using System.Diagnostics;
using Azaion.Missions.E2E.Helpers;
using Npgsql;
using Xunit;

namespace Azaion.Missions.E2E.Tests.Resilience;

/// <summary>
/// NFT-RES-05 (config fail-fast + DB-down differentiator) and
/// NFT-RES-06 (Npgsql 3D000 on missing database). The 4 missing-env rows
/// overlap with NFT-SEC-12 in the security category — same docker-run
/// primitive, separate Sec/Res CSV rows.
/// Traces: AC-6.1, AC-6.2, AC-6.7, AC-6.8, E3, E4.
/// </summary>
[Collection("MigratorRestart")]
[Trait("Category", "Res")]
[Trait("db_access", "seed-or-assert-only")]
public sealed class ConfigDbStartupTests
{
    private const string PostgresUrl =
        "postgresql://postgres:postgres-test@missions-postgres-test:5432/azaion";
    private const string JwksUrlHttps =
        "https://jwks-mock:8443/.well-known/jwks.json";
    private const string Issuer  = "https://admin-test.azaion.local";
    private const string Audience = "azaion-edge";

    public static IEnumerable<object[]> FailFastCases() => new[]
    {
        new object[] { "all_missing",       Array.Empty<string>() },
        new object[] { "db_url_missing",    new[] { "DATABASE_URL" } },
        new object[] { "jwt_issuer_missing", new[] { "JWT_ISSUER" } },
        new object[] { "jwt_audience_missing", new[] { "JWT_AUDIENCE" } },
        new object[] { "jwks_url_missing",  new[] { "JWT_JWKS_URL" } },
    };

    [SkippableTheory]
    [MemberData(nameof(FailFastCases))]
    [Trait("Traces", "AC-6.1,AC-6.2,E3")]
    [Trait("max_ms", "30000")]
    public void NFT_RES_05_missing_required_env_var_throws_invalid_operation_exception(
        string caseName, string[] omittedVars)
    {
        Skip.IfNot(MissionsContainerHelper.Enabled,
            "MissionsContainerHelper requires COMPOSE_RESTART_ENABLED=1 and docker CLI access.");

        // Arrange
        var env = BaseEnv();
        foreach (var v in omittedVars) env.Remove(v);
        if (omittedVars.Length == 0)
        {
            env.Remove("DATABASE_URL");
            env.Remove("JWT_ISSUER");
            env.Remove("JWT_AUDIENCE");
            env.Remove("JWT_JWKS_URL");
        }

        // Act
        var result = MissionsContainerHelper.RunUntilExit(
            $"missions-res05-{caseName}", env, TimeSpan.FromSeconds(20));

        // Assert
        Assert.NotEqual(0, result.ExitCode);
        Assert.Contains("InvalidOperationException", result.Logs, StringComparison.Ordinal);
    }

    [SkippableFact]
    [Trait("Traces", "AC-6.1,E3")]
    [Trait("max_ms", "30000")]
    public void NFT_RES_05_whitespace_required_env_var_treated_as_missing()
    {
        Skip.IfNot(MissionsContainerHelper.Enabled,
            "MissionsContainerHelper requires COMPOSE_RESTART_ENABLED=1 and docker CLI access.");

        // Arrange — whitespace-only value triggers the same fail-fast path
        // as an absent value (ResolveRequiredOrThrow uses IsNullOrWhiteSpace).
        var env = BaseEnv();
        env["JWT_ISSUER"] = "   ";

        // Act
        var result = MissionsContainerHelper.RunUntilExit(
            "missions-res05-whitespace-iss", env, TimeSpan.FromSeconds(20));

        // Assert
        Assert.NotEqual(0, result.ExitCode);
        Assert.Contains("InvalidOperationException", result.Logs, StringComparison.Ordinal);
        var mentionsIssuer =
            result.Logs.Contains("JWT_ISSUER", StringComparison.Ordinal)
            || result.Logs.Contains("Jwt:Issuer", StringComparison.Ordinal);
        Assert.True(mentionsIssuer,
            $"logs must mention JWT_ISSUER. Logs:\n{result.Logs}");
    }

    [SkippableFact]
    [Trait("Traces", "AC-6.7,E4")]
    [Trait("max_ms", "60000")]
    public void NFT_RES_05_db_down_after_config_resolution_logs_npgsql_connection_refused()
    {
        Skip.IfNot(MissionsContainerHelper.Enabled,
            "MissionsContainerHelper requires COMPOSE_RESTART_ENABLED=1 and docker CLI access.");

