev4 for the line, `hg annotate` gives original, rev0.
		 * However `hg annotate -r 4` shows rev4 for the line, too. The aforementioned rev0 for 
		 * the merge rev8 results from the iteration order and is implementation specific 
		 * (i.e. one can't tell which one is right). Mercurial walks from parents to children,
		 * and traces equal lines, wile HgBlameFacility walks from child to parents and records 
		 * changes (additions). Seems it processes branch with rev3 and rev6 first 
		 * (printout in context.py, annotate and annotate.pair reveals that), and the line 0_5
		 * comes as unchanged through this branch, and later processing rev2 and rev4 doesn't 
		 * change that. 
		 */
	}
	
	@Test
	public void testComplexHistoryAnnotate() throws Exception {
		HgRepository repo = Configuration.get().find("test-annotate");
		HgDataFile df = repo.getFileNode("file1");
		HgBlameFacility af = new HgBlameFacility(df);
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		DiffOutInspector dump = new DiffOutInspector(new PrintStream(bos));
		af.annotate(TIP, dump, HgIterateDirection.OldToNew);
		LinkedList<String> apiResult = new LinkedList<String>(Arrays.asList(splitLines(bos.toString())));
		
		/*
		 * FIXME this is an ugly hack to deal with the way `hg diff -c <mergeRev>` describes the change
		 * and our merge handling approach. For merged revision m, and lines changed both in p1 and p2
		 * we report lines from p2 as pure additions, regardless of intersecting p1 changes (which
		 * are reported as deletions, if no sufficient changed lines in m found)
		 * So, here we try to combine deletion that follows a change (based on identical insertionPoint)
		 * into a single change
		 * To fix, need to find better approach to find out reference info (i.e. `hg diff -c` is flawed in this case,
		 * as it uses first parent only).
		 */
		Pattern fix = Pattern.compile("@@ -(\\d+),(\\d+) \\+(\\d+),(\\d+) @@");
		int v1, v2, v3, v4;
		v1 = v2 = v3 = v4 = -1;
		for (ListIterator<String> it = apiResult.listIterator(); it.hasNext();) {
			String n = it.next();
			Matcher m = fix.matcher(n);
			if (m.find()) {
				int d1 = Integer.parseInt(m.group(1));
				int d2 = Integer.parseInt(m.group(2));
				int d3 = Integer.parseInt(m.group(3));
				int d4 = Integer.parseInt(m.group(4));
				if (v1 == d1 && d4 == 0) {
					it.previous(); // shift to current element
					it.previous(); // to real previous
					it.remove();
					it.next();
					it.set(String.format("@@ -%d,%d +%d,%d @@", v1, v2+d2, v3, v4));
				}
				v1 = d1;
				v2 = d2;
				v3 = d3;
				v4 = d4;
			}
		}
		
		LineGrepOutputParser gp = new LineGrepOutputParser("^@@.+");
		ExecHelper eh = new ExecHelper(gp, repo.getWorkingDir());
		for (int cs : dump.getReportedTargetRevisions()) {
			gp.reset();
			eh.run("hg", "diff", "-c", String.valueOf(cs), "-U", "0", df.getPath().toString());
			for (String expected : splitLines(gp.result())) {
				if (!apiResult.remove(expected)) {
					errorCollector.fail(String.format("Expected diff output '%s' for changes in revision %d", expected, cs));
				}
			}
		}
		errorCollector.assertTrue(String.format("Annotate API reported excessive diff: %s ", apiResult.toString()), apiResult.isEmpty());
	}

	
	@Test
	public void testPartialHistoryFollow() throws Exception {
		HgRepository repo = Configuration.get().find("test-annotate2");
		HgDataFile df = repo.getFileNode("file1b.txt");
		// rev3: file1 -> file1a,  rev7: file1a -> file1b, tip: rev10
		HgBlameFacility bf = new HgBlameFacility(df);
		DiffOutInspector insp = new DiffOutInspector(new PrintStream(new OutputStream() {
			@Override
			public void write(int b) throws IOException {
				// NULL OutputStream
			}
		}));
		// rev6 changes rev4, rev4 changes rev3. Plus, anything changed 
		// earlier than rev2 shall be reported as new from change3
		int[] change_2_8_new2old = new int[] {4, 6, 3, 4, -1, 3}; 
		int[] change_2_8_old2new = new int[] {-1, 3, 3, 4, 4, 6 };
		bf.annotate(2, 8, insp, NewToOld);
		Assert.assertArrayEquals(change_2_8_new2old, insp.getReportedRevisionPairs());
		insp.reset();
		bf.annotate(2, 8, insp, OldToNew);
		Assert.assertArrayEquals(change_2_8_old2new, insp.getReportedRevisionPairs());
		// same as 2 to 8, with addition of rev9 changes rev7  (rev6 to rev7 didn't change content, only name)
		int[] change_3_9_new2old = new int[] {7, 9, 4, 6, 3, 4, -1, 3 }; 
		int[] change_3_9_old2new = new int[] {-1, 3, 3, 4, 4, 6, 7, 9 };
		insp.reset();
		bf.annotate(3, 9, insp, NewToOld);
		Assert.assertArrayEquals(change_3_9_new2old, insp.getReportedRevisionPairs());
		insp.reset();
		bf.annotate(3, 9, insp, OldToNew);
		Assert.assertArrayEquals(change_3_9_old2new, insp.getReportedRevisionPairs());
	}

