using System.Net.Http.Json;
using System.Text.Json;
using Microsoft.AspNetCore.Mvc.Testing;
using Vanguard.Server.Api;
using Vanguard.Shared.Protocol;
using Xunit.Sdk;

namespace Vanguard.Server.Tests;

public class GameServerE2ETests
{
    [Fact]
    public async Task Two_Clients_Play_A_Full_Match_Over_WebSocket()
    {
        using var factory = NewFactory();
        using var http = factory.CreateClient();
        var deck = ServerTestData.BuildDeck();

        var firstQueue = await EnqueueAsync(http, "p1", deck);
        var secondQueue = await EnqueueAsync(http, "p2", deck);

        var firstStatus = await WaitForMatchAsync(http, firstQueue.QueueId, "p1");
        var secondStatus = await WaitForMatchAsync(http, secondQueue.QueueId, "p2");

        Assert.Equal(firstStatus.MatchId, secondStatus.MatchId);
        Assert.Equal(0, firstStatus.Seat);
        Assert.Equal(1, secondStatus.Seat);

        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(120));

        await using var first = await TestGameClient.ConnectAsync(
            factory, firstStatus.MatchId!, firstStatus.Ticket!, "p1", 0, cts.Token);

        await using var second = await TestGameClient.ConnectAsync(
            factory, secondStatus.MatchId!, secondStatus.Ticket!, "p2", 0, cts.Token);

        await Task.WhenAll(
            PlayAsync(first, seed: 11, cts.Token),
            PlayAsync(second, seed: 22, cts.Token));

        Assert.True(first.View.IsFinished, "Первый клиент не увидел завершение партии.");
        Assert.True(second.View.IsFinished, "Второй клиент не увидел завершение партии.");
        Assert.Equal(first.View.Winner, second.View.Winner);
        Assert.InRange(first.View.Winner, 0, 1);

        var loser = 1 - first.View.Winner;
        Assert.False(first.View.Players[first.View.Winner].IsDefeated);
        Assert.True(first.View.Players[loser].IsDefeated);

        var health = await http.GetFromJsonAsync<JsonElement>("/health");
        Assert.True(health.GetProperty("matches").GetInt32() >= 1);
    }

    [Fact]
    public async Task Client_Can_Reconnect_And_Resume_After_Disconnect()
    {
        using var factory = NewFactory();
        using var http = factory.CreateClient();
        var deck = ServerTestData.BuildDeck();

        var firstQueue = await EnqueueAsync(http, "p1", deck);
        var secondQueue = await EnqueueAsync(http, "p2", deck);

        var firstStatus = await WaitForMatchAsync(http, firstQueue.QueueId, "p1");
        var secondStatus = await WaitForMatchAsync(http, secondQueue.QueueId, "p2");

        using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(60));

        var first = await TestGameClient.ConnectAsync(
            factory, firstStatus.MatchId!, firstStatus.Ticket!, "p1", 0, cts.Token);

        await using var second = await TestGameClient.ConnectAsync(
            factory, secondStatus.MatchId!, secondStatus.Ticket!, "p2", 0, cts.Token);

        var result = await first.SubmitAsync("mulligan-1", new FinishMulliganIntent(), cts.Token);
        Assert.True(result.Accepted, result.Reason);

        var lastSeq = result.EventSeq;
        await first.DisposeAsync();

        var ticketResponse = await http.PostAsJsonAsync(
            "/api/game/tickets",
            new TicketRequest("p1", firstStatus.MatchId));

        if (!ticketResponse.IsSuccessStatusCode)
            throw new XunitException(await ticketResponse.Content.ReadAsStringAsync());

        var ticket = await ticketResponse.Content.ReadFromJsonAsync<TicketResponse>();
        Assert.NotNull(ticket);

        await using var reconnected = await TestGameClient.ConnectAsync(
            factory, firstStatus.MatchId!, ticket!.Ticket, "p1", lastSeq, cts.Token);

        Assert.True(reconnected.View.EventSeq >= lastSeq);
        Assert.Equal(0, reconnected.Seat);

        await second.RequestSnapshotAsync(cts.Token);
        Assert.Equal(reconnected.View.EventSeq, second.View.EventSeq);
        Assert.Equal(reconnected.View.ActivePlayer, second.View.ActivePlayer);
        Assert.False(reconnected.View.IsFinished);
    }

    private static WebApplicationFactory<Program> NewFactory() => new();

    private static async Task<QueueAccepted> EnqueueAsync(
        HttpClient http,
        string playerId,
        List<string> deck)
    {
        var response = await http.PostAsJsonAsync(
            "/api/game/queue",
            new QueueRequest(playerId, "classic-ranked", deck));

        if (!response.IsSuccessStatusCode)
            throw new XunitException(await response.Content.ReadAsStringAsync());

        return (await response.Content.ReadFromJsonAsync<QueueAccepted>())!;
    }

    private static async Task<QueueStatusResponse> WaitForMatchAsync(
        HttpClient http,
        Guid queueId,
        string playerId)
    {
        for (var attempt = 0; attempt < 200; attempt++)
        {
            var status = await http.GetFromJsonAsync<QueueStatusResponse>(
                $"/api/game/queue/{queueId}?playerId={playerId}");

            if (status is null)
                throw new XunitException("Очередь исчезла.");

            if (status.Status == "matched")
                return status;

            if (status.Status is "failed" or "expired" or "cancelled")
                throw new XunitException($"Очередь в состоянии {status.Status}: {status.Reason}");

            await Task.Delay(50);
        }

        throw new XunitException("Матч не был найден за 10 секунд.");
    }

    private static async Task PlayAsync(
        TestGameClient client,
        int seed,
        CancellationToken cancellationToken)
    {
        var random = new Random(seed);
        var deadline = DateTime.UtcNow.AddSeconds(90);

        while (!client.View.IsFinished)
        {
            if (DateTime.UtcNow > deadline)
                throw new XunitException(
                    $"Тест не доиграл партию за 90 секунд (seat {client.Seat}).");

            if (client.View.ActivePlayer == client.Seat)
            {
                var choices = client.View.LegalIntents
                    .Where(intent => intent is not ConcedeIntent)
                    .ToList();

                if (choices.Count == 0)
                    throw new XunitException(
                        $"Нет легальных интентов для seat {client.Seat}, " +
                        $"фаза {client.View.Phase}, шаг {client.View.Step}.");

                var intent = choices[random.Next(choices.Count)];
                var intentId = Guid.NewGuid().ToString("N");

                var result = await client.SubmitAsync(intentId, intent, cancellationToken);
                if (result.Duplicate)
                    throw new XunitException($"Неожиданный duplicate для {intentId}.");

                if (!result.Accepted)
                    throw new XunitException(
                        $"Интент {intent.GetType().Name} отклонён: {result.Code} {result.Reason}");

                // держимся ниже лимита 16 интентов в секунду
                await Task.Delay(75, cancellationToken);
            }

            await client.RequestSnapshotAsync(cancellationToken);

            if (!client.View.IsFinished && client.View.ActivePlayer != client.Seat)
                await Task.Delay(20, cancellationToken);
        }
    }
}