package task

import (
	"bytes"
	"context"
	"encoding/csv"
	stderrors "errors"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/bytedance/sonic"
	"github.com/hibiken/asynq"
	"go.uber.org/zap"
	"gorm.io/gorm"

	"github.com/break/junhong_cmp_fiber/internal/infrastructure/audit"
	"github.com/break/junhong_cmp_fiber/internal/model"
	assetSvc "github.com/break/junhong_cmp_fiber/internal/service/asset"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/auditcontext"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	pkgerrors "github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/sanitizer"
	"github.com/break/junhong_cmp_fiber/pkg/storage"
	"github.com/break/junhong_cmp_fiber/pkg/utils"
)

// PhoneAssetUnbindImportPayload 手机号—资产关联 CSV 解绑导入任务载荷。
type PhoneAssetUnbindImportPayload struct {
	TaskID uint `json:"task_id"`
}

// PhoneAssetUnbindImportHandler 手机号—资产关联 CSV 解绑导入任务处理器。
// 逐行独立事务：成功行提交、失败行不解除任何关系；任务级失败与行级失败分开记录。
// 行内只填资产标识与可选备注，解绑原因取任务级必填字段。
type PhoneAssetUnbindImportHandler struct {
	db                   *gorm.DB
	taskStore            *postgres.PhoneAssetUnbindImportTaskStore
	associationStore     *postgres.PhoneAssetAssociationStore
	assetIdentifierStore *postgres.AssetIdentifierStore
	iotCardStore         *postgres.IotCardStore
	deviceStore          *postgres.DeviceStore
	storageService       *storage.Service
	auditWriter          *audit.Writer
	logger               *zap.Logger
}

// NewPhoneAssetUnbindImportHandler 创建解绑导入任务处理器。
func NewPhoneAssetUnbindImportHandler(
	db *gorm.DB,
	taskStore *postgres.PhoneAssetUnbindImportTaskStore,
	associationStore *postgres.PhoneAssetAssociationStore,
	assetIdentifierStore *postgres.AssetIdentifierStore,
	iotCardStore *postgres.IotCardStore,
	deviceStore *postgres.DeviceStore,
	storageService *storage.Service,
	logger *zap.Logger,
	auditWriters ...*audit.Writer,
) *PhoneAssetUnbindImportHandler {
	handler := &PhoneAssetUnbindImportHandler{
		db: db, taskStore: taskStore, associationStore: associationStore,
		assetIdentifierStore: assetIdentifierStore, iotCardStore: iotCardStore,
		deviceStore: deviceStore, storageService: storageService, logger: logger,
	}
	if len(auditWriters) > 0 {
		handler.auditWriter = auditWriters[0]
	}
	return handler
}

// Handle 处理手机号—资产关联 CSV 解绑导入任务。
func (h *PhoneAssetUnbindImportHandler) Handle(ctx context.Context, taskMessage *asynq.Task) error {
	var payload PhoneAssetUnbindImportPayload
	if err := sonic.Unmarshal(taskMessage.Payload(), &payload); err != nil {
		h.logger.Error("解析手机号资产解绑导入任务载荷失败", zap.Error(err))
		return asynq.SkipRetry
	}
	taskRecord, err := h.taskStore.GetByID(ctx, payload.TaskID)
	if err != nil {
		h.logger.Error("查询手机号资产解绑导入任务失败", zap.Uint("task_id", payload.TaskID), zap.Error(err))
		return asynq.SkipRetry
	}
	if h.auditWriter == nil {
		return pkgerrors.New(pkgerrors.CodeInvalidStatus, "手机号资产解绑导入统一审计接缝未配置")
	}
	ctx = auditcontext.With(ctx, auditcontext.Context{
		ActorKind: constants.AuditActorSystemTask, ActorID: constants.TaskTypePhoneAssetUnbindImport,
		ActorName: "手机号资产解绑导入任务", Source: constants.AuditSourceWorker,
		CorrelationID: taskRecord.TaskNo,
		ParentEventID: audit.TaskEventID(constants.AuditResourcePhoneAssetUnbindImportTask, taskRecord.ID, "completed"),
	})
	claimed, err := h.taskStore.ResetForProcessing(ctx, taskRecord.ID)
	if err != nil {
		return err
	}
	if !claimed {
		h.logger.Info("手机号资产解绑导入任务已终结，跳过重复消费", zap.Uint("task_id", taskRecord.ID))
		return nil
	}

