// Copyright (c) 2012, 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.

library status_file_parser;

import "dart:async";
import "dart:convert" show LineSplitter, UTF8;
import "dart:io";

import "path.dart";
import "status_expression.dart";

class Expectation {
  // Possible outcomes of running a test.
  static Expectation PASS = byName('Pass');
  static Expectation CRASH = byName('Crash');
  static Expectation TIMEOUT = byName('Timeout');
  static Expectation FAIL = byName('Fail');

  // Special 'FAIL' cases
  static Expectation RUNTIME_ERROR = byName('RuntimeError');
  static Expectation COMPILETIME_ERROR = byName('CompileTimeError');
  static Expectation MISSING_RUNTIME_ERROR = byName('MissingRuntimeError');
  static Expectation MISSING_COMPILETIME_ERROR =
      byName('MissingCompileTimeError');
  static Expectation STATIC_WARNING = byName('StaticWarning');
  static Expectation MISSING_STATIC_WARNING = byName('MissingStaticWarning');
  static Expectation PUB_GET_ERROR = byName('PubGetError');

  // "meta expectations"
  static Expectation OK = byName('Ok');
  static Expectation SLOW = byName('Slow');
  static Expectation SKIP = byName('Skip');
  static Expectation SKIP_SLOW = byName('SkipSlow');
  static Expectation SKIP_BY_DESIGN = byName('SkipByDesign');

  static Expectation byName(String name) {
    _initialize();
    name = name.toLowerCase();
    if (!_AllExpectations.containsKey(name)) {
      throw new Exception("Expectation.byName(name='$name'): Invalid name.");
    }
    return _AllExpectations[name];
  }

  // Keep a map of all possible Expectation objects, initialized lazily.
  static Map<String, Expectation> _AllExpectations;
  static void _initialize() {
    if (_AllExpectations == null) {
      _AllExpectations = new Map<String, Expectation>();

      Expectation build(prettyName, {group: null, isMetaExpectation: false}) {
        var expectation = new Expectation._(prettyName,
            group: group, isMetaExpectation: isMetaExpectation);
        assert(!_AllExpectations.containsKey(expectation.name));
        return _AllExpectations[expectation.name] = expectation;
      }

      var fail = build("Fail");
      build("Pass");
      build("Crash");
      build("Timeout");

      build("MissingCompileTimeError", group: fail);
      build("MissingRuntimeError", group: fail);
      build("CompileTimeError", group: fail);
      build("RuntimeError", group: fail);

      build("MissingStaticWarning", group: fail);
      build("StaticWarning", group: fail);

      build("PubGetError", group: fail);

      var skip = build("Skip", isMetaExpectation: true);
      build("SkipByDesign", isMetaExpectation: true);
      build("SkipSlow", group: skip, isMetaExpectation: true);
      build("Ok", isMetaExpectation: true);
      build("Slow", isMetaExpectation: true);
    }
  }

  final String prettyName;
  final String name;
  final Expectation group;
  // Indicates whether this expectation cannot be a test outcome (i.e. it is a
  // "meta marker").
  final bool isMetaExpectation;

  Expectation._(prettyName,
      {Expectation this.group: null, bool this.isMetaExpectation: false})
      : prettyName = prettyName,
        name = prettyName.toLowerCase();

  bool canBeOutcomeOf(Expectation expectation) {
    Expectation outcome = this;
    while (outcome != null) {
      if (outcome == expectation) {
        return true;
      }
      outcome = outcome.group;
    }
    return false;
  }

  String toString() => prettyName;
}

final RegExp SplitComment = new RegExp("^([^#]*)(#.*)?\$");
final RegExp HeaderPattern = new RegExp(r"^\[([^\]]+)\]");
final RegExp RulePattern = new RegExp(r"\s*([^: ]*)\s*:(.*)");
final RegExp IssueNumberPattern = new RegExp("[Ii]ssue ([0-9]+)");

class StatusFile {
  final Path location;

  StatusFile(this.location);
}

// TODO(whesse): Implement configuration_info library that contains data
// structures for test configuration, including Section.
class Section {
  final StatusFile statusFile;

  final BooleanExpression condition;
  final List<TestRule> testRules;
  final int lineNumber;

  Section.always(this.statusFile, this.lineNumber)
      : condition = null,
        testRules = new List<TestRule>();
  Section(this.statusFile, this.condition, this.lineNumber)
      : testRules = new List<TestRule>();

  bool isEnabled(environment) =>
      condition == null || condition.evaluate(environment);

  String toString() {
    return "Section: $condition";
  }
}

Future<TestExpectations> ReadTestExpectations(
    List<String> statusFilePaths, Map environment) {
  var testExpectations = new TestExpectations();
  return Future.wait(statusFilePaths.map((String statusFile) {
    return ReadTestExpectationsInto(testExpectations, statusFile, environment);
  })).then((_) => testExpectations);
}

Future ReadTestExpectationsInto(
    TestExpectations expectations, String statusFilePath, environment) {
  var completer = new Completer();
  List<Section> sections = new List<Section>();

  void sectionsRead() {
    for (Section section in sections) {
      if (section.isEnabled(environment)) {
        for (var rule in section.testRules) {
          expectations.addRule(rule, environment);
        }
      }
    }
    completer.complete();
  }

