package lifecycle

import (
	"context"
	"sort"
	"strings"
	"sync"

	"github.com/gogf/gf/v2/errors/gerror"

	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/consts"
	"git.5iot.com/iotlcm-public/iotlcm-worker-svr/internal/model"
)

type executor struct {
	repository Repository
	upstream   Upstream
}

func NewExecutor(repository Repository, upstream Upstream) Executor {
	return &executor{repository: repository, upstream: upstream}
}

func (e *executor) Execute(ctx context.Context, batchNo string) error {
	task, err := e.repository.Load(ctx, strings.TrimSpace(batchNo))
	if err != nil {
		return gerror.Wrap(err, "load lifecycle batch")
	}
	if !validateTask(task) {
		if err = e.repository.SaveValidationFailure(ctx, task); err != nil {
			return gerror.Wrap(err, "save lifecycle validation failure")
		}
		return gerror.Wrap(e.repository.Finalize(ctx, task), "finalize lifecycle validation failure")
	}

	groups := groupByChanKey(task.Details)
	keys := make([]string, 0, len(groups))
	for chanKey := range groups {
		keys = append(keys, chanKey)
	}
	sort.Strings(keys)
	for _, chanKey := range keys {
		for index, outcome := range e.changeGroup(ctx, task, groups[chanKey]) {
			detail := groups[chanKey][index]
			resolved, saveErr := e.repository.SaveResult(ctx, task, detail, outcome)
			if saveErr != nil {
				return gerror.Wrapf(saveErr, "save lifecycle detail %d result", detail.ID)
			}
			detail.ApplyOutcome(resolved)
		}
	}
	return gerror.Wrap(e.repository.Finalize(ctx, task), "finalize lifecycle batch")
}

func validateTask(task *Task) bool {
	if task == nil || len(task.Details) == 0 {
		return false
	}
	hasFailure := false
	for _, detail := range task.Details {
		if detail == nil {
			hasFailure = true
			continue
		}
		validateDetail(task.Operation, detail)
		if detail.Reason != "" {
			hasFailure = true
		}
	}
	if !hasFailure {
		task.ValidationOK = true
		return true
	}
	for _, detail := range task.Details {
		if detail != nil && detail.Reason == "" {
			detail.Reason = "same batch contains validation failure; upstream request was skipped"
		}
	}
	task.FailureReason = "batch validation failed; upstream request was skipped"
	return false
}

func validateDetail(operation Operation, detail *Detail) {
	if detail.Reason != "" {
		return
	}
	if detail.Card == nil {
		detail.Reason = "ICCID does not exist in SIM card records"
		return
	}
	detail.MSISDN = strings.TrimSpace(detail.Card.MSISDN)
	detail.IMSI = strings.TrimSpace(detail.Card.IMSI)
	detail.ChanKey = strings.TrimSpace(detail.Card.ChanKey)
	detail.StatusBefore = detail.Card.BossCardStatus

	if !detail.Authorized {
		detail.Reason = "ICCID is outside the current operator authorization scope"
		return
	}
	if detail.ChanKey == "" {
		detail.Reason = "ICCID is missing chanKey"
		return
	}
	if detail.InputMSISDN != "" && detail.InputMSISDN != detail.MSISDN {
		detail.Reason = "MSISDN does not match the SIM card record"
		return
	}
	if detail.InputIMSI != "" && detail.InputIMSI != detail.IMSI {
		detail.Reason = "IMSI does not match the SIM card record"
		return
	}
	// TODO: 正常系统开发完成后恢复卡状态限制
	// 注释原因：开发环境经常出现卡状态不在预期可操作范围内的情况，先放行
	// if detail.Card.BossCardStatus != operation.ExpectedStatus {
	//     detail.Reason = "SIM card status does not allow this lifecycle operation"
	//     return
	// }
}

func groupByChanKey(details []*Detail) map[string][]*Detail {
	groups := make(map[string][]*Detail)
	for _, detail := range details {
		groups[detail.ChanKey] = append(groups[detail.ChanKey], detail)
	}
	return groups
}

func (e *executor) changeGroup(ctx context.Context, task *Task, details []*Detail) []Outcome {
	subBatches := splitDetails(details, consts.BatchSubBatchSize)
	subOutcomes := make([][]Outcome, len(subBatches))

	sem := make(chan struct{}, consts.BatchSubBatchConcurrency)
	var wg sync.WaitGroup
	for i, sub := range subBatches {
		wg.Add(1)
		sem <- struct{}{}
		go func(index int, batch []*Detail) {
			defer wg.Done()
			defer func() { <-sem }()
			subOutcomes[index] = e.changeSubBatch(ctx, task, batch)
		}(i, sub)
	}
	wg.Wait()

	outcomes := make([]Outcome, 0, len(details))
	for _, subOutcome := range subOutcomes {
		outcomes = append(outcomes, subOutcome...)
	}
	return outcomes
}

