// 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.

library analyzer.src.generated.sdk_io;

import 'dart:collection';
import 'dart:io';

import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/src/context/context.dart';
import 'package:analyzer/src/dart/scanner/reader.dart';
import 'package:analyzer/src/dart/scanner/scanner.dart';
import 'package:analyzer/src/generated/engine.dart';
import 'package:analyzer/src/generated/error.dart';
import 'package:analyzer/src/generated/java_core.dart';
import 'package:analyzer/src/generated/java_engine.dart';
import 'package:analyzer/src/generated/java_engine_io.dart';
import 'package:analyzer/src/generated/java_io.dart';
import 'package:analyzer/src/generated/parser.dart';
import 'package:analyzer/src/generated/sdk.dart';
import 'package:analyzer/src/generated/source_io.dart';
import 'package:analyzer/src/summary/idl.dart' show PackageBundle;
import 'package:analyzer/src/summary/summary_sdk.dart';
import 'package:path/path.dart' as pathos;

/**
 * A Dart SDK installed in a specified directory. Typical Dart SDK layout is
 * something like...
 *
 *     dart-sdk/
 *        bin/
 *           dart[.exe]  <-- VM
 *        lib/
 *           core/
 *              core.dart
 *              ... other core library files ...
 *           ... other libraries ...
 *        util/
 *           ... Dart utilities ...
 *     Chromium/   <-- Dartium typically exists in a sibling directory
 */
class DirectoryBasedDartSdk implements DartSdk {
  /**
   * The default SDK, or `null` if the default SDK either has not yet been
   * created or cannot be created for some reason.
   */
  static DirectoryBasedDartSdk _DEFAULT_SDK;

  /**
   * The name of the directory within the SDK directory that contains
   * executables.
   */
  static String _BIN_DIRECTORY_NAME = "bin";

  /**
   * The name of the directory on non-Mac that contains dartium.
   */
  static String _DARTIUM_DIRECTORY_NAME = "chromium";

  /**
   * The name of the dart2js executable on non-windows operating systems.
   */
  static String _DART2JS_EXECUTABLE_NAME = "dart2js";

  /**
   * The name of the file containing the dart2js executable on Windows.
   */
  static String _DART2JS_EXECUTABLE_NAME_WIN = "dart2js.bat";

  /**
   * The name of the file containing the Dartium executable on Linux.
   */
  static String _DARTIUM_EXECUTABLE_NAME_LINUX = "chrome";

  /**
   * The name of the file containing the Dartium executable on Macintosh.
   */
  static String _DARTIUM_EXECUTABLE_NAME_MAC =
      "Chromium.app/Contents/MacOS/Chromium";

  /**
   * The name of the file containing the Dartium executable on Windows.
   */
  static String _DARTIUM_EXECUTABLE_NAME_WIN = "Chrome.exe";

  /**
   * The name of the [System] property whose value is the path to the default
   * Dart SDK directory.
   */
  static String _DEFAULT_DIRECTORY_PROPERTY_NAME = "com.google.dart.sdk";

  /**
   * The name of the directory within the SDK directory that contains
   * documentation for the libraries.
   */
  static String _DOCS_DIRECTORY_NAME = "docs";

  /**
   * The suffix added to the name of a library to derive the name of the file
   * containing the documentation for that library.
   */
  static String _DOC_FILE_SUFFIX = "_api.json";

  /**
   * The name of the directory within the SDK directory that contains the
   * sdk_library_metadata directory.
   */
  static String _INTERNAL_DIR = "_internal";

  /**
   * The name of the sdk_library_metadata directory that contains the package
   * holding the libraries.dart file.
   */
  static String _SDK_LIBRARY_METADATA_DIR = "sdk_library_metadata";

  /**
   * The name of the directory within the sdk_library_metadata that contains
   * libraries.dart.
   */
  static String _SDK_LIBRARY_METADATA_LIB_DIR = "lib";

  /**
   * The name of the directory within the SDK directory that contains the
   * libraries.
   */
  static String _LIB_DIRECTORY_NAME = "lib";

  /**
   * The name of the libraries file.
   */
  static String _LIBRARIES_FILE = "libraries.dart";

  /**
   * The name of the pub executable on windows.
   */
  static String _PUB_EXECUTABLE_NAME_WIN = "pub.bat";

  /**
   * The name of the pub executable on non-windows operating systems.
   */
  static String _PUB_EXECUTABLE_NAME = "pub";

