// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.Windows.Data;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CodeStyle;
using Microsoft.CodeAnalysis.CSharp.CodeStyle;
using Microsoft.CodeAnalysis.Options;
using Microsoft.CodeAnalysis.Simplification;
using Microsoft.VisualStudio.LanguageServices.Implementation.Options;

namespace Microsoft.VisualStudio.LanguageServices.CSharp.Options.Formatting
{
    /// <summary>
    /// This is the view model for CodeStyle options page.
    /// </summary>
    /// <remarks>
    /// The codestyle options page is defined in <see cref="CodeStylePage"/>
    /// </remarks>
    internal class StyleViewModel : AbstractOptionPreviewViewModel
    {
        #region "Preview Text"

        private static readonly string s_fieldDeclarationPreviewTrue = @"
class C{
    int capacity;
    void Method()
    {
//[
        this.capacity = 0;
//]
    }
}";

        private static readonly string s_fieldDeclarationPreviewFalse = @"
class C{
    int capacity;
    void Method()
    {
//[
        capacity = 0;
//]
    }
}";

        private static readonly string s_propertyDeclarationPreviewTrue = @"
class C{
    public int Id { get; set; }
    void Method()
    {
//[
        this.Id = 0;
//]
    }
}";

        private static readonly string s_propertyDeclarationPreviewFalse = @"
class C{
    public int Id { get; set; }
    void Method()
    {
//[
        Id = 0;
//]
    }
}";

        private static readonly string s_eventDeclarationPreviewTrue = @"
using System;
class C{
    event EventHandler Elapsed;
    void Handler(object sender, EventArgs args)
    {
//[
        this.Elapsed += Handler;
//]
    }
}";

        private static readonly string s_eventDeclarationPreviewFalse = @"
using System;
class C{
    event EventHandler Elapsed;
    void Handler(object sender, EventArgs args)
    {
//[
        Elapsed += Handler;
//]
    }
}";

        private static readonly string s_methodDeclarationPreviewTrue = @"
using System;
class C{
    void Display()
    {
//[
        this.Display();
//]
    }
}";

        private static readonly string s_methodDeclarationPreviewFalse = @"
using System;
class C{
    void Display()
    {
//[
        Display();
//]
    }
}";

        private static readonly string s_intrinsicPreviewDeclarationTrue = @"
class Program
{
//[
    private int _member;
    static void M(int argument)
    {
        int local;
    }
//]
}";

        private static readonly string s_intrinsicPreviewDeclarationFalse = @"
using System;
class Program
{
//[
    private Int32 _member;
    static void M(Int32 argument)
    {
        Int32 local;
    }
//]
}";

        private static readonly string s_intrinsicPreviewMemberAccessTrue = @"
class Program
{
//[
    static void M()
    {
        var local = int.MaxValue;
    }
//]
}";

        private static readonly string s_intrinsicPreviewMemberAccessFalse = @"
using System;
class Program
{
//[
    static void M()
    {
        var local = Int32.MaxValue;
    }
//]
}";

        private static readonly string s_varForIntrinsicsPreviewFalse = @"
using System;
class C{
    void Method()
    {
//[
        int x = 5; // built-in types
//]
    }
}";

        private static readonly string s_varForIntrinsicsPreviewTrue = @"
using System;
class C{
    void Method()
    {
//[
        var x = 5; // built-in types
//]
    }
}";

        private static readonly string s_varWhereApparentPreviewFalse = @"
using System;
class C{
    void Method()
    {
//[
        C cobj = new C(); // type is apparent from assignment expression
//]
    }
}";

        private static readonly string s_varWhereApparentPreviewTrue = @"
using System;
class C{
    void Method()
    {
//[
        var cobj = new C(); // type is apparent from assignment expression
//]
    }
}";

        private static readonly string s_varWherePossiblePreviewFalse = @"
using System;
class C{
    void Init()
    {
//[
        Action f = this.Init(); // everywhere else.
//]
    }
}";

        private static readonly string s_varWherePossiblePreviewTrue = @"
using System;
class C{
    void Init()
    {
//[
        var f = this.Init(); // everywhere else.
//]
    }
}";

        private static readonly string s_preferThrowExpression = @"
using System;

class C
{
    private string s;

    public C(string s)
    {
//[
        // Prefer:
        this.s = s ?? throw new ArgumentNullException(nameof(s));

