using Microsoft.AspNetCore.Builder;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using NDB.Infrastructure.DatabaseMigration.Constants;
using NDB.Infrastructure.DatabaseMigration.DbContexts;
using NDB.Infrastructure.DatabaseMigration.Models;
using NDB.Infrastructure.DatabaseMigration.Repositories;
using NDB.Infrastructure.DatabaseMigration.Services;
using NDB.Infrastructure.DatabaseMigration.Services.Abstractions;
using System;

namespace NDB.Infrastructure.DatabaseMigration
{
    public static class DependencyInjectionExtensions
    {
        private const string _workspacePlaceholder = "{Workspace}";

        public static void AddMigration(this IServiceCollection services,
            DatabaseType databaseType = DatabaseType.SQLite,
            MetadataLocation metadataLocation = MetadataLocation.XmlFile,
            string connectionName = "DatabaseConnection",
            string workspace = "Workspace",
            string scriptsDirectoryPath = "Scripts")
        {
            var serviceConfiguration = new ServiceConfiguration(databaseType, metadataLocation, connectionName, workspace, scriptsDirectoryPath);
            services.AddSingleton(serviceConfiguration);
            services.AddDataAccess(serviceConfiguration);
            services.AddSingleton<IMetadataLocationService, MetadataLocationService>();
            services.AddSingleton<IMigrationSignaturesService, MigrationSignaturesService>();
            services.AddSingleton<IMigrationService, MigrationService>();
        }

        private static void AddDataAccess(this IServiceCollection services, ServiceConfiguration serviceConfiguration)
        {
            services.AddScoped<IMigrationRepository, MigrationRepository>();
            services.AddDbContextPool<MigrationDbContext>((serviceProvider, options) =>
            {
                var connectionString = GetDatabaseConnectionString(serviceProvider, serviceConfiguration.ConnectionName, serviceConfiguration.Workspace);

                switch (serviceConfiguration.DatabaseType)
                {
                    case DatabaseType.SQLite:
                        options.UseSqlite(connectionString);
                        break;

                    case DatabaseType.SQLServer:
                        options.UseSqlServer(connectionString);
                        break;

                    default:
                        throw new NotImplementedException($"Database type {serviceConfiguration.DatabaseType} is not implemented.");
                }
            });
        }

        private static string GetDatabaseConnectionString(IServiceProvider serviceProvider, string connectionName, string workspace)
        {
            var configuration = serviceProvider.GetService<IConfiguration>();
            var connectionString = configuration.GetConnectionString(connectionName);

            if (connectionString.Contains(_workspacePlaceholder))
            {
                connectionString = connectionString.Replace(_workspacePlaceholder, workspace);
            }

            return connectionString;
        }

        public static void UseMigration(this IApplicationBuilder app)
        {
            var migrationService = app.ApplicationServices.GetService<IMigrationService>();
            migrationService.Execute();
        }
    }
}