  /**
   * The name of the file within the SDK directory that contains the version
   * number of the SDK.
   */
  static String _VERSION_FILE_NAME = "version";

  /**
   * The name of the file containing the VM executable on the Windows operating
   * system.
   */
  static String _VM_EXECUTABLE_NAME_WIN = "dart.exe";

  /**
   * The name of the file containing the VM executable on non-Windows operating
   * systems.
   */
  static String _VM_EXECUTABLE_NAME = "dart";

  /**
   * Return the default Dart SDK, or `null` if the directory containing the
   * default SDK cannot be determined (or does not exist).
   */
  static DirectoryBasedDartSdk get defaultSdk {
    if (_DEFAULT_SDK == null) {
      JavaFile sdkDirectory = defaultSdkDirectory;
      if (sdkDirectory == null) {
        return null;
      }
      _DEFAULT_SDK = new DirectoryBasedDartSdk(sdkDirectory);
    }
    return _DEFAULT_SDK;
  }

  /**
   * Return the default directory for the Dart SDK, or `null` if the directory
   * cannot be determined (or does not exist). The default directory is provided
   * by a system property named `com.google.dart.sdk`.
   */
  static JavaFile get defaultSdkDirectory {
    String sdkProperty =
        JavaSystemIO.getProperty(_DEFAULT_DIRECTORY_PROPERTY_NAME);
    if (sdkProperty == null) {
      return null;
    }
    JavaFile sdkDirectory = new JavaFile(sdkProperty);
    if (!sdkDirectory.exists()) {
      return null;
    }
    return sdkDirectory;
  }

  /**
   * The [AnalysisContext] which is used for all of the sources in this sdk.
   */
  InternalAnalysisContext _analysisContext;

  /**
   * The directory containing the SDK.
   */
  JavaFile _sdkDirectory;

  /**
   * The directory within the SDK directory that contains the libraries.
   */
  JavaFile _libraryDirectory;

  /**
   * The flag that specifies whether SDK summary should be used.
   */
  bool _useSummary = false;

  /**
   * The revision number of this SDK, or `"0"` if the revision number cannot be
   * discovered.
   */
  String _sdkVersion;

  /**
   * The file containing the dart2js executable.
   */
  JavaFile _dart2jsExecutable;

  /**
   * The file containing the Dartium executable.
   */
  JavaFile _dartiumExecutable;

  /**
   * The file containing the pub executable.
   */
  JavaFile _pubExecutable;

  /**
   * The file containing the VM executable.
   */
  JavaFile _vmExecutable;

  /**
   * A mapping from Dart library URI's to the library represented by that URI.
   */
  LibraryMap _libraryMap;

  /**
   * The mapping from Dart URI's to the corresponding sources.
   */
  Map<String, Source> _uriToSourceMap = new HashMap<String, Source>();

  /**
   * The [AnalysisOptions] to use to create the [context].
   */
  AnalysisOptions _analysisOptions;

  /**
   * Initialize a newly created SDK to represent the Dart SDK installed in the
   * [sdkDirectory]. The flag [useDart2jsPaths] is `true` if the dart2js path
   * should be used when it is available
   */
  DirectoryBasedDartSdk(JavaFile sdkDirectory, [bool useDart2jsPaths = false]) {
    this._sdkDirectory = sdkDirectory.getAbsoluteFile();
    _libraryMap = initialLibraryMap(useDart2jsPaths);
  }

  /**
   * Set the [options] for this SDK analysis context.  Throw [StateError] if the
   * context has been already created.
   */
  void set analysisOptions(AnalysisOptions options) {
    if (_analysisContext != null) {
      throw new StateError(
          'Analysis options cannot be changed after context creation.');
    }
    _analysisOptions = options;
  }

  @override
  AnalysisContext get context {
    if (_analysisContext == null) {
      _analysisContext = new SdkAnalysisContext(_analysisOptions);
      SourceFactory factory = new SourceFactory([new DartUriResolver(this)]);
      _analysisContext.sourceFactory = factory;
      if (_useSummary) {
        PackageBundle sdkBundle = getSummarySdkBundle();
        if (sdkBundle != null) {
          bool strongMode = _analysisOptions?.strongMode ?? false;
          _analysisContext.resultProvider = new SdkSummaryResultProvider(
              _analysisContext, sdkBundle, strongMode);
        }
      }
    }
    return _analysisContext;
  }