        // Over:
        if (s == null)
        {
            throw new ArgumentNullException(nameof(s));
        }

        this.s = s;
//]
    }
}
";

        private static readonly string s_preferCoalesceExpression = @"
using System;

class C
{
    private string s;

    public C(string s)
    {
//[
        // Prefer:
        var v = x ?? y;

        // Over:
        var v = x != null ? x : y; // or
        var v = x == null ? y : x;
//]
    }
}
";

        private static readonly string s_preferConditionalDelegateCall = @"
using System;

class C
{
    private string s;

    public C(string s)
    {
//[
        // Prefer:
        func?.Invoke(args);

        // Over:
        if (func != null)
        {
            func(args);
        }
//]
    }
}
";

    private static readonly string s_preferNullPropagation = @"
using System;

class C
{
    public C(object o)
    {
//[
        // Prefer:
        var v = o?.ToString();

        // Over:
        var v = o == null ? null : o.ToString(); // or
        var v = o != null ? o.ToString() : null;
//]
    }
}
";

        private static readonly string s_preferPatternMatchingOverAsWithNullCheck = @"
class C
{
    void M()
    {
//[
        // Prefer:
        if (o is string s)
        {
        }

        // Over:
        var s = o as string;
        if (s != null)
        {
        }
//]
    }
}
";

        private static readonly string s_preferPatternMatchingOverIsWithCastCheck = @"
class C
{
    void M()
    {
//[
        // Prefer:
        if (o is int i)
        {
        }

        // Over:
        if (o is int)
        {
            var i = (int)o;
        }
//]
    }
}
";

        private static readonly string s_preferObjectInitializer = @"
using System;

class Customer
{
    private int Age;

    public Customer()
    {
//[
        // Prefer:
        var c = new Customer()
        {
            Age = 21
        };

        // Over:
        var c = new Customer();
        c.Age = 21;
//]
    }
}
";

        private static readonly string s_preferCollectionInitializer = @"
using System.Collections.Generic;

class Customer
{
    private int Age;

    public Customer()
    {
//[
        // Prefer:
        var list = new List<int>
        {
            1,
            2,
            3
        };

        // Over:
        var list = new List<int>();
        list.Add(1);
        list.Add(2);
        list.Add(3);
//]
    }
}
";

        private static readonly string s_preferExplicitTupleName = @"
class Customer
{
    public Customer()
    {
//[
        // Prefer:
        (string name, int age) customer = GetCustomer();
        var name = customer.name;
        var age = customer.age;

        // Over:
        (string name, int age) customer = GetCustomer();
        var name = customer.Item1;
        var age = customer.Item2;
//]
    }
}
";

        private static readonly string s_preferInlinedVariableDeclaration = @"
using System;

class Customer
{
    public Customer(string value)
    {
//[
        // Prefer:
        if (int.TryParse(value, out int i))
        {
        }

        // Over:
        int i;
        if (int.TryParse(value, out i))
        {
        }
//]
    }
}
";

        private static readonly string s_preferExpressionBodyForMethods = @"
using System;

//[
class Customer
{
    private int Age;

    public int GetAge() => this.Age;
}
//]
";

        private static readonly string s_preferBlockBodyForMethods = @"
using System;

//[
class Customer
{
    private int Age;

    public int GetAge()
    {
        return this.Age;
    }
}
//]
";

        private static readonly string s_preferExpressionBodyForConstructors = @"
using System;

//[
class Customer
{
    private int Age;

    public Customer(int age) => Age = age;
}
//]
";

        private static readonly string s_preferBlockBodyForConstructors = @"
using System;

//[
class Customer
{
    private int Age;

    public Customer(int age)
    {
        Age = age;
    }
}
//]
";

        private static readonly string s_preferExpressionBodyForOperators = @"
using System;

struct ComplexNumber
{
//[
    public static ComplexNumber operator +(ComplexNumber c1, ComplexNumber c2)
        => new ComplexNumber(c1.Real + c2.Real, c1.Imaginary + c2.Imaginary);
//]
}
";

        private static readonly string s_preferBlockBodyForOperators = @"
using System;

struct ComplexNumber
{
//[
    public static ComplexNumber operator +(ComplexNumber c1, ComplexNumber c2)
    {
        return new ComplexNumber(c1.Real + c2.Real, c1.Imaginary + c2.Imaginary);
    }
//]
}
";

        private static readonly string s_preferExpressionBodyForProperties = @"
using System;

