// Copyright (c) 2017, 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.

import "dart:async" show Future, Stream;

import "dart:convert" show utf8;

import "dart:io" show File;

import "dart:typed_data" show Uint8List;

import "package:testing/testing.dart"
    show Chain, ChainContext, Result, Step, TestDescription, runMe;

import "package:yaml/yaml.dart" show YamlList, YamlMap, YamlNode, loadYamlNode;

import 'package:front_end/src/api_prototype/compiler_options.dart'
    show ProblemHandler;

import 'package:front_end/src/api_prototype/memory_file_system.dart'
    show MemoryFileSystem, MemoryFileSystemEntity;

import 'package:front_end/src/fasta/fasta_codes.dart' show LocatedMessage;

import 'package:front_end/src/fasta/severity.dart'
    show Severity, severityEnumValues;

import 'package:front_end/src/testing/hybrid_file_system.dart'
    show HybridFileSystem;

import "../../tool/_fasta/entry_points.dart" show BatchCompiler;

ProblemHandler problemHandler(List<List> problems) {
  return (LocatedMessage problem, Severity severity, String formatted, int line,
      int column) {
    problems.add([problem, severity, formatted, line, column]);
  };
}

class MessageTestDescription extends TestDescription {
  @override
  final Uri uri;

  @override
  final String shortName;

  final String name;

  final YamlMap data;

  final Example example;

  final String problem;

  MessageTestDescription(this.uri, this.shortName, this.name, this.data,
      this.example, this.problem);
}

class MessageTestSuite extends ChainContext {
  final List<Step> steps = const <Step>[
    const Validate(),
    const Compile(),
  ];

  final MemoryFileSystem fileSystem;

  final BatchCompiler compiler;

  final List<List> problems;

  MessageTestSuite()
      : this.internal(new MemoryFileSystem(Uri.parse("org-dartlang-fasta:///")),
            <List>[]);

  MessageTestSuite.internal(this.fileSystem, this.problems)
      : compiler = new BatchCompiler.forTesting(
            new HybridFileSystem(fileSystem), problemHandler(problems));

  /// Convert all the examples found in `messages.yaml` to a test
  /// description. In addition, create a test description for each kind of
  /// problem that a message can have. This problem will then be reported as a
  /// failure by the [Validate] step that can be suppressed via the status
  /// file.
  Stream<MessageTestDescription> list(Chain suite) async* {
    Uri uri = suite.uri.resolve("messages.yaml");
    File file = new File.fromUri(uri);
    YamlMap messages = loadYamlNode(await file.readAsString(), sourceUrl: uri);
    for (String name in messages.keys) {
      YamlNode messageNode = messages.nodes[name];
      var message = messageNode.value;
      if (message is String) continue;

      List<String> unknownKeys = <String>[];
      List<Example> examples = <Example>[];
      String analyzerCode;
      String dart2jsCode;
      Severity severity;
      YamlNode badSeverity;

      for (String key in message.keys) {
        YamlNode node = message.nodes[key];
        var value = node.value;
        switch (key) {
          case "template":
          case "tip":
            break;

          case "severity":
            severity = severityEnumValues[value];
            if (severity == null) {
              badSeverity = node;
            }
            break;

          case "analyzerCode":
            analyzerCode = value;
            break;

          case "dart2jsCode":
            dart2jsCode = value;
            break;

          case "bytes":
            YamlList list = node;
            if (list.first is List) {
              for (YamlList bytes in list.nodes) {
                int i = 0;
                examples.add(new BytesExample("bytes${++i}", name, bytes));
              }
            } else {
              examples.add(new BytesExample("bytes", name, list));
            }
            break;

          case "declaration":
            if (node is YamlList) {
              int i = 0;
              for (YamlNode declaration in node.nodes) {
                examples.add(new DeclarationExample(
                    "declaration${++i}", name, declaration));
              }
            } else {
              examples.add(new DeclarationExample("declaration", name, node));
            }
            break;

          case "expression":
            if (node is YamlList) {
              int i = 0;
              for (YamlNode expression in node.nodes) {
                examples.add(new ExpressionExample(
                    "expression${++i}", name, expression));
              }
            } else {
              examples.add(new ExpressionExample("expression", name, node));
            }
            break;

          case "script":
            if (node is YamlList) {
              int i = 0;
              for (YamlNode script in node.nodes) {
                examples.add(new ScriptExample("script${++i}", name, script));
              }
            } else {
              examples.add(new ScriptExample("script", name, node));
            }
            break;

          case "statement":
            if (node is YamlList) {
              int i = 0;
              for (YamlNode statement in node.nodes) {
                examples.add(
                    new StatementExample("statement${++i}", name, statement));
              }
            } else {
              examples.add(new StatementExample("statement", name, node));
            }
            break;

          default:
            unknownKeys.add(key);
        }
      }

      MessageTestDescription createDescription(
          String subName, Example example, String problem,
          {location}) {
        String shortName = "$name/$subName";
        if (problem != null) {
          String filename = relativize(uri);
          location ??= message.span.start;
          int line = location.line;
          int column = location.column;
          problem = "$filename:$line:$column: error:\n$problem";
        }
        return new MessageTestDescription(uri.resolve("#$shortName"), shortName,
            name, messageNode, example, problem);
      }

      for (Example example in examples) {
        yield createDescription(example.name, example, null);
      }

      yield createDescription(
          "knownKeys",
          null,
          unknownKeys.isNotEmpty
              ? "Unknown keys: ${unknownKeys.join(' ')}."
              : null);

      yield createDescription(
          "severity",
          null,
          badSeverity != null
              ? "Unknown severity: '${badSeverity.value}'."
              : null,
          location: badSeverity?.span?.start);

