using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using Microsoft.AspNetCore.Mvc.Testing;
using Xunit;

namespace StellaOps.Findings.Ledger.Tests.Integration;

[Trait("Category", "Integration")]
public sealed class FeatureVerificationProbeTests : IClassFixture<FindingsLedgerWebApplicationFactory>
{
    private readonly FindingsLedgerWebApplicationFactory _factory;

    public FeatureVerificationProbeTests(FindingsLedgerWebApplicationFactory factory)
    {
        _factory = factory;
    }

    [Fact(DisplayName = "Feature verification probe captures request/response evidence")]
    public async Task CaptureFeatureProbeEvidence()
    {
        var scenario = Environment.GetEnvironmentVariable("STELLA_FEATURE_PROBE_SCENARIO");
        var outputPath = Environment.GetEnvironmentVariable("STELLA_FEATURE_PROBE_OUT");

        // Keep this test no-op for normal test runs unless explicitly invoked for feature verification.
        if (string.IsNullOrWhiteSpace(scenario) || string.IsNullOrWhiteSpace(outputPath))
        {
            return;
        }

        using var authedClient = _factory.CreateClient(new WebApplicationFactoryClientOptions { AllowAutoRedirect = false });
        using var anonClient = _factory.CreateClient(new WebApplicationFactoryClientOptions { AllowAutoRedirect = false });

        authedClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "test-token");
        authedClient.DefaultRequestHeaders.Add("X-Scopes", "findings:read findings:write");
        authedClient.DefaultRequestHeaders.Add("X-Tenant-Id", "11111111-1111-1111-1111-111111111111");
        authedClient.DefaultRequestHeaders.Add("X-Stella-Tenant", "tenant-qa");

        var requests = BuildScenario(scenario);
        var capturedAt = DateTimeOffset.UtcNow;
        var results = new List<ProbeResult>(requests.Count);

        foreach (var req in requests)
        {
            var client = req.Auth ? authedClient : anonClient;
            using var message = new HttpRequestMessage(new HttpMethod(req.Method), req.Path);
            if (req.JsonBody is not null)
            {
                message.Content = new StringContent(req.JsonBody, Encoding.UTF8, "application/json");
            }

            var requestAt = DateTimeOffset.UtcNow;
            using var response = await client.SendAsync(message);
            var body = await response.Content.ReadAsStringAsync();
            var snippet = body.Length > 600 ? body[..600] : body;

            results.Add(new ProbeResult(
                req.Description,
                req.Method,
                req.Path,
                req.ExpectedStatus,
                (int)response.StatusCode,
                req.Assertion,
                (int)response.StatusCode == req.ExpectedStatus ? "pass" : "fail",
                requestAt.ToString("O"),
                snippet));
        }

        var artifact = new ProbeArtifact(
            Type: "api",
            Module: "api",
            Feature: scenario,
            BaseUrl: "in-memory-testserver",
            CapturedAtUtc: capturedAt.ToString("O"),
            Requests: results,
            Verdict: results.All(r => string.Equals(r.Result, "pass", StringComparison.Ordinal)) ? "pass" : "fail");

        var directory = Path.GetDirectoryName(outputPath);
        if (!string.IsNullOrWhiteSpace(directory))
        {
            Directory.CreateDirectory(directory);
        }

        var json = JsonSerializer.Serialize(artifact, new JsonSerializerOptions { WriteIndented = true });
        await File.WriteAllTextAsync(outputPath, json);

        Assert.All(results, r => Assert.Equal("pass", r.Result));
    }

    private static IReadOnlyList<ProbeRequest> BuildScenario(string scenario)
    {
        if (string.Equals(scenario, "policy-trace-panel", StringComparison.Ordinal))
        {
            return
            [
                new("List finding summaries with auth", "GET", "/api/v1/findings/summaries", true, 200, null, "authorized summaries query succeeds"),
                new("Invalid finding id returns bad request", "GET", "/api/v1/findings/not-a-guid/summary", true, 400, null, "invalid GUID is rejected"),
                new("Unknown finding summary returns not found", "GET", $"/api/v1/findings/{Guid.NewGuid():D}/summary", true, 404, null, "unknown finding returns 404"),
                new("Unknown finding evidence graph returns not found", "GET", $"/api/v1/findings/{Guid.NewGuid():D}/evidence-graph", true, 404, null, "unknown graph returns 404"),
                new("Unauthorized summaries request is rejected", "GET", "/api/v1/findings/summaries", false, 401, null, "missing token returns 401")
            ];
        }

        if (string.Equals(scenario, "score-api-endpoints", StringComparison.Ordinal))
        {
            return
            [
                new("Scoring policy endpoint returns active policy", "GET", "/api/v1/scoring/policy", true, 200, null, "authorized policy read succeeds"),
                new("Batch scoring rejects empty list", "POST", "/api/v1/findings/scores", true, 400, "{\"findingIds\":[]}", "empty batch rejected"),
                new("Cached score unknown finding returns not found", "GET", "/api/v1/findings/CVE-9999-0000%40pkg%3Anpm%2Fnone%401.0.0/score", true, 404, null, "unknown score returns 404"),
                new("Scoring policy without auth is rejected", "GET", "/api/v1/scoring/policy", false, 401, null, "missing token returns 401")
            ];
        }

        throw new InvalidOperationException($"Unknown feature probe scenario: {scenario}");
    }

    private sealed record ProbeRequest(
        string Description,
        string Method,
        string Path,
        bool Auth,
        int ExpectedStatus,
        string? JsonBody,
        string Assertion);

    private sealed record ProbeResult(
        string Description,
        string Method,
        string Path,
        int ExpectedStatus,
        int ActualStatus,
        string Assertion,
        string Result,
        string RequestCapturedAtUtc,
        string ResponseSnippet);

    private sealed record ProbeArtifact(
        string Type,
        string Module,
        string Feature,
        string BaseUrl,
        string CapturedAtUtc,
        IReadOnlyList<ProbeResult> Requests,
        string Verdict);
}