namespace ScadaLink.Host.Tests;

/// <summary>
/// Host-003: <c>appsettings.Central.json</c> no longer commits database connection
/// strings — they are externalised to environment variables. Tests that exercise the
/// full <c>Program</c> startup pipeline against the real SQL provider must therefore
/// supply the local dev connection strings the way a deployment would: via
/// environment variables (<c>Program</c>'s configuration builder calls
/// <c>AddEnvironmentVariables()</c>).
///
/// Dispose restores the previous values so tests stay isolated.
/// </summary>
internal sealed class CentralDbTestEnvironment : IDisposable
{
    // Local dev/test database — same credentials the infra docker-compose stack uses.
    // This is a test fixture value, not a committed production secret.
    private const string ConfigurationDb =
        "Server=localhost,1433;Database=ScadaLinkConfig;User Id=scadalink_app;Password=ScadaLink_Dev1#;TrustServerCertificate=true";
    private const string MachineDataDb =
        "Server=localhost,1433;Database=ScadaLinkMachineData;User Id=scadalink_app;Password=ScadaLink_Dev1#;TrustServerCertificate=true";

    private const string ConfigKey = "ScadaLink__Database__ConfigurationDb";
    private const string MachineKey = "ScadaLink__Database__MachineDataDb";

    private readonly string? _previousConfig;
    private readonly string? _previousMachine;

    public CentralDbTestEnvironment()
    {
        _previousConfig = Environment.GetEnvironmentVariable(ConfigKey);
        _previousMachine = Environment.GetEnvironmentVariable(MachineKey);
        Environment.SetEnvironmentVariable(ConfigKey, ConfigurationDb);
        Environment.SetEnvironmentVariable(MachineKey, MachineDataDb);
    }

    public void Dispose()
    {
        Environment.SetEnvironmentVariable(ConfigKey, _previousConfig);
        Environment.SetEnvironmentVariable(MachineKey, _previousMachine);
    }
}