package callback

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	stderrors "errors"
	"strconv"
	"strings"
	"time"

	"github.com/bytedance/sonic"
	"github.com/gofiber/fiber/v2"
	"go.uber.org/zap"

	cardapp "github.com/break/junhong_cmp_fiber/internal/application/cardobservation"
	carddomain "github.com/break/junhong_cmp_fiber/internal/domain/cardobservation"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/carriercallback"
	"github.com/break/junhong_cmp_fiber/internal/infrastructure/integrationlog"
	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/pkg/constants"
	apperrors "github.com/break/junhong_cmp_fiber/pkg/errors"
	"github.com/break/junhong_cmp_fiber/pkg/middleware"
)

// ResourceSeriesCompleter 提前完成同资源未执行的观测序列。
type ResourceSeriesCompleter interface {
	CompleteResourceSeries(ctx context.Context, resourceType, resourceID, syncType string) error
}

// CTCCRealnameHandler 处理电信实名 XML 回调。
type CTCCRealnameHandler struct {
	translator  *carriercallback.CTCCRealnameTranslator
	resolver    *carriercallback.CTCCCardResolver
	integration *integrationlog.Repository
	observation *cardapp.Service
	series      ResourceSeriesCompleter
	config      SystemConfigReader
	logger      *zap.Logger
}

// NewCTCCRealnameHandler 创建电信实名回调 Handler。
func NewCTCCRealnameHandler(
	translator *carriercallback.CTCCRealnameTranslator,
	resolver *carriercallback.CTCCCardResolver,
	integration *integrationlog.Repository,
	observation *cardapp.Service,
	series ResourceSeriesCompleter,
	config SystemConfigReader,
	logger *zap.Logger,
) *CTCCRealnameHandler {
	return &CTCCRealnameHandler{
		translator: translator, resolver: resolver, integration: integration,
		observation: observation, series: series, config: config, logger: logger,
	}
}

// Realname 接收电信实名结果并返回固定成功应答。
// POST /api/callback/carriers/ctcc/realname
func (h *CTCCRealnameHandler) Realname(c *fiber.Ctx) error {
	startedAt := time.Now()
	enabled, err := carrierCallbackEnabled(c.UserContext(), h.config, constants.SystemConfigCarrierCallbackCTCCRealnameEnabled)
	if err != nil {
		if h.logger != nil {
			h.logger.Error("读取电信实名回调启停配置失败，已按关闭处理并返回成功", zap.Error(err))
		}
		return sendCTCCSuccess(c, startedAt)
	}
	if !enabled {
		if err := recordDisabledCarrierCallback(c.UserContext(), h.integration, constants.IntegrationProviderCTCC, constants.IntegrationOperationCTCCRealnameCallback, "ctcc-realname", c.Body(), c.Get("Content-Type")); err != nil && h.logger != nil {
			h.logger.Error("电信实名回调已关闭，但留痕失败", zap.Error(err))
		}
		return sendCTCCSuccess(c, startedAt)
	}
	if err := h.process(c.UserContext(), c.Body(), c.Get("Content-Type")); err != nil && h.logger != nil {
		h.logger.Error("处理电信实名回调失败，已按运营商约定返回成功", zap.Error(err))
	}
	return sendCTCCSuccess(c, startedAt)
}

func (h *CTCCRealnameHandler) process(ctx context.Context, body []byte, contentType string) error {
	if h == nil || h.translator == nil || h.resolver == nil || h.integration == nil || h.observation == nil {
		return apperrors.New(apperrors.CodeInternalError, "电信实名回调能力未完整配置")
	}
	translated, translateErr := h.translator.Translate(body)
	idempotencyKey := ctccIdempotencyKey(body, translated)
	integrationID := "ctcc-realname:" + shortHash(idempotencyKey)
	resourceKey := optionalHashedResourceKey(translated.ICCID)
	requestID := middleware.GetRequestIDFromContext(ctx)
	log, created, err := h.integration.RecordInbound(ctx, integrationlog.InboundAttempt{
		IntegrationID: integrationID, IdempotencyKey: idempotencyKey,
		Provider: constants.IntegrationProviderCTCC, Operation: constants.IntegrationOperationCTCCRealnameCallback,
		ExternalID: translated.GroupTransactionID, ResourceType: constants.CardObservationResourceTypeCard,
		ResourceKey: resourceKey, RawPayload: body, ContentType: contentType,
		RequestID: requestID, CorrelationID: requestID,
	})
	if err != nil {
		if isAppConflict(err) {
			return h.recordPayloadConflict(ctx, body, contentType, idempotencyKey, translated, requestID)
		}
		return err
	}
	if !created {
		claimed, claimErr := h.claimExistingPending(ctx, log)
		if claimErr != nil || !claimed {
			return claimErr
		}
	}
	if translateErr != nil {
		return h.complete(ctx, log.IntegrationID, constants.IntegrationResultInvalidPayload, false, "报文解析或 ICCID 校验失败")
	}
	if translated.Action != carriercallback.CTCCRealnameActionVerified {
		return h.complete(ctx, log.IntegrationID, constants.IntegrationResultIgnored, false, "合法业务结果无需更新实名事实")
	}
	cards, err := h.resolver.Resolve(ctx, translated.ICCID)
	if err != nil {
		return h.failPending(ctx, log.IntegrationID, err)
	}
	if len(cards) == 0 {
		return h.complete(ctx, log.IntegrationID, constants.IntegrationResultNotFound, false, "精确列未找到卡")
	}
	if len(cards) > 1 {
		return h.complete(ctx, log.IntegrationID, constants.IntegrationResultConflict, false, "精确列匹配多张卡")
	}
	card := cards[0]
	now := time.Now().UTC()
	decision, err := h.observation.ApplyCardObservation(ctx, carddomain.RealnameObservation{
		CardID: card.ID, Verified: true,
		Metadata: carddomain.ObservationMetadata{
			ObservationID: log.IntegrationID, Source: constants.CardObservationSourceCarrierCallback,
			Scene: constants.CardObservationSceneCarrierCallback, ObservedAt: now,
			RequestID: optionalStringValue(requestID), CorrelationID: optionalStringValue(requestID),
			UpstreamSummary: "电信实名补录成功",
		},
	})
	if err != nil {
		return h.failPending(ctx, log.IntegrationID, err)
	}
	if h.series != nil {
		if err := h.series.CompleteResourceSeries(ctx, constants.CardObservationResourceTypeCard, uintString(card.ID), constants.CardObservationSyncTypeRealname); err != nil && h.logger != nil {
			h.logger.Warn("电信实名事实已应用但提前完成观测序列失败", zap.Uint("card_id", card.ID), zap.Error(err))
		}
	}
	return h.complete(ctx, log.IntegrationID, constants.IntegrationResultSuccess, decision.StatusChanged, "实名事实已幂等应用")
}

