// 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.

/// A documentation generator for Dart.
library dartdoc;

import 'dart:async';
import 'dart:io';

import 'package:analyzer/file_system/file_system.dart' as fileSystem;
import 'package:analyzer/file_system/physical_file_system.dart';
import 'package:analyzer/source/package_map_provider.dart';
import 'package:analyzer/source/package_map_resolver.dart';
import 'package:analyzer/source/pub_package_map_provider.dart';
import 'package:analyzer/source/sdk_ext.dart';
import 'package:analyzer/src/generated/element.dart';
import 'package:analyzer/src/generated/engine.dart';
import 'package:analyzer/src/generated/error.dart';
import 'package:analyzer/src/generated/java_io.dart';
import 'package:analyzer/src/generated/sdk.dart';
import 'package:analyzer/src/generated/sdk_io.dart';
import 'package:analyzer/src/generated/source.dart';
import 'package:analyzer/src/generated/source_io.dart';

import 'generator.dart';
import 'resource_loader.dart' as loader;
import 'src/html_generator.dart' show dartdocVersion, HtmlGenerator;
import 'src/io_utils.dart';
import 'src/model.dart';
import 'src/model_utils.dart';
import 'src/package_meta.dart';

export 'src/model.dart';
export 'src/package_meta.dart';

const String name = 'dartdoc';
// Update when pubspec version changes.
const String version = '0.6.0+1';

final String defaultOutDir = 'doc${Platform.pathSeparator}api';

/// Initialize and setup the generators.
List<Generator> initGenerators(
    String url, String headerFilePath, String footerFilePath) {
  dartdocVersion = version;
  return [
    new HtmlGenerator(url, header: headerFilePath, footer: footerFilePath)
  ];
}

/// Generates Dart documentation for all public Dart libraries in the given
/// directory.
class DartDoc {
  final Directory rootDir;
  final List<String> excludes;
  final Directory sdkDir;
  final List<Generator> generators;
  final Directory outputDir;
  final Directory packageRootDir;
  final PackageMeta packageMeta;
  final Map<String, String> urlMappings;
  final List<String> includes;

  Stopwatch _stopwatch;

  DartDoc(
      this.rootDir,
      this.excludes,
      this.sdkDir,
      this.generators,
      this.outputDir,
      this.packageRootDir,
      this.packageMeta,
      this.urlMappings,
      this.includes);

  /// Generate DartDoc documentation.
  ///
  /// [DartDocResults] is returned if dartdoc succeeds. [DartDocFailure] is
  /// thrown if dartdoc fails in an expected way, for example if there is an
  /// anaysis error in the code. Any other exception can be throw if there is an
  /// unexpected failure.
  Future<DartDocResults> generateDocs() async {
    _stopwatch = new Stopwatch()..start();

    if (packageRootDir != null) loader.packageRootPath = packageRootDir.path;

    List<String> files =
        packageMeta.isSdk ? [] : findFilesToDocumentInPackage(rootDir.path);

    List<LibraryElement> libraries = _parseLibraries(files);

    if (includes != null && includes.isNotEmpty) {
      Iterable knownLibraryNames = libraries.map((l) => l.name);
      Set notFound =
          new Set.from(includes).difference(new Set.from(knownLibraryNames));
      if (notFound.isNotEmpty) {
        return new Future.error('Did not find: [${notFound.join(', ')}] in ' +
            'known libraries: [${knownLibraryNames.join(', ')}]');
      }
      libraries.removeWhere((lib) => !includes.contains(lib.name));
    } else {
      // remove excluded libraries
      excludes.forEach((pattern) {
        libraries.removeWhere((lib) {
          return lib.name.startsWith(pattern) || lib.name == pattern;
        });
      });
    }

    if (includes.isNotEmpty || excludes.isNotEmpty) {
      print('Generating docs for libraries ${libraries.join(', ')}\n');
    }

    Package package = new Package(libraries, packageMeta);

    // Create the out directory.
    if (!outputDir.existsSync()) outputDir.createSync(recursive: true);

    for (var generator in generators) {
      await generator.generate(package, outputDir);
    }

    double seconds = _stopwatch.elapsedMilliseconds / 1000.0;
    print(
        "Documented ${libraries.length} librar${libraries.length == 1 ? 'y' : 'ies'} "
        "in ${seconds.toStringAsFixed(1)} seconds.");

    return new DartDocResults(packageMeta, package, outputDir);
  }

  List<LibraryElement> _parseLibraries(List<String> files) {
    Set<LibraryElement> libraries = new Set();
    DartSdk sdk = new DirectoryBasedDartSdk(new JavaFile(sdkDir.path));
    List<UriResolver> resolvers = [new DartUriResolver(sdk)];
    if (urlMappings != null) resolvers.insert(
        0, new CustomUriResolver(urlMappings));

