package research

import (
	"context"
	"encoding/json"
	"strconv"

	"github.com/redis/go-redis/v9"
)

const (
	taskQueueKey   = "research:tasks"
	statusKeyPrefix = "research:status:"
)

// redisBackend 同时实现 Queue 与 Cache：任务下发到列表队列、快速状态读自 hash。
// 与 research-worker 的 TASK_QUEUE / TASK_STATUS_PREFIX 约定保持一致。
type redisBackend struct {
	rdb *redis.Client
}

func NewRedisBackend(rdb *redis.Client) *redisBackend {
	return &redisBackend{rdb: rdb}
}

func (b *redisBackend) Enqueue(ctx context.Context, taskID string) error {
	msg, _ := json.Marshal(map[string]string{"task_id": taskID})
	return b.rdb.LPush(ctx, taskQueueKey, msg).Err()
}

func (b *redisBackend) GetStatus(ctx context.Context, taskID string) (*CachedStatus, bool) {
	m, err := b.rdb.HGetAll(ctx, statusKeyPrefix+taskID).Result()
	if err != nil || len(m) == 0 {
		return nil, false
	}
	progress, _ := strconv.Atoi(m["progress"])
	return &CachedStatus{
		Status:   m["status"],
		Progress: progress,
		Message:  m["message"],
	}, true
}