package task

import (
	"context"
	"encoding/json"
	"time"

	"go.uber.org/zap"

	"github.com/break/junhong_cmp_fiber/internal/polling/carrierqueue"
)

// 设备判断的推后时长：旧路径持设备锁时、判断失败时。
const (
	deviceEvalLegacyLockDelay = 5 * time.Second
	deviceEvalFailureDelay    = 30 * time.Second
	deviceEvalTimeout         = 30 * time.Second
)

// DeviceEvalExecutor 设备维度判断执行器：抢设备判断锁，读取最新数据为设备下各卡生成指令；锁内不调网关。
type DeviceEvalExecutor struct {
	store      *carrierqueue.Store
	service    StopResumeCommandService
	instanceID string
	logger     *zap.Logger
}

// NewDeviceEvalExecutor 创建设备判断执行器。
func NewDeviceEvalExecutor(store *carrierqueue.Store, service StopResumeCommandService, instanceID string, logger *zap.Logger) *DeviceEvalExecutor {
	if logger == nil {
		logger = zap.NewNop()
	}
	return &DeviceEvalExecutor{store: store, service: service, instanceID: instanceID, logger: logger}
}

// Handle 消费一条设备判断消息。收尾只移除本次已处理的场景；版本变大时用最新数据再判断一次。
func (e *DeviceEvalExecutor) Handle(ctx context.Context, body []byte, _ func()) {
	var msg carrierqueue.DeviceEvalMessage
	if err := json.Unmarshal(body, &msg); err != nil || msg.DeviceID == 0 || msg.Token == "" {
		e.logger.Warn("设备判断消息无效，丢弃", zap.ByteString("body", body))
		return
	}
	got, err := e.store.AcquireDeviceEvalLock(ctx, msg.DeviceID, msg.Token, msg.Token+"|"+e.instanceID, 2*deviceEvalTimeout)
	if err != nil || got != 1 {
		return
	}
	claimed := carrierqueue.DeviceEvalClaimed{DeviceID: msg.DeviceID, Token: msg.Token, Version: msg.Version, Scenes: msg.Scenes}
	deferFor := time.Duration(0)
	if e.service.LegacyDeviceOpLocked(ctx, msg.DeviceID) {
		// 旧路径正在对该设备执行停复机：推后，不并行判断。
		deferFor = deviceEvalLegacyLockDelay
	} else {
		evalCtx, cancel := context.WithTimeout(ctx, deviceEvalTimeout)
		if evalErr := e.service.EvaluateDeviceCommands(evalCtx, msg.DeviceID, msg.Scenes); evalErr != nil {
			e.logger.Warn("设备判断失败，稍后再判断", zap.Uint("device_id", msg.DeviceID), zap.Strings("scenes", msg.Scenes), zap.Error(evalErr))
			deferFor = deviceEvalFailureDelay
		}
		cancel()
	}
	finishCtx, finishCancel := context.WithTimeout(context.WithoutCancel(ctx), 5*time.Second)
	defer finishCancel()
	result, err := e.store.FinishDeviceEval(finishCtx, claimed, deferFor)
	if err != nil {
		e.logger.Warn("设备判断收尾失败，等待租约到期后重新领取", zap.Uint("device_id", msg.DeviceID), zap.Error(err))
		return
	}
	if result == 2 {
		e.logger.Info("设备判断期间有新请求，按最新数据再判断", zap.Uint("device_id", msg.DeviceID))
	}
}