//[
class Customer
{
    private int _age;
    public int Age => _age;
}
//]
";

        private static readonly string s_preferBlockBodyForProperties = @"
using System;

//[
class Customer
{
    private int _age;
    public int Age { get { return _age; } }
}
//]
";

        private static readonly string s_preferExpressionBodyForAccessors = @"
using System;

//[
class Customer
{
    private int _age;
    public int Age
    {
        get => _age;
        set => _age = value;
    }
}
//]
";

        private static readonly string s_preferBlockBodyForAccessors = @"
using System;

//[
class Customer
{
    private int _age;
    public int Age
    {
        get { return _age; }
        set { _age = value; }
    }
}
//]
";

        private static readonly string s_preferExpressionBodyForIndexers= @"
using System;

//[
class List<T>
{
    private T[] _values;
    public T this[int i] => _values[i];
}
//]
";

        private static readonly string s_preferBlockBodyForIndexers = @"
using System;

//[
class List<T>
{
    private T[] _values;
    public T this[int i] { get { return _values[i]; } }
}
//]
";

        #endregion

        internal StyleViewModel(OptionSet optionSet, IServiceProvider serviceProvider) : base(optionSet, serviceProvider, LanguageNames.CSharp)
        {
            var collectionView = (ListCollectionView)CollectionViewSource.GetDefaultView(CodeStyleItems);
            collectionView.GroupDescriptions.Add(new PropertyGroupDescription(nameof(AbstractCodeStyleOptionViewModel.GroupName)));

            var qualifyGroupTitle = CSharpVSResources.this_preferences_colon;
            var predefinedTypesGroupTitle = CSharpVSResources.predefined_type_preferences_colon;
            var varGroupTitle = CSharpVSResources.var_preferences_colon;
            var nullCheckingGroupTitle = CSharpVSResources.null_checking_colon;
            var codeBlockPreferencesGroupTitle = ServicesVSResources.Code_block_preferences_colon;
            var expressionPreferencesGroupTitle = ServicesVSResources.Expression_preferences_colon;
            var variablePreferencesGroupTitle = ServicesVSResources.Variable_preferences_colon;

            var qualifyMemberAccessPreferences = new List<CodeStylePreference>
            {
                new CodeStylePreference(CSharpVSResources.Prefer_this, isChecked: true),
                new CodeStylePreference(CSharpVSResources.Do_not_prefer_this, isChecked: false),
            };

            var predefinedTypesPreferences = new List<CodeStylePreference>
            {
                new CodeStylePreference(ServicesVSResources.Prefer_predefined_type, isChecked: true),
                new CodeStylePreference(ServicesVSResources.Prefer_framework_type, isChecked: false),
            };

            var typeStylePreferences = new List<CodeStylePreference>
            {
                new CodeStylePreference(CSharpVSResources.Prefer_var, isChecked: true),
                new CodeStylePreference(CSharpVSResources.Prefer_explicit_type, isChecked: false),
            };

            var codeBlockPreferences = new List<CodeStylePreference>
            {
                new CodeStylePreference(CSharpVSResources.Prefer_expression_body, isChecked: true),
                new CodeStylePreference(CSharpVSResources.Prefer_block_body, isChecked: false),
            };

            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.QualifyFieldAccess, CSharpVSResources.Qualify_field_access_with_this, s_fieldDeclarationPreviewTrue, s_fieldDeclarationPreviewFalse, this, optionSet, qualifyGroupTitle, qualifyMemberAccessPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.QualifyPropertyAccess, CSharpVSResources.Qualify_property_access_with_this, s_propertyDeclarationPreviewTrue, s_propertyDeclarationPreviewFalse, this, optionSet, qualifyGroupTitle, qualifyMemberAccessPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.QualifyMethodAccess, CSharpVSResources.Qualify_method_access_with_this, s_methodDeclarationPreviewTrue, s_methodDeclarationPreviewFalse, this, optionSet, qualifyGroupTitle, qualifyMemberAccessPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.QualifyEventAccess, CSharpVSResources.Qualify_event_access_with_this, s_eventDeclarationPreviewTrue, s_eventDeclarationPreviewFalse, this, optionSet, qualifyGroupTitle, qualifyMemberAccessPreferences));