	rows, err := h.downloadAndParse(ctx, taskRecord.StorageKey)
	if err != nil {
		h.logger.Warn("下载或解析手机号资产解绑导入CSV失败", zap.Uint("task_id", taskRecord.ID), zap.Error(err))
		if finishErr := h.finishTask(ctx, taskRecord, nil, 0, 0, model.ImportTaskStatusFailed, err.Error()); finishErr != nil {
			return finishErr
		}
		return asynq.SkipRetry
	}

	items, successCount, err := h.processRows(ctx, taskRecord, rows)
	if err != nil {
		message := "导入执行中断：" + err.Error()
		h.logger.Error("手机号资产解绑导入行执行中断", zap.Uint("task_id", taskRecord.ID), zap.Error(err))
		if finishErr := h.finishTask(ctx, taskRecord, nil, 0, 0, model.ImportTaskStatusFailed, message); finishErr != nil {
			return finishErr
		}
		return asynq.SkipRetry
	}
	failCount := len(items) - successCount
	if err := h.finishTask(ctx, taskRecord, items, successCount, failCount, model.ImportTaskStatusCompleted, ""); err != nil {
		return err
	}
	h.logger.Info("手机号资产解绑导入任务完成",
		zap.Uint("task_id", taskRecord.ID), zap.Int("success", successCount), zap.Int("fail", failCount))
	return nil
}

// finishTask 在单事务内写任务终态、逐行明细与任务根审计事件。
// 任务级失败不产生行明细，与行级失败原因分开记录。
func (h *PhoneAssetUnbindImportHandler) finishTask(
	ctx context.Context,
	taskRecord *model.PhoneAssetUnbindImportTask,
	items model.PhoneAssetUnbindImportResults,
	successCount, failCount, status int,
	errorMessage string,
) error {
	return h.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		store := h.taskStore.WithTx(tx)
		if status == model.ImportTaskStatusFailed {
			// 任务级失败：未命中非终态说明任务已被其他执行路径终结，按库内事实跳过重复收尾。
			hit, err := store.MarkFailed(ctx, taskRecord.ID, errorMessage)
			if err != nil {
				return err
			}
			if !hit {
				return nil
			}
		} else if err := store.Complete(ctx, taskRecord.ID, len(items), successCount, failCount, items); err != nil {
			return err
		}
		result := batchAuditResult(successCount, failCount)
		afterData := map[string]any{
			"status": status, "total_count": len(items), "success_count": successCount, "fail_count": failCount,
		}
		if status == model.ImportTaskStatusFailed {
			result = constants.AuditResultFailed
			afterData["error_message"] = errorMessage
		}
		return h.auditWriter.WriteTask(ctx, tx, audit.TaskInput{
			EventID:    audit.TaskEventID(constants.AuditResourcePhoneAssetUnbindImportTask, taskRecord.ID, "completed"),
			ActionCode: constants.AuditActionPhoneAssetUnbindImportTaskCompleted,
			Summary:    "完成手机号资产解绑导入任务", TaskID: taskRecord.ID, TaskNo: taskRecord.TaskNo,
			Result: result, CorrelationID: taskRecord.TaskNo,
			ParentEventID: audit.TaskEventID(constants.AuditResourcePhoneAssetUnbindImportTask, taskRecord.ID, "created"),
			BatchTotal:    len(items), SuccessCount: successCount, FailCount: failCount,
			IdentitySnapshot: map[string]any{
				"id": taskRecord.ID, "task_no": taskRecord.TaskNo, "file_name": taskRecord.FileName,
			},
			BeforeData:   map[string]any{"status": model.ImportTaskStatusProcessing},
			AfterData:    afterData,
			ErrorSummary: errorMessage,
		})
	})
}

