// Copyright (c) 2019, 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 'dart:convert';

import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/source/line_info.dart';
import 'package:analyzer/src/dart/element/element.dart';
import 'package:dartdoc/src/model/model.dart';
import 'package:dartdoc/src/utils.dart';

/// Mixin for top-level variables and fields (aka properties)
mixin GetterSetterCombo on ModelElement {
  Accessor get getter;

  Accessor get setter;

  Iterable<Accessor> get allAccessors sync* {
    for (Accessor a in [getter, setter]) {
      if (a != null) yield a;
    }
  }

  Set<String> get comboFeatures {
    Set<String> allFeatures = Set();
    if (hasExplicitGetter && hasPublicGetter) {
      allFeatures.addAll(getter.features);
    }
    if (hasExplicitSetter && hasPublicSetter) {
      allFeatures.addAll(setter.features);
    }
    if (readOnly && !isFinal && !isConst) allFeatures.add('read-only');
    if (writeOnly) allFeatures.add('write-only');
    if (readWrite) allFeatures.add('read / write');
    return allFeatures;
  }

  @override
  ModelElement enclosingElement;

  bool get isInherited;

  Expression get constantInitializer =>
      (element as ConstVariableElement).constantInitializer;

  String linkifyConstantValue(String original) {
    if (constantInitializer is! InstanceCreationExpression) return original;
    String constructorName = (constantInitializer as InstanceCreationExpression)
        .constructorName
        .toString();
    Element staticElement =
        (constantInitializer as InstanceCreationExpression).staticElement;
    Constructor target = ModelElement.fromElement(staticElement, packageGraph);
    Class targetClass = target.enclosingElement;
    // TODO(jcollins-g): this logic really should be integrated into Constructor,
    // but that's not trivial because of linkedName's usage.
    if (targetClass.name == target.name) {
      return original.replaceAll(constructorName, "${target.linkedName}");
    }
    return original.replaceAll("${targetClass.name}.${target.name}",
        "${targetClass.linkedName}.${target.linkedName}");
  }

  String _buildConstantValueBase() {
    String result = constantInitializer?.toString() ?? '';
    return const HtmlEscape(HtmlEscapeMode.unknown).convert(result);
  }

  @override
  CharacterLocation get characterLocation {
    // Handle all synthetic possibilities.  Ordinarily, warnings for
    // explicit setters/getters will be handled by those objects, but
    // if a warning comes up for an enclosing synthetic field we have to
    // put it somewhere.  So pick an accessor.
    if (element.isSynthetic) {
      if (hasExplicitGetter) return getter.characterLocation;
      if (hasExplicitSetter) return setter.characterLocation;
      assert(false, 'Field and accessors can not all be synthetic');
    }
    return super.characterLocation;
  }

  String get constantValue => linkifyConstantValue(constantValueBase);

  String get constantValueTruncated =>
      linkifyConstantValue(truncateString(constantValueBase, 200));
  String _constantValueBase;

  String get constantValueBase =>
      _constantValueBase ??= _buildConstantValueBase();

  bool get hasPublicGetter => hasGetter && getter.isPublic;

  bool get hasPublicSetter => hasSetter && setter.isPublic;

  @override
  bool get isPublic => hasPublicGetter || hasPublicSetter;

  List<ModelElement> _documentationFrom;

  @override
  List<ModelElement> get documentationFrom {
    if (_documentationFrom == null) {
      _documentationFrom = [];
      if (hasPublicGetter) {
        _documentationFrom.addAll(getter.documentationFrom);
      } else if (hasPublicSetter) {
        _documentationFrom.addAll(setter.documentationFrom);
      }
      if (_documentationFrom.isEmpty ||
          _documentationFrom.every((e) => e.documentationComment == '')) {
        _documentationFrom = computeDocumentationFrom;
      }
    }
    return _documentationFrom;
  }

  bool get hasAccessorsWithDocs => (hasPublicGetter &&
          !getter.isSynthetic &&
          getter.documentation.isNotEmpty ||
      hasPublicSetter &&
          !setter.isSynthetic &&
          setter.documentation.isNotEmpty);

  bool get getterSetterBothAvailable => (hasPublicGetter &&
      getter.documentation.isNotEmpty &&
      hasPublicSetter &&
      setter.documentation.isNotEmpty);

  String _oneLineDoc;

  @override
  String get oneLineDoc {
    if (_oneLineDoc == null) {
      if (!hasAccessorsWithDocs) {
        _oneLineDoc = computeOneLineDoc();
      } else {
        StringBuffer buffer = StringBuffer();
        if (hasPublicGetter && getter.oneLineDoc.isNotEmpty) {
          buffer.write('${getter.oneLineDoc}');
        }
        if (hasPublicSetter && setter.oneLineDoc.isNotEmpty) {
          buffer.write('${getterSetterBothAvailable ? "" : setter.oneLineDoc}');
        }
        _oneLineDoc = buffer.toString();
      }
    }
    return _oneLineDoc;
  }

  String get getterSetterDocumentationComment {
    var buffer = StringBuffer();

    if (hasPublicGetter && !getter.isSynthetic) {
      assert(getter.documentationFrom.length == 1);
      // We have to check against dropTextFrom here since documentationFrom
      // doesn't yield the real elements for GetterSetterCombos.
      if (!config.dropTextFrom
          .contains(getter.documentationFrom.first.element.library.name)) {
        String docs = getter.documentationFrom.first.documentationComment;
        if (docs != null) buffer.write(docs);
      }
    }

    if (hasPublicSetter && !setter.isSynthetic) {
      assert(setter.documentationFrom.length == 1);
      if (!config.dropTextFrom
          .contains(setter.documentationFrom.first.element.library.name)) {
        String docs = setter.documentationFrom.first.documentationComment;
        if (docs != null) {
          if (buffer.isNotEmpty) buffer.write('\n\n');
          buffer.write(docs);
        }
      }
    }
    return buffer.toString();
  }

  String get linkedReturnType {
    if (hasGetter) {
      return getter.linkedReturnType;
    } else {
      return setter.linkedParamsNoMetadataOrNames;
    }
  }

  @override
  bool get canHaveParameters => hasSetter;

  @override
  List<Parameter> get parameters => setter.parameters;

  @override
  String get linkedParamsNoMetadata {
    if (hasSetter) return setter.linkedParamsNoMetadata;
    return null;
  }

  bool get hasExplicitGetter => hasPublicGetter && !getter.isSynthetic;

  bool get hasExplicitSetter => hasPublicSetter && !setter.isSynthetic;

  bool get hasGetter => getter != null;

  bool get hasNoGetterSetter => !hasGetterOrSetter;

  bool get hasGetterOrSetter => hasExplicitGetter || hasExplicitSetter;

  bool get hasSetter => setter != null;

  bool get hasPublicGetterNoSetter => (hasPublicGetter && !hasPublicSetter);

  String get arrow {
    // →
    if (readOnly) return r'&#8594;';
    // ←
    if (writeOnly) return r'&#8592;';
    // ↔
    if (readWrite) return r'&#8596;';
    throw UnsupportedError(
        'GetterSetterCombo must be one of readOnly, writeOnly, or readWrite');
  }

  bool get readOnly => hasPublicGetter && !hasPublicSetter;

  bool get readWrite => hasPublicGetter && hasPublicSetter;

  bool get writeOnly => hasPublicSetter && !hasPublicGetter;
}