using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Vanguard.Server.Configuration;
using Vanguard.Server.Matches;
using Vanguard.Server.Matchmaking;
using Vanguard.Server.Profiles;
using Vanguard.Server.Tickets;

namespace Vanguard.Server.Tests;

public class MatchmakingServiceTests
{
    [Fact]
    public void Two_Players_Are_Matched_And_Get_One_Time_Tickets()
    {
        var harness = NewHarness();

        var first = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);
        var second = harness.Matchmaking.Enqueue("p2", ServerTestData.BuildDeck(), GameMode.ClassicRanked);

        harness.Matchmaking.Matchmake(harness.Time.GetUtcNow());

        var firstStatus = harness.Matchmaking.Poll(first.QueueId, "p1");
        var secondStatus = harness.Matchmaking.Poll(second.QueueId, "p2");

        Assert.NotNull(firstStatus);
        Assert.NotNull(secondStatus);
        Assert.Equal("matched", firstStatus!.Status);
        Assert.Equal("matched", secondStatus!.Status);
        Assert.Equal(firstStatus.MatchId, secondStatus.MatchId);
        Assert.Equal(0, firstStatus.Seat);
        Assert.Equal(1, secondStatus.Seat);
        Assert.Equal("p2", firstStatus.Opponent);
        Assert.Equal("p1", secondStatus.Opponent);

        Assert.NotNull(firstStatus.Ticket);
        Assert.NotNull(secondStatus.Ticket);

        var firstTicket = harness.Tickets.Redeem(firstStatus.Ticket);
        var secondTicket = harness.Tickets.Redeem(secondStatus.Ticket);
        Assert.Equal(0, firstTicket!.Seat);
        Assert.Equal(1, secondTicket!.Seat);
        Assert.Equal(firstStatus.MatchId, firstTicket.MatchId);

        Assert.Equal(1, harness.Registry.Count);
        Assert.Equal(1, harness.Registry.ActiveCount);
        Assert.Equal(0, harness.Matchmaking.QueuedCount);
    }

    [Fact]
    public void Ranked_And_Casual_Queues_Are_Separate()
    {
        var harness = NewHarness();

        harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);
        var casual = harness.Matchmaking.Enqueue("p2", ServerTestData.BuildDeck(), GameMode.ClassicCasual);

        harness.Matchmaking.Matchmake(harness.Time.GetUtcNow());

        Assert.Equal("queued", harness.Matchmaking.Poll(casual.QueueId, "p2")!.Status);
        Assert.Equal(0, harness.Registry.Count);
        Assert.Equal(2, harness.Matchmaking.QueuedCount);
    }

    [Fact]
    public void Window_Expands_While_Waiting()
    {
        var harness = NewHarness();
        var ticket = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);

        var initial = harness.Matchmaking.Poll(ticket.QueueId, "p1")!;
        Assert.Equal(100, initial.Window);

        harness.Time.Advance(TimeSpan.FromSeconds(20));
        var later = harness.Matchmaking.Poll(ticket.QueueId, "p1")!;
        Assert.Equal(300, later.Window); // 100 + 4 * 50

        harness.Time.Advance(TimeSpan.FromSeconds(200));
        var capped = harness.Matchmaking.Poll(ticket.QueueId, "p1")!;
        Assert.Equal(2000, capped.Window);
    }

    [Fact]
    public void Invalid_Deck_Is_Rejected_At_Enqueue()
    {
        var harness = NewHarness();
        var deck = ServerTestData.BuildDeck();
        deck.RemoveAt(0);

        var exception = Assert.Throws<DeckRejectedException>(
            () => harness.Matchmaking.Enqueue("p1", deck, GameMode.ClassicRanked));

        Assert.Contains(exception.Violations, violation => violation.Code == "deck.size");
    }

    [Fact]
    public void Deck_Without_Starting_Vanguard_Is_Rejected()
    {
        var harness = NewHarness();
        var deck = new List<string>();

        foreach (var printing in ServerTestData.Catalog.Printings
                     .Where(printing => !printing.IsParallel)
                     .OrderBy(printing => printing.PrintingId, StringComparer.Ordinal))
        {
            if (deck.Count >= 50)
                break;

            var card = ServerTestData.Catalog.CardOf(printing.PrintingId);
            if (card.Grade == 0 || card.IsSentinel || card.Trigger == Vanguard.Rules.Cards.TriggerType.Heal)
                continue;

            for (var i = 0; i < 4 && deck.Count < 50; i++)
                deck.Add(printing.PrintingId);
        }