// downloadAndParse 下载并解析导入 CSV，编码、表头或格式问题一律按任务级失败返回。
func (h *PhoneAssetUnbindImportHandler) downloadAndParse(ctx context.Context, key string) ([]phoneAssetUnbindImportRow, error) {
	if h.storageService == nil {
		return nil, phoneAssetUnbindImportError("对象存储服务未配置")
	}
	if key == "" {
		return nil, phoneAssetUnbindImportError("导入文件Key不能为空")
	}
	localPath, cleanup, err := h.storageService.DownloadToTemp(ctx, key)
	if err != nil {
		return nil, phoneAssetUnbindImportError("下载导入CSV失败")
	}
	defer cleanup()
	// 不设行数与体积硬上限：体积沿用上传用途的既有校验，此处按文件实际大小读取。
	data, err := os.ReadFile(localPath)
	if err != nil {
		return nil, phoneAssetUnbindImportError("读取导入CSV失败")
	}
	decoded, err := utils.DecodeTextToUTF8(data)
	if err != nil {
		return nil, phoneAssetUnbindImportError(constants.PhoneAssetUnbindImportErrorEncoding)
	}
	return parsePhoneAssetUnbindImportCSV(decoded)
}

// phoneAssetUnbindImportRow 是导入文件的单行业务事实；行号自数据首行起计，表头不计入。
type phoneAssetUnbindImportRow struct {
	Line               int
	ColumnCountMatched bool
	AssetIdentifier    string
	Remark             string
}

// parsePhoneAssetUnbindImportCSV 解析固定列序的导入 CSV。
// 表头必须与固定列序完全一致，不一致即任务级失败且不进入逐行阶段；
// 数据行列数不符属行级「行格式错误」，因此必须关闭字段数一致性校验，
// 否则标准库在首条记录定型字段数后会让后续异常行直接返回 ErrFieldCount，
// 把行级问题误升级为任务级失败且不产生行明细。
func parsePhoneAssetUnbindImportCSV(data []byte) ([]phoneAssetUnbindImportRow, error) {
	reader := csv.NewReader(bytes.NewReader(data))
	reader.TrimLeadingSpace = true
	reader.FieldsPerRecord = -1
	rows := make([]phoneAssetUnbindImportRow, 0)
	line := 0
	for {
		record, err := reader.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			// 关闭字段数校验后仍报错，说明是引号未闭合等真实 CSV 语法错误，属任务级失败。
			return nil, phoneAssetUnbindImportError(constants.PhoneAssetUnbindImportErrorFileFormat)
		}
		if line == 0 {
			if !matchPhoneAssetUnbindImportHeader(record) {
				return nil, phoneAssetUnbindImportError(constants.PhoneAssetUnbindImportErrorFileFormat)
			}
			line++
			continue
		}
		line++
		row := phoneAssetUnbindImportRow{Line: line - 1}
		if len(record) != len(constants.PhoneAssetUnbindImportColumns) {
			// 列数不符的行不参与业务校验，直接以行格式错误记录并保留原状。
			rows = append(rows, row)
			continue
		}
		row.ColumnCountMatched = true
		row.AssetIdentifier = strings.TrimSpace(record[0])
		row.Remark = strings.TrimSpace(record[1])
		rows = append(rows, row)
	}
	if len(rows) == 0 {
		return nil, phoneAssetUnbindImportError(constants.PhoneAssetUnbindImportErrorNoDataRow)
	}
	return rows, nil
}

// matchPhoneAssetUnbindImportHeader 逐列比较表头与固定列序，仅容忍列内两侧空白差异。
func matchPhoneAssetUnbindImportHeader(record []string) bool {
	columns := constants.PhoneAssetUnbindImportColumns
	if len(record) != len(columns) {
		return false
	}
	for index, column := range columns {
		if strings.TrimSpace(record[index]) != column {
			return false
		}
	}
	return true
}

// processRows 逐行独立执行并按批更新进度计数；进度写失败不回滚已提交行。
// 返回错误表示行执行遇到基础设施故障，由调用方按任务级失败收尾。
func (h *PhoneAssetUnbindImportHandler) processRows(ctx context.Context, taskRecord *model.PhoneAssetUnbindImportTask, rows []phoneAssetUnbindImportRow) (model.PhoneAssetUnbindImportResults, int, error) {
	items := make(model.PhoneAssetUnbindImportResults, 0, len(rows))
	successCount, failCount := 0, 0
	for index, row := range rows {
		item, err := h.processRow(ctx, taskRecord, row)
		if err != nil {
			return nil, 0, err
		}
		items = append(items, item)
		if item.Status == constants.PhoneAssetUnbindImportItemStatusSuccess {
			successCount++
		} else {
			failCount++
		}
		if (index+1)%constants.PhoneAssetUnbindImportProgressBatchSize == 0 {
			if err := h.taskStore.UpdateProgress(ctx, taskRecord.ID, len(rows), successCount, failCount); err != nil {
				h.logger.Warn("更新手机号资产解绑导入进度失败", zap.Uint("task_id", taskRecord.ID), zap.Error(err))
			}
		}
	}
	return items, successCount, nil
}

