using System.Collections.Generic;
using System.IO;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using UnityEngine;

namespace wvdet.CodeChecker
{
    /// <summary>
    /// Class [类] 命名规范
    /// 使用 Pascal Case。
    /// 使用名词或者名词性词组命名。
    /// 文件名应和类名相同。
    /// 不要轻易使用缩写。
    /// 不使用type前缀。
    /// 比如，C来标识Class。
    /// 比如，使用FileStream而不是CFileStream。
    /// 不使用下划线。
    /// 在合适的时候，使用单词复合来标识从某个基类继承而来。
    /// 比如，xxxException。
    /// 同一功能下，可以考虑同一命名前缀。
    /// </summary>
    public class CheckClass : ICheckable
    {
        public List<Detail> Check(string filepath, CompilationUnitSyntax root)
        {
            var results = new List<Detail>();
            var classDecs = root.DescendantNodes().OfType<ClassDeclarationSyntax>().ToList();
            foreach (var dec in classDecs)
            {
                CheckClassName(dec, results);
                CheckProperty(dec, results);
                CheckField(dec, results);
                CheckMethod(dec, results);
            }

            var filename = Path.GetFileNameWithoutExtension(filepath);
            if (classDecs.Count > 0 && classDecs.All(x => x.Identifier.ValueText != filename))
            {
                results.Add(new Detail
                {
                    level = Level.Warning,
                    guideline = "文件名应和类名相同",
                });
            }

            return results;
        }

        private static void CheckClassName(ClassDeclarationSyntax dec, List<Detail> results)
        {
            var identifier = dec.Identifier.ValueText;
            var lineNumber = dec.GetLocation().GetLineSpan().StartLinePosition.Line;

            if (CheckerUtils.IsChineseIdentifier(identifier, lineNumber, out var ret))
                results.Add(ret);

            if (char.IsLower(identifier[0]))
            {
                results.Add(new Detail
                {
                    level = Level.Warning,
                    line = lineNumber,
                    codeSnippet = identifier.Trim(),
                    suggestion = CheckerUtils.ConvertPascalCase(identifier),
                    guideline = "类名必须使用PascalCase",
                });
            }

            if (identifier[0] == '_')
            {
                results.Add(new Detail
                {
                    level = Level.Error,
                    line = lineNumber,
                    codeSnippet = identifier.Trim(),
                    suggestion = CheckerUtils.ConvertPascalCase(identifier.Substring(1)),
                    guideline = "类名禁用以下划线开始",
                });
            }
        }

        /// <summary>
        /// Static Field [静态变量] 命名规范
        /// 使用 Pascal Case。
        /// 使用名词、名词性词组或者名词地缩写来命名静态变量。
        /// 不要在静态变量名称中使用匈牙利命名法[变量名=属性+类型+对象描述]。
        /// 在任何可能的情况下推荐你使用静态properties[属性]而不是public static fields。
        /// </summary>
        private static void CheckField(ClassDeclarationSyntax dec, List<Detail> results)
        {
            var fields = dec.DescendantNodes().OfType<FieldDeclarationSyntax>();
            foreach (var field in fields)
            {
                var modifiers = field.Modifiers;
                var isConst = modifiers.Any(x => x.IsKind(SyntaxKind.ConstKeyword));
                var isPublic = modifiers.Any(x => x.IsKind(SyntaxKind.PublicKeyword));
                var isStatic = modifiers.Any(x => x.IsKind(SyntaxKind.StaticKeyword));
                var identifier = field.GetIdentifier().ValueText;
                var lineNumber = field.GetLocation().GetLineSpan().StartLinePosition.Line;

                if (CheckerUtils.IsChineseIdentifier(identifier, lineNumber, out var ret))
                    results.Add(ret);

                if (isConst)
                {
                    if (identifier.Any(char.IsLower))
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = field.GetFieldGreenText(),
                            guideline = "Const Field[常量]全大写命名，下划线分隔。例如：SCENE_CAMERA。",
                        });