func (h *CTCCRealnameHandler) failPending(ctx context.Context, integrationID string, original error) error {
	if err := h.complete(ctx, integrationID, constants.IntegrationResultFailed, false, "内部处理失败"); err != nil && h.logger != nil {
		h.logger.Error("电信实名回调失败终态写入失败", zap.String("integration_id", integrationID), zap.Error(err))
	}
	return original
}

func (h *CTCCRealnameHandler) recordPayloadConflict(ctx context.Context, body []byte, contentType, baseKey string, translated carriercallback.CTCCRealnameTranslation, requestID *string) error {
	conflictKey := baseKey + ":conflict:" + shortHashBytes(body)
	log, created, err := h.integration.RecordInbound(ctx, integrationlog.InboundAttempt{
		IntegrationID: "ctcc-realname-conflict:" + shortHash(conflictKey), IdempotencyKey: conflictKey,
		Provider: constants.IntegrationProviderCTCC, Operation: constants.IntegrationOperationCTCCRealnameCallback,
		ExternalID: translated.GroupTransactionID, ResourceType: constants.CardObservationResourceTypeCard,
		ResourceKey: optionalHashedResourceKey(translated.ICCID), RawPayload: body, ContentType: contentType,
		RequestID: requestID, CorrelationID: requestID,
	})
	if err != nil {
		return err
	}
	if !created {
		claimed, claimErr := h.claimExistingPending(ctx, log)
		if claimErr != nil || !claimed {
			return claimErr
		}
	}
	return h.complete(ctx, log.IntegrationID, constants.IntegrationResultConflict, false, "同一幂等语义对应不同载荷")
}

func (h *CTCCRealnameHandler) claimExistingPending(ctx context.Context, log *model.IntegrationLog) (bool, error) {
	if log == nil || log.Result != constants.IntegrationResultPending {
		return false, nil
	}
	return h.integration.ClaimExpiredInboundPending(ctx, log.IntegrationID, constants.IntegrationInboundProcessingLease)
}

func (h *CTCCRealnameHandler) complete(ctx context.Context, integrationID, result string, stateChanged bool, reason string) error {
	_, err := h.integration.Complete(ctx, integrationID, integrationlog.Completion{
		Result: result, HTTPStatus: fiber.StatusOK, StateChanged: stateChanged,
		ResponseSummary: map[string]any{"reason": reason},
	})
	return err
}

func ctccIdempotencyKey(body []byte, translated carriercallback.CTCCRealnameTranslation) string {
	if strings.TrimSpace(translated.GroupTransactionID) != "" {
		return "ctcc-external:" + shortHash(strings.TrimSpace(translated.GroupTransactionID))
	}
	return "ctcc-body:" + shortHashBytes(body)
}

func optionalHashedResourceKey(iccid string) *string {
	if strings.TrimSpace(iccid) == "" {
		return nil
	}
	value := "iccid-sha256:" + shortHash(strings.TrimSpace(iccid))
	return &value
}

func shortHash(value string) string {
	return shortHashBytes([]byte(value))
}

func shortHashBytes(value []byte) string {
	sum := sha256.Sum256(value)
	return hex.EncodeToString(sum[:])[:32]
}

func optionalStringValue(value *string) string {
	if value == nil {
		return ""
	}
	return *value
}

func isAppConflict(err error) bool {
	var appErr *apperrors.AppError
	return stderrors.As(err, &appErr) && appErr.Code == apperrors.CodeConflict
}

func uintString(value uint) string {
	return strconv.FormatUint(uint64(value), 10)
}

type ctccSuccessResponse struct {
	Code      int    `json:"code"`
	Message   string `json:"msg"`
	Timestamp string `json:"timestamp"`
}

func sendCTCCSuccess(c *fiber.Ctx, startedAt time.Time) error {
	body, err := sonic.Marshal(ctccSuccessResponse{Code: 200, Message: "success", Timestamp: startedAt.Format("2006-01-02 15:04:05")})
	if err != nil {
		return apperrors.Wrap(apperrors.CodeInternalError, err, "生成电信回调应答失败")
	}
	c.Type("json", "utf-8")
	return c.Status(fiber.StatusOK).Send(body)
}