package domain

import (
	"errors"
	"reflect"
	"sync"
	"testing"
	"time"
)

func TestQueueFencesOneActiveTicketPerPlayerAndReplaysCreate(t *testing.T) {
	q := NewQueue()
	now := time.Unix(1000, 0)
	c := Candidate{TicketID: "ticket-a", PlayerID: "player-a", EnqueuedAt: now, PredictedRTT: map[string]float64{"EU": 20}}
	first, err := q.Create("player-a", "ticket-a", "create-key-123456", c, now)
	if err != nil {
		t.Fatal(err)
	}
	replay, err := q.Create("player-a", "ticket-a", "create-key-123456", c, now.Add(time.Second))
	if err != nil || !reflect.DeepEqual(replay, first) {
		t.Fatalf("create replay = %+v, %v", replay, err)
	}
	other := c
	other.TicketID = "ticket-b"
	if _, err := q.Create("player-a", "ticket-b", "create-key-654321", other, now); !errors.Is(err, ErrPlayerQueued) {
		t.Fatalf("second active ticket error = %v", err)
	}
}

func TestQueueHeartbeatExtendsExpiryExactlyAndRejectsStaleReplay(t *testing.T) {
	q := NewQueue()
	now := time.Unix(1000, 0)
	c := Candidate{TicketID: "ticket-a", PlayerID: "player-a", EnqueuedAt: now}
	if _, err := q.Create("player-a", "ticket-a", "create-key-123456", c, now); err != nil {
		t.Fatal(err)
	}
	updated, err := q.Heartbeat("player-a", "ticket-a", "heartbeat-key-123", 0, now.Add(10*time.Second))
	if err != nil {
		t.Fatal(err)
	}
	if !updated.ExpiresAt.Equal(now.Add(40*time.Second)) || updated.Revision != 1 {
		t.Fatalf("bad heartbeat: %+v", updated)
	}
	replay, err := q.Heartbeat("player-a", "ticket-a", "heartbeat-key-123", 0, now.Add(50*time.Second))
	if err != nil || !reflect.DeepEqual(replay, updated) {
		t.Fatalf("heartbeat replay = %+v, %v", replay, err)
	}
	if _, err := q.Heartbeat("player-a", "ticket-a", "heartbeat-key-456", 0, now.Add(20*time.Second)); !errors.Is(err, ErrStaleRevision) {
		t.Fatalf("stale heartbeat error = %v", err)
	}
}

func TestQueueExpiryReleasesOwnershipAndDoesNotReturnExpiredCandidates(t *testing.T) {
	q := NewQueue()
	now := time.Unix(1000, 0)
	c := Candidate{TicketID: "ticket-a", PlayerID: "player-a", EnqueuedAt: now}
	if _, err := q.Create("player-a", "ticket-a", "create-key-123456", c, now); err != nil {
		t.Fatal(err)
	}
	if got := q.Candidates(now.Add(QueueExpiryWindow)); len(got) != 0 {
		t.Fatalf("expired candidate returned: %+v", got)
	}
	if _, err := q.Create("player-a", "ticket-b", "create-key-654321", Candidate{TicketID: "ticket-b", PlayerID: "player-a"}, now.Add(QueueExpiryWindow)); err != nil {
		t.Fatalf("ownership was not released: %v", err)
	}
}

func TestQueueCreateIdempotencyIncludesCandidatePayload(t *testing.T) {
	q := NewQueue()
	now := time.Unix(1000, 0)
	base := Candidate{TicketID: "ticket-a", PlayerID: "player-a", Rating: 1500, EnqueuedAt: now, PredictedRTT: map[string]float64{"EU": 20}}
	if _, err := q.Create("player-a", "ticket-a", "create-key-123456", base, now); err != nil {
		t.Fatal(err)
	}
	changed := base
	changed.Rating = 1800
	if _, err := q.Create("player-a", "ticket-a", "create-key-123456", changed, now); !errors.Is(err, ErrConflict) {
		t.Fatalf("changed create payload error = %v", err)
	}
}

func TestQueueConcurrentCreateKeepsOneActiveTicketPerPlayer(t *testing.T) {
	q := NewQueue()
	now := time.Unix(1000, 0)
	var wg sync.WaitGroup
	results := make(chan error, 2)
	for i := 0; i < 2; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			id := string(rune('a' + i))
			_, err := q.Create("same-player", "ticket-"+id, "create-"+id+"-123456", Candidate{TicketID: "ticket-" + id, PlayerID: "same-player", EnqueuedAt: now}, now)
			results <- err
		}(i)
	}
	wg.Wait()
	close(results)
	succeeded := 0
	for err := range results {
		if err == nil {
			succeeded++
		} else if !errors.Is(err, ErrPlayerQueued) {
			t.Fatalf("unexpected concurrent create error: %v", err)
		}
	}
	if succeeded != 1 {
		t.Fatalf("concurrent creates succeeded %d times", succeeded)
	}
}