            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInDeclaration, ServicesVSResources.For_locals_parameters_and_members, s_intrinsicPreviewDeclarationTrue, s_intrinsicPreviewDeclarationFalse, this, optionSet, predefinedTypesGroupTitle, predefinedTypesPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInMemberAccess, ServicesVSResources.For_member_access_expressions, s_intrinsicPreviewMemberAccessTrue, s_intrinsicPreviewMemberAccessFalse, this, optionSet, predefinedTypesGroupTitle, predefinedTypesPreferences));

            // Use var
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.UseImplicitTypeForIntrinsicTypes, CSharpVSResources.For_built_in_types, s_varForIntrinsicsPreviewTrue, s_varForIntrinsicsPreviewFalse, this, optionSet, varGroupTitle, typeStylePreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.UseImplicitTypeWhereApparent, CSharpVSResources.When_variable_type_is_apparent, s_varWhereApparentPreviewTrue, s_varWhereApparentPreviewFalse, this, optionSet, varGroupTitle, typeStylePreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.UseImplicitTypeWherePossible, CSharpVSResources.Elsewhere, s_varWherePossiblePreviewTrue, s_varWherePossiblePreviewFalse, this, optionSet, varGroupTitle, typeStylePreferences));

            // Code block
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedMethods, ServicesVSResources.For_methods, s_preferExpressionBodyForMethods, s_preferBlockBodyForMethods, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedConstructors, ServicesVSResources.For_constructors, s_preferExpressionBodyForConstructors, s_preferBlockBodyForConstructors, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedOperators, ServicesVSResources.For_operators, s_preferExpressionBodyForOperators, s_preferBlockBodyForOperators, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedProperties, ServicesVSResources.For_properties, s_preferExpressionBodyForProperties, s_preferBlockBodyForProperties, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedIndexers, ServicesVSResources.For_indexers, s_preferExpressionBodyForIndexers, s_preferBlockBodyForIndexers, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferExpressionBodiedAccessors, ServicesVSResources.For_accessors, s_preferExpressionBodyForAccessors, s_preferBlockBodyForAccessors, this, optionSet, codeBlockPreferencesGroupTitle, codeBlockPreferences));

            // Expression preferences
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferObjectInitializer, ServicesVSResources.Prefer_object_initializer, s_preferObjectInitializer, s_preferObjectInitializer, this, optionSet, expressionPreferencesGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferCollectionInitializer, ServicesVSResources.Prefer_collection_initializer, s_preferCollectionInitializer, s_preferCollectionInitializer, this, optionSet, expressionPreferencesGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferPatternMatchingOverIsWithCastCheck, CSharpVSResources.Prefer_pattern_matching_over_is_with_cast_check, s_preferPatternMatchingOverIsWithCastCheck, s_preferPatternMatchingOverIsWithCastCheck, this, optionSet, expressionPreferencesGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferPatternMatchingOverAsWithNullCheck, CSharpVSResources.Prefer_pattern_matching_over_as_with_null_check, s_preferPatternMatchingOverAsWithNullCheck, s_preferPatternMatchingOverAsWithNullCheck, this, optionSet, expressionPreferencesGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferExplicitTupleNames, ServicesVSResources.Prefer_explicit_tuple_name, s_preferExplicitTupleName, s_preferExplicitTupleName, this, optionSet, expressionPreferencesGroupTitle));

            // Variable preferences
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferInlinedVariableDeclaration, ServicesVSResources.Prefer_inlined_variable_declaration, s_preferInlinedVariableDeclaration, s_preferInlinedVariableDeclaration, this, optionSet, variablePreferencesGroupTitle));

            // Null preferences.
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferThrowExpression, CSharpVSResources.Prefer_throw_expression, s_preferThrowExpression, s_preferThrowExpression, this, optionSet, nullCheckingGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CSharpCodeStyleOptions.PreferConditionalDelegateCall, CSharpVSResources.Prefer_conditional_delegate_call, s_preferConditionalDelegateCall, s_preferConditionalDelegateCall, this, optionSet, nullCheckingGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferCoalesceExpression, ServicesVSResources.Prefer_coalesce_expression, s_preferCoalesceExpression, s_preferCoalesceExpression, this, optionSet, nullCheckingGroupTitle));
            CodeStyleItems.Add(new SimpleCodeStyleOptionViewModel(CodeStyleOptions.PreferNullPropagation, ServicesVSResources.Prefer_null_propagation, s_preferNullPropagation, s_preferNullPropagation, this, optionSet, nullCheckingGroupTitle));
        }
    }
}