using Catalogger.Backend.Bot.Commands;
using Catalogger.Backend.Bot.Responders;
using Catalogger.Backend.Cache;
using Catalogger.Backend.Database;
using Catalogger.Backend.Database.Queries;
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.Interactivity.Services;
using Remora.Rest.Core;
using Serilog;
using Serilog.Events;

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)
    {
        var config = builder.Configuration.Get<Config>() ?? new();

        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)
            .WriteTo.Console();

        // 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<GuildCacheService>()
        .AddSingleton<ChannelCacheService>()
        .AddSingleton<UserCacheService>()
        .AddSingleton<PluralkitApiService>()
        .AddSingleton<IWebhookCache, InMemoryWebhookCache>()
        .AddScoped<IEncryptionService, EncryptionService>()
        .AddScoped<MessageRepository>()
        .AddSingleton<WebhookExecutorService>()
        .AddSingleton<PkMessageHandler>()
        .AddSingleton(InMemoryDataService<Snowflake, ChannelCommandData>.Instance)
        .AddHostedService<MetricsCollectionService>();

    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");

        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");
    }
}