using System.Net;
using System.Text;
using Xunit;
using ytLive.Models;
using ytLive.Services;

namespace ytLive.Tests;

/// <summary>
/// The one integration test for ship step 7 (private-only go live): the
/// broadcast-insert request must carry privacyStatus "private" — the dialog is
/// locked to Private and the service must never send anything else.
/// </summary>
public class YouTubeStreamServiceTests
{
    private sealed class RecordingHandler : HttpMessageHandler
    {
        public string? LastBody;
        public string ResponseBody = """{"id":"BC123","snippet":{"title":"t"}}""";
        public Func<HttpRequestMessage, string?>? ResponseSelector;
        public HttpStatusCode StatusCode = HttpStatusCode.OK;
        public readonly List<string> Requests = new();

        protected override Task<HttpResponseMessage> SendAsync(
            HttpRequestMessage request, CancellationToken cancellationToken)
        {
            Requests.Add($"{request.Method.Method} {request.RequestUri}");
            LastBody = request.Content?.ReadAsStringAsync().GetAwaiter().GetResult();
            var body = ResponseSelector?.Invoke(request) ?? ResponseBody;
            return Task.FromResult(new HttpResponseMessage(StatusCode)
            {
                Content = new StringContent(body, Encoding.UTF8, "application/json"),
            });
        }
    }

    private static YouTubeAuthService CreateAuth() => new("test-id", "test-secret");

    private static YouTubeAuthService CreateAuthed()
    {
        var auth = CreateAuth();
        auth.SetSession(new YouTubeChannel
        {
            AccessToken = "acc-123",
            TokenExpiry = DateTime.UtcNow.AddHours(1),
        });
        return auth;
    }

    [Fact]
    public async Task CreateBroadcast_Always_Sends_Private_PrivacyStatus()
    {
        var handler = new RecordingHandler();
        var auth = CreateAuth();
        auth.SetSession(new YouTubeChannel
        {
            AccessToken = "acc-123",
            TokenExpiry = DateTime.UtcNow.AddHours(1),
        });
        var service = new YouTubeStreamService(auth, new HttpClient(handler));

        var id = await service.CreateBroadcast("Test Stream", "A description", DateTime.UtcNow);

        Assert.Equal("BC123", id);
        Assert.NotNull(handler.LastBody);
        Assert.Contains("\"privacyStatus\":\"private\"", handler.LastBody);
    }

    [Fact]
    public async Task CreateBroadcast_Without_Session_Returns_Null()
    {
        var handler = new RecordingHandler();
        var auth = CreateAuth(); // no session
        var service = new YouTubeStreamService(auth, new HttpClient(handler));

        var id = await service.CreateBroadcast("Test Stream", "A description", DateTime.UtcNow);

        Assert.Null(id);
        Assert.Null(handler.LastBody); // never reached the API
    }

    // TASK 5: a reusable stream, when given, binds at broadcast insert via
    // contentDetails.boundStreamId — no separate bind round-trip. One-click
    // go-live also completes the v3 flags (no monitor stream, low latency).
    [Fact]
    public async Task CreateBroadcast_With_StreamId_Binds_Reusable_Stream_At_Insert()
    {
        var handler = new RecordingHandler { ResponseBody = """{"id":"BC123","snippet":{"title":"t"}}""" };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var id = await service.CreateBroadcast("Test Stream", "A description", DateTime.UtcNow, "S456");

        Assert.Equal("BC123", id);
        Assert.NotNull(handler.LastBody);
        Assert.Contains("\"boundStreamId\":\"S456\"", handler.LastBody);
        Assert.Contains("\"enableMonitorStream\":false", handler.LastBody);
        Assert.Contains("\"latencyPreference\":\"low\"", handler.LastBody);
        Assert.Contains("\"privacyStatus\":\"private\"", handler.LastBody);
    }

    // TASK 5 design decision 2: reuse the existing cdn.isReusable stream instead
    // of creating a new one per broadcast.
    [Fact]
    public async Task GetOrCreateReusableStreamAsync_Reuses_Existing_Reusable_Stream()
    {
        var handler = new RecordingHandler
        {
            ResponseBody = """
                {"items":[{"id":"S456","cdn":{"isReusable":true,"ingestionInfo":{"ingestionAddress":"rtmp://a.rtmp.youtube.com/live2","streamName":"KEY123"}}}]}
                """
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var stream = await service.GetOrCreateReusableStreamAsync();

        Assert.NotNull(stream);
        Assert.Equal("S456", stream.Id);
        Assert.Equal("rtmp://a.rtmp.youtube.com/live2", stream.IngestionAddress);
        Assert.Equal("KEY123", stream.StreamName);
        Assert.Equal("rtmp://a.rtmp.youtube.com/live2/KEY123", stream.RtmpUrl);
        Assert.Contains(handler.Requests, r => r.StartsWith("GET") && r.Contains("liveStreams") && r.Contains("mine=true"));
        Assert.DoesNotContain(handler.Requests, r => r.StartsWith("POST"));
    }

