// 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 dartdoc.model_utils;

import 'dart:convert';
import 'dart:io';

import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/src/dart/ast/utilities.dart';
import 'package:dartdoc/src/model.dart';

final Map<String, String> _fileContents = <String, String>{};

/// Returns the [AstNode] for a given [Element].
///
/// Uses a precomputed map of [element.source.fullName] to [CompilationUnit]
/// to avoid linear traversal in [ResolvedLibraryElementImpl.getElementDeclaration].
AstNode getAstNode(
    Element element, Map<String, CompilationUnit> compilationUnitMap) {
  if (element?.source?.fullName != null &&
      !element.isSynthetic &&
      element.nameOffset != -1) {
    CompilationUnit unit = compilationUnitMap[element.source.fullName];
    if (unit != null) {
      var locator = NodeLocator2(element.nameOffset);
      return (locator.searchWithin(unit)?.parent);
    }
  }
  return null;
}

/// Remove elements that aren't documented.
Iterable<T> filterNonDocumented<T extends Documentable>(
    Iterable<T> maybeDocumentedItems) {
  return maybeDocumentedItems.where((me) => me.isDocumented);
}

/// Returns an iterable containing only public elements from [privacyItems].
Iterable<T> filterNonPublic<T extends Privacy>(Iterable<T> privacyItems) {
  return privacyItems.where((me) => me.isPublic);
}

/// Finds canonical classes for all classes in the iterable, if possible.
/// If a canonical class can not be found, returns the original class.
Iterable<Class> findCanonicalFor(Iterable<Class> classes) {
  return classes.map((c) =>
      c.packageGraph.findCanonicalModelElementFor(c.element) as Class ?? c);
}

String getFileContentsFor(Element e) {
  var location = e.source.fullName;
  if (!_fileContents.containsKey(location)) {
    var contents = File(location).readAsStringSync();
    _fileContents.putIfAbsent(location, () => contents);
  }
  return _fileContents[location];
}

final RegExp slashes = RegExp('[\/]');
bool hasPrivateName(Element e) {
  if (e.name == null) return false;

  if (e.name.startsWith('_')) {
    return true;
  }
  // GenericFunctionTypeElements have the name we care about in the enclosing
  // element.
  if (e is GenericFunctionTypeElement) {
    if (e.enclosingElement.name.startsWith('_')) {
      return true;
    }
  }
  if (e is LibraryElement &&
      (e.identifier.startsWith('dart:_') ||
          e.identifier.startsWith('dart:nativewrappers/') ||
          ['dart:nativewrappers'].contains(e.identifier))) {
    return true;
  }
  if (e is LibraryElement) {
    List<String> locationParts = e.location.components[0].split(slashes);
    // TODO(jcollins-g): Implement real cross package detection
    if (locationParts.length >= 2 &&
        locationParts[0].startsWith('package:') &&
        locationParts[1] == 'src') return true;
  }
  return false;
}

bool hasPublicName(Element e) => !hasPrivateName(e);

/// Strip leading dartdoc comments from the given source code.
String stripDartdocCommentsFromSource(String source) {
  String remainer = source.trimLeft();
  HtmlEscape sanitizer = const HtmlEscape();
  bool lineComments = remainer.startsWith('///') ||
      remainer.startsWith(sanitizer.convert('///'));
  bool blockComments = remainer.startsWith('/**') ||
      remainer.startsWith(sanitizer.convert('/**'));

  return source.split('\n').where((String line) {
    if (lineComments) {
      if (line.startsWith('///') || line.startsWith(sanitizer.convert('///'))) {
        return false;
      }
      lineComments = false;
      return true;
    } else if (blockComments) {
      if (line.contains('*/') || line.contains(sanitizer.convert('*/'))) {
        blockComments = false;
        return false;
      }
      if (line.startsWith('/**') || line.startsWith(sanitizer.convert('/**'))) {
        return false;
      }
      return false;
    }

    return true;
  }).join('\n');
}

/// Strip the common indent from the given source fragment.
String stripIndentFromSource(String source) {
  String remainer = source.trimLeft();
  String indent = source.substring(0, source.length - remainer.length);
  return source.split('\n').map((line) {
    line = line.trimRight();
    return line.startsWith(indent) ? line.substring(indent.length) : line;
  }).join('\n');
}