package capabilityevaluation_test

import (
	"context"
	"io"
	"log/slog"
	"sync"
	"testing"
	"time"

	"galaxy/lobby/internal/adapters/evaluationguardinmem"
	"galaxy/lobby/internal/adapters/gameinmem"
	"galaxy/lobby/internal/adapters/gameturnstatsinmem"
	"galaxy/lobby/internal/adapters/membershipinmem"
	"galaxy/lobby/internal/adapters/racenameinmem"
	"galaxy/lobby/internal/domain/common"
	"galaxy/lobby/internal/domain/game"
	"galaxy/lobby/internal/domain/membership"
	"galaxy/lobby/internal/ports"
	"galaxy/lobby/internal/service/capabilityevaluation"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func silentLogger() *slog.Logger { return slog.New(slog.NewTextHandler(io.Discard, nil)) }

func fixedClock(at time.Time) func() time.Time { return func() time.Time { return at } }

type spyIntents struct {
	mu      sync.Mutex
	pending []capabilityevaluation.EligibleEvent
	denied  []capabilityevaluation.DeniedEvent
}

func (spy *spyIntents) PublishEligible(_ context.Context, ev capabilityevaluation.EligibleEvent) error {
	spy.mu.Lock()
	defer spy.mu.Unlock()
	spy.pending = append(spy.pending, ev)
	return nil
}

func (spy *spyIntents) PublishDenied(_ context.Context, ev capabilityevaluation.DeniedEvent) error {
	spy.mu.Lock()
	defer spy.mu.Unlock()
	spy.denied = append(spy.denied, ev)
	return nil
}

type fixture struct {
	finishedAt  time.Time
	gameID      common.GameID
	gameName    string
	games       *gameinmem.Store
	memberships *membershipinmem.Store
	stats       *gameturnstatsinmem.Store
	directory   *racenameinmem.Directory
	intents     *spyIntents
	guard       *evaluationguardinmem.Store
	service     *capabilityevaluation.Service
}

func newFixture(t *testing.T) *fixture {
	t.Helper()
	now := time.Date(2026, 4, 25, 12, 0, 0, 0, time.UTC)
	finishedAt := now

	games := gameinmem.NewStore()
	memberships := membershipinmem.NewStore()
	stats := gameturnstatsinmem.NewStore()
	directory, err := racenameinmem.NewDirectory(racenameinmem.WithClock(fixedClock(now.Add(-time.Hour))))
	require.NoError(t, err)
	intents := &spyIntents{}
	guard := evaluationguardinmem.NewStore()

	gameID := common.GameID("game-finished")
	gameName := "Final Showdown"

	gameRecord, err := game.New(game.NewGameInput{
		GameID:              gameID,
		GameName:            gameName,
		GameType:            game.GameTypePublic,
		MinPlayers:          2,
		MaxPlayers:          4,
		StartGapHours:       2,
		StartGapPlayers:     1,
		EnrollmentEndsAt:    now.Add(-12 * time.Hour),
		TurnSchedule:        "0 */6 * * *",
		TargetEngineVersion: "1.0.0",
		Now:                 now.Add(-24 * time.Hour),
	})
	require.NoError(t, err)
	gameRecord.Status = game.StatusFinished
	startedAt := now.Add(-12 * time.Hour)
	gameRecord.StartedAt = &startedAt
	gameRecord.FinishedAt = &finishedAt
	require.NoError(t, games.Save(context.Background(), gameRecord))

	service, err := capabilityevaluation.NewService(capabilityevaluation.Dependencies{
		Games:       games,
		Memberships: memberships,
		Stats:       stats,
		Directory:   directory,
		Intents:     intents,
		Guard:       guard,
		Clock:       fixedClock(now),
		Logger:      silentLogger(),
	})
	require.NoError(t, err)