    // TASK 5: first-ever use creates the one reusable stream — variable
    // resolution/frame rate so any quality tier works without recreation.
    [Fact]
    public async Task GetOrCreateReusableStreamAsync_Creates_When_None_Exists()
    {
        var handler = new RecordingHandler
        {
            ResponseSelector = request => request.Method.Method == "GET"
                ? """{"items":[]}"""
                : """{"id":"S789","cdn":{"ingestionInfo":{"ingestionAddress":"rtmp://a.rtmp.youtube.com/live2","streamName":"KEY789"}}}"""
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var stream = await service.GetOrCreateReusableStreamAsync();

        Assert.NotNull(stream);
        Assert.Equal("S789", stream.Id);
        Assert.Equal("rtmp://a.rtmp.youtube.com/live2/KEY789", stream.RtmpUrl);
        var post = Assert.Single(handler.Requests, r => r.StartsWith("POST"));
        Assert.Contains("liveStreams", post);
        Assert.Contains("\"isReusable\":true", handler.LastBody);
        Assert.Contains("\"resolution\":\"variable\"", handler.LastBody);
        Assert.Contains("\"frameRate\":\"variable\"", handler.LastBody);
    }

    [Fact]
    public async Task GetOrCreateReusableStreamAsync_Without_Session_Returns_Null()
    {
        var handler = new RecordingHandler();
        var service = new YouTubeStreamService(CreateAuth(), new HttpClient(handler));

        var stream = await service.GetOrCreateReusableStreamAsync();

        Assert.Null(stream);
        Assert.Empty(handler.Requests); // never reached the API
    }

    // TASK 5 item 3: liveStreams.status — status.healthStatus = {status,
    // configurationIssues[]} (the REAL API shape — nested object, not a string;
    // the flat-string shape was our own wrong fixture) parsed into the
    // report-by-exception surface. This fixture is what a live test/real stream
    // actually returns — it used to crash the poll with
    // "requires an element of type 'String'" (2026-09-22 log, two sessions).
    [Fact]
    public async Task GetStreamHealthAsync_Parses_Status_And_Issue_Severities()
    {
        var handler = new RecordingHandler
        {
            ResponseBody = """
                {"items":[{"status":{"healthStatus":{"status":"bad","lastUpdateTimeSeconds":1748000000,
                    "configurationIssues":[
                    {"type":"bitrateHigh","severity":"error"},
                    {"type":"reconnect","severity":"warning"}]}}}]}
                """
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var health = await service.GetStreamHealthAsync("S456");

        Assert.NotNull(health);
        Assert.Equal("bad", health.HealthStatus);
        Assert.Equal(2, health.ConfigurationIssues.Count);
        Assert.Equal(StreamIssueSeverity.Error, health.ConfigurationIssues[0].Severity);
        Assert.Equal("bitrateHigh", health.ConfigurationIssues[0].Type);
        Assert.Equal(StreamIssueSeverity.Warning, health.ConfigurationIssues[1].Severity);
        Assert.Contains(handler.Requests, r => r.Contains("liveStreams") && r.Contains("part=status"));
    }

    [Fact]
    public async Task GetStreamHealthAsync_Good_Health_Yields_No_Issues()
    {
        var handler = new RecordingHandler { ResponseBody = """{"items":[{"status":{"healthStatus":{"status":"good"}}}]}""" };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var health = await service.GetStreamHealthAsync("S456");

        Assert.Equal("good", health?.HealthStatus);
        Assert.Empty(health?.ConfigurationIssues ?? []);
    }

    [Fact]
    public async Task GetStreamHealthAsync_Without_Session_Returns_Null()
    {
        var handler = new RecordingHandler();
        var service = new YouTubeStreamService(CreateAuth(), new HttpClient(handler));

        var health = await service.GetStreamHealthAsync("S456");

        Assert.Null(health);
        Assert.Empty(handler.Requests); // never reached the API
    }

    /// <summary>The ONE integration test for TASK 5 item 3 (report-by-exception):
    /// a healthy stream (good, no issues) produces no banner; a mid-stream
    /// problem (bad + error configuration issue) drives the banner text and its
    /// error color — through the real service JSON parse into the real reporter.</summary>
    [Fact]
    public async Task GetStreamHealthAsync_Report_By_Exception_Banner_Only_On_Warning_Or_Error()
    {
        var handler = new RecordingHandler
        {
            ResponseBody = """{"items":[{"status":{"healthStatus":{"status":"good"}}}]}"""
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var healthy = await service.GetStreamHealthAsync("S456");
        Assert.Equal("good", healthy?.HealthStatus);
        Assert.Empty(healthy?.ConfigurationIssues ?? []);
        Assert.Null(StreamHealthReporter.BannerFor(healthy!.ConfigurationIssues).Text);