// processRow 校验并执行单行；失败行只记录固定枚举原因，不解除任何关系。
func (h *PhoneAssetUnbindImportHandler) processRow(ctx context.Context, taskRecord *model.PhoneAssetUnbindImportTask, row phoneAssetUnbindImportRow) (model.PhoneAssetUnbindImportResultItem, error) {
	item := model.PhoneAssetUnbindImportResultItem{Line: row.Line, AssetIdentifier: row.AssetIdentifier}
	if !row.ColumnCountMatched {
		return failedPhoneAssetUnbindImportItem(item, constants.PhoneAssetUnbindImportRowErrorFormat), nil
	}
	if row.AssetIdentifier == "" {
		return failedPhoneAssetUnbindImportItem(item, constants.PhoneAssetUnbindImportRowErrorIdentifier), nil
	}
	if len(row.Remark) > constants.PhoneAssetUnbindImportRemarkMaxLength {
		return failedPhoneAssetUnbindImportItem(item, constants.PhoneAssetUnbindImportRowErrorRemarkTooLong), nil
	}
	assetType, assetID, err := h.resolveAsset(ctx, row.AssetIdentifier)
	if err != nil {
		return item, err
	}
	if assetType == "" {
		return failedPhoneAssetUnbindImportItem(item, constants.PhoneAssetUnbindImportRowErrorAssetMissing), nil
	}
	item.AssetType = assetType
	item.AssetID = assetID
	// 每行独立事务：成功行提交，失败行回滚并保留原状。
	rowErr := h.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		locked, err := h.associationStore.WithTx(tx).LockValidByAsset(ctx, tx, assetType, assetID)
		if err != nil {
			return pkgerrors.Wrap(pkgerrors.CodeDatabaseError, err, "锁定资产关联失败")
		}
		if len(locked) == 0 {
			return pkgerrors.New(pkgerrors.CodeNotFound, constants.PhoneAssetUnbindImportRowErrorNoAssociation)
		}
		ids := make([]uint, 0, len(locked))
		phones := make([]string, 0, len(locked))
		for _, association := range locked {
			ids = append(ids, association.ID)
			phones = append(phones, association.Phone)
		}
		now := time.Now()
		affected, err := h.associationStore.WithTx(tx).InvalidateByIDs(ctx, tx, ids,
			constants.PhoneAssetAssociationInvalidateMethodCSVImport, taskRecord.UnbindReason, taskRecord.Creator, now)
		if err != nil {
			return pkgerrors.Wrap(pkgerrors.CodeDatabaseError, err, "解除手机号资产关联失败")
		}
		if int(affected) != len(locked) {
			return pkgerrors.New(pkgerrors.CodeNotFound, constants.PhoneAssetUnbindImportRowErrorNoAssociation)
		}
		item.UnboundCount = len(locked)
		item.AssociatedPhones = phones
		return h.appendRowAudit(ctx, tx, taskRecord, row, locked, now)
	})
	if rowErr != nil {
		var appErr *pkgerrors.AppError
		if stderrors.As(rowErr, &appErr) && appErr.Code == pkgerrors.CodeNotFound {
			return failedPhoneAssetUnbindImportItem(item, appErr.Message), nil
		}
		return item, rowErr
	}
	item.Status = constants.PhoneAssetUnbindImportItemStatusSuccess
	return item, nil
}

// resolveAsset 按资产标识定位资产，未命中返回空类型；解析口径与后台关联列表一致。
func (h *PhoneAssetUnbindImportHandler) resolveAsset(ctx context.Context, identifier string) (string, uint, error) {
	return assetSvc.ResolveIdentifier(ctx, h.assetIdentifierStore, h.iotCardStore, h.deviceStore, identifier)
}