	return &fixture{
		finishedAt:  finishedAt,
		gameID:      gameID,
		gameName:    gameName,
		games:       games,
		memberships: memberships,
		stats:       stats,
		directory:   directory,
		intents:     intents,
		guard:       guard,
		service:     service,
	}
}

func (f *fixture) addMember(t *testing.T, userID, raceName string, status membership.Status) {
	t.Helper()
	member, err := membership.New(membership.NewMembershipInput{
		MembershipID: common.MembershipID("membership-" + userID),
		GameID:       f.gameID,
		UserID:       userID,
		RaceName:     raceName,
		CanonicalKey: raceName,
		Now:          f.finishedAt.Add(-3 * time.Hour),
	})
	require.NoError(t, err)
	require.NoError(t, f.memberships.Save(context.Background(), member))
	if status != membership.StatusActive {
		require.NoError(t, f.memberships.UpdateStatus(context.Background(), ports.UpdateMembershipStatusInput{
			MembershipID: member.MembershipID,
			ExpectedFrom: membership.StatusActive,
			To:           status,
			At:           f.finishedAt.Add(-time.Hour),
		}))
	}
}

func (f *fixture) reserveRaceName(t *testing.T, userID, raceName string) {
	t.Helper()
	require.NoError(t, f.directory.Reserve(context.Background(), f.gameID.String(), userID, raceName))
}

func (f *fixture) seedStats(t *testing.T, userID string, initialPlanets, initialPopulation, maxPlanets, maxPopulation int64) {
	t.Helper()
	require.NoError(t, f.stats.SaveInitial(context.Background(), f.gameID, []ports.PlayerInitialStats{
		{UserID: userID, Planets: initialPlanets, Population: initialPopulation, ShipsBuilt: 0},
	}))
	require.NoError(t, f.stats.UpdateMax(context.Background(), f.gameID, []ports.PlayerObservedStats{
		{UserID: userID, Planets: maxPlanets, Population: maxPopulation, ShipsBuilt: 0},
	}))
}

func TestEvaluateRequiresFinishedStatus(t *testing.T) {
	f := newFixture(t)

	record, err := f.games.Get(context.Background(), f.gameID)
	require.NoError(t, err)
	record.Status = game.StatusRunning
	record.FinishedAt = nil
	require.NoError(t, f.games.Save(context.Background(), record))

	err = f.service.Evaluate(context.Background(), f.gameID, f.finishedAt)
	require.Error(t, err)
}

func TestEvaluateCapableMemberMarksPending(t *testing.T) {
	f := newFixture(t)
	f.reserveRaceName(t, "user-capable", "Stellaris")
	f.addMember(t, "user-capable", "Stellaris", membership.StatusActive)
	f.seedStats(t, "user-capable", 3, 100, 5, 200)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	pending, err := f.directory.ListPendingRegistrations(context.Background(), "user-capable")
	require.NoError(t, err)
	require.Len(t, pending, 1)
	assert.Equal(t, "Stellaris", pending[0].RaceName)
	expectedEligible := f.finishedAt.Add(capabilityevaluation.PendingRegistrationWindow).UnixMilli()
	assert.Equal(t, expectedEligible, pending[0].EligibleUntilMs)

	require.Len(t, f.intents.pending, 1)
	assert.Equal(t, "user-capable", f.intents.pending[0].UserID)
	assert.Equal(t, f.gameName, f.intents.pending[0].GameName)
	assert.Empty(t, f.intents.denied)
}

func TestEvaluateIncapableMemberReleasesReservation(t *testing.T) {
	f := newFixture(t)
	f.reserveRaceName(t, "user-incap", "Loseman")
	f.addMember(t, "user-incap", "Loseman", membership.StatusActive)
	f.seedStats(t, "user-incap", 3, 100, 3, 100)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	reservations, err := f.directory.ListReservations(context.Background(), "user-incap")
	require.NoError(t, err)
	assert.Empty(t, reservations)

	pending, err := f.directory.ListPendingRegistrations(context.Background(), "user-incap")
	require.NoError(t, err)
	assert.Empty(t, pending)