        Assert.Equal(50, deck.Count);

        var exception = Assert.Throws<DeckRejectedException>(
            () => harness.Matchmaking.Enqueue("p1", deck, GameMode.ClassicRanked));

        Assert.Contains(exception.Violations,
            violation => violation.Code == "deck.starting-vanguard");
    }

    [Fact]
    public void Cancel_Removes_From_Queue()
    {
        var harness = NewHarness();
        var ticket = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);

        Assert.True(harness.Matchmaking.Cancel(ticket.QueueId, "p1"));

        var status = harness.Matchmaking.Poll(ticket.QueueId, "p1")!;
        Assert.Equal("cancelled", status.Status);
        Assert.Equal(0, harness.Matchmaking.QueuedCount);
        Assert.False(harness.Matchmaking.Cancel(ticket.QueueId, "p1"));
    }

    [Fact]
    public void Second_Queue_Request_Replaces_The_First()
    {
        var harness = NewHarness();
        var old = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);
        var current = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);

        Assert.Equal("cancelled", harness.Matchmaking.Poll(old.QueueId, "p1")!.Status);
        Assert.Equal("queued", harness.Matchmaking.Poll(current.QueueId, "p1")!.Status);
        Assert.Equal(1, harness.Matchmaking.QueuedCount);
    }

    [Fact]
    public void Queue_Expires_After_Timeout()
    {
        var harness = NewHarness();
        var ticket = harness.Matchmaking.Enqueue("p1", ServerTestData.BuildDeck(), GameMode.ClassicRanked);

        harness.Time.Advance(TimeSpan.FromSeconds(harness.Options.QueueExpirySeconds + 1));
        harness.Matchmaking.Matchmake(harness.Time.GetUtcNow());

        Assert.Equal("expired", harness.Matchmaking.Poll(ticket.QueueId, "p1")!.Status);
        Assert.Equal(0, harness.Matchmaking.QueuedCount);
    }

    [Fact]
    public async Task Ranked_Result_Changes_Hidden_Mmr_Casual_Does_Not()
    {
        var profiles = new PlayerProfileStore();

        await profiles.RecordAsync(new MatchResult(
            "m1", GameMode.ClassicRanked, "winner", "loser", 0));

        Assert.True(profiles.GetMmr("winner") > 1000);
        Assert.True(profiles.GetMmr("loser") < 1000);

        var winnerAfterRanked = profiles.GetMmr("winner");
        var loserAfterRanked = profiles.GetMmr("loser");

        await profiles.RecordAsync(new MatchResult(
            "m2", GameMode.ClassicCasual, "winner", "loser", 0));

        Assert.Equal(winnerAfterRanked, profiles.GetMmr("winner"));
        Assert.Equal(loserAfterRanked, profiles.GetMmr("loser"));
    }

    private static Harness NewHarness()
    {
        var time = new FakeTimeProvider(new DateTimeOffset(2026, 10, 21, 12, 0, 0, TimeSpan.Zero));
        var options = ServerTestData.SmallOptions();
        var profiles = new PlayerProfileStore();
        var tickets = new GameTicketService(options, time);

        var services = new ServiceCollection();
        services.AddSingleton(ServerTestData.Catalog);
        services.AddSingleton(options);
        services.AddSingleton<TimeProvider>(time);
        services.AddSingleton<IMatchResultSink>(profiles);
        services.AddLogging();

        var provider = services.BuildServiceProvider();
        var registry = new MatchGrainRegistry(provider, options, NullLogger<MatchGrainRegistry>.Instance);
        var matchmaking = new MatchmakingService(
            ServerTestData.Catalog,
            registry,
            tickets,
            profiles,
            options,
            time,
            NullLogger<MatchmakingService>.Instance);

        return new Harness(time, options, profiles, tickets, registry, matchmaking);
    }

    private sealed record Harness(
        FakeTimeProvider Time,
        GameOptions Options,
        PlayerProfileStore Profiles,
        GameTicketService Tickets,
        MatchGrainRegistry Registry,
        MatchmakingService Matchmaking);
}