using DCGEngine.Database.Configuration;
using DCGEngine.Database.Interfaces;
using DCGEngine.Database.Models;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace DCGEngine.Database;

public class DCGEDbContext : DbContext
{
    private readonly DCGEDatabaseConfiguration _configuration;
    private readonly ILogger _logger;

    public DCGEDbContext(IOptions<DCGEDatabaseConfiguration> configuration, ILogger<DCGEDbContext> logger, DbContextOptions options) : base(options)
    {
        _logger = logger;
        _configuration = configuration.Value;
    }

    /// <inheritdoc/>
    public override async Task<int> SaveChangesAsync(CancellationToken cancellationToken = new CancellationToken())
    {
        foreach (var entityEntry in ChangeTracker.Entries())
        {
            if (entityEntry.Entity is ITimeTrackedEntity timeTrackedEntity)
            {
                if (entityEntry.State is EntityState.Added && timeTrackedEntity.DateCreated is null)
                {
                    timeTrackedEntity.DateCreated = DateTime.UtcNow;
                }
                if (entityEntry.State is EntityState.Modified or EntityState.Added)
                {
                    timeTrackedEntity.DateUpdated = DateTime.UtcNow;
                }
            }
        }

        return await base.SaveChangesAsync(cancellationToken);
    }

    /// <inheritdoc/>
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        _configuration.DbSetSearchAssemblies.ForEach(assembly =>
        {
            foreach (var typeInfo in assembly.DefinedTypes.Where(type => type.IsAssignableTo(typeof(IDbTrackedEntity))))
            {
                modelBuilder.Entity(typeInfo.AsType());
            }
        });
        base.OnModelCreating(modelBuilder);
    }

    public void UpdateDatabase()
    {
        IEnumerable<string> pendingMigrations = Database.GetPendingMigrations();
        if (!pendingMigrations.Any())
        {
            return;
        }

        foreach (string migration in pendingMigrations)
        {
            _logger.LogInformation("Found pending migration with name {migrationName}.", migration);
        }
        _logger.LogInformation("Attempting to apply pending migrations...");
        Database.Migrate();
        _logger.LogInformation("Migrations applied.");
    }
}