// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

@TestOn("vm")
library dart_style.test.formatter_test;

import 'dart:io';
import 'dart:mirrors';

import 'package:path/path.dart' as p;
import 'package:test/test.dart';

import 'package:dart_style/dart_style.dart';

void main() {
  testDirectory("comments");
  testDirectory("regression");
  testDirectory("selections");
  testDirectory("splitting");
  testDirectory("whitespace");

  test("throws a FormatterException on failed parse", () {
    var formatter = new DartFormatter();
    expect(() => formatter.format('wat?!'),
        throwsA(new isInstanceOf<FormatterException>()));
  });

  test("FormatterException.message() does not throw", () {
    // This is a regression test for #358 where an error whose position is
    // past the end of the source caused FormatterException to throw.
    try {
      new DartFormatter().format("library");
    } on FormatterException catch (err) {
      var message = err.message();
      expect(message, contains("Could not format"));
    }
  });

  test("FormatterException describes parse errors", () {
    try {
      new DartFormatter().format(
          """

      var a = some error;

      var b = another one;
      """,
          uri: "my_file.dart");

      fail("Should throw.");
    } on FormatterException catch (err) {
      var message = err.message();
      expect(message, contains("my_file.dart"));
      expect(message, contains("line 2"));
      expect(message, contains("line 4"));
    }
  });

  test("adds newline to unit", () {
    expect(new DartFormatter().format("var x = 1;"), equals("var x = 1;\n"));
  });

  test("adds newline to unit after trailing comment", () {
    expect(new DartFormatter().format("library foo; //zamm"),
        equals("library foo; //zamm\n"));
  });

  test("removes extra newlines", () {
    expect(
        new DartFormatter().format("var x = 1;\n\n\n"), equals("var x = 1;\n"));
  });

  test("does not add newline to statement", () {
    expect(new DartFormatter().formatStatement("var x = 1;"),
        equals("var x = 1;"));
  });

  test("fails if anything is after the statement", () {
    try {
      new DartFormatter().formatStatement("var x = 1;;");

      fail("Should throw.");
    } on FormatterException catch (ex) {
      expect(ex.errors.length, equals(1));
      expect(ex.errors.first.offset, equals(10));
    }
  });

  test('preserves initial indent', () {
    var formatter = new DartFormatter(indent: 3);
    expect(
        formatter.formatStatement('if (foo) {bar;}'),
        equals('   if (foo) {\n'
            '     bar;\n'
            '   }'));
  });

  group("line endings", () {
    test("uses given line ending", () {
      // Use zero width no-break space character as the line ending. We have
      // to use a whitespace character for the line ending as the formatter
      // will throw an error if it accidentally makes non-whitespace changes
      // as will occur
      var lineEnding = "\t";
      expect(new DartFormatter(lineEnding: lineEnding).format("var i = 1;"),
          equals("var i = 1;\t"));
    });

    test('infers \\r\\n if the first newline uses that', () {
      expect(new DartFormatter().format("var\r\ni\n=\n1;\n"),
          equals("var i = 1;\r\n"));
    });

    test('infers \\n if the first newline uses that', () {
      expect(new DartFormatter().format("var\ni\r\n=\r\n1;\r\n"),
          equals("var i = 1;\n"));
    });

    test('defaults to \\n if there are no newlines', () {
      expect(new DartFormatter().format("var i =1;"), equals("var i = 1;\n"));
    });

    test('handles Windows line endings in multiline strings', () {
      expect(
          new DartFormatter(lineEnding: "\r\n").formatStatement('  """first\r\n'
              'second\r\n'
              'third"""  ;'),
          equals('"""first\r\n'
              'second\r\n'
              'third""";'));
    });
  });

  test('throws an UnexpectedOutputException on non-whitespace changes', () {
    // Use an invalid line ending character to ensure the formatter will
    // attempt to make non-whitespace changes.
    var formatter = new DartFormatter(lineEnding: '%');
    expect(() => formatter.format("var i = 1;"),
        throwsA(new isInstanceOf<UnexpectedOutputException>()));
  });
}