	@Test
	public void testAnnotateCmdFollowNoFollow() throws Exception {
		HgRepoFacade hgRepoFacade = new HgRepoFacade();
		HgRepository repo = Configuration.get().find("test-annotate2");
		hgRepoFacade.init(repo);
		HgAnnotateCommand cmd = hgRepoFacade.createAnnotateCommand();
		final Path fname = Path.create("file1b.txt");
		final int changeset = TIP;
		AnnotateInspector ai = new AnnotateInspector();

		cmd.changeset(changeset);
		// follow
		cmd.file(fname);
		cmd.execute(ai);
		AnnotateRunner ar = new AnnotateRunner(fname, repo.getWorkingDir());
		ar.run(changeset, true);
		doAnnotateLineCheck(changeset, ar.getLines(), ai.changesets, ai.lines);
		
		// no follow
		cmd.file(fname, false);
		ai = new AnnotateInspector();
		cmd.execute(ai);
		ar.run(changeset, false);
		doAnnotateLineCheck(changeset, ar.getLines(), ai.changesets, ai.lines);
	}

	private void doAnnotateLineCheck(int cs, String[] hgAnnotateLines, List<Integer> cmdChangesets, List<String> cmdLines) {
		assertTrue("[sanity]", hgAnnotateLines.length > 0);
		assertEquals("Number of lines reported by native annotate and our impl", hgAnnotateLines.length, cmdLines.size());

		for (int i = 0; i < cmdChangesets.size(); i++) {
			int hgAnnotateRevIndex = Integer.parseInt(hgAnnotateLines[i].substring(0, hgAnnotateLines[i].indexOf(':')).trim());
			errorCollector.assertEquals(String.format("Revision mismatch for line %d (annotating rev: %d)", i+1, cs), hgAnnotateRevIndex, cmdChangesets.get(i));
			String hgAnnotateLine = hgAnnotateLines[i].substring(hgAnnotateLines[i].indexOf(':') + 1);
			String apiLine = cmdLines.get(i).trim();
			errorCollector.assertEquals(hgAnnotateLine.trim(), apiLine);
		}
	}

	// FIXME HgWorkingCopyStatusCollector (and HgStatusCollector), with their ancestors (rev 59/69) have examples
	// of *incorrect* assignment of common lines (like "}") - our impl doesn't process common lines in any special way
	// while original diff lib does. Would be nice to behave as close to original, as possible.
	
	private static String[] splitLines(CharSequence seq) {
		int lineCount = 0;
		for (int i = 0, x = seq.length(); i < x; i++) {
			if (seq.charAt(i) == '\n') {
				lineCount++;
			}
		}
		if (seq.length() > 0 && seq.charAt(seq.length()-1) != '\n') {
			lineCount++;
		}
		String[] rv = new String[lineCount];
		int lineStart = 0, lineEnd = 0, ix = 0;
		do {
			while (lineEnd < seq.length() && seq.charAt(lineEnd) != '\n') lineEnd++;
			if (lineEnd == lineStart) {
				continue;
			}
			CharSequence line = seq.subSequence(lineStart, lineEnd);
			rv[ix++] = line.toString();
			lineStart = ++lineEnd;
		} while (lineStart < seq.length());
		assert ix == lineCount;
		return rv;
	}
	
	
	private void aaa() throws Exception {
		HgRepository repo = new HgLookup().detectFromWorkingDir();
		final String fname = "src/org/tmatesoft/hg/internal/PatchGenerator.java";
		final int checkChangeset = 539;
		HgDataFile df = repo.getFileNode(fname);
		HgBlameFacility af = new HgBlameFacility(df);
		DiffOutInspector dump = new DiffOutInspector(System.out);
		System.out.println("541 -> 543");
		af.annotateSingleRevision(543, dump);
		System.out.println("539 -> 541");
		af.annotateSingleRevision(541, dump);
		System.out.println("536 -> 539");
		af.annotateSingleRevision(checkChangeset, dump);
		System.out.println("531 -> 536");
		af.annotateSingleRevision(536, dump);
		System.out.println(" -1 -> 531");
		af.annotateSingleRevision(531, dump);
		