  ReadConfigurationInto(new Path(statusFilePath), sections, sectionsRead);
  return completer.future;
}

void ReadConfigurationInto(Path path, sections, onDone) {
  StatusFile statusFile = new StatusFile(path);
  File file = new File(path.toNativePath());
  if (!file.existsSync()) {
    throw new Exception('Cannot find test status file $path');
  }
  int lineNumber = 0;
  Stream<String> lines =
      file.openRead().transform(UTF8.decoder).transform(new LineSplitter());

  Section currentSection = new Section.always(statusFile, -1);
  sections.add(currentSection);

  lines.listen((String line) {
    lineNumber++;
    Match match = SplitComment.firstMatch(line);
    line = (match == null) ? "" : match[1];
    line = line.trim();
    if (line.isEmpty) return;

    // Extract the comment to get the issue number if needed.
    String comment = (match == null || match[2] == null) ? "" : match[2];

    match = HeaderPattern.firstMatch(line);
    if (match != null) {
      String condition_string = match[1].trim();
      List<String> tokens = new Tokenizer(condition_string).tokenize();
      ExpressionParser parser = new ExpressionParser(new Scanner(tokens));
      currentSection =
          new Section(statusFile, parser.parseBooleanExpression(), lineNumber);
      sections.add(currentSection);
      return;
    }

    match = RulePattern.firstMatch(line);
    if (match != null) {
      String name = match[1].trim();
      // TODO(whesse): Handle test names ending in a wildcard (*).
      String expression_string = match[2].trim();
      List<String> tokens = new Tokenizer(expression_string).tokenize();
      SetExpression expression =
          new ExpressionParser(new Scanner(tokens)).parseSetExpression();

      // Look for issue number in comment.
      String issueString = null;
      match = IssueNumberPattern.firstMatch(comment);
      if (match != null) {
        issueString = match[1];
        if (issueString == null) issueString = match[2];
      }
      int issue = issueString != null ? int.parse(issueString) : null;
      currentSection.testRules
          .add(new TestRule(name, expression, issue, lineNumber));
      return;
    }

    print("unmatched line: $line");
  }, onDone: onDone);
}

class TestRule {
  String name;
  SetExpression expression;
  int issue;
  int lineNumber;

  TestRule(this.name, this.expression, this.issue, this.lineNumber);

  bool get hasIssue => issue != null;

  String toString() => 'TestRule($name, $expression, $issue)';
}

class TestExpectations {
  // Only create one copy of each Set<Expectation>.
  // We just use .toString as a key, so we may make a few
  // sets that only differ in their toString element order.
  static Map _cachedSets = new Map();

  Map _map;
  bool _preprocessed = false;
  Map _regExpCache;
  Map _keyToRegExps;

  /**
   * Create a TestExpectations object. See the [expectations] method
   * for an explanation of matching.
   */
  TestExpectations() : _map = new Map();

  /**
   * Add a rule to the expectations.
   */
  void addRule(testRule, environment) {
    // Once we have started using the expectations we cannot add more
    // rules.
    if (_preprocessed) {
      throw "TestExpectations.addRule: cannot add more rules";
    }
    var names = testRule.expression.evaluate(environment);
    var expectations = names.map((name) => Expectation.byName(name));
    _map.putIfAbsent(testRule.name, () => new Set()).addAll(expectations);
  }

  /**
   * Compute the expectations for a test based on the filename.
   *
   * For every (key, expectation) pair. Match the key with the file
   * name. Return the union of the expectations for all the keys
   * that match.
   *
   * Normal matching splits the key and the filename into path
   * components and checks that the anchored regular expression
   * "^$keyComponent\$" matches the corresponding filename component.
   */
  Set<Expectation> expectations(String filename) {
    var result = new Set();
    var splitFilename = filename.split('/');

    // Create mapping from keys to list of RegExps once and for all.
    _preprocessForMatching();

    _map.forEach((key, expectation) {
      List regExps = _keyToRegExps[key];
      if (regExps.length > splitFilename.length) return;
      for (var i = 0; i < regExps.length; i++) {
        if (!regExps[i].hasMatch(splitFilename[i])) return;
      }
      // If all components of the status file key matches the filename
      // add the expectations to the result.
      result.addAll(expectation);
    });

    // If no expectations were found the expectation is that the test
    // passes.
    if (result.isEmpty) {
      result.add(Expectation.PASS);
    }
    return _cachedSets.putIfAbsent(result.toString(), () => result);
  }

  // Preprocess the expectations for matching against
  // filenames. Generate lists of regular expressions once and for all
  // for each key.
  void _preprocessForMatching() {
    if (_preprocessed) return;

    _keyToRegExps = new Map();
    _regExpCache = new Map();

    _map.forEach((key, expectations) {
      if (_keyToRegExps[key] != null) return;
      var splitKey = key.split('/');
      var regExps = new List(splitKey.length);
      for (var i = 0; i < splitKey.length; i++) {
        var component = splitKey[i];
        var regExp = _regExpCache[component];
        if (regExp == null) {
          var pattern = "^${splitKey[i]}\$".replaceAll('*', '.*');
          regExp = new RegExp(pattern);
          _regExpCache[component] = regExp;
        }
        regExps[i] = regExp;
      }
      _keyToRegExps[key] = regExps;
    });

    _regExpCache = null;
    _preprocessed = true;
  }
}