  /**
   * Return the file containing the dart2js executable, or `null` if it does not
   * exist.
   */
  JavaFile get dart2JsExecutable {
    if (_dart2jsExecutable == null) {
      _dart2jsExecutable = _verifyExecutable(new JavaFile.relative(
          new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME),
          OSUtilities.isWindows()
              ? _DART2JS_EXECUTABLE_NAME_WIN
              : _DART2JS_EXECUTABLE_NAME));
    }
    return _dart2jsExecutable;
  }

  /**
   * Return the name of the file containing the Dartium executable.
   */
  String get dartiumBinaryName {
    if (OSUtilities.isWindows()) {
      return _DARTIUM_EXECUTABLE_NAME_WIN;
    } else if (OSUtilities.isMac()) {
      return _DARTIUM_EXECUTABLE_NAME_MAC;
    } else {
      return _DARTIUM_EXECUTABLE_NAME_LINUX;
    }
  }

  /**
   * Return the file containing the Dartium executable, or `null` if it does not
   * exist.
   */
  JavaFile get dartiumExecutable {
    if (_dartiumExecutable == null) {
      _dartiumExecutable = _verifyExecutable(
          new JavaFile.relative(dartiumWorkingDirectory, dartiumBinaryName));
    }
    return _dartiumExecutable;
  }

  /**
   * Return the directory where dartium can be found (the directory that will be
   * the working directory is Dartium is invoked without changing the default).
   */
  JavaFile get dartiumWorkingDirectory =>
      getDartiumWorkingDirectory(_sdkDirectory.getParentFile());

  /**
   * Return the directory containing the SDK.
   */
  JavaFile get directory => _sdkDirectory;

  /**
   * Return the directory containing documentation for the SDK.
   */
  JavaFile get docDirectory =>
      new JavaFile.relative(_sdkDirectory, _DOCS_DIRECTORY_NAME);

  /**
   * Return `true` if this SDK includes documentation.
   */
  bool get hasDocumentation => docDirectory.exists();

  /**
   * Return `true` if the Dartium binary is available.
   */
  bool get isDartiumInstalled => dartiumExecutable != null;

  /**
   * Return the directory within the SDK directory that contains the libraries.
   */
  JavaFile get libraryDirectory {
    if (_libraryDirectory == null) {
      _libraryDirectory =
          new JavaFile.relative(_sdkDirectory, _LIB_DIRECTORY_NAME);
    }
    return _libraryDirectory;
  }

  /**
   * Return the file containing the Pub executable, or `null` if it does not exist.
   */
  JavaFile get pubExecutable {
    if (_pubExecutable == null) {
      _pubExecutable = _verifyExecutable(new JavaFile.relative(
          new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME),
          OSUtilities.isWindows()
              ? _PUB_EXECUTABLE_NAME_WIN
              : _PUB_EXECUTABLE_NAME));
    }
    return _pubExecutable;
  }

  @override
  List<SdkLibrary> get sdkLibraries => _libraryMap.sdkLibraries;

  /**
   * Return the revision number of this SDK, or `"0"` if the revision number
   * cannot be discovered.
   */
  @override
  String get sdkVersion {
    if (_sdkVersion == null) {
      _sdkVersion = DartSdk.DEFAULT_VERSION;
      JavaFile revisionFile =
          new JavaFile.relative(_sdkDirectory, _VERSION_FILE_NAME);
      try {
        String revision = revisionFile.readAsStringSync();
        if (revision != null) {
          _sdkVersion = revision.trim();
        }
      } on FileSystemException {
        // Fall through to return the default.
      }
    }
    return _sdkVersion;
  }

  @override
  List<String> get uris => _libraryMap.uris;

  /**
   * Whether an SDK summary should be used.
   */
  bool get useSummary => _useSummary;

  /**
   * Specify whether SDK summary should be used.
   */
  void set useSummary(bool use) {
    if (_analysisContext != null) {
      throw new StateError(
          'The "useSummary" flag cannot be changed after context creation.');
    }
    _useSummary = use;
  }

  /**
   * Return the name of the file containing the VM executable.
   */
  String get vmBinaryName {
    if (OSUtilities.isWindows()) {
      return _VM_EXECUTABLE_NAME_WIN;
    } else {
      return _VM_EXECUTABLE_NAME;
    }
  }

