using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using Sozsoft.Languages.Caching;
using Sozsoft.Platform.Data.Seeds;
using Volo.Abp.Data;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Identity;
using Volo.Abp.MultiTenancy;
using Volo.Abp.TenantManagement;

namespace Sozsoft.Platform.Data;

public class PlatformDbMigrationService : ITransientDependency
{
    public ILogger<PlatformDbMigrationService> Logger { get; set; }

    private readonly IDataSeeder _dataSeeder;
    private readonly IEnumerable<IPlatformDbSchemaMigrator> _dbSchemaMigrators;
    private readonly ITenantRepository _tenantRepository;
    private readonly ICurrentTenant _currentTenant;
    private readonly IConfiguration _configuration;
    private readonly IEnumerable<IFinalSeeder> _finalSeeders;
    private readonly IListFormSeedDataApplier _listFormSeedDataApplier;
    private readonly DistributedCacheCleaner _cacheCleaner;

    public PlatformDbMigrationService(
        IDataSeeder dataSeeder,
        IEnumerable<IPlatformDbSchemaMigrator> dbSchemaMigrators,
        ITenantRepository tenantRepository,
        ICurrentTenant currentTenant,
        IConfiguration configuration,
        IEnumerable<IFinalSeeder> finalSeeders,
        IListFormSeedDataApplier listFormSeedDataApplier,
        DistributedCacheCleaner cacheCleaner)
    {
        _dataSeeder = dataSeeder;
        _dbSchemaMigrators = dbSchemaMigrators;
        _tenantRepository = tenantRepository;
        _currentTenant = currentTenant;
        _configuration = configuration;
        _finalSeeders = finalSeeders;
        _listFormSeedDataApplier = listFormSeedDataApplier;
        _cacheCleaner = cacheCleaner;

        Logger = NullLogger<PlatformDbMigrationService>.Instance;
    }

    public async Task MigrateAsync()
    {
        var seed = _configuration.GetValue("Seed", false);
        Logger.LogInformation($"Migrating database. Seed: {seed}. Env: {Environment.GetEnvironmentVariable("DOTNET_ENVIRONMENT")}");

        await ClearCacheAsync();

        var tenantSeedId = _configuration.GetValue<Guid?>(TenantSeedOptions.TenantIdKey);
        if (tenantSeedId.HasValue)
        {
            await SeedSingleTenantAsync(tenantSeedId.Value);
            return;
        }

        Logger.LogInformation("Started database migrations...");

        await MigrateDatabaseSchemaAsync();

        var tenants = await _tenantRepository.GetListAsync(includeDetails: true);

        // Bekleyen wizard kurulumu dosyaları uygulayan son veritabanında kapanır; host'ta kapansaydı
        // ekranın eski sürümü kurulu olan ayrı veritabanlı tenant onu "kurulu" sayıp güncellemezdi.
        var lastSeedFileTenant = tenants.LastOrDefault(SeedFileScope.AppliesTo);

        if (seed)
        {
            await SeedDataAsync(completesPending: lastSeedFileTenant == null);
        }

        Logger.LogInformation($"Successfully completed host database migrations.");

        var migratedDatabaseSchemas = new HashSet<string>();
        foreach (var tenant in tenants)
        {
            using (_currentTenant.Change(tenant.Id))
            {
                if (tenant.ConnectionStrings.Any())
                {
                    var tenantConnectionStrings = tenant.ConnectionStrings
                        .Select(x => x.Value)
                        .ToList();

                    if (!migratedDatabaseSchemas.IsSupersetOf(tenantConnectionStrings))
                    {
                        await MigrateDatabaseSchemaAsync(tenant);

                        migratedDatabaseSchemas.AddIfNotContains(tenantConnectionStrings);
                    }
                }
                if (seed)
                {
                    await SeedDataAsync(tenant, completesPending: tenant == lastSeedFileTenant);
                }
            }

            Logger.LogInformation($"Successfully completed {tenant.Name} tenant database migrations.");
        }

        Logger.LogInformation("Successfully completed all database migrations.");

        await ExecuteFinalSeedersAsync(tenants, includeHost: true);

        // Seed; menu, yetki ve dil metni ekler. Calisan uygulama bu arada eski halleri onbellege
        // almis olabilir (ornegin wizard'in yeni menusu); migrate sonrasinda da temizlenir.
        if (seed)
            await ClearCacheAsync();

        Logger.LogInformation("You can safely end this process...");
    }

    /// <summary>
    /// Tenants ekranının "Seed" sekmesi: yalnızca verilen tenant'ın şemasını ve seed'ini
    /// tam migrate'le aynı adımlarla çalıştırır. Yönetici bilgisi bu tenant için ekrandan gelir;
    /// tam migrate'teki varsayılan yönetici kullanılmaz.
    /// </summary>
    private async Task SeedSingleTenantAsync(Guid tenantId)
    {
        var tenant = await _tenantRepository.FindAsync(tenantId, includeDetails: true)
            ?? throw new InvalidOperationException($"Tenant not found: {tenantId}");

        var adminEmail = _configuration[TenantSeedOptions.AdminEmailKey];
        var adminPassword = _configuration[TenantSeedOptions.AdminPasswordKey];
        if (string.IsNullOrWhiteSpace(adminEmail) || string.IsNullOrWhiteSpace(adminPassword))
        {
            throw new InvalidOperationException("Admin email and password are required for tenant seed.");
        }