		FileAnnotateInspector fai = new FileAnnotateInspector();
		FileAnnotation.annotate(df, 541, fai);
		for (int i = 0; i < fai.lineRevisions.length; i++) {
			System.out.printf("%3d: LINE %d\n", fai.lineRevisions[i], i+1);
		}
	}

	private void bbb() throws Exception {
		HgRepository repo = new HgLookup().detectFromWorkingDir();
		final String fname = "src/org/tmatesoft/hg/repo/HgManifest.java";
		final int checkChangeset = 415;
		HgDataFile df = repo.getFileNode(fname);
		HgBlameFacility af = new HgBlameFacility(df);
		DiffOutInspector dump = new DiffOutInspector(System.out);
//		System.out.println("413 -> 415");
//		af.diff(df, 413, 415, dump);
//		System.out.println("408 -> 415");
//		af.diff(df, 408, 415, dump);
//		System.out.println("Combined (with merge):");
//		dump.needRevisions(true);
//		af.annotateChange(df, checkChangeset, dump);
		dump.needRevisions(true);
		af.annotate(checkChangeset, dump, HgIterateDirection.OldToNew);
	}
	
	private void ccc() throws Throwable {
		HgRepository repo = new HgLookup().detect("/home/artem/hg/hgtest-annotate-merge/");
		HgDataFile df = repo.getFileNode("file.txt");
		HgBlameFacility af = new HgBlameFacility(df);
		DiffOutInspector dump = new DiffOutInspector(System.out);
		dump.needRevisions(true);
		af.annotate(8, dump, HgIterateDirection.NewToOld);
//		af.annotateSingleRevision(df, 113, dump);
//		System.out.println();
//		af.annotate(df, TIP, new LineDumpInspector(true), HgIterateDirection.NewToOld);
//		System.out.println();
//		af.annotate(df, TIP, new LineDumpInspector(false), HgIterateDirection.NewToOld);
//		System.out.println();
		/*
		OutputParser.Stub op = new OutputParser.Stub();
		eh = new ExecHelper(op, repo.getWorkingDir());
		for (int cs : new int[] { 24, 46, 49, 52, 59, 62, 64, TIP}) {
			doLineAnnotateTest(df, cs, op);
		}
		errorCollector.verify();
		*/
		FileAnnotateInspector fa = new FileAnnotateInspector();
		FileAnnotation.annotate(df, 8, fa);
		for (int i = 0; i < fa.lineRevisions.length; i++) {
			System.out.printf("%d: %s", fa.lineRevisions[i], fa.line(i) == null ? "null\n" : fa.line(i));
		}
	}

	public static void main(String[] args) throws Throwable {
//		System.out.println(Arrays.equals(new String[0], splitLines("")));
//		System.out.println(Arrays.equals(new String[] { "abc" }, splitLines("abc")));
//		System.out.println(Arrays.equals(new String[] { "a", "bc" }, splitLines("a\nbc")));
//		System.out.println(Arrays.equals(new String[] { "a", "bc" }, splitLines("a\nbc\n")));
		TestBlame tt = new TestBlame();
		tt.ccc();
	}

	private static class DiffOutInspector implements HgBlameFacility.Inspector {
		private final PrintStream out;
		private boolean dumpRevs;
		private IntVector reportedRevisionPairs = new IntVector();
		
		DiffOutInspector(PrintStream ps) {
			out = ps;
		}
		
		// Note, true makes output incompatible with 'hg diff'
		public void needRevisions(boolean dumpRevs) {
			this.dumpRevs = dumpRevs;
		}
		
		private void printRevs(Block b) {
			if (dumpRevs) {
				out.printf("[%3d -> %3d] ", b.originChangesetIndex(), b.targetChangesetIndex());
			}
			reportedRevisionPairs.add(b.originChangesetIndex(), b.targetChangesetIndex());
		}
		
		int[] getReportedTargetRevisions() {
			LinkedHashSet<Integer> rv = new LinkedHashSet<Integer>();
			for (int i = 1; i < reportedRevisionPairs.size(); i += 2) {
				rv.add(reportedRevisionPairs.get(i));
			}
			int[] x = new int[rv.size()];
			int i = 0;
			for (int v : rv) {
				x[i++] = v;
			}
			return x;
		}
		
		int[] getReportedRevisionPairs() {
			return reportedRevisionPairs.toArray();
		}
		
		void reset() {
			reportedRevisionPairs.clear();
		}
		
		public void same(EqualBlock block) {
			// nothing 
		}
		
		public void deleted(DeleteBlock block) {
			printRevs(block);
			out.printf("@@ -%d,%d +%d,0 @@\n", block.firstRemovedLine() + 1, block.totalRemovedLines(), block.removedAt());
		}
		
