using System;
using System.Linq;
using System.Text;
using GFramework.Godot.SourceGenerators.Abstractions.logging;
using GFramework.SourceGenerators.Common.constants;
using GFramework.SourceGenerators.Common.generator;
using Microsoft.CodeAnalysis;

namespace GFramework.Godot.SourceGenerators.logging;

/// <summary>
/// 日志生成器，用于为标记了GodotLogAttribute的类自动生成日志字段
/// </summary>
[Generator]
public sealed class GodotLoggerGenerator : TypeAttributeClassGeneratorBase
{
    protected override Type AttributeType => typeof(GodotLogAttribute);


    protected override string AttributeShortNameWithoutSuffix => "GodotLog";

    /// <summary>
    /// 生成日志字段的源代码
    /// </summary>
    /// <param name="symbol">类符号</param>
    /// <param name="attr">GodotLogAttribute属性数据</param>
    /// <returns>生成的源代码字符串</returns>
    protected override string Generate(INamedTypeSymbol symbol, AttributeData attr)
    {
        var ns = symbol.ContainingNamespace.IsGlobalNamespace
            ? null
            : symbol.ContainingNamespace.ToDisplayString();
        var className = symbol.Name;

        // 解析构造函数参数
        var name = className;
        if (attr.ConstructorArguments.Length > 0 && attr.ConstructorArguments[0].Value is string s &&
            !string.IsNullOrWhiteSpace(s))
        {
            name = s;
        }

        // 解析命名参数
        var fieldName = GetNamedArg(attr, "FieldName")?.ToString() ?? "_log";
        var access = GetNamedArg(attr, "AccessModifier")?.ToString() ?? "private";
        var isStatic = GetNamedArg(attr, "IsStatic") is not bool b || b;
        var staticKeyword = isStatic ? "static " : "";

        var sb = new StringBuilder();
        sb.AppendLine("// <auto-generated />");
        sb.AppendLine($"using {PathContests.CoreAbstractionsNamespace}.logging;");
        sb.AppendLine($"using {PathContests.GodotNamespace}.logging;");
        sb.AppendLine();

        if (ns is not null)
        {
            sb.AppendLine($"namespace {ns}");
            sb.AppendLine("{");
        }

        sb.AppendLine($"    public partial class {className}");
        sb.AppendLine("    {");
        sb.AppendLine("        /// <summary>Auto-generated logger</summary>");
        sb.AppendLine(
            $"        {access} {staticKeyword}readonly ILogger {fieldName} = new GodotLoggerFactory().GetLogger(\"{name}\");");
        sb.AppendLine("    }");

        if (ns is not null)
            sb.AppendLine("}");

        return sb.ToString();
    }

    /// <summary>
    /// 获取生成文件的提示名称
    /// </summary>
    /// <param name="symbol">类型符号</param>
    /// <returns>生成文件的提示名称</returns>
    protected override string GetHintName(INamedTypeSymbol symbol)
        => $"{symbol.Name}.Logger.g.cs";

    /// <summary>
    /// 获取属性的命名参数值
    /// </summary>
    /// <param name="attr">属性数据</param>
    /// <param name="name">参数名称</param>
    /// <returns>参数值</returns>
    private static object? GetNamedArg(AttributeData attr, string name)
        => attr.NamedArguments.FirstOrDefault(kv => kv.Key == name).Value.Value;
}