	require.Len(t, f.intents.denied, 1)
	assert.Equal(t, capabilityevaluation.ReasonCapabilityNotMet, f.intents.denied[0].Reason)
}

func TestEvaluateMissingStatsReleasesAndReportsReason(t *testing.T) {
	f := newFixture(t)
	f.reserveRaceName(t, "user-no-stats", "Phantom")
	f.addMember(t, "user-no-stats", "Phantom", membership.StatusActive)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	require.Len(t, f.intents.denied, 1)
	assert.Equal(t, capabilityevaluation.ReasonMissingStats, f.intents.denied[0].Reason)

	reservations, err := f.directory.ListReservations(context.Background(), "user-no-stats")
	require.NoError(t, err)
	assert.Empty(t, reservations)
}

func TestEvaluateMixedRoster(t *testing.T) {
	f := newFixture(t)

	f.reserveRaceName(t, "user-A", "Alpha")
	f.addMember(t, "user-A", "Alpha", membership.StatusActive)
	f.seedStats(t, "user-A", 1, 10, 9, 100)

	f.reserveRaceName(t, "user-B", "Beta")
	f.addMember(t, "user-B", "Beta", membership.StatusActive)
	f.seedStats(t, "user-B", 4, 50, 4, 50)

	f.reserveRaceName(t, "user-C", "Gamma")
	f.addMember(t, "user-C", "Gamma", membership.StatusRemoved)

	f.reserveRaceName(t, "user-D", "Delta")
	f.addMember(t, "user-D", "Delta", membership.StatusBlocked)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	pending, err := f.directory.ListPendingRegistrations(context.Background(), "user-A")
	require.NoError(t, err)
	assert.Len(t, pending, 1)

	for _, userID := range []string{"user-B", "user-C", "user-D"} {
		reservations, err := f.directory.ListReservations(context.Background(), userID)
		require.NoError(t, err)
		assert.Empty(t, reservations, "user %s reservation not released", userID)
	}

	require.Len(t, f.intents.pending, 1)
	require.Len(t, f.intents.denied, 1, "removed/blocked must not produce denied intents")
	assert.Equal(t, "user-A", f.intents.pending[0].UserID)
	assert.Equal(t, "user-B", f.intents.denied[0].UserID)
}

func TestEvaluateReplayDoesNotDoubleEmit(t *testing.T) {
	f := newFixture(t)
	f.reserveRaceName(t, "user-A", "Alpha")
	f.addMember(t, "user-A", "Alpha", membership.StatusActive)
	f.seedStats(t, "user-A", 1, 10, 9, 100)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))
	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	pending, err := f.directory.ListPendingRegistrations(context.Background(), "user-A")
	require.NoError(t, err)
	assert.Len(t, pending, 1)

	assert.Len(t, f.intents.pending, 1)
	assert.Empty(t, f.intents.denied)
}

func TestEvaluateDeletesStatsAggregate(t *testing.T) {
	f := newFixture(t)
	f.reserveRaceName(t, "user-A", "Alpha")
	f.addMember(t, "user-A", "Alpha", membership.StatusActive)
	f.seedStats(t, "user-A", 1, 10, 2, 11)

	require.NoError(t, f.service.Evaluate(context.Background(), f.gameID, f.finishedAt))

	aggregate, err := f.stats.Load(context.Background(), f.gameID)
	require.NoError(t, err)
	assert.Empty(t, aggregate.Players)
}

func TestEvaluateRequiresFinishedAt(t *testing.T) {
	f := newFixture(t)

	err := f.service.Evaluate(context.Background(), f.gameID, time.Time{})
	require.Error(t, err)
}

func TestEvaluateRejectsInvalidGameID(t *testing.T) {
	f := newFixture(t)

	err := f.service.Evaluate(context.Background(), common.GameID(""), f.finishedAt)
	require.Error(t, err)
}