package service

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strconv"
	"strings"
	"time"
)

func (s *Service) adminState(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	writeJSON(w, http.StatusOK, s.store.Snapshot())
}

func (s *Service) adminAppIDs(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodPost:
		var cred Credential
		if err := json.NewDecoder(r.Body).Decode(&cred); err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		if cred.AppID == "" || cred.Password == "" {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "appid and password are required"})
			return
		}
		if cred.Name == "" {
			cred.Name = cred.AppID
		}
		cred.Enabled = true
		cred.CreatedAt = time.Now().Format("2006-01-02 15:04:05")
		err := s.store.SaveMutation(func(st *Store) error {
			for i := range st.AppIDs {
				if st.AppIDs[i].AppID == cred.AppID {
					st.AppIDs[i].Password = cred.Password
					st.AppIDs[i].Name = cred.Name
					st.AppIDs[i].Enabled = cred.Enabled
					st.AppIDs[i].LastToken = ""
					st.AppIDs[i].TokenExpires = ""
					delete(st.Tokens, cred.AppID)
					return nil
				}
			}
			st.AppIDs = append(st.AppIDs, cred)
			return nil
		})
		if err != nil {
			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
			return
		}
		writeJSON(w, http.StatusOK, s.store.Snapshot())
	case http.MethodDelete:
		appid := r.URL.Query().Get("appid")
		_ = s.store.SaveMutation(func(st *Store) error {
			next := st.AppIDs[:0]
			for _, c := range st.AppIDs {
				if c.AppID != appid {
					next = append(next, c)
				}
			}
			st.AppIDs = next
			delete(st.Tokens, appid)
			return nil
		})
		writeJSON(w, http.StatusOK, s.store.Snapshot())
	default:
		w.WriteHeader(http.StatusMethodNotAllowed)
	}
}

func (s *Service) adminCards(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		page, pageSize := pagination(r)
		filter, err := cardFilterFromRequest(r)
		if err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		writeJSON(w, http.StatusOK, s.store.QueryCardsByGroup(filter.keyword, filter.exportStatus, filter.groupID, filter.filterGroup, page, pageSize))
	case http.MethodPost:
		var card SIMCard
		if err := json.NewDecoder(r.Body).Decode(&card); err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		normalizeCard(&card)
		err := s.store.SaveMutation(func(st *Store) error {
			for i := range st.Cards {
				if st.Cards[i].MSISDN == card.MSISDN {
					st.Cards[i] = card
					return nil
				}
			}
			st.Cards = append(st.Cards, card)
			return nil
		})
		if err != nil {
			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
			return
		}
		writeJSON(w, http.StatusOK, s.store.Snapshot())
	case http.MethodDelete:
		msisdn := r.URL.Query().Get("msisdn")
		_ = s.store.SaveMutation(func(st *Store) error {
			next := st.Cards[:0]
			for _, c := range st.Cards {
				if c.MSISDN != msisdn {
					next = append(next, c)
				}
			}
			st.Cards = next
			return nil
		})
		writeJSON(w, http.StatusOK, s.store.Snapshot())
	default:
		w.WriteHeader(http.StatusMethodNotAllowed)
	}
}

func (s *Service) adminCardGroups(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		st := s.store.Snapshot()
		counts := map[int64]int{}
		for _, card := range st.Cards {
			counts[card.GroupID]++
		}
		for i := range st.Groups {
			st.Groups[i].CardCount = counts[st.Groups[i].ID]
		}
		writeJSON(w, http.StatusOK, st.Groups)
	case http.MethodPost:
		var input struct {
			Name string `json:"name"`
		}
		if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		input.Name = strings.TrimSpace(input.Name)
		if input.Name == "" {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "group name is required"})
			return
		}
		var created CardGroup
		err := s.store.SaveMutation(func(st *Store) error {
			for _, group := range st.Groups {
				if strings.EqualFold(group.Name, input.Name) {
					return fmt.Errorf("group name already exists")
				}
			}
			id := int64(1)
			for _, group := range st.Groups {
				if group.ID >= id {
					id = group.ID + 1
				}
			}
			now := time.Now().Format("2006-01-02 15:04:05")
			created = CardGroup{ID: id, Name: input.Name, CreatedAt: now, UpdatedAt: now}
			st.Groups = append(st.Groups, created)
			return nil
		})
		if err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		writeJSON(w, http.StatusOK, created)
	case http.MethodDelete:
		id, err := strconv.ParseInt(r.URL.Query().Get("id"), 10, 64)
		if err != nil || id <= 0 {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": "invalid group id"})
			return
		}
		err = s.store.SaveMutation(func(st *Store) error {
			found := false
			next := st.Groups[:0]
			for _, group := range st.Groups {
				if group.ID == id {
					found = true
				} else {
					next = append(next, group)
				}
			}
			if !found {
				return fmt.Errorf("card group not found")
			}
			st.Groups = next
			for i := range st.Cards {
				if st.Cards[i].GroupID == id {
					st.Cards[i].GroupID = 0
					st.Cards[i].GroupName = ""
				}
			}
			return nil
		})
		if err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		writeJSON(w, http.StatusOK, s.store.Snapshot())
	default:
		w.WriteHeader(http.StatusMethodNotAllowed)
	}
}