        // Arrange — all 4 required vars set, but point DATABASE_URL at a
        // host that is not running. Config resolution succeeds; Npgsql
        // fails on the migrator's first connection attempt.
        var env = BaseEnv();
        env["DATABASE_URL"] =
            "postgresql://postgres:postgres-test@nonexistent-host-for-res05:5432/azaion";

        // Act
        var result = MissionsContainerHelper.RunUntilExit(
            "missions-res05-db-down", env, TimeSpan.FromSeconds(45));

        // Assert
        Assert.NotEqual(0, result.ExitCode);
        // Connection-refused / name-not-resolved / unreachable are the
        // acceptable Npgsql failure shapes; the differentiator is that
        // InvalidOperationException must NOT appear — proving config
        // resolution completed before the connection broke.
        Assert.DoesNotContain("InvalidOperationException", result.Logs, StringComparison.Ordinal);
        var connectionShape =
            result.Logs.Contains("Connection refused", StringComparison.OrdinalIgnoreCase)
            || result.Logs.Contains("could not resolve", StringComparison.OrdinalIgnoreCase)
            || result.Logs.Contains("could not connect", StringComparison.OrdinalIgnoreCase)
            || result.Logs.Contains("Name or service not known", StringComparison.OrdinalIgnoreCase)
            || result.Logs.Contains("Temporary failure in name resolution", StringComparison.OrdinalIgnoreCase);
        Assert.True(connectionShape,
            $"logs must show Npgsql connection failure (not InvalidOperationException). Logs:\n{result.Logs}");
    }

    [SkippableFact]
    [Trait("Traces", "AC-6.8")]
    [Trait("max_ms", "60000")]
    public void NFT_RES_06_dropping_target_database_causes_3D000_exit()
    {
        Skip.IfNot(MissionsContainerHelper.Enabled,
            "Requires docker CLI + COMPOSE_RESTART_ENABLED=1 + Postgres admin access.");

        // Arrange — drop the azaion database via a side-channel that
        // connects to the `postgres` admin DB. Caller is responsible for
        // recreating the DB in teardown (handled by ComposeRestartFixture
        // in the surrounding collection).
        try
        {
            DropAzaionDatabase();
        }
        catch (PostgresException ex)
        {
            Skip.If(true,
                $"could not drop azaion database for NFT-RES-06 setup ({ex.SqlState}: {ex.MessageText}); " +
                "the test requires superuser admin access on the postgres-test container.");
            return;
        }

        try
        {
            // Act
            var result = MissionsContainerHelper.RunUntilExit(
                "missions-res06-dropdb", BaseEnv(), TimeSpan.FromSeconds(45));

            // Assert
            Assert.NotEqual(0, result.ExitCode);
            Assert.Contains("3D000", result.Logs, StringComparison.Ordinal);
        }
        finally
        {
            RestoreAzaionDatabase();
        }
    }

    private static void DropAzaionDatabase()
    {
        var adminConn = TestEnvironment.DbSideChannel
            .Replace("Database=azaion", "Database=postgres", StringComparison.Ordinal);
        using var conn = new NpgsqlConnection(adminConn);
        conn.Open();
        using var cmd = conn.CreateCommand();
        // WITH (FORCE) terminates any other backends still on azaion.
        cmd.CommandText = "DROP DATABASE IF EXISTS azaion WITH (FORCE);";
        cmd.ExecuteNonQuery();
    }

    private static void RestoreAzaionDatabase()
    {
        var adminConn = TestEnvironment.DbSideChannel
            .Replace("Database=azaion", "Database=postgres", StringComparison.Ordinal);
        using var conn = new NpgsqlConnection(adminConn);
        conn.Open();
        using var cmd = conn.CreateCommand();
        cmd.CommandText = "CREATE DATABASE azaion;";
        cmd.ExecuteNonQuery();
    }

    private static Dictionary<string, string> BaseEnv() => new(StringComparer.Ordinal)
    {
        { "DATABASE_URL",          PostgresUrl },
        { "JWT_ISSUER",            Issuer },
        { "JWT_AUDIENCE",          Audience },
        { "JWT_JWKS_URL",          JwksUrlHttps },
        { "ASPNETCORE_URLS",       "http://+:8080" },
        { "ASPNETCORE_ENVIRONMENT","Test" },
    };
}