/// Run tests defined in "*.unit" and "*.stmt" files inside directory [name].
void testDirectory(String name) {
  var indentPattern = new RegExp(r"^\(indent (\d+)\)\s*");

  // Locate the "test" directory. Use mirrors so that this works with the test
  // package, which loads this suite into an isolate.
  var testDir = p.dirname(currentMirrorSystem()
      .findLibrary(#dart_style.test.formatter_test)
      .uri
      .toFilePath());

  var entries = new Directory(p.join(testDir, name))
      .listSync(recursive: true, followLinks: false);
  for (var entry in entries) {
    if (!entry.path.endsWith(".stmt") && !entry.path.endsWith(".unit")) {
      continue;
    }

    group("$name ${p.basename(entry.path)}", () {
      // Explicitly create a File, in case the entry is a Link.
      var lines = new File(entry.path).readAsLinesSync();

      // The first line may have a "|" to indicate the page width.
      var pageWidth;
      if (lines[0].endsWith("|")) {
        pageWidth = lines[0].indexOf("|");
        lines = lines.skip(1).toList();
      }

      var i = 0;
      while (i < lines.length) {
        var description = lines[i++].replaceAll(">>>", "").trim();

        // Let the test specify a leading indentation. This is handy for
        // regression tests which often come from a chunk of nested code.
        var leadingIndent = 0;
        var indentMatch = indentPattern.firstMatch(description);
        if (indentMatch != null) {
          leadingIndent = int.parse(indentMatch[1]);
          description = description.substring(indentMatch.end);
        }

        if (description == "") {
          description = "line ${i + 1}";
        } else {
          description = "line ${i + 1}: $description";
        }

        var input = "";
        while (!lines[i].startsWith("<<<")) {
          input += lines[i++] + "\n";
        }

        var expectedOutput = "";
        while (++i < lines.length && !lines[i].startsWith(">>>")) {
          expectedOutput += lines[i] + "\n";
        }

        // TODO(rnystrom): Stop skipping these tests when possible.
        if (description.contains("(skip:")) {
          print("skipping $description");
          continue;
        }

        test(description, () {
          var isCompilationUnit = p.extension(entry.path) == ".unit";

          var inputCode =
              _extractSelection(input, isCompilationUnit: isCompilationUnit);

          var expected = _extractSelection(expectedOutput,
              isCompilationUnit: isCompilationUnit);

          var formatter =
              new DartFormatter(pageWidth: pageWidth, indent: leadingIndent);

          var actual = formatter.formatSource(inputCode);

          // The test files always put a newline at the end of the expectation.
          // Statements from the formatter (correctly) don't have that, so add
          // one to line up with the expected result.
          var actualText = actual.text;
          if (!isCompilationUnit) actualText += "\n";

          // Fail with an explicit message because it's easier to read than
          // the matcher output.
          if (actualText != expected.text) {
            fail("Formatting did not match expectation. Expected:\n"
                "${expected.text}\nActual:\n$actualText");
          }

          expect(actual.selectionStart, equals(expected.selectionStart));
          expect(actual.selectionLength, equals(expected.selectionLength));
        });
      }
    });
  }
}

/// Given a source string that contains ‹ and › to indicate a selection, returns
/// a [SourceCode] with the text (with the selection markers removed) and the
/// correct selection range.
SourceCode _extractSelection(String source, {bool isCompilationUnit: false}) {
  var start = source.indexOf("‹");
  source = source.replaceAll("‹", "");

  var end = source.indexOf("›");
  source = source.replaceAll("›", "");

  return new SourceCode(source,
      isCompilationUnit: isCompilationUnit,
      selectionStart: start == -1 ? null : start,
      selectionLength: end == -1 ? null : end - start);
}