func (s *Service) adminSettings(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	var settings SimulationSettings
	if err := json.NewDecoder(r.Body).Decode(&settings); err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
		return
	}
	_ = s.store.SaveMutation(func(st *Store) error {
		st.Settings = settings
		return nil
	})
	writeJSON(w, http.StatusOK, s.store.Snapshot())
}

func (s *Service) adminOrders(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodGet {
		page, pageSize := pagination(r)
		writeJSON(w, http.StatusOK, s.store.QueryOrders(page, pageSize))
		return
	}
	if r.Method != http.MethodDelete {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	_ = s.store.SaveMutation(func(st *Store) error {
		st.Orders = []Order{}
		return nil
	})
	writeJSON(w, http.StatusOK, s.store.Snapshot())
}

func pagination(r *http.Request) (int, int) {
	page, _ := strconv.Atoi(r.URL.Query().Get("page"))
	pageSize, _ := strconv.Atoi(r.URL.Query().Get("pageSize"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	return page, pageSize
}

type cardFilter struct {
	keyword      string
	exportStatus string
	groupID      int64
	filterGroup  bool
}

func cardFilterFromRequest(r *http.Request) (cardFilter, error) {
	filter := cardFilter{
		keyword:      r.URL.Query().Get("keyword"),
		exportStatus: strings.TrimSpace(r.URL.Query().Get("exportStatus")),
	}
	if filter.exportStatus != "" && filter.exportStatus != "exported" && filter.exportStatus != "not_exported" {
		return cardFilter{}, fmt.Errorf("invalid export status")
	}
	groupRaw := strings.TrimSpace(r.URL.Query().Get("groupId"))
	if groupRaw == "" {
		return filter, nil
	}
	groupID, err := strconv.ParseInt(groupRaw, 10, 64)
	if err != nil || groupID < 0 {
		return cardFilter{}, fmt.Errorf("invalid group id")
	}
	filter.groupID = groupID
	filter.filterGroup = true
	return filter, nil
}

func (s *Service) adminGenerate(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	count, groupID, err := generationRequest(r)
	if err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
		return
	}
	result, err := s.store.GenerateCardsInGroup(count, groupID)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
		return
	}
	writeJSON(w, http.StatusOK, result)
}

func (s *Service) adminSync(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	count, _, err := generationRequest(r)
	if err != nil {
		writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
		return
	}
	result, err := s.store.GenerateCards(count)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
		return
	}
	writeJSON(w, http.StatusOK, result)
}

func (s *Service) adminCardsExport(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodGet {
		w.WriteHeader(http.StatusMethodNotAllowed)
		return
	}
	var cards []SIMCard
	if r.URL.Query().Get("selection") == "filtered" {
		filter, err := cardFilterFromRequest(r)
		if err != nil {
			writeJSON(w, http.StatusBadRequest, map[string]string{"error": err.Error()})
			return
		}
		cards = s.store.QueryAllCardsByGroup(filter.keyword, filter.exportStatus, filter.groupID, filter.filterGroup)
	} else {
		cards = exportCardsByMSISDN(s.store.Snapshot().Cards, r.URL.Query().Get("msisdns"))
	}
	raw, err := exportInboundCardsXLSX(cards)
	if err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
		return
	}
	exportedAt := time.Now().Format("2006-01-02 15:04:05")
	exportedMSISDNs := make(map[string]struct{}, len(cards))
	for _, card := range cards {
		exportedMSISDNs[card.MSISDN] = struct{}{}
	}
	if err := s.store.SaveMutation(func(st *Store) error {
		for i := range st.Cards {
			if _, ok := exportedMSISDNs[st.Cards[i].MSISDN]; ok {
				st.Cards[i].Exported = true
				st.Cards[i].ExportCheckedAt = exportedAt
			}
		}
		return nil
	}); err != nil {
		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
		return
	}
	w.Header().Set("Content-Type", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
	w.Header().Set("Content-Disposition", `attachment; filename="sim_card_export.xlsx"`)
	w.WriteHeader(http.StatusOK)
	_, _ = w.Write(raw)
}

