using MeterVault.Infrastructure.Ingestion;
using MeterVault.Infrastructure.Security;
using Microsoft.AspNetCore.DataProtection;

namespace MeterVault.Integration.Tests.Ingestion;

/// <summary>
/// Connector secrets may be stored two ways (SDD §6.4): encrypted at rest after being typed into
/// the admin UI, or as the name of an environment variable resolved at runtime. These pin which
/// form wins and, more importantly, that neither form ever leaves plaintext in the config JSON.
/// </summary>
public sealed class EndpointSecretTests
{
    private const string UnsetVar = "METERVAULT_DEFINITELY_UNSET_TOKEN_VAR";

    private static SecretProtector NewProtector() => new(new EphemeralDataProtectionProvider());

    [Fact]
    public void Encrypted_token_round_trips_and_is_not_plaintext_in_the_config()
    {
        var protector = NewProtector();
        var config = new HaEndpointConfig
        {
            BaseUrl = "http://ha.local:8123",
            TokenEnc = protector.Protect("super-secret-token"),
        };

        Assert.Equal("super-secret-token", config.ResolveToken(protector));

        // This JSON is what lands in ingestion_endpoint.config, in pg_dump, and in a JSON export.
        Assert.DoesNotContain("super-secret-token", config.ToJson(), StringComparison.Ordinal);
    }

    [Fact]
    public void Env_var_is_used_when_no_encrypted_token_is_present()
    {
        var variable = $"MV_TEST_TOKEN_{Guid.NewGuid():N}";
        Environment.SetEnvironmentVariable(variable, "from-the-environment");
        try
        {
            var config = new HaEndpointConfig { TokenEnv = variable };
            Assert.Equal("from-the-environment", config.ResolveToken(NewProtector()));
        }
        finally
        {
            Environment.SetEnvironmentVariable(variable, null);
        }
    }

    [Fact]
    public void Encrypted_token_wins_when_both_forms_are_set()
    {
        var protector = NewProtector();
        var variable = $"MV_TEST_TOKEN_{Guid.NewGuid():N}";
        Environment.SetEnvironmentVariable(variable, "from-the-environment");
        try
        {
            var config = new HaEndpointConfig
            {
                TokenEnv = variable,
                TokenEnc = protector.Protect("typed-in-the-ui"),
            };

            Assert.Equal("typed-in-the-ui", config.ResolveToken(protector));
        }
        finally
        {
            Environment.SetEnvironmentVariable(variable, null);
        }
    }

    [Fact]
    public void Undecryptable_ciphertext_falls_back_instead_of_throwing()
    {
        // A key ring restored without its keys: the worker must degrade, not crash on a timer.
        var config = new HaEndpointConfig { TokenEnc = "not-valid-ciphertext", TokenEnv = UnsetVar };

        var exception = Record.Exception(() => config.ResolveToken(NewProtector()));

        Assert.Null(exception);
        Assert.Null(config.ResolveToken(NewProtector()));
    }

    [Fact]
    public void Resolving_without_a_protector_still_reads_the_env_var()
    {
        // ResolveToken() is called with no protector in unit contexts; the env-var path must work.
        var variable = $"MV_TEST_TOKEN_{Guid.NewGuid():N}";
        Environment.SetEnvironmentVariable(variable, "plain-env");
        try
        {
            Assert.Equal("plain-env", new HaEndpointConfig { TokenEnv = variable }.ResolveToken());
        }
        finally
        {
            Environment.SetEnvironmentVariable(variable, null);
        }
    }

    [Fact]
    public void Mqtt_password_is_encrypted_while_username_stays_readable()
    {
        var protector = NewProtector();
        var config = new EndpointConfig
        {
            Host = "broker.local",
            Username = "metervault",
            PasswordEnc = protector.Protect("broker-password"),
        };

        Assert.Equal("metervault", config.ResolveUsername(protector));
        Assert.Equal("broker-password", config.ResolvePassword(protector));

        var json = config.ToJson();
        Assert.DoesNotContain("broker-password", json, StringComparison.Ordinal);
        Assert.Contains("metervault", json, StringComparison.Ordinal);
    }
}