                    continue;
                }

                if (isPublic)
                {
                    if (isStatic && char.IsLower(identifier[0]))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = field.GetFieldGreenText(),
                            guideline = "public静态变量首字母必须大写",
                        });
                    }
                    else if (!isStatic && char.IsUpper(identifier[0]))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = field.GetFieldGreenText(),
                            guideline = "public字段首字母必须小写",
                        });
                    }
                }
                else //私有
                {
                  if (char.IsUpper(identifier[0]))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = field.GetFieldGreenText(),
                            guideline = "private及protected字段首字母必须小写",
                        });
                    }

                    var declarator = field.GetPredefined();
                    if (declarator != null)
                    {
                        if (declarator.Keyword.IsKind(SyntaxKind.BoolKeyword) &&
                            (identifier.Length < 3 || !identifier.StartsWith("is")))
                        {
                            results.Add(new Detail
                            {
                                level = Level.Warning,
                                line = lineNumber,
                                codeSnippet = field.GetFieldGreenText(),
                                guideline = "private及protected布尔字段应以is开始，如isFileFound",
                            });
                        }
                    }

                    if (identifier.TrimStart('_').Contains('_'))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Warning,
                            line = lineNumber,
                            codeSnippet = field.GetFieldGreenText(),
                            guideline = "private及protected中间不使用下划线(如：isPlayer)",
                        });
                    }
                }
            }
        }

        private static void CheckMethod(ClassDeclarationSyntax dec, List<Detail> results)
        {
            var methods = dec.DescendantNodes().OfType<MethodDeclarationSyntax>();
            foreach (var method in methods)
            {
                var identifier = method.Identifier.ValueText;
                var lineNumber = method.GetLocation().GetLineSpan().StartLinePosition.Line;

                if (CheckerUtils.IsChineseIdentifier(identifier, lineNumber, out var ret))
                    results.Add(ret);

                if (!char.IsUpper(identifier[0]))
                {
                    results.Add(new Detail
                    {
                        level = Level.Error,
                        line = lineNumber,
                        codeSnippet = identifier.Trim(),
                        suggestion = CheckerUtils.ConvertPascalCase(identifier),
                        guideline = "方法名必须使用PascalCase",
                    });
                }

                method.ParameterList.Parameters.ToList().ForEach(parameter =>
                {
                    var parameterName = parameter.Identifier.ValueText;

                    if (CheckerUtils.IsChineseIdentifier(parameterName, lineNumber, out var ret2))
                        results.Add(ret2);

                    if (!char.IsLower(parameterName[0]))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = parameter.GetText().ToString().Trim(),
                            guideline = "方法参数名必须使用小写字母开始",
                        });
                    }

                    if (identifier.Contains('_'))
                    {
                        results.Add(new Detail
                        {
                            level = Level.Error,
                            line = lineNumber,
                            codeSnippet = parameter.GetText().ToString().Trim(),
                            guideline = "方法参数名禁止包含下划线(_)",
                        });
                    }
                });
            }
        }

        private static void CheckProperty(ClassDeclarationSyntax dec, List<Detail> results)
        {
            var properties = dec.DescendantNodes().OfType<PropertyDeclarationSyntax>();
            foreach (var property in properties)
            {
                var identifier = property.Identifier.ValueText;
                var lineNumber = property.GetLocation().GetLineSpan().StartLinePosition.Line;

                if (CheckerUtils.IsChineseIdentifier(identifier, lineNumber, out var ret))
                    results.Add(ret);

                if (!char.IsUpper(identifier[0]))
                {
                    results.Add(new Detail
                    {
                        level = Level.Error,
                        line = lineNumber,
                        codeSnippet = property.GetText().ToString().Trim(),
                        suggestion = CheckerUtils.ConvertPascalCase(identifier),
                        guideline = "属性名须使用Camel Case命名",
                    });
                }
            }
        }
    }
}