using MiaoJiZhang.Domain.Entities;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion;

namespace MiaoJiZhang.Infrastructure.Persistence;

public class AppDbContext(DbContextOptions<AppDbContext> options) : DbContext(options)
{
    public DbSet<User> Users => Set<User>();
    public DbSet<UserFeaturePermission> UserFeaturePermissions => Set<UserFeaturePermission>();
    public DbSet<AiCompanionSetting> AiCompanionSettings => Set<AiCompanionSetting>();
    public DbSet<Ledger> Ledgers => Set<Ledger>();
    public DbSet<Category> Categories => Set<Category>();
    public DbSet<Transaction> Transactions => Set<Transaction>();
    public DbSet<Budget> Budgets => Set<Budget>();
    public DbSet<ChatMessage> ChatMessages => Set<ChatMessage>();
    public DbSet<AppConfig> AppConfigs => Set<AppConfig>();
    public DbSet<AiPersona> AiPersonas => Set<AiPersona>();
    public DbSet<AiAvatar> AiAvatars => Set<AiAvatar>();
    public DbSet<Sticker> Stickers => Set<Sticker>();

    protected override void OnModelCreating(ModelBuilder b)
    {
        b.Entity<User>(e =>
        {
            e.HasIndex(x => x.Username).IsUnique();
            e.Property(x => x.Username).HasMaxLength(32);
            e.Property(x => x.Nickname).HasMaxLength(32);
            // 预留字段索引（唯一但允许 null）
            e.HasIndex(x => x.Email).IsUnique();
            e.HasIndex(x => x.Phone).IsUnique();
            e.HasIndex(x => x.WeChatOpenId).IsUnique();
            e.HasIndex(x => x.AccountClosureScheduledAt);
            e.HasOne(x => x.AiCompanion).WithOne(x => x.User)
                .HasForeignKey<AiCompanionSetting>(x => x.UserId);
        });

        b.Entity<UserFeaturePermission>(e =>
        {
            e.Property(x => x.PermissionKey).HasMaxLength(32);
            e.HasIndex(x => new { x.UserId, x.PermissionKey }).IsUnique();
            e.HasOne(x => x.User).WithMany(x => x.FeaturePermissions)
                .HasForeignKey(x => x.UserId).OnDelete(DeleteBehavior.Cascade);
        });

        b.Entity<Transaction>(e =>
        {
            e.Property(x => x.Amount).HasPrecision(12, 2);
            e.HasIndex(x => new { x.LedgerId, x.OccurredAt });
            e.HasIndex(x => new { x.UserId, x.IsDeleted });
            e.Property(x => x.ClientRequestId).HasMaxLength(64);
            e.HasIndex(x => new { x.UserId, x.ClientRequestId }).IsUnique();
            e.HasQueryFilter(x => !x.IsDeleted); // 软删除全局过滤
        });

        b.Entity<Category>(e => e.Property(x => x.ColorKey).HasMaxLength(32));

        b.Entity<Budget>(e =>
        {
            e.Property(x => x.Amount).HasPrecision(12, 2);
            e.HasIndex(x => new { x.LedgerId, x.Period, x.CategoryId }).IsUnique();
        });

        b.Entity<ChatMessage>(e => e.HasIndex(x => new { x.UserId, x.CreatedAt }));
        b.Entity<AppConfig>(e => e.HasIndex(x => x.Key).IsUnique());
        b.Entity<AiPersona>(e => e.HasIndex(x => x.Key).IsUnique());
        b.Entity<AiAvatar>(e => e.HasIndex(x => x.Key).IsUnique());
        b.Entity<Sticker>(e => e.HasIndex(x => x.Key).IsUnique());

        // MySQL DATETIME has no timezone metadata. Preserve stored UTC wall-clock
        // values and restore DateTimeKind.Utc whenever EF materializes them.
        var utcDateTimeConverter = new ValueConverter<DateTime, DateTime>(
            value => value.Kind == DateTimeKind.Local
                ? value.ToUniversalTime()
                : DateTime.SpecifyKind(value, DateTimeKind.Utc),
            value => DateTime.SpecifyKind(value, DateTimeKind.Utc));
        var nullableUtcDateTimeConverter = new ValueConverter<DateTime?, DateTime?>(
            value => value.HasValue
                ? value.Value.Kind == DateTimeKind.Local
                    ? value.Value.ToUniversalTime()
                    : DateTime.SpecifyKind(value.Value, DateTimeKind.Utc)
                : value,
            value => value.HasValue
                ? DateTime.SpecifyKind(value.Value, DateTimeKind.Utc)
                : value);

        foreach (var property in b.Model.GetEntityTypes().SelectMany(entity => entity.GetProperties()))
        {
            if (property.ClrType == typeof(DateTime))
            {
                property.SetValueConverter(utcDateTimeConverter);
            }
            else if (property.ClrType == typeof(DateTime?))
            {
                property.SetValueConverter(nullableUtcDateTimeConverter);
            }
        }
    }
}