        handler.ResponseBody = """
            {"items":[{"status":{"healthStatus":{"status":"bad",
                "configurationIssues":[
                {"type":"bitrateHigh","severity":"error"}]}}}]}
            """;
        var degraded = await service.GetStreamHealthAsync("S456");
        Assert.Equal("bad", degraded?.HealthStatus);
        var report = StreamHealthReporter.BannerFor(degraded!.ConfigurationIssues);
        Assert.Equal("bitrateHigh", report.Text);
        Assert.True(report.IsError);
    }
    // TASK 9 close-out, hardened 2026-09-22 (the ONE integration test): the end now
    // pre-flights the broadcast's OWN lifeCycleStatus before POSTing complete —
    // every 2026-09-22 end logged 403 invalidTransition (enableAutoStop/auto-stop
    // raced us to complete), so a blind POST only earned the 403 + noise. This
    // proves the contract: live → GET pre-check + POST transition; already
    // complete → skip entirely (zero transition POSTs); an inconclusive pre-check
    // still posts and a 403 on the POST surfaces as an error string, never a throw.
    [Fact]
    public async Task EndBroadcast_Verifies_LifeCycle_Then_Transitions_Complete_Never_Throws()
    {
        var handler = new RecordingHandler
        {
            ResponseSelector = request =>
                request.Method == HttpMethod.Get
                    ? """{"items":[{"id":"BC-42","status":{"lifeCycleStatus":"live"}}]}"""
                    : """{"id":"BC-42","status":{"lifeCycleStatus":"live"}}""",
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        // live → pre-check passes → POST complete with the documented URL shape.
        var error = await service.EndBroadcastAsync("BC-42");
        Assert.Null(error);
        Assert.Equal(2, handler.Requests.Count);
        Assert.StartsWith("GET ", handler.Requests[0]);
        Assert.Contains("/liveBroadcasts?", handler.Requests[0]);
        Assert.Contains("part=status", handler.Requests[0]);
        Assert.StartsWith("POST ", handler.Requests[1]);
        Assert.Contains("/liveBroadcasts/transition?", handler.Requests[1]);
        Assert.Contains("broadcastStatus=complete", handler.Requests[1]);
        Assert.Contains("id=BC-42", handler.Requests[1]);

        // Already complete → skip; no transition POST is ever sent, no error.
        handler.ResponseSelector = request =>
            request.Method == HttpMethod.Get
                ? """{"items":[{"id":"BC-42","status":{"lifeCycleStatus":"complete"}}]}"""
                : """{"id":"BC-42"}""";
        var skipped = await service.EndBroadcastAsync("BC-42");
        Assert.Null(skipped);
        Assert.Equal(3, handler.Requests.Count);
        Assert.StartsWith("GET ", handler.Requests[2]);

        // Inconclusive pre-check (list 403) still posts; a 403 on the POST itself
        // surfaces as an error string, never an exception (autoStop backstop) — the
        // stop path must complete regardless.
        handler.StatusCode = HttpStatusCode.Forbidden;
        handler.ResponseSelector = null;
        var closeOutError = await service.EndBroadcastAsync("BC-42");
        Assert.NotNull(closeOutError);
        Assert.Contains("403", closeOutError);
        Assert.StartsWith("POST ", handler.Requests[^1]);
    }

    /// <summary>The ONE integration test for the 2026-09-25 TEST-tab chat fix:
    /// "Chat polling couldn't start — Mock Chat Input is disabled" because the
    /// liveChatId never resolved. Two facts pin it: (1) the id lives in
    /// <c>snippet.liveChatId</c> — part=contentDetails could NEVER return it, and
    /// (2) YouTube only populates it once the broadcast is live, so a single fetch
    /// right after insert (lifecycleStatus ready) comes back empty. The fix reads
    /// part=snippet AND polls with a bounded retry — this test drives a fake
    /// broadcast that starts WITHOUT the id (broadcast not yet live) and gains it on
    /// a later poll, proving the retry resolves it and that every request asked for
    /// snippet (never contentDetails).</summary>
    [Fact]
    public async Task GetBroadcastLiveChatIdAsync_Polls_Snippet_Until_Id_Appears()
    {
        var polls = 0;
        var handler = new RecordingHandler
        {
            ResponseSelector = request =>
            {
                polls++;
                // First polls: broadcast exists but not yet live → no liveChatId.
                return polls < 3
                    ? """{"items":[{"id":"BC-42","snippet":{"title":"t"}}]}"""
                    : """{"items":[{"id":"BC-42","snippet":{"title":"t","liveChatId":"Cg0LIVECHAT42"}}]}""";
            }
        };
        var service = new YouTubeStreamService(CreateAuthed(), new HttpClient(handler));

        var chatId = await service.GetBroadcastLiveChatIdAsync("BC-42", maxAttempts: 5, delayMs: 25);

        Assert.Equal("Cg0LIVECHAT42", chatId);
        Assert.True(polls >= 3, $"expected the retry to poll until the id appears (polled {polls}x)");
        Assert.All(handler.Requests, r =>
        {
            Assert.Contains("part=snippet", r);
            Assert.DoesNotContain("part=contentDetails", r);
        });
    }
}