  /**
   * Return the file containing the VM executable, or `null` if it does not
   * exist.
   */
  JavaFile get vmExecutable {
    if (_vmExecutable == null) {
      _vmExecutable = _verifyExecutable(new JavaFile.relative(
          new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME),
          vmBinaryName));
    }
    return _vmExecutable;
  }

  /**
   * Determine the search order for trying to locate the [_LIBRARIES_FILE].
   */
  Iterable<JavaFile> get _libraryMapLocations sync* {
    yield new JavaFile.relative(
        new JavaFile.relative(
            new JavaFile.relative(
                new JavaFile.relative(libraryDirectory, _INTERNAL_DIR),
                _SDK_LIBRARY_METADATA_DIR),
            _SDK_LIBRARY_METADATA_LIB_DIR),
        _LIBRARIES_FILE);
    yield new JavaFile.relative(
        new JavaFile.relative(libraryDirectory, _INTERNAL_DIR),
        _LIBRARIES_FILE);
  }

  @override
  Source fromFileUri(Uri uri) {
    JavaFile file = new JavaFile.fromUri(uri);
    String filePath = file.getAbsolutePath();
    String libPath = libraryDirectory.getAbsolutePath();
    if (!filePath.startsWith("$libPath${JavaFile.separator}")) {
      return null;
    }
    filePath = filePath.substring(libPath.length + 1);
    for (SdkLibrary library in _libraryMap.sdkLibraries) {
      String libraryPath = library.path;
      if (filePath.replaceAll('\\', '/') == libraryPath) {
        String path = library.shortName;
        try {
          return new FileBasedSource(file, parseUriWithException(path));
        } on URISyntaxException catch (exception, stackTrace) {
          AnalysisEngine.instance.logger.logInformation(
              "Failed to create URI: $path",
              new CaughtException(exception, stackTrace));
          return null;
        }
      }
      libraryPath = new JavaFile(library.path).getParent();
      if (filePath.startsWith("$libraryPath${JavaFile.separator}")) {
        String path =
            "${library.shortName}/${filePath.substring(libraryPath.length + 1)}";
        try {
          return new FileBasedSource(file, parseUriWithException(path));
        } on URISyntaxException catch (exception, stackTrace) {
          AnalysisEngine.instance.logger.logInformation(
              "Failed to create URI: $path",
              new CaughtException(exception, stackTrace));
          return null;
        }
      }
    }
    return null;
  }

  /**
   * Return the directory where dartium can be found (the directory that will be
   * the working directory if Dartium is invoked without changing the default),
   * assuming that the Editor was installed in the [installDir].
   */
  JavaFile getDartiumWorkingDirectory(JavaFile installDir) =>
      new JavaFile.relative(installDir, _DARTIUM_DIRECTORY_NAME);

  /**
   * Return the auxiliary documentation file for the library with the given
   * [libraryName], or `null` if no such file exists.
   */
  JavaFile getDocFileFor(String libraryName) {
    JavaFile dir = docDirectory;
    if (!dir.exists()) {
      return null;
    }
    JavaFile libDir = new JavaFile.relative(dir, libraryName);
    JavaFile docFile =
        new JavaFile.relative(libDir, "$libraryName$_DOC_FILE_SUFFIX");
    if (docFile.exists()) {
      return docFile;
    }
    return null;
  }

  @override
  SdkLibrary getSdkLibrary(String dartUri) => _libraryMap.getLibrary(dartUri);

  /**
   * Return the [PackageBundle] for this SDK, if it exists, or `null` otherwise.
   * This method should not be used outside of `analyzer` and `analyzer_cli`
   * packages.
   */
  PackageBundle getSummarySdkBundle() {
    String rootPath = directory.getAbsolutePath();
    bool strongMode = _analysisOptions?.strongMode ?? false;
    String name = strongMode ? 'strong.sum' : 'spec.sum';
    String path = pathos.join(rootPath, 'lib', '_internal', name);
    try {
      File file = new File(path);
      if (file.existsSync()) {
        List<int> bytes = file.readAsBytesSync();
        return new PackageBundle.fromBuffer(bytes);
      }
    } catch (exception, stackTrace) {
      AnalysisEngine.instance.logger.logError(
          'Failed to load SDK analysis summary from $path',
          new CaughtException(exception, stackTrace));
    }
    return null;
  }