        Logger.LogInformation("Started {TenantName} tenant migration and seed...", tenant.Name);

        using (_currentTenant.Change(tenant.Id))
        {
            if (tenant.ConnectionStrings.Any())
            {
                await MigrateDatabaseSchemaAsync(tenant);
            }

            // Host ve diğer tenant'lar bu çalışmada kurulmadığı için bekleyen wizard kurulumu açık kalır.
            await SeedDataAsync(tenant, completesPending: false, adminEmail, adminPassword);
        }

        Logger.LogInformation("Successfully completed {TenantName} tenant database migrations.", tenant.Name);

        await ExecuteFinalSeedersAsync([tenant], includeHost: false);

        await ClearCacheAsync();

        Logger.LogInformation("You can safely end this process...");
    }

    private async Task ClearCacheAsync()
    {
        var removed = await _cacheCleaner.ClearAsync();
        Logger.LogInformation("Distributed cache cleared. {Count} key(s) removed.", removed);
    }

    /// <summary>
    /// Tüm host ve tenant migration/seed adımları bittikten sonra,
    /// {sql|postgres}/execute klasöründeki script'lerin dosya adından türeyen procedure'lerini
    /// host'ta ve kendi veritabanı olan her tenant'ta çalıştırır. Host veritabanını paylaşan tenant
    /// atlanır; procedure o veritabanında host adımında zaten çalışmıştır.
    /// </summary>
    private async Task ExecuteFinalSeedersAsync(List<Tenant> tenants, bool includeHost)
    {
        if (!_finalSeeders.Any())
        {
            Logger.LogInformation("No SQL executor registered, skipping execute scripts.");
            return;
        }

        Logger.LogInformation(
            "Executing SQL scripts for {Host}{TenantCount} tenant(s)...",
            includeHost ? "host and " : string.Empty,
            tenants.Count);

        if (includeHost)
        {
            using (_currentTenant.Change(null))
            {
                foreach (var executor in _finalSeeders)
                {
                    Logger.LogInformation("Running SQL scripts for host...");
                    await executor.ExecuteAsync();
                    Logger.LogInformation("Completed SQL scripts for host.");
                }
            }
        }

        foreach (var tenant in tenants.Where(SeedFileScope.AppliesTo))
        {
            using (_currentTenant.Change(tenant.Id))
            {
                foreach (var executor in _finalSeeders)
                {
                    Logger.LogInformation(
                        "Running SQL scripts for {TenantName} tenant...",
                        tenant.Name);
                    await executor.ExecuteAsync();
                    Logger.LogInformation(
                        "Completed SQL scripts for {TenantName} tenant.",
                        tenant.Name);
                }
            }
        }

        Logger.LogInformation("Successfully completed all SQL scripts.");
    }

    private async Task MigrateDatabaseSchemaAsync(Tenant? tenant = null)
    {
        Logger.LogInformation(
            $"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");

        foreach (var migrator in _dbSchemaMigrators)
        {
            await migrator.MigrateAsync();
        }
    }

    private async Task SeedDataAsync(
        Tenant? tenant = null,
        bool completesPending = true,
        string adminEmail = PlatformConsts.AbpIdentity.User.AdminEmailDefaultValue,
        string adminPassword = PlatformConsts.AbpIdentity.User.AdminPasswordDefaultValue)
    {
        Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");

        var applySeedFiles = SeedFileScope.AppliesTo(tenant);
        if (!applySeedFiles)
        {
            Logger.LogInformation("{TenantName} tenant shares the host database; seed files are already applied there.", tenant!.Name);
        }

        await _dataSeeder.SeedAsync(new DataSeedContext(tenant?.Id)
            .WithProperty(IdentityDataSeedContributor.AdminEmailPropertyName, adminEmail)
            .WithProperty(IdentityDataSeedContributor.AdminPasswordPropertyName, adminPassword)
            .WithProperty(IdentityDataSeedContributor.AdminUserNamePropertyName, adminEmail)
            .WithProperty(SeedFileScope.PropertyName, applySeedFiles)
            .WithProperty(SeedFileScope.CompletesPendingPropertyName, completesPending)
        );

        // Veri seed dosyalari ListForm tanimlarina ve tablolara dayandigi icin butun
        // contributor'lar bittikten sonra uygulanir; ABP contributor sirasi garanti degildir.
        if (applySeedFiles)
        {
            await _listFormSeedDataApplier.ApplyAsync(tenant?.Id);
        }
    }
}