      bool exampleAndAnalyzerCodeRequired = (severity != Severity.context &&
          severity != Severity.internalProblem);

      yield createDescription(
          "example",
          null,
          exampleAndAnalyzerCodeRequired && examples.isEmpty
              ? "No example for $name, please add at least one example."
              : null);

      yield createDescription(
          "analyzerCode",
          null,
          exampleAndAnalyzerCodeRequired && analyzerCode == null
              ? "No analyzer code for $name."
                  "\nTry running"
                  " <BUILDDIR>/dart-sdk/bin/dartanalyzer --format=machine"
                  " on an example to find the code."
                  " The code is printed just before the file name."
              : null);

      yield createDescription(
          "dart2jsCode",
          null,
          exampleAndAnalyzerCodeRequired &&
                  analyzerCode != null &&
                  dart2jsCode == null
              ? "No dart2js code for $name."
                  " Try using *ignored* or *fatal*"
              : null);
    }
  }

  Uri addSource(String name, List<int> bytes) {
    Uri uri = fileSystem.currentDirectory.resolve(name);
    MemoryFileSystemEntity entity = fileSystem.entityForUri(uri);
    entity.writeAsBytesSync(bytes);
    return uri;
  }

  List<List> takeProblems() {
    List<List> result = problems.toList();
    problems.clear();
    return result;
  }

  String formatProblems(String message, Example example, List<List> problems) {
    var span = example.node.span;
    StringBuffer buffer = new StringBuffer();
    buffer
      ..write(relativize(span.sourceUrl))
      ..write(":")
      ..write(span.start.line)
      ..write(":")
      ..write(span.start.column)
      ..write(": error: ")
      ..write(message);
    buffer.write("\n${span.text}");
    for (List problem in problems) {
      LocatedMessage messsage = problem[0];
      String formatted = problem[2];
      buffer.write("\nCode: ${messsage.code.name}");
      buffer.write("\n  > ");
      buffer.write(formatted.replaceAll("\n", "\n  > "));
    }

    return "$buffer";
  }
}

abstract class Example {
  final String name;

  final String expectedCode;

  Example(this.name, this.expectedCode);

  YamlNode get node;

  Uint8List get bytes;
}

class BytesExample extends Example {
  @override
  final YamlList node;

  @override
  final Uint8List bytes;

  BytesExample(String name, String code, this.node)
      : bytes = new Uint8List.fromList(node.value),
        super(name, code);
}

class DeclarationExample extends Example {
  @override
  final YamlNode node;

  final String declaration;

  DeclarationExample(String name, String code, this.node)
      : declaration = node.value,
        super(name, code);

  @override
  Uint8List get bytes {
    return new Uint8List.fromList(utf8.encode("""
$declaration

main() {
}
"""));
  }
}

class StatementExample extends Example {
  @override
  final YamlNode node;

  final String statement;

  StatementExample(String name, String code, this.node)
      : statement = node.value,
        super(name, code);

  @override
  Uint8List get bytes {
    return new Uint8List.fromList(utf8.encode("""
main() {
  $statement
}
"""));
  }
}

class ExpressionExample extends Example {
  @override
  final YamlNode node;

  final String expression;

  ExpressionExample(String name, String code, this.node)
      : expression = node.value,
        super(name, code);

  @override
  Uint8List get bytes {
    return new Uint8List.fromList(utf8.encode("""
main() {
  $expression;
}
"""));
  }
}

class ScriptExample extends Example {
  @override
  final YamlNode node;

  final String script;

  ScriptExample(String name, String code, this.node)
      : script = node.value,
        super(name, code);

  @override
  Uint8List get bytes {
    return new Uint8List.fromList(utf8.encode(script));
  }
}

class Validate extends Step<MessageTestDescription, Example, MessageTestSuite> {
  const Validate();

  String get name => "validate";

  Future<Result<Example>> run(
      MessageTestDescription description, MessageTestSuite suite) async {
    if (description.problem != null) {
      return fail(null, description.problem);
    } else {
      return pass(description.example);
    }
  }
}

class Compile extends Step<Example, Null, MessageTestSuite> {
  const Compile();

  String get name => "compile";

  Future<Result<Null>> run(Example example, MessageTestSuite suite) async {
    if (example == null) return pass(null);
    String name = "${example.expectedCode}/${example.name}";
    Uri uri = suite.addSource("${name}.dart", example.bytes);
    print("Compiling $uri");
    List<List> problems;
    try {
      await suite.compiler.batchCompile(<String>["--strong", "$uri"]);
    } finally {
      problems = suite.takeProblems();
    }
    List<List> unexpectedProblems = <List>[];
    for (List problem in problems) {
      LocatedMessage message = problem[0];
      if (message.code.name != example.expectedCode) {
        unexpectedProblems.add(problem);
      }
    }
    if (unexpectedProblems.isEmpty) {
      switch (problems.length) {
        case 0:
          return fail(
              null,
              suite.formatProblems("No problem reported in ${example.name}:",
                  example, problems));
        case 1:
          return pass(null);
        default:
          return fail(
              null,
              suite.formatProblems(
                  "Problem reported multiple times in ${example.name}:",
                  example,
                  problems));
      }
    }
    return fail(
        null,
        suite.formatProblems("Too many problems reported in ${example.name}:",
            example, problems));
  }
}

Future<MessageTestSuite> createContext(
    Chain suite, Map<String, String> environment) async {
  return new MessageTestSuite();
}

String relativize(Uri uri) {
  String base = "${Uri.base}";
  String filename = "$uri";
  if (filename.startsWith(base)) {
    return filename.substring(base.length);
  } else {
    return filename;
  }
}

main([List<String> arguments = const []]) =>
    runMe(arguments, createContext, "../../testing.json");