using CodePlay.Core.Models;
using CodePlay.Core.Common;

namespace CodePlay.Core.Services;

public class TodoGenerator
{
    private static readonly List<PatternInfo> CSharpPatterns = new()
    {
        new PatternInfo("linq", @"\.(Where|Select|OrderBy|FirstOrDefault|Any|All|Count|ToList)\s*\(", "LINQ 查询", "Java 没有 LINQ", "Stream API"),
        new PatternInfo("async_await", @"async\s+[\w<>]+\s+\w+\s*\([^)]*\)", "async/await 异步方法", "Java 使用 CompletableFuture", "CompletableFuture"),
        new PatternInfo("attributes", @"\[(?:Obsolete|Serializable|DataContract|DllImport)\b", "C# 特性", "Java 使用注解", "@Annotation"),
        new PatternInfo("delegate", @"\b(?:Action|Func|EventHandler)\b", "委托类型", "Java 使用函数式接口", "Function/Consumer"),
        new PatternInfo("event", @"\bevent\s+", "C# 事件", "Java 使用观察者模式", "PropertyChangeListener"),
        new PatternInfo("dynamic", @"\bdynamic\b", "dynamic 类型", "Java 使用 Object", "Object/反射"),
        new PatternInfo("pattern_match", @"\bis\s+(?:not\s+)?null", "模式匹配", "Java 16+ 支持", "instanceof"),
        new PatternInfo("nullable", @"\?\s+", "可空引用", "Java 使用 Optional", "Optional"),
        new PatternInfo("using_stmt", @"using\s*\([^)]+\)\s*\{", "using 语句", "Java try-with-resources", "try-with-resources"),
        new PatternInfo("yield", @"\byield\s+return", "yield return", "Java 使用 Iterator", "Iterator"),
        new PatternInfo("record", @"\brecord\s+\w+", "C# record", "Java 16+ record", "Java record"),
        new PatternInfo("init_only", @"\binit\s*;", "init-only", "Java 使用 final", "final 字段"),
        new PatternInfo("var", @"\bvar\s+\w+\s*=", "var 推断", "Java 10+ var", "var (Java 10+)")
    };
    
    private static readonly List<PatternInfo> JavaPatterns = new()
    {
        new PatternInfo("stream", @"\.(stream|filter|map|collect|reduce)\s*\(", "Stream API", "C# 使用 LINQ", "LINQ"),
        new PatternInfo("lambda", @"->\s*\{", "Lambda 表达式", "C# 使用 =>", "=> lambda"),
        new PatternInfo("optional", @"Optional<", "Optional 类型", "C# 使用可空", "Nullable"),
        new PatternInfo("annotation", @"@(?:Override|Deprecated|FunctionalInterface)\b", "Java 注解", "C# 使用特性", "[Attribute]"),
        new PatternInfo("wildcard", @"\?\s+(?:extends|super)", "泛型通配符", "C# in/out", "in/out"),
        new PatternInfo("diamond", @"<>\s*;", "菱形操作符", "C# var 推断", "var"),
        new PatternInfo("method_ref", @"::\s*\w+", "方法引用", "C# 组方法", "组方法")
    };
    
    public List<TodoItem> GenerateTodos(string sourceCode, LanguageType sourceLanguage, LanguageType targetLanguage)
    {
        var todos = new List<TodoItem>();
        var patterns = sourceLanguage == LanguageType.CSharp ? CSharpPatterns : JavaPatterns;
        
        foreach (var pattern in patterns)
        {
            var matches = System.Text.RegularExpressions.Regex.Matches(sourceCode, pattern.Pattern);
            foreach (System.Text.RegularExpressions.Match match in matches)
            {
                todos.Add(new TodoItem
                {
                    Description = pattern.Name,
                    LineNumber = GetLineNumber(sourceCode, match.Index),
                    OriginalSyntax = match.Value.Trim(),
                    WhyNotDirect = pattern.Reason,
                    RecommendedAlternative = pattern.Alternative
                });
            }
        }
        
        return todos.GroupBy(t => new { t.Description, t.LineNumber })
            .Select(g => g.First())
            .OrderBy(t => t.LineNumber)
            .ToList();
    }
    
    public string GenerateTodoComment(TodoItem todo)
    {
        return $"// TODO: {todo.Description} - {todo.WhyNotDirect}";
    }
    
    public ConversionSuggestion Analyze(string sourceCode, LanguageType sourceLanguage, LanguageType targetLanguage)
    {
        var todos = GenerateTodos(sourceCode, sourceLanguage, targetLanguage);
        return new ConversionSuggestion
        {
            TotalIssues = todos.Count,
            ConfidenceScore = Math.Max(0, 100 - todos.Count * 5),
            TodoItems = todos
        };
    }
    
    private int GetLineNumber(string sourceCode, int index)
    {
        return sourceCode.Substring(0, index).Count(c => c == '\n') + 1;
    }
}

public class PatternInfo
{
    public string Key { get; set; } = "";
    public string Pattern { get; set; } = "";
    public string Name { get; set; } = "";
    public string Reason { get; set; } = "";
    public string Alternative { get; set; } = "";
    
    public PatternInfo(string key, string pattern, string name, string reason, string alternative)
    {
        Key = key;
        Pattern = pattern;
        Name = name;
        Reason = reason;
        Alternative = alternative;
    }
}

public class ConversionSuggestion
{
    public int TotalIssues { get; set; }
    public int ConfidenceScore { get; set; }
    public List<TodoItem> TodoItems { get; set; } = new();
}