using DataModel.Database.Common;
using DataModel.MigrationScripts;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace DataModel;

public static class Setup
{
    private const string ENV_EF_TOOLING_DATABASE = "ENV_EF_TOOLING_DATABASE";
    private const string DB_READ_WRITE_MODE = "ReadWrite";
    private const string DB_READ_WRITE_CREATE_MODE = "ReadWriteCreate";

    private static string usedDataFile = string.Empty;
    
    public static string DataFile => Setup.usedDataFile;

    /// <summary>
    /// Tries to migrate the database.
    /// </summary>
    public static async Task PerformDataMigration(DataContext dbContext)
    {
        var pendingMigrations = (await dbContext.Database.GetPendingMigrationsAsync()).ToList();
        foreach (var pendingMigration in pendingMigrations)
        {
            Console.WriteLine($"The migration '{pendingMigration}' is pending.");
        }

        await dbContext.Database.MigrateAsync();
        
        //
        // Post migration actions:
        //
        if (pendingMigrations.Contains("20221106193544_202211AddUniqueIds"))
            await Script202211AddUniqueIds.PostMigrationAsync(dbContext);
    }

    /// <summary>
    /// Add the database to the DI system
    /// </summary>
    public static void AddDatabase(this IServiceCollection serviceCollection, string path2DataFile, bool createWhenNecessary = true)
    {
        Setup.usedDataFile = path2DataFile;
        serviceCollection.AddDbContext<DataContext>(options => options.UseSqlite($"Filename={path2DataFile};Mode={(createWhenNecessary ? DB_READ_WRITE_CREATE_MODE : DB_READ_WRITE_MODE)};"), ServiceLifetime.Transient);
    }
    
    /// <summary>
    /// Create the database instance from the given path.
    /// </summary>
    public static DataContext CreateDatabaseInstance(string path2DataFile, bool createWhenNecessary = true)
    {
        // Store the path to the database:
        Setup.usedDataFile = path2DataFile;
        
        // Create a database builder:
        var builder = new DbContextOptionsBuilder<DataContext>();
        
        // Add the database configuration to the builder:
        builder.UseSqlite($"Filename={path2DataFile};Mode={(createWhenNecessary ? DB_READ_WRITE_CREATE_MODE : DB_READ_WRITE_MODE)};");
        
        // Next, construct the database context:
        var dbContext = new DataContext(builder.Options);
        return dbContext;
    }

    /// <summary>
    /// Sets up the DI & db context ready for the EF tooling.
    /// </summary>
    public static IHostBuilder Setup4EFTooling(string[] args)
    {
        var dataFile = Environment.GetEnvironmentVariable(ENV_EF_TOOLING_DATABASE);
        if (string.IsNullOrWhiteSpace(dataFile))
        {
            Console.WriteLine("In order to use EF tooling, point the environment variable ENV_EF_TOOLING_DATABASE to the data file, which should be used for the EF tooling.");
            Environment.Exit(100);
        }
        
        var builder = Host.CreateDefaultBuilder(args);
        builder.ConfigureServices((hostContext, serviceCollection) =>
        {
            serviceCollection.AddDbContext<DataContext>(options => options.UseSqlite($"Filename={dataFile};Mode=ReadWriteCreate"));
        });

        return builder;
    }
}