// changeSubBatch 处理单个子批次：构建请求并调用上游，返回与该子批次明细等长的 Outcome 切片。
func (e *executor) changeSubBatch(ctx context.Context, task *Task, details []*Detail) []Outcome {
	input := &model.SimCardStatusChangeInput{
		SimKeys: make([]*model.SimKey, 0, len(details)),
		ReqData: model.SimCardStatusChangeInputItem{OperType: task.Operation.OperType},
	}
	for _, detail := range details {
		input.SimKeys = append(input.SimKeys, &model.SimKey{ChanKey: detail.ChanKey, ICCID: detail.ICCID, MSISDN: detail.MSISDN, IMSI: detail.IMSI})
	}
	response, err := e.upstream.ChangeSimStatus(ctx, input)
	if err != nil {
		outcomes := make([]Outcome, len(details))
		for index := range outcomes {
			outcomes[index].Message = "upstream request failed: " + err.Error()
		}
		return outcomes
	}
	return mapOutcomes(details, response)
}

// splitDetails 按固定大小把明细切成有序的子批次；空输入返回空切片。
func splitDetails(details []*Detail, size int) [][]*Detail {
	if size <= 0 {
		size = 1
	}
	batches := make([][]*Detail, 0, (len(details)+size-1)/size)
	for i := 0; i < len(details); i += size {
		end := i + size
		if end > len(details) {
			end = len(details)
		}
		batches = append(batches, details[i:end])
	}
	return batches
}

func mapOutcomes(details []*Detail, response []model.SimBaseRes[model.SimCardStatusChangeOutputItem]) []Outcome {
	outcomes := make([]Outcome, len(details))
	used := make([]bool, len(response))
	for detailIndex, detail := range details {
		matched := -1
		for responseIndex, item := range response {
			if !used[responseIndex] && sameSim(detail, item.SimKey) {
				matched = responseIndex
				break
			}
		}
		if matched < 0 && detailIndex < len(response) && !used[detailIndex] && response[detailIndex].SimKey == nil {
			matched = detailIndex
		}
		if matched < 0 {
			outcomes[detailIndex] = Outcome{Message: "upstream did not return a result for this SIM card"}
			continue
		}
		used[matched] = true
		item := response[matched]
		message := strings.TrimSpace(item.Message)
		if item.Code != 0 && message == "" {
			message = "upstream processing failed"
		}
		outcomes[detailIndex] = Outcome{Success: item.Code == 0, Code: item.Code, Message: message, OrderNum: strings.TrimSpace(item.ResData.OrderNum)}
	}
	return outcomes
}

func sameSim(detail *Detail, key *model.SimKey) bool {
	if detail == nil || key == nil {
		return false
	}
	if value := strings.TrimSpace(key.ICCID); value != "" {
		return value == detail.ICCID
	}
	if value := strings.TrimSpace(key.MSISDN); value != "" {
		return value == detail.MSISDN
	}
	if value := strings.TrimSpace(key.IMSI); value != "" {
		return value == detail.IMSI
	}
	return false
}

func OperationByBatchType(batchType int) (Operation, error) {
	switch batchType {
	case consts.BatchTypeSimCardStart:
		return Operation{BatchType: batchType, OperType: consts.SimCardStatusOperTypeStart, ExpectedStatus: consts.SimBossCardStatusStopped, TargetStatus: consts.SimBossCardStatusActivated}, nil
	case consts.BatchTypeSimCardStop:
		return Operation{BatchType: batchType, OperType: consts.SimCardStatusOperTypeStop, ExpectedStatus: consts.SimBossCardStatusActivated, TargetStatus: consts.SimBossCardStatusStopped}, nil
	default:
		return Operation{}, gerror.Newf("unsupported lifecycle batch type %d", batchType)
	}
}