// 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 'package:analyzer/error/error.dart';
import 'package:analyzer/error/listener.dart';
import 'package:analyzer/file_system/file_system.dart';
import 'package:analyzer/src/generated/source.dart';
import 'package:analyzer/src/pubspec/pubspec_validator.dart';
import 'package:analyzer/src/pubspec/pubspec_warning_code.dart';
import 'package:path/path.dart' as path;
import 'package:yaml/yaml.dart';

class FlutterValidator extends BasePubspecValidator {
  FlutterValidator(ResourceProvider provider, Source source)
      : super(provider, source);

  /// Validate the value of the optional `flutter` field.
  void validate(ErrorReporter reporter, Map<dynamic, YamlNode> contents) {
    var flutterField = contents[PubspecField.FLUTTER_FIELD];
    if (flutterField is YamlMap) {
      var assetsField = flutterField.nodes[PubspecField.ASSETS_FIELD];
      if (assetsField is YamlList) {
        path.Context context = provider.pathContext;
        String packageRoot = context.dirname(source.fullName);
        for (YamlNode entryValue in assetsField.nodes) {
          if (entryValue is YamlScalar) {
            Object entry = entryValue.value;
            if (entry is String) {
              if (entry.startsWith('packages/')) {
                // TODO(brianwilkerson) Add validation of package references.
              } else {
                bool isDirectoryEntry = entry.endsWith("/");
                String normalizedEntry =
                    context.joinAll(path.posix.split(entry));
                String assetPath = context.join(packageRoot, normalizedEntry);
                if (!_assetExistsAtPath(assetPath)) {
                  ErrorCode errorCode = isDirectoryEntry
                      ? PubspecWarningCode.ASSET_DIRECTORY_DOES_NOT_EXIST
                      : PubspecWarningCode.ASSET_DOES_NOT_EXIST;
                  reportErrorForNode(
                      reporter, entryValue, errorCode, [entryValue.value]);
                }
              }
            } else {
              reportErrorForNode(
                  reporter, entryValue, PubspecWarningCode.ASSET_NOT_STRING);
            }
          } else {
            reportErrorForNode(
                reporter, entryValue, PubspecWarningCode.ASSET_NOT_STRING);
          }
        }
      } else if (assetsField != null) {
        reportErrorForNode(
            reporter, assetsField, PubspecWarningCode.ASSET_FIELD_NOT_LIST);
      }

      if (flutterField.length > 1) {
        // TODO(brianwilkerson) Should we report an error if `flutter` contains
        // keys other than `assets`?
      }
    } else if (flutterField != null) {
      if (flutterField.value == null) {
        // allow an empty `flutter:` section; explicitly fail on a non-empty,
        // non-map one
      } else {
        reportErrorForNode(
            reporter, flutterField, PubspecWarningCode.FLUTTER_FIELD_NOT_MAP);
      }
    }
  }

  /// Return `true` if an asset (file) exists at the given absolute, normalized
  /// [assetPath] or in a subdirectory of the parent of the file.
  bool _assetExistsAtPath(String assetPath) {
    // Check for asset directories.
    Folder assetDirectory = provider.getFolder(assetPath);
    if (assetDirectory.exists) {
      return true;
    }

    // Else, check for an asset file.
    File assetFile = provider.getFile(assetPath);
    if (assetFile.exists) {
      return true;
    }
    String fileName = assetFile.shortName;
    Folder assetFolder = assetFile.parent;
    if (!assetFolder.exists) {
      return false;
    }
    for (Resource child in assetFolder.getChildren()) {
      if (child is Folder) {
        File innerFile = child.getChildAssumingFile(fileName);
        if (innerFile.exists) {
          return true;
        }
      }
    }
    return false;
  }
}