package task

import (
	"context"
	"strconv"
	"time"

	"go.uber.org/zap"
	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/auditfailure"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
)

// pollingPriorityTaskNames 是纳入优先轮询的既有任务类型的中文名，用于日志与审计展示。
var pollingPriorityTaskNames = map[string]string{
	constants.TaskTypePollingRealname:   "实名状态轮询任务",
	constants.TaskTypePollingCarddata:   "卡流量轮询任务",
	constants.TaskTypePollingPackage:    "套餐状态轮询任务",
	constants.TaskTypePollingCardStatus: "卡网络状态轮询任务",
}

// pollingPriorityRound 承载本轮轮询执行是否同时是一次优先执行。
//
// 无活动优先项时接缝返回 nil，其所有方法都是无操作，因此调用方在「无优先项」路径上
// 完全保持既有行为（入队、出队、移除与延后一行不改）。领取成功时必须恰好调用一次结果收口方法
// （Complete / FailRetryable / FailFinal），以保证不出现「领了优先项却没执行也没落终态或退回活动态」的路径。
//
// 上下文约定（照 PollingBase 既有约定）：本类型的写库与审计一律忽略调用方 ctx，
// 内部改用 pollingFallbackContext 的独立短超时上下文。Asynq 任务 ctx 超时或取消后，
// 失败事实、终态与审计仍必须尽量落下，否则优先项会停在执行中只能等租约接管。
type pollingPriorityRound struct {
	base     *PollingBase
	item     *model.PollingPriorityItem
	taskType string
	taskName string
	// attempts 与库内 attempt_count 保持同步，用于判定是否达到尝试上限。
	attempts int
}

// beginPollingPriority 轮询共享基类的优先项认领接缝。
//
// 位置约定：必须在取并发信号量之后、调用上游之前（carddata 还需在流量同步锁获取成功之后）。
// 返回语义：
//   - round 非 nil：本轮领取成功，本轮执行同时就是优先执行；
//   - skip 为 true：存在活动优先项但本轮必须跳过并延后（已被其它执行持有，或超租约接管未命中），
//     调用方必须释放并发、按既有间隔 requeueCard 延后、零上游调用、不写失败审计；
//   - err 非 nil：活动项探测失败，调用方按既有失败分支处理；
//   - round 为 nil 且 skip 为 false：无活动优先项，调用方后续行为与既有实现完全一致。
func (b *PollingBase) beginPollingPriority(ctx context.Context, cardID uint, taskType string) (*pollingPriorityRound, bool, error) {
	if b == nil || b.priorityStore == nil {
		return nil, false, nil
	}
	item, err := b.priorityStore.FindActive(ctx, cardID, taskType)
	if err != nil {
		return nil, false, err
	}
	if item == nil {
		return nil, false, nil
	}

	now := time.Now()
	switch item.Status {
	case constants.PollingPriorityStatusPending:
		// 待执行项必须由到达的执行认领并执行，否则提示通道产生的执行会被自己跳过、优先项永远无人执行。
		claimed, claimErr := b.priorityStore.ClaimPending(ctx, cardID, taskType, now)
		if claimErr != nil {
			return nil, false, claimErr
		}
		if claimed == nil {
			return nil, true, nil
		}
		return b.newPriorityRound(ctx, claimed, taskType, now), false, nil
	case constants.PollingPriorityStatusProcessing:
		// 执行中且认领租约未到期：不发第二次上游调用。
		if item.ClaimedAt != nil && now.Before(item.ClaimedAt.Add(time.Duration(constants.PollingPriorityClaimLease)*time.Second)) {
			return nil, true, nil
		}
		// 超过租约或认领时间缺失视为崩溃遗留：允许相邻执行接管，该卡该任务类型不被永久跳过。
		takenOver, takeoverErr := b.priorityStore.TakeOverExpiredClaim(ctx, cardID, taskType, now, constants.PollingPriorityClaimLease)
		if takeoverErr != nil {
			return nil, false, takeoverErr
		}
		if takenOver == nil {
			return nil, true, nil
		}
		return b.newPriorityRound(ctx, takenOver, taskType, now), false, nil
	default:
		// 终态行不属于活动集合，FindActive 不会返回；防御性按跳过处理。
		return nil, true, nil
	}
}

// newPriorityRound 创建领取成功后的执行轮次，并记录领取事实。
func (b *PollingBase) newPriorityRound(ctx context.Context, item *model.PollingPriorityItem, taskType string, now time.Time) *pollingPriorityRound {
	round := &pollingPriorityRound{
		base:     b,
		item:     item,
		taskType: taskType,
		taskName: pollingPriorityTaskName(taskType),
		attempts: item.AttemptCount,
	}
	before := round.stateData()
	item.Status = constants.PollingPriorityStatusProcessing
	item.ClaimedAt = &now
	round.writeAudit(constants.AuditActionPollingPriorityClaimed, "卡轮询优先项已领取", constants.AuditResultSuccess, "", "", before)
	return round
}