    fileSystem.Resource cwd =
        PhysicalResourceProvider.INSTANCE.getResource('.');
    PubPackageMapProvider pubPackageMapProvider =
        new PubPackageMapProvider(PhysicalResourceProvider.INSTANCE, sdk);
    PackageMapInfo packageMapInfo =
        pubPackageMapProvider.computePackageMap(cwd);
    Map<String, List<fileSystem.Folder>> packageMap = packageMapInfo.packageMap;
    if (packageMap != null) {
      resolvers.add(new SdkExtUriResolver(packageMap));
      resolvers.add(new PackageMapUriResolver(
          PhysicalResourceProvider.INSTANCE, packageMap));
    }
    resolvers.add(new FileUriResolver());
    SourceFactory sourceFactory =
        new SourceFactory(/*contentCache,*/ resolvers);

    var options = new AnalysisOptionsImpl()..cacheSize = 512;

    AnalysisContext context = AnalysisEngine.instance.createAnalysisContext()
      ..analysisOptions = options
      ..sourceFactory = sourceFactory;

    if (packageMeta.isSdk) {
      libraries.addAll(getSdkLibrariesToDocument(sdk, context));
    }

    List<Source> sources = [];

    files.forEach((String filePath) {
      String name = filePath;
      if (name.startsWith(Directory.current.path)) {
        name = name.substring(Directory.current.path.length);
        if (name.startsWith(Platform.pathSeparator)) name = name.substring(1);
      }
      print('parsing ${name}...');
      JavaFile javaFile = new JavaFile(filePath);
      Source source = new FileBasedSource(new JavaFile(filePath));
      Uri uri = context.sourceFactory.restoreUri(source);
      if (uri != null) {
        source = new FileBasedSource(javaFile, uri);
      }
      sources.add(source);
      if (context.computeKindOf(source) == SourceKind.LIBRARY) {
        LibraryElement library = context.computeLibraryElement(source);
        libraries.add(library);
      }
    });

    // Ensure that the analysis engine performs all remaining work.
    AnalysisResult result = context.performAnalysisTask();
    while (result.hasMoreWork) {
      result = context.performAnalysisTask();
    }

    List<AnalysisErrorInfo> errorInfos = [];

    for (Source source in sources) {
      context.computeErrors(source);
      errorInfos.add(context.getErrors(source));
    }

    List<_Error> errors = errorInfos.expand((AnalysisErrorInfo info) {
      return info.errors.map(
          (error) => new _Error(error, info.lineInfo, packageMeta.dir.path));
    }).where((_Error error) => error.isError).toList()..sort();

    double seconds = _stopwatch.elapsedMilliseconds / 1000.0;
    print("Parsed ${libraries.length} "
        "file${libraries.length == 1 ? '' : 's'} in "
        "${seconds.toStringAsFixed(1)} seconds.\n");

    if (errors.isNotEmpty) {
      errors.forEach(print);
      int len = errors.length;
      throw new DartDocFailure(
          "encountered ${len} analysis error${len == 1 ? '' : 's'}");
    }

    return libraries.toList();
  }
}

/// The results of a [DartDoc.generateDocs] call.
class DartDocResults {
  final PackageMeta packageMeta;
  final Package package;
  final Directory outDir;

  DartDocResults(this.packageMeta, this.package, this.outDir);
}

/// This class is returned if dartdoc fails in an expected way (for instance, if
/// there is an analysis error in the library).
class DartDocFailure {
  final String message;

  DartDocFailure(this.message);

  String toString() => message;
}

class _Error implements Comparable {
  final AnalysisError error;
  final LineInfo lineInfo;
  final String projectPath;

  _Error(this.error, this.lineInfo, this.projectPath);

  int get severity => error.errorCode.errorSeverity.ordinal;
  bool get isError => error.errorCode.errorSeverity == ErrorSeverity.ERROR;
  String get severityName => error.errorCode.errorSeverity.displayName;
  String get description => '${error.message} at ${location}, line ${line}.';
  int get line => lineInfo.getLocation(error.offset).lineNumber;

  String get location {
    String path = error.source.fullName;
    if (path.startsWith(projectPath)) {
      path = path.substring(projectPath.length + 1);
    }
    return path;
  }

  int compareTo(_Error other) {
    if (severity == other.severity) {
      int cmp = error.source.fullName.compareTo(other.error.source.fullName);
      return cmp == 0 ? line - other.line : cmp;
    } else {
      return other.severity - severity;
    }
  }

  String toString() => '[${severityName}] ${description}';
}