package asynq

import (
	"encoding/json"
	"math/rand"
	"testing"
	"time"

	"github.com/go-redis/redis/v7"
	"github.com/google/go-cmp/cmp"
	"github.com/google/uuid"
)

var client *redis.Client

func init() {
	rand.Seed(time.Now().UnixNano())
}

// setup connects to a redis database and flush all keys
// before returning an instance of rdb.
func setup() *rdb {
	client = redis.NewClient(&redis.Options{
		Addr: "localhost:6379",
		DB:   15, // use database 15 to separate from other applications
	})
	// Start each test with a clean slate.
	if err := client.FlushDB().Err(); err != nil {
		panic(err)
	}
	return newRDB(client)
}

func randomTask(taskType, qname string) *taskMessage {
	return &taskMessage{
		ID:    uuid.New(),
		Type:  taskType,
		Queue: qname,
		Retry: rand.Intn(100),
	}
}

func TestPush(t *testing.T) {
	r := setup()
	msg := randomTask("send_email", "default")

	err := r.push(msg)
	if err != nil {
		t.Fatalf("could not push message to queue: %v", err)
	}

	res := client.LRange("asynq:queues:default", 0, -1).Val()
	if len(res) != 1 {
		t.Fatalf("len(res) = %d, want %d", len(res), 1)
	}
	bytes, err := json.Marshal(msg)
	if err != nil {
		t.Fatalf("json.Marshal(msg) failed: %v", err)
	}
	if res[0] != string(bytes) {
		t.Fatalf("res[0] = %s, want %s", res[0], string(bytes))
	}
}

func TestDequeueImmediateReturn(t *testing.T) {
	r := setup()
	msg := randomTask("export_csv", "csv")
	r.push(msg)

	res, err := r.dequeue("asynq:queues:csv", time.Second)
	if err != nil {
		t.Fatalf("r.bpop() failed: %v", err)
	}

	if !cmp.Equal(res, msg) {
		t.Errorf("cmp.Equal(res, msg) = %t, want %t", false, true)
	}
	jobs := client.LRange(inProgress, 0, -1).Val()
	if len(jobs) != 1 {
		t.Fatalf("len(jobs) = %d, want %d", len(jobs), 1)
	}
	var tm taskMessage
	if err := json.Unmarshal([]byte(jobs[0]), &tm); err != nil {
		t.Fatalf("json.Marshal() failed: %v", err)
	}
	if diff := cmp.Diff(res, &tm); diff != "" {
		t.Errorf("cmp.Diff(res, tm) = %s", diff)
	}
}

func TestDequeueTimeout(t *testing.T) {
	r := setup()

	_, err := r.dequeue("asynq:queues:default", time.Second)
	if err != errQueuePopTimeout {
		t.Errorf("err = %v, want %v", err, errQueuePopTimeout)
	}
}

func TestMoveAll(t *testing.T) {
	r := setup()
	seed := []*taskMessage{
		randomTask("send_email", "default"),
		randomTask("export_csv", "csv"),
		randomTask("sync_stuff", "sync"),
	}
	for _, task := range seed {
		bytes, err := json.Marshal(task)
		if err != nil {
			t.Errorf("json.Marhsal() failed: %v", err)
		}
		if err := client.LPush(inProgress, string(bytes)).Err(); err != nil {
			t.Errorf("LPUSH %q %s failed: %v", inProgress, string(bytes), err)
		}
	}

	err := r.moveAll(inProgress, defaultQueue)
	if err != nil {
		t.Errorf("moveAll failed: %v", err)
	}

	if l := client.LLen(inProgress).Val(); l != 0 {
		t.Errorf("LLEN %q = %d, want 0", inProgress, l)
	}
	if l := client.LLen(defaultQueue).Val(); int(l) != len(seed) {
		t.Errorf("LLEN %q = %d, want %d", defaultQueue, l, len(seed))
	}
}