// priorityInPollingScope 执行前校验该卡是否仍在轮询范围内：卡自身与绑定设备的轮询开关均为启用。
//
// 优先通道不得重启已停止轮询的卡；既有人工触发入口的范围语义不受本方法影响。
// 无活动优先项（round 为 nil）时恒为真，普通轮询保持既有行为；不在范围内时按业务校验类失败
// 终结优先项并返回 false，调用方据此跳过上游调用。
func (b *PollingBase) priorityInPollingScope(_ context.Context, round *pollingPriorityRound, card *model.IotCard) bool {
	if round == nil {
		return true
	}
	if card == nil {
		round.FailFinal(nil, "卡不存在")
		return false
	}
	scopeCtx, cancel := pollingFallbackContext()
	inScope := b.scopeChecker == nil || b.scopeChecker.ShouldEnqueue(scopeCtx, card)
	cancel()
	if inScope {
		return true
	}
	round.FailFinal(nil, "卡已不在轮询范围内")
	return false
}

// MarkExecution 标记即将真正发起上游调用，并在调用之前累加尝试次数。
// 崩溃遗留的执行中项被接管后据此按尝试上限收敛。
func (r *pollingPriorityRound) MarkExecution(_ context.Context) {
	if r == nil {
		return
	}
	ctx, cancel := pollingFallbackContext()
	defer cancel()
	hit, err := r.base.priorityStore.IncrementAttempt(ctx, r.item.ID)
	if err != nil {
		r.base.logger.Warn("累加优先轮询项尝试次数失败",
			zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
	}
	if !hit {
		r.base.logger.Warn("优先轮询项已不处于执行中，尝试次数未累加",
			zap.Uint("priority_item_id", r.item.ID))
	}
	r.attempts = r.item.AttemptCount + 1
	r.item.AttemptCount = r.attempts
}

// Complete 记录优先项执行成功并出队，该卡继续按普通轮询运行。
func (r *pollingPriorityRound) Complete(_ context.Context) {
	if r == nil {
		return
	}
	ctx, cancel := pollingFallbackContext()
	defer cancel()
	before := r.stateData()
	hit, err := r.base.priorityStore.MarkCompleted(ctx, r.item.ID)
	if err != nil {
		r.base.logger.Warn("更新优先轮询项完成状态失败",
			zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
	}
	if !hit {
		r.base.logger.Warn("优先轮询项已完成或不处于执行中，跳过完成收口",
			zap.Uint("priority_item_id", r.item.ID))
		return
	}
	r.item.Status = constants.PollingPriorityStatusCompleted
	r.item.Result = constants.PollingPriorityResultSuccess
	r.item.FailureReason = ""
	r.writeAudit(constants.AuditActionPollingPriorityCompleted, "卡轮询优先项执行完成并出队", constants.AuditResultSuccess, "", "", before)
}

// FailRetryable 记录一次可恢复失败（上游超时、失败或响应无效）。
// 未达尝试上限时退回活动态并按既有轮询间隔由调用方重排；达到上限时记录失败终态并出队。
func (r *pollingPriorityRound) FailRetryable(_ context.Context, reason string) {
	if r == nil {
		return
	}
	ctx, cancel := pollingFallbackContext()
	defer cancel()
	before := r.stateData()
	if r.attempts < constants.PollingPriorityMaxAttempts {
		hit, err := r.base.priorityStore.ReturnToPending(ctx, r.item.ID, reason)
		if err != nil {
			r.base.logger.Warn("退回优先轮询项活动状态失败",
				zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
		}
		if !hit {
			r.base.logger.Warn("优先轮询项不处于执行中，跳过退回活动态收口",
				zap.Uint("priority_item_id", r.item.ID))
			return
		}
		r.item.Status = constants.PollingPriorityStatusPending
		r.item.Result = constants.PollingPriorityResultFailed
		r.item.FailureReason = reason
		r.item.ClaimedAt = nil
		r.writeAudit(constants.AuditActionPollingPriorityFailed, "卡轮询优先项执行失败", constants.AuditResultFailed, "", reason, before)
		r.writeAudit(constants.AuditActionPollingPriorityRetried, "卡轮询优先项未达尝试上限，退回活动态重新排期", constants.AuditResultFailed, "", reason, before)
		return
	}

	hit, err := r.base.priorityStore.MarkFailed(ctx, r.item.ID, reason)
	if err != nil {
		r.base.logger.Warn("更新优先轮询项失败状态失败",
			zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
	}
	if !hit {
		r.base.logger.Warn("优先轮询项不处于执行中，跳过失败出队收口",
			zap.Uint("priority_item_id", r.item.ID))
		return
	}
	r.item.Status = constants.PollingPriorityStatusFailed
	r.item.Result = constants.PollingPriorityResultFailed
	r.item.FailureReason = reason
	r.writeAudit(constants.AuditActionPollingPriorityFailed, "卡轮询优先项执行失败", constants.AuditResultFailed, "", reason, before)
	r.writeAudit(constants.AuditActionPollingPriorityDequeued, "卡轮询优先项达到尝试上限，失败出队", constants.AuditResultFailed, "", reason, before)
}

