using System.Linq.Expressions;
using BuildFlow.Shared.Domain.Common;
using BuildFlow.Shared.Infrastructure;
using Microsoft.EntityFrameworkCore;
using Scripting.Domain.Entities;

namespace Scripting.Infrastructure.Persistence;

/// <summary>
/// Scripting 持久化上下文。承载脚本函数定义与执行日志。
/// 注册 AuditInterceptor 自动维护审计字段；对实现 ISoftDelete 的实体统一生成全局查询过滤器，
/// 自动排除已软删除记录。约定与 WorkflowDbContext 保持一致。
/// </summary>
public class ScriptingDbContext : DbContext
{
    private readonly ICurrentUserContext? _currentUserContext;

    public DbSet<ScriptFunction> Scripts => Set<ScriptFunction>();
    public DbSet<ScriptExecutionLog> ScriptExecutionLogs => Set<ScriptExecutionLog>();

    public ScriptingDbContext(DbContextOptions<ScriptingDbContext> options) : base(options) { }

    public ScriptingDbContext(DbContextOptions<ScriptingDbContext> options, ICurrentUserContext currentUserContext)
        : base(options)
    {
        _currentUserContext = currentUserContext;
    }

    // 注意：此处通过 OnConfiguring 注册拦截器（而非 DI AddInterceptors），与 rag-backend 约定一致，
    // 保证无参构造（如设计时工厂、测试夹具）也能正常工作。
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        if (_currentUserContext is not null)
        {
            optionsBuilder.AddInterceptors(new AuditInterceptor(_currentUserContext));
        }
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // 自动发现本程序集内所有 IEntityTypeConfiguration 实现
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(ScriptingDbContext).Assembly);

        // 为所有实现 ISoftDelete 的实体动态生成 HasQueryFilter(e => !e.IsDeleted)
        foreach (var entityType in modelBuilder.Model.GetEntityTypes())
        {
            if (typeof(ISoftDelete).IsAssignableFrom(entityType.ClrType))
            {
                modelBuilder.Entity(entityType.ClrType).HasQueryFilter(
                    CreateSoftDeleteFilter(entityType.ClrType));
            }
        }
    }

    /// <summary>用表达式树动态构造 e => !e.IsDeleted，避免对每个实体类型手写泛型过滤。</summary>
    private static LambdaExpression CreateSoftDeleteFilter(Type entityType)
    {
        var param = Expression.Parameter(entityType, "e");
        var isDeletedProp = Expression.Property(param, nameof(ISoftDelete.IsDeleted));
        var filter = Expression.Lambda(Expression.Not(isDeletedProp), param);
        return filter;
    }
}