func exportCardsByMSISDN(cards []SIMCard, rawMSISDNs string) []SIMCard {
	rawMSISDNs = strings.TrimSpace(rawMSISDNs)
	if rawMSISDNs == "" {
		return cards
	}
	selected := map[string]bool{}
	for _, item := range strings.FieldsFunc(rawMSISDNs, func(r rune) bool {
		return r == ',' || r == '_' || r == ' '
	}) {
		item = strings.TrimSpace(item)
		if item != "" {
			selected[item] = true
		}
	}
	if len(selected) == 0 {
		return cards
	}
	out := make([]SIMCard, 0, len(selected))
	for _, card := range cards {
		if selected[card.MSISDN] {
			out = append(out, card)
		}
	}
	return out
}

func generationCount(r *http.Request) (int, error) {
	count := 100
	if r.Body != nil {
		var payload struct {
			Count int `json:"count"`
		}
		if err := json.NewDecoder(r.Body).Decode(&payload); err == nil && payload.Count > 0 {
			count = payload.Count
		}
	}
	if value := r.URL.Query().Get("count"); value != "" {
		parsed, err := strconv.Atoi(value)
		if err != nil {
			return 0, err
		}
		count = parsed
	}
	if count <= 0 {
		return 0, strconv.ErrSyntax
	}
	return count, nil
}

func generationRequest(r *http.Request) (int, int64, error) {
	var input struct {
		Count   int    `json:"count"`
		GroupID *int64 `json:"groupId"`
	}
	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
		if err == io.EOF {
			count, countErr := generationCount(r)
			return count, 0, countErr
		}
		return 0, 0, err
	}
	if input.Count <= 0 {
		return 0, 0, fmt.Errorf("count must be greater than 0")
	}
	if input.GroupID == nil || *input.GroupID < 0 {
		return input.Count, 0, nil
	}
	return input.Count, *input.GroupID, nil
}

func normalizeCard(card *SIMCard) {
	now := time.Now()
	card.MSISDN = strings.TrimSpace(card.MSISDN)
	card.ICCID = strings.TrimSpace(card.ICCID)
	card.IMSI = strings.TrimSpace(card.IMSI)
	if card.CardStatus == "" {
		card.CardStatus = "2"
	}
	if card.StopReason == "" {
		card.StopReason = defaultStopReason(card.CardStatus)
	}
	if card.FrozenStatus == "" {
		card.FrozenStatus = "0"
	}
	if card.FrozenOperTime == "" {
		card.FrozenOperTime = diagnosticTime(now)
	}
	if card.LastChangeDate == "" {
		card.LastChangeDate = now.Format("2006-01-02 15:04:05")
	}
	if card.OpenDate == "" {
		card.OpenDate = now.Format("2006-01-02 15:04:05")
	}
	if card.ActiveDate == "" {
		card.ActiveDate = now.Format("2006-01-02 15:04:05")
	}
	if card.OnOffStatus == "" {
		card.OnOffStatus = "1"
	}
	if card.SessionStatus == "" {
		card.SessionStatus = "01"
	}
	if card.SessionStatus != "00" && card.SessionStatus != "01" {
		card.SessionStatus = "00"
	}
	if card.SessionCreateDate == "" {
		card.SessionCreateDate = card.LastChangeDate
	}
	if card.SessionCreateDate == "" {
		card.SessionCreateDate = card.LastChangeDate
	}
	if card.RAT == "" {
		card.RAT = "6"
	}
	if card.CardBindStatus == "" {
		card.CardBindStatus = "1"
	}
	if card.RegionLimitStatus == "" {
		card.RegionLimitStatus = "0"
	}
	if card.AreaRestrictType == "" {
		card.AreaRestrictType = "1"
	}
	if card.RestrictedArea == "" {
		card.RestrictedArea = "200"
	}
	if card.LastUsageUpdateTime == "" {
		card.LastUsageUpdateTime = now.Format(time.RFC3339)
	}
	card.GrowthPerMinuteKB = 0
	if len(card.APNs) == 0 {
		card.APNs = []APN{{Name: "CMIOT", Status: "1", UsageBytes: card.MonthUsageKB * 1024}}
	}
	for i := range card.APNs {
		apn := &card.APNs[i]
		if apn.Name == "" {
			apn.Name = "CMIOT"
		}
		if apn.Status