pkgs/jot/lib/src/analysis.dart

// Copyright (c) 2025, 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 'package:analyzer/dart/analysis/analysis_context.dart';
import 'package:analyzer/dart/analysis/analysis_context_collection.dart';
import 'package:analyzer/dart/analysis/results.dart';
import 'package:analyzer/file_system/file_system.dart';
import 'package:analyzer/file_system/physical_file_system.dart';
import 'package:path/path.dart' as p;

class Analyzer {
  late AnalysisContextCollection _collection;
  late ResourceProvider resourceProvider;

  int _lastCheckedMillis = DateTime.now().millisecondsSinceEpoch;

  /// Create an analysis context using the given paths.
  ///
  /// Note that all paths must the absolute. These are assumed to the paths to
  /// packages; for these packages, only the code in `lib/` will be analyzed.
  Analyzer.packages({
    required List<String> includedPaths,
    ResourceProvider? resourceProvider,
  }) {
    this.resourceProvider =
        resourceProvider ?? PhysicalResourceProvider.INSTANCE;

    _collection = AnalysisContextCollection(
      includedPaths: [...includedPaths.map((path) => p.join(path, 'lib'))],
      resourceProvider: this.resourceProvider,
    );
  }

  AnalysisContext get context => _collection.contexts.first;

  AnalysisContext contextFor(String path) {
    return _collection.contextFor(path);
  }

  Stream<ResolvedLibraryResult> resolvedPublicLibraries() async* {
    for (var file in _publicFiles) {
      var lib =
          await context.currentSession.getResolvedLibrary(file.path)
              as ResolvedLibraryResult;

      // TODO: Filter out parts?

      yield lib;
    }
  }

  Stream<ResolvedLibraryResult> resolvedLibrariesFor(String path) async* {
    var context = contextFor(path);

    for (var file in context.publicFiles) {
      var lib =
          await context.currentSession.getResolvedLibrary(file.path)
              as ResolvedLibraryResult;

      // TODO: Filter out parts?

      yield lib;
    }
  }

  /// Check for any changed files and reanalyze changes.
  ///
  /// Returns `true` if any changed files had been detected.
  Future<bool> reanalyzeChanges() async {
    var hasChanges = false;

    var context = _collection.contexts.first;

    final currentMillis = DateTime.now().millisecondsSinceEpoch;

    for (var path in context.contextRoot.analyzedFiles().where(
      (path) => path.endsWith('.dart'),
    )) {
      var modificationStamp = context.contextRoot.resourceProvider
          .getFile(path)
          .modificationStamp;

      if (modificationStamp > _lastCheckedMillis) {
        hasChanges = true;
        context.changeFile(path);
      }
    }

    _lastCheckedMillis = currentMillis;

    await context.applyPendingFileChanges();

    return hasChanges;
  }

  Iterable<File> get _publicFiles sync* {
    for (var context in _collection.contexts) {
      var root = context.contextRoot;
      var src = root.root.getChildAssumingFolder('src');

      var dartFiles =
          context.contextRoot
              .analyzedFiles()
              .where((path) => path.endsWith('.dart'))
              .toList()
            ..sort();

      for (var path in dartFiles) {
        if (src.contains(path)) continue;
        // TODO: Ignore files whose names starts with '_'?

        yield root.resourceProvider.getFile(path);
      }
    }
  }

  Future<LibraryElementResult> getLibraryByUri(String uri) async {
    var result = await context.currentSession.getLibraryByUri(uri);
    return result as LibraryElementResult;
  }
}

extension AnalysisContextExtension on AnalysisContext {
  Iterable<File> get publicFiles sync* {
    var root = contextRoot;
    var src = root.root.getChildAssumingFolder('src');

    var dartFiles =
        contextRoot
            .analyzedFiles()
            .where((path) => path.endsWith('.dart'))
            .toList()
          ..sort();

    for (var path in dartFiles) {
      if (src.contains(path)) continue;
      // TODO: Ignore files whose names starts with '_' ?

      yield root.resourceProvider.getFile(path);
    }
  }
}