using System.Linq.Expressions;
using System.Reflection;
using DysonNetwork.Common.Models;
using DysonNetwork.Sphere.Permission;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using NodaTime;
using Quartz;

namespace DysonNetwork.Pass.Data;

public class PassDatabase(
    DbContextOptions<PassDatabase> options,
    IConfiguration configuration
) : DbContext(options)
{
    public DbSet<PermissionNode> PermissionNodes { get; set; }
    public DbSet<PermissionGroup> PermissionGroups { get; set; }
    public DbSet<PermissionGroupMember> PermissionGroupMembers { get; set; }

    public DbSet<MagicSpell> MagicSpells { get; set; }
    public DbSet<Account> Accounts { get; set; }
    public DbSet<AccountConnection> AccountConnections { get; set; }
    public DbSet<Profile> AccountProfiles { get; set; }
    public DbSet<AccountContact> AccountContacts { get; set; }
    public DbSet<AccountAuthFactor> AccountAuthFactors { get; set; }
    public DbSet<Relationship> AccountRelationships { get; set; }
    public DbSet<Notification> Notifications { get; set; }
    public DbSet<Badge> Badges { get; set; }
    public DbSet<ActionLog> ActionLogs { get; set; }
    public DbSet<AbuseReport> AbuseReports { get; set; }

    public DbSet<AuthSession> AuthSessions { get; set; }
    public DbSet<AuthChallenge> AuthChallenges { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseNpgsql(
            configuration.GetConnectionString("App"),
            opt => opt
                .ConfigureDataSource(optSource => optSource.EnableDynamicJson())
                .UseQuerySplittingBehavior(QuerySplittingBehavior.SplitQuery)
                .UseNetTopologySuite()
                .UseNodaTime()
        ).UseSnakeCaseNamingConvention();

        optionsBuilder.UseAsyncSeeding(async (context, _, cancellationToken) =>
        {
            // Add any initial seeding logic here if needed for PassDatabase
        });

        optionsBuilder.UseSeeding((context, _) => {});

        base.OnConfiguring(optionsBuilder);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        
        modelBuilder.Entity<PermissionGroupMember>()
            .HasKey(pg => new { pg.GroupId, pg.Actor });
        modelBuilder.Entity<PermissionGroupMember>()
            .HasOne(pg => pg.Group)
            .WithMany(g => g.Members)
            .HasForeignKey(pg => pg.GroupId)
            .OnDelete(DeleteBehavior.Cascade);

        modelBuilder.Entity<Relationship>()
            .HasKey(r => new { FromAccountId = r.AccountId, ToAccountId = r.RelatedId });
        modelBuilder.Entity<Relationship>()
            .HasOne(r => r.Account)
            .WithMany(a => a.OutgoingRelationships)
            .HasForeignKey(r => r.AccountId);
        modelBuilder.Entity<Relationship>()
            .HasOne(r => r.Related)
            .WithMany(a => a.IncomingRelationships)
            .HasForeignKey(r => r.RelatedId);

        // Automatically apply soft-delete filter to all entities inheriting BaseModel
        foreach (var entityType in modelBuilder.Model.GetEntityTypes())
        {
            if (!typeof(ModelBase).IsAssignableFrom(entityType.ClrType)) continue;
            var method = typeof(PassDatabase)
                .GetMethod(nameof(SetSoftDeleteFilter),
                    BindingFlags.NonPublic | BindingFlags.Static)!
                .MakeGenericMethod(entityType.ClrType);

            method.Invoke(null, [modelBuilder]);
        }
    }

    private static void SetSoftDeleteFilter<TEntity>(ModelBuilder modelBuilder)
        where TEntity : ModelBase
    {
        modelBuilder.Entity<TEntity>().HasQueryFilter(e => e.DeletedAt == null);
    }

    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = default)
    {
        var now = SystemClock.Instance.GetCurrentInstant();

        foreach (var entry in ChangeTracker.Entries<ModelBase>())
        {
            switch (entry.State)
            {
                case EntityState.Added:
                    entry.Entity.CreatedAt = now;
                    entry.Entity.UpdatedAt = now;
                    break;
                case EntityState.Modified:
                    entry.Entity.UpdatedAt = now;
                    break;
                case EntityState.Deleted:
                    entry.State = EntityState.Modified;
                    entry.Entity.DeletedAt = now;
                    break;
                case EntityState.Detached:
                case EntityState.Unchanged:
                default:
                    break;
            }
        }

        return await base.SaveChangesAsync(cancellationToken);
    }
}

public class PassDatabaseFactory : IDesignTimeDbContextFactory<PassDatabase>
{
    public PassDatabase CreateDbContext(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("appsettings.json")
            .Build();

        var optionsBuilder = new DbContextOptionsBuilder<PassDatabase>();
        return new PassDatabase(optionsBuilder.Options, configuration);
    }
}

public class PassDatabaseRecyclingJob(PassDatabase db, ILogger<PassDatabaseRecyclingJob> logger) : IJob
{
    public async Task Execute(IJobExecutionContext context)
    {
        var now = SystemClock.Instance.GetCurrentInstant();

        logger.LogInformation("Cleaning up expired records...");

        // Expired relationships
        var affectedRows = await db.AccountRelationships
            .Where(x => x.ExpiredAt != null && x.ExpiredAt <= now)
            .ExecuteDeleteAsync();
        logger.LogDebug("Removed {Count} records of expired relationships.", affectedRows);

        logger.LogInformation("Deleting soft-deleted records...");

        var threshold = now - Duration.FromDays(7);

        var entityTypes = db.Model.GetEntityTypes()
            .Where(t => typeof(ModelBase).IsAssignableFrom(t.ClrType) && t.ClrType != typeof(ModelBase))
            .Select(t => t.ClrType);

        foreach (var entityType in entityTypes)
        {
            var set = (IQueryable)db.GetType().GetMethod(nameof(DbContext.Set), Type.EmptyTypes)!
                .MakeGenericMethod(entityType).Invoke(db, null)!;
            var parameter = Expression.Parameter(entityType, "e");
            var property = Expression.Property(parameter, nameof(ModelBase.DeletedAt));
            var condition = Expression.LessThan(property, Expression.Constant(threshold, typeof(Instant?)));
            var notNull = Expression.NotEqual(property, Expression.Constant(null, typeof(Instant?)));
            var finalCondition = Expression.AndAlso(notNull, condition);
            var lambda = Expression.Lambda(finalCondition, parameter);

            var queryable = set.Provider.CreateQuery(
                Expression.Call(
                    typeof(Queryable),
                    "Where",
                    [entityType],
                    set.Expression,
                    Expression.Quote(lambda)
                )
            );

            var toListAsync = typeof(EntityFrameworkQueryableExtensions)
                .GetMethod(nameof(EntityFrameworkQueryableExtensions.ToListAsync))!
                .MakeGenericMethod(entityType);

            var items = await (dynamic)toListAsync.Invoke(null, [queryable, CancellationToken.None])!;
            db.RemoveRange(items);
        }

        await db.SaveChangesAsync();
    }
}