// Copyright (C) 2021-present sam (starshines.gay)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

using Catalogger.Backend.Database.Models;
using Catalogger.Backend.Extensions;
using EntityFramework.Exceptions.PostgreSQL;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.ChangeTracking;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
using Npgsql;

namespace Catalogger.Backend.Database;

public class DatabaseContext : DbContext
{
    private readonly NpgsqlDataSource _dataSource;
    private readonly ILoggerFactory? _loggerFactory;

    public DbSet<Guild> Guilds { get; set; }
    public DbSet<Message> Messages { get; set; }
    public DbSet<IgnoredMessage> IgnoredMessages { get; set; }
    public DbSet<Invite> Invites { get; set; }
    public DbSet<Watchlist> Watchlists { get; set; }
    public DbSet<ApiToken> ApiTokens { get; set; }

    public DatabaseContext(Config config, ILoggerFactory? loggerFactory)
    {
        var connString = new NpgsqlConnectionStringBuilder(config.Database.Url)
        {
            Timeout = config.Database.Timeout ?? 5,
            MaxPoolSize = config.Database.MaxPoolSize ?? 50,
        }.ConnectionString;

        var dataSourceBuilder = new NpgsqlDataSourceBuilder(connString);
        dataSourceBuilder.EnableDynamicJson().UseNodaTime();
        _dataSource = dataSourceBuilder.Build();
        _loggerFactory = loggerFactory;
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) =>
        optionsBuilder
            .ConfigureWarnings(c =>
                c.Ignore(CoreEventId.ManyServiceProvidersCreatedWarning)
                    .Ignore(CoreEventId.SaveChangesFailed)
            )
            .UseNpgsql(_dataSource, o => o.UseNodaTime())
            .UseSnakeCaseNamingConvention()
            .UseLoggerFactory(_loggerFactory)
            .UseExceptionProcessor();

    protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
    {
        configurationBuilder.Properties<ulong>().HaveConversion<UlongValueConverter>();
        configurationBuilder.Properties<List<ulong>>().HaveConversion<UlongArrayValueConverter>();
    }

    private static readonly ValueComparer<List<ulong>> UlongListValueComparer =
        new(
            (c1, c2) => c1 != null && c2 != null && c1.SequenceEqual(c2),
            c => c.Aggregate(0, (a, v) => HashCode.Combine(a, v.GetHashCode()))
        );

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder
            .Entity<Guild>()
            .Property(g => g.KeyRoles)
            .Metadata.SetValueComparer(UlongListValueComparer);

        modelBuilder.Entity<Invite>().HasKey(i => i.Code);
        modelBuilder.Entity<Invite>().HasIndex(i => i.GuildId);

        modelBuilder.Entity<Watchlist>().HasKey(w => new { w.GuildId, w.UserId });
        modelBuilder.Entity<Watchlist>().Property(w => w.AddedAt).HasDefaultValueSql("now()");
    }
}

public class DesignTimeDatabaseContextFactory : IDesignTimeDbContextFactory<DatabaseContext>
{
    public DatabaseContext CreateDbContext(string[] args)
    {
        // Read the configuration file
        var config =
            new ConfigurationBuilder()
                .AddConfiguration()
                .Build()
                // Get the configuration as our config class
                .Get<Config>() ?? new();

        return new DatabaseContext(config, null);
    }
}

public class UlongValueConverter()
    : ValueConverter<ulong, long>(
        convertToProviderExpression: x => (long)x,
        convertFromProviderExpression: x => (ulong)x
    );

public class UlongArrayValueConverter()
    : ValueConverter<List<ulong>, List<long>>(
        convertToProviderExpression: x => x.Select(i => (long)i).ToList(),
        convertFromProviderExpression: x => x.Select(i => (ulong)i).ToList()
    );