  /**
   * Read all of the configuration files to initialize the library maps. The
   * flag [useDart2jsPaths] is `true` if the dart2js path should be used when it
   * is available. Return the initialized library map.
   */
  LibraryMap initialLibraryMap(bool useDart2jsPaths) {
    List<String> searchedPaths = <String>[];
    var lastStackTrace = null;
    var lastException = null;
    for (JavaFile librariesFile in _libraryMapLocations) {
      try {
        String contents = librariesFile.readAsStringSync();
        return new SdkLibrariesReader(useDart2jsPaths)
            .readFromFile(librariesFile, contents);
      } catch (exception, stackTrace) {
        searchedPaths.add(librariesFile.getAbsolutePath());
        lastException = exception;
        lastStackTrace = stackTrace;
      }
    }
    AnalysisEngine.instance.logger.logError(
        "Could not initialize the library map from $searchedPaths",
        new CaughtException(lastException, lastStackTrace));
    return new LibraryMap();
  }

  @override
  Source mapDartUri(String dartUri) {
    Source source = _uriToSourceMap[dartUri];
    if (source == null) {
      source = _mapDartUri(dartUri);
      _uriToSourceMap[dartUri] = source;
    }
    return source;
  }

  FileBasedSource _mapDartUri(String dartUri) {
    String libraryName;
    String relativePath;
    int index = dartUri.indexOf('/');
    if (index >= 0) {
      libraryName = dartUri.substring(0, index);
      relativePath = dartUri.substring(index + 1);
    } else {
      libraryName = dartUri;
      relativePath = "";
    }
    SdkLibrary library = getSdkLibrary(libraryName);
    if (library == null) {
      return null;
    }
    try {
      JavaFile file = new JavaFile.relative(libraryDirectory, library.path);
      if (!relativePath.isEmpty) {
        file = file.getParentFile();
        file = new JavaFile.relative(file, relativePath);
      }
      return new FileBasedSource(file, parseUriWithException(dartUri));
    } on URISyntaxException {
      return null;
    }
  }

  /**
   * Return the given [file] if it exists and is executable, or `null` if it
   * does not exist or is not executable.
   */
  JavaFile _verifyExecutable(JavaFile file) =>
      file.isExecutable() ? file : null;
}

/**
 * An object used to read and parse the libraries file
 * (dart-sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart) for information
 * about the libraries in an SDK. The library information is represented as a
 * Dart file containing a single top-level variable whose value is a const map.
 * The keys of the map are the names of libraries defined in the SDK and the
 * values in the map are info objects defining the library. For example, a
 * subset of a typical SDK might have a libraries file that looks like the
 * following:
 *
 *     final Map<String, LibraryInfo> LIBRARIES = const <LibraryInfo> {
 *       // Used by VM applications
 *       "builtin" : const LibraryInfo(
 *         "builtin/builtin_runtime.dart",
 *         category: "Server",
 *         platforms: VM_PLATFORM),
 *
 *       "compiler" : const LibraryInfo(
 *         "compiler/compiler.dart",
 *         category: "Tools",
 *         platforms: 0),
 *     };
 */
class SdkLibrariesReader {
  /**
   * A flag indicating whether the dart2js path should be used when it is
   * available.
   */
  final bool _useDart2jsPaths;

  /**
   * Initialize a newly created library reader to use the dart2js path if
   * [_useDart2jsPaths] is `true`.
   */
  SdkLibrariesReader(this._useDart2jsPaths);

  /**
   * Return the library map read from the given [file], given that the content
   * of the file is already known to be [libraryFileContents].
   */
  LibraryMap readFromFile(JavaFile file, String libraryFileContents) =>
      readFromSource(new FileBasedSource(file), libraryFileContents);

  /**
   * Return the library map read from the given [source], given that the content
   * of the file is already known to be [libraryFileContents].
   */
  LibraryMap readFromSource(Source source, String libraryFileContents) {
    BooleanErrorListener errorListener = new BooleanErrorListener();
    Scanner scanner = new Scanner(
        source, new CharSequenceReader(libraryFileContents), errorListener);
    Parser parser = new Parser(source, errorListener);
    CompilationUnit unit = parser.parseCompilationUnit(scanner.tokenize());
    SdkLibrariesReader_LibraryBuilder libraryBuilder =
        new SdkLibrariesReader_LibraryBuilder(_useDart2jsPaths);
    // If any syntactic errors were found then don't try to visit the AST
    // structure.
    if (!errorListener.errorReported) {
      unit.accept(libraryBuilder);
    }
    return libraryBuilder.librariesMap;
  }
}