		public void changed(ChangeBlock block) {
			printRevs(block);
			out.printf("@@ -%d,%d +%d,%d @@\n", block.firstRemovedLine() + 1, block.totalRemovedLines(), block.firstAddedLine() + 1, block.totalAddedLines());
		}
		
		public void added(AddBlock block) {
			printRevs(block);
			out.printf("@@ -%d,0 +%d,%d @@\n", block.insertedAt(), block.firstAddedLine() + 1, block.totalAddedLines());
		}
	}
	
	public static class LineGrepOutputParser implements OutputParser {
		
		private final Pattern pattern;
		private final StringBuilder result = new StringBuilder();

		public LineGrepOutputParser(String regexp) {
			pattern = Pattern.compile(regexp);
		}
		
		public void reset() {
			result.setLength(0);
		}
		
		public CharSequence result() {
			return result;
		}

		public void parse(CharSequence seq) {
			int lineStart = 0, lineEnd = 0;
			do {
				while (lineEnd < seq.length() && seq.charAt(lineEnd) != '\n') lineEnd++;
				if (lineEnd == lineStart) {
					continue;
				}
				CharSequence line = seq.subSequence(lineStart, lineEnd);
				if (pattern.matcher(line).matches()) {
					result.append(line);
					result.append('\n');
				}
				lineStart = ++lineEnd;
			} while (lineStart < seq.length());
		}
	}

	private static class FileAnnotateInspector implements LineInspector {
		private Integer[] lineRevisions;
		private String[] lines;
		
		FileAnnotateInspector() {
		}
		
		public void line(int lineNumber, int changesetRevIndex, BlockData lineContent, LineDescriptor ld) {
			if (lineRevisions == null) {
				lineRevisions = new Integer[ld.totalLines()];
				Arrays.fill(lineRevisions, NO_REVISION);
				lines = new String[ld.totalLines()];
			}
			lineRevisions[lineNumber] = changesetRevIndex;
			lines[lineNumber] = new String(lineContent.asArray());
		}
		
		public String line(int i) {
			return lines[i];
		}
	}

	private static class LineDumpInspector implements HgBlameFacility.Inspector {
		
		private final boolean lineByLine;

		public LineDumpInspector(boolean lineByLine) {
			this.lineByLine = lineByLine;
		}

		public void same(EqualBlock block) {
		}

		public void added(AddBlock block) {
			BlockData lines = block.addedLines();
			printBlock(lines, block.targetChangesetIndex(), block.firstAddedLine(), block.totalAddedLines(), "+++");
		}

		public void changed(ChangeBlock block) {
			deleted(block);
			added(block);
		}

		public void deleted(DeleteBlock block) {
			BlockData lines = block.removedLines();
			assert lines.elementCount() == block.totalRemovedLines();
			printBlock(lines, block.originChangesetIndex(), block.firstRemovedLine(), block.totalRemovedLines(), "---");
		}
		
		private void printBlock(BlockData lines, int cset, int first, int length, String marker) {
			assert lines.elementCount() == length;
			if (lineByLine) {
				for (int i = 0, ln = first; i < length; i++, ln++) {
					String line = new String(lines.elementAt(i).asArray());
					System.out.printf("%3d:%3d:%s:%s", cset, ln, marker, line);
				}
			} else {
				String content = new String(lines.asArray());
				System.out.printf("%3d:%s:[%d..%d):\n%s", cset, marker, first, first+length, content);
			}
		}
	}
	
	static class AnnotateInspector implements HgAnnotateCommand.Inspector {
		private int lineNumber = 1;
		public final ArrayList<String> lines = new ArrayList<String>();
		public final ArrayList<Integer> changesets = new ArrayList<Integer>();
		
		public void next(LineInfo lineInfo) throws HgCallbackTargetException {
			Assert.assertEquals(lineInfo.getLineNumber(), lineNumber);
			lineNumber++;
			lines.add(new String(lineInfo.getContent()));
			changesets.add(lineInfo.getChangesetIndex());
		}
	}
	
	private static class AnnotateRunner {
		private final ExecHelper eh;
		private final OutputParser.Stub op;
		private final Path file;
		
		public AnnotateRunner(Path filePath, File repoDir) {
			file = filePath;
			op = new OutputParser.Stub();
			eh = new ExecHelper(op, repoDir);
		}
		
		public void run(int cset, boolean follow) throws Exception {
			op.reset();
			ArrayList<String> args = new ArrayList<String>();
			args.add("hg");
			args.add("annotate");
			args.add("-r");
			args.add(cset == TIP ? "tip" : String.valueOf(cset));
			if (!follow) {
				args.add("--no-follow");
			}
			args.add(file.toString());
			eh.run(args);
		}
		
		public String[] getLines() {
			return splitLines(op.result());
		}
	}
}