// FailFinal 记录业务校验类失败（卡不存在、不在轮询范围、能力未配置等）：不重试，直接失败出队。
func (r *pollingPriorityRound) FailFinal(_ context.Context, reason string) {
	if r == nil {
		return
	}
	ctx, cancel := pollingFallbackContext()
	defer cancel()
	before := r.stateData()
	hit, err := r.base.priorityStore.MarkFailed(ctx, r.item.ID, reason)
	if err != nil {
		r.base.logger.Warn("更新优先轮询项失败状态失败",
			zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
	}
	if !hit {
		r.base.logger.Warn("优先轮询项不处于执行中，跳过失败出队收口",
			zap.Uint("priority_item_id", r.item.ID))
		return
	}
	r.item.Status = constants.PollingPriorityStatusFailed
	r.item.Result = constants.PollingPriorityResultFailed
	r.item.FailureReason = reason
	r.writeAudit(constants.AuditActionPollingPriorityFailed, "卡轮询优先项执行业务校验失败", constants.AuditResultFailed, "", reason, before)
	r.writeAudit(constants.AuditActionPollingPriorityDequeued, "卡轮询优先项失败出队且不重试", constants.AuditResultFailed, "", reason, before)
}

// stateData 返回当前优先项状态的前后值快照，覆盖触发来源、操作来源、时间与执行结果。
func (r *pollingPriorityRound) stateData() map[string]any {
	return map[string]any{
		"status":            r.item.Status,
		"result":            r.item.Result,
		"trigger_type":      r.item.TriggerType,
		"trigger_types":     r.item.TriggerTypes,
		"trigger_count":     r.item.TriggerCount,
		"last_triggered_at": r.item.LastTriggeredAt,
		"attempt_count":     r.item.AttemptCount,
		"claimed_at":        r.item.ClaimedAt,
		"failure_reason":    r.item.FailureReason,
		"source":            constants.AuditSourceWorker,
		"occurred_at":       time.Now(),
	}
}

// writeAudit 以独立短事务写入一条优先项生命周期审计。
// 审计写入失败不阻断轮询执行，按既有约定登记为失败审计二次写入故障。
func (r *pollingPriorityRound) writeAudit(
	actionCode, summary, result, errorCode, errorSummary string,
	before map[string]any,
) {
	base := r.base
	if base == nil || base.priorityAudit == nil || base.db == nil || r.item == nil || r.item.ID == 0 {
		return
	}
	ctx, cancel := pollingFallbackContext()
	defer cancel()
	input := audit.TaskInput{
		ActionCode: actionCode, Summary: summary,
		TaskID: r.item.ID, TaskNo: pollingPriorityResourceKey(r.item), DisplayName: "卡轮询优先项",
		Actor: audit.ActorInput{
			Kind: constants.AuditActorSystemTask, ID: r.taskType, Name: r.taskName,
		},
		Source:        constants.AuditSourceWorker,
		ScopeType:     constants.AuditScopePlatform,
		Result:        result,
		ErrorCode:     errorCode,
		ErrorSummary:  errorSummary,
		CorrelationID: r.taskType,
		IdentitySnapshot: map[string]any{
			"id": r.item.ID, "card_id": r.item.CardID, "task_type": r.item.TaskType,
			"status": r.item.Status, "trigger_type": r.item.TriggerType,
			"trigger_count": r.item.TriggerCount, "manual_operator_id": r.item.ManualOperatorID,
		},
		BeforeData: before,
		AfterData:  r.stateData(),
	}
	err := base.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		return base.priorityAudit.WriteTask(ctx, tx, input)
	})
	if err != nil {
		auditfailure.RecordSecondaryWriteFailure(actionCode, input.TaskNo, "", r.taskType, errorCode, err)
		base.logger.Error("优先轮询项审计写入失败",
			zap.String("action", actionCode), zap.Uint("priority_item_id", r.item.ID), zap.Error(err))
	}
}

// pollingPriorityTaskName 返回优先轮询任务类型的中文名，未知类型回退为完整任务类型。
func pollingPriorityTaskName(taskType string) string {
	if name, ok := pollingPriorityTaskNames[taskType]; ok {
		return name
	}
	return taskType
}

// pollingPriorityResourceKey 返回优先项在审计里的稳定资源键。
func pollingPriorityResourceKey(item *model.PollingPriorityItem) string {
	if item == nil {
		return ""
	}
	return strconv.FormatUint(uint64(item.ID), 10)
}