// appendRowAudit 在行事务内写单行解除审计，手机号一律脱敏，完整快照只进任务明细。
func (h *PhoneAssetUnbindImportHandler) appendRowAudit(
	ctx context.Context,
	tx *gorm.DB,
	taskRecord *model.PhoneAssetUnbindImportTask,
	row phoneAssetUnbindImportRow,
	locked []*model.PhoneAssetAssociation,
	now time.Time,
) error {
	if h.auditWriter == nil {
		return pkgerrors.New(pkgerrors.CodeInvalidStatus, "手机号资产解绑导入统一审计接缝未配置")
	}
	metadata := map[string]any{
		"import_task_id": taskRecord.ID, "import_task_no": taskRecord.TaskNo,
		"line": row.Line, "unbound_count": len(locked),
	}
	if row.Remark != "" {
		metadata["remark"] = row.Remark
	}
	resources := make([]audit.ResourceInput, 0, len(locked)+1)
	for index, association := range locked {
		relation := constants.AuditResourceRelationReference
		if index == 0 {
			relation = constants.AuditResourceRelationPrimary
		}
		associationID := strconv.FormatUint(uint64(association.ID), 10)
		resources = append(resources, audit.ResourceInput{
			Type: constants.AuditResourcePhoneAssetAssociation, ID: &associationID,
			Key: associationID, DisplayName: sanitizer.MaskPhone(association.Phone),
			Relation: relation, Role: constants.AuditResourceRolePhoneAssetAssociationTarget,
			IdentitySnapshot: map[string]any{
				"id": association.ID, "phone_masked": sanitizer.MaskPhone(association.Phone),
				"asset_type": association.AssetType, "asset_id": association.AssetID,
				"status": constants.PhoneAssetAssociationStatusInvalid, "source": association.Source,
				"invalidated_at": now, "invalidation_method": constants.PhoneAssetAssociationInvalidateMethodCSVImport,
				"invalidation_reason": taskRecord.UnbindReason,
			},
			BeforeData: map[string]any{"status": constants.PhoneAssetAssociationStatusValid},
			AfterData: map[string]any{
				"status": constants.PhoneAssetAssociationStatusInvalid, "invalidated_at": now,
				"invalidation_method": constants.PhoneAssetAssociationInvalidateMethodCSVImport,
				"invalidation_reason": taskRecord.UnbindReason,
			},
			SubjectVisibility: constants.AuditSubjectInternalOnly, SortOrder: index + 1,
		})
	}
	assetID := strconv.FormatUint(uint64(locked[0].AssetID), 10)
	resources = append(resources, audit.ResourceInput{
		Type: locked[0].AssetType, ID: &assetID, Key: assetID, DisplayName: row.AssetIdentifier,
		Relation: constants.AuditResourceRelationReference, Role: constants.AuditResourceRolePhoneAssetAssociationAsset,
		IdentitySnapshot:  map[string]any{"id": locked[0].AssetID},
		SubjectVisibility: constants.AuditSubjectInternalOnly,
	})
	// 稳定事件 ID 由任务与行号决定，任务重复消费时同行为幂等重放。
	return h.auditWriter.Append(ctx, tx, audit.AppendInput{
		EventID:    audit.TaskEventID(constants.AuditResourcePhoneAssetUnbindImportTask, taskRecord.ID, fmt.Sprintf("item:%d", row.Line)),
		ActionCode: constants.AuditActionPhoneAssetAssociationImported,
		Summary:    "导入解除手机号资产关联",
		Result:     constants.AuditResultSuccess, Metadata: metadata,
		ScopeType: constants.AuditScopePlatform, Resources: resources,
	})
}

func failedPhoneAssetUnbindImportItem(item model.PhoneAssetUnbindImportResultItem, reason string) model.PhoneAssetUnbindImportResultItem {
	item.Status, item.Reason = constants.PhoneAssetUnbindImportItemStatusFailed, reason
	return item
}

// phoneAssetUnbindImportError 是任务级失败原因，与行级失败原因分开记录。
type phoneAssetUnbindImportError string

// Error 返回任务级失败原因原文。
func (e phoneAssetUnbindImportError) Error() string { return string(e) }