using Catalogger.Backend.Bot;
using Catalogger.Backend.Bot.Commands;
using Catalogger.Backend.Bot.Responders.Messages;
using Catalogger.Backend.Cache;
using Catalogger.Backend.Cache.InMemoryCache;
using Catalogger.Backend.Cache.RedisCache;
using Catalogger.Backend.Database;
using Catalogger.Backend.Database.Queries;
using Catalogger.Backend.Database.Redis;
using Catalogger.Backend.Services;
using Microsoft.EntityFrameworkCore;
using NodaTime;
using Remora.Discord.API;
using Remora.Discord.API.Abstractions.Rest;
using Remora.Discord.Commands.Services;
using Remora.Discord.Gateway.Extensions;
using Remora.Discord.Interactivity.Services;
using Remora.Rest.Core;
using Serilog;
using Serilog.Events;
using Serilog.Sinks.SystemConsole.Themes;

namespace Catalogger.Backend.Extensions;

public static class StartupExtensions
{
    /// <summary>
    /// Adds Serilog to this service collection. This method also initializes Serilog, so it should be called as early as possible, before any log calls.
    /// </summary>
    public static WebApplicationBuilder AddSerilog(
        this WebApplicationBuilder builder,
        Config config
    )
    {
        var logCfg = new LoggerConfiguration()
            .Enrich.FromLogContext()
            .MinimumLevel.Is(config.Logging.LogEventLevel)
            // ASP.NET's built in request logs are extremely verbose, so we use Serilog's instead.
            // Serilog doesn't disable the built-in logs, so we do it here.
            .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
            .MinimumLevel.Override(
                "Microsoft.EntityFrameworkCore.Database.Command",
                config.Logging.LogQueries ? LogEventLevel.Information : LogEventLevel.Fatal
            )
            .MinimumLevel.Override("Microsoft.AspNetCore.Hosting", LogEventLevel.Warning)
            .MinimumLevel.Override("Microsoft.AspNetCore.Mvc", LogEventLevel.Warning)
            .MinimumLevel.Override("Microsoft.AspNetCore.Routing", LogEventLevel.Warning)
            // The default theme doesn't support light mode
            .WriteTo.Console(theme: AnsiConsoleTheme.Sixteen);

        // AddSerilog doesn't seem to add an ILogger to the service collection, so add that manually.
        builder.Services.AddSerilog().AddSingleton(Log.Logger = logCfg.CreateLogger());

        return builder;
    }

    public static Config AddConfiguration(this WebApplicationBuilder builder)
    {
        builder.Configuration.Sources.Clear();
        builder.Configuration.AddConfiguration();

        var config = builder.Configuration.Get<Config>() ?? new();
        builder.Services.AddSingleton(config);
        return config;
    }

    public static IConfigurationBuilder AddConfiguration(this IConfigurationBuilder builder)
    {
        var file = Environment.GetEnvironmentVariable("CATALOGGER_CONFIG_FILE") ?? "config.ini";

        return builder
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddIniFile(file, optional: false, reloadOnChange: false)
            .AddEnvironmentVariables();
    }

    public static IServiceCollection AddCustomServices(this IServiceCollection services) =>
        services
            .AddSingleton<IClock>(SystemClock.Instance)
            .AddSingleton<GuildCache>()
            .AddSingleton<RoleCache>()
            .AddSingleton<ChannelCache>()
            .AddSingleton<UserCache>()
            .AddSingleton<AuditLogCache>()
            .AddSingleton<PluralkitApiService>()
            .AddScoped<IEncryptionService, EncryptionService>()
            .AddSingleton<MetricsCollectionService>()
            .AddSingleton<AuditLogEnrichedResponderService>()
            .AddScoped<MessageRepository>()
            .AddSingleton<WebhookExecutorService>()
            .AddSingleton<PkMessageHandler>()
            .AddSingleton(InMemoryDataService<Snowflake, ChannelCommandData>.Instance)
            .AddSingleton<GuildFetchService>()
            .AddHostedService(serviceProvider =>
                serviceProvider.GetRequiredService<GuildFetchService>()
            );

    public static IHostBuilder AddShardedDiscordService(
        this IHostBuilder builder,
        Func<IServiceProvider, string> tokenFactory
    ) =>
        builder.ConfigureServices(
            (_, services) =>
                services
                    .AddDiscordGateway(tokenFactory)
                    .AddSingleton<ShardedGatewayClient>()
                    .AddHostedService<ShardedDiscordService>()
        );

    public static IServiceCollection MaybeAddRedisCaches(
        this IServiceCollection services,
        Config config
    )
    {
        if (config.Database.Redis == null)
        {
            return services
                .AddSingleton<IWebhookCache, InMemoryWebhookCache>()
                .AddSingleton<IMemberCache, InMemoryMemberCache>()
                .AddSingleton<IInviteCache, InMemoryInviteCache>();
        }

        return services
            .AddSingleton<RedisService>()
            .AddSingleton<IWebhookCache, RedisWebhookCache>()
            .AddSingleton<IMemberCache, RedisMemberCache>()
            .AddSingleton<IInviteCache, RedisInviteCache>();
    }

    public static async Task Initialize(this WebApplication app)
    {
        await using var scope = app.Services.CreateAsyncScope();
        var logger = scope.ServiceProvider.GetRequiredService<ILogger>().ForContext<Program>();
        logger.Information("Starting Catalogger.NET");

        CataloggerMetrics.Startup = scope
            .ServiceProvider.GetRequiredService<IClock>()
            .GetCurrentInstant();

        await using (var db = scope.ServiceProvider.GetRequiredService<DatabaseContext>())
        {
            var migrationCount = (await db.Database.GetPendingMigrationsAsync()).Count();
            if (migrationCount != 0)
            {
                logger.Information("Applying {Count} database migrations", migrationCount);
                await db.Database.MigrateAsync();
            }
            else
                logger.Information("There are no pending migrations");
        }

        var config = scope.ServiceProvider.GetRequiredService<Config>();
        var slashService = scope.ServiceProvider.GetRequiredService<SlashService>();

        if (config.Discord.ApplicationId == 0)
        {
            logger.Warning(
                "Application ID not set in config. Fetching and setting it now, but for future restarts, please add it to config.ini as Discord.ApplicationId."
            );
            var restApi = scope.ServiceProvider.GetRequiredService<IDiscordRestApplicationAPI>();
            var application = await restApi.GetCurrentApplicationAsync().GetOrThrow();
            config.Discord.ApplicationId = application.ID.ToUlong();
            logger.Information(
                "Current application ID is {ApplicationId}",
                config.Discord.ApplicationId
            );
        }

        if (config.Discord.SyncCommands)
        {
            if (config.Discord.CommandsGuildId != null)
            {
                logger.Information(
                    "Syncing application commands with guild {GuildId}",
                    config.Discord.CommandsGuildId
                );
                await slashService.UpdateSlashCommandsAsync(
                    guildID: DiscordSnowflake.New(config.Discord.CommandsGuildId.Value)
                );
            }
            else
            {
                logger.Information("Syncing application commands globally");
                await slashService.UpdateSlashCommandsAsync();
            }
        }
        else
            logger.Information(
                "Not syncing slash commands, Discord.SyncCommands is false or unset"
            );
    }
}