using Microsoft.EntityFrameworkCore;

namespace JobTrackerApi.Data;

public static class DatabaseConfiguration
{
    public static string GetProvider(IConfiguration configuration) =>
        (configuration["Database:Provider"] ?? "mariadb").Trim().ToLowerInvariant() switch
        {
            "mysql" or "mariadb" => "mariadb",
            "sqlite" => "sqlite",
            _ => throw new InvalidOperationException("Database:Provider must be mariadb (or mysql) or explicitly sqlite for transitional preservation."),
        };

    public static string GetConnectionString(IConfiguration configuration, string sqlitePath)
    {
        var provider = GetProvider(configuration);
        var connection = configuration.GetConnectionString("JobTracker");
        if (!string.IsNullOrWhiteSpace(connection)) return connection;
        if (provider == "sqlite") return $"Data Source={sqlitePath}";
        throw new InvalidOperationException("ConnectionStrings:JobTracker is required for MariaDB. SQLite is only used when Database:Provider is explicitly sqlite.");
    }

    public static void Configure(DbContextOptionsBuilder options, IConfiguration configuration, string sqlitePath)
    {
        var provider = GetProvider(configuration);
        var connection = GetConnectionString(configuration, sqlitePath);
        if (provider == "mariadb")
        {
            var configuredVersion = configuration["Database:ServerVersion"] ?? "12.2.2";
            if (!Version.TryParse(configuredVersion, out var version) || version.Major < 1 || version.Build < 0)
                throw new InvalidOperationException("Database:ServerVersion must be a MariaDB version in major.minor.patch form.");
            // AutoDetect would open a server connection while options are being registered.
            options.UseMySql(connection, new MariaDbServerVersion(version), mysql => mysql.MigrationsAssembly("JobTrackerApi"));
        }
        else
            options.UseSqlite(connection, sqlite => sqlite.MigrationsAssembly("JobTrackerApi"));
    }
}