using System;
using System.Linq;
using System.Text;
using GFramework.SourceGenerators.Abstractions.rule;
using GFramework.SourceGenerators.Common.generator;
using GFramework.SourceGenerators.diagnostics;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Syntax;

namespace GFramework.SourceGenerators.rule;

[Generator]
public sealed class ContextAwareGenerator : AttributeClassGeneratorBase
{
    /// <summary>
    /// 使用强类型 Attribute，替代字符串
    /// </summary>
    protected override Type AttributeType => typeof(ContextAwareAttribute);

    /// <summary>
    /// 仅用于 Syntax 粗筛选
    /// </summary>
    protected override string AttributeShortNameWithoutSuffix => "ContextAware";

    /// <summary>
    /// 额外语义校验：必须实现 IContextAware
    /// </summary>
    protected override bool ValidateSymbol(
        SourceProductionContext context,
        ClassDeclarationSyntax syntax,
        INamedTypeSymbol symbol,
        AttributeData attr)
    {
        if (!symbol.AllInterfaces.Any(i =>
                i.ToDisplayString() == typeof(IContextAware).FullName))
        {
            context.ReportDiagnostic(Diagnostic.Create(
                ContextAwareDiagnostic.ClassMustImplementIContextAware,
                syntax.Identifier.GetLocation(),
                symbol.Name));
            return false;
        }

        return true;
    }

    /// <summary>
    /// 生成源码
    /// </summary>
    protected override string Generate(
        INamedTypeSymbol symbol,
        AttributeData attr)
    {
        var ns = symbol.ContainingNamespace.IsGlobalNamespace
            ? null
            : symbol.ContainingNamespace.ToDisplayString();

        var sb = new StringBuilder();
        sb.AppendLine("// <auto-generated/>");
        sb.AppendLine("#nullable enable");

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

        sb.AppendLine($"partial class {symbol.Name}");
        sb.AppendLine("{");
        sb.AppendLine(
            "    protected GFramework.Core.architecture.IArchitectureContext Context { get; private set; } = null!;");
        sb.AppendLine("    void GFramework.Core.rule.IContextAware.SetContext(");
        sb.AppendLine("        GFramework.Core.architecture.IArchitectureContext context)");
        sb.AppendLine("    {");
        sb.AppendLine("        Context = context;");
        sb.AppendLine("    }");
        sb.AppendLine("}");

        return sb.ToString().TrimEnd();
    }

    /// <summary>
    /// 自定义生成文件名
    /// </summary>
    protected override string GetHintName(INamedTypeSymbol symbol)
        => $"{symbol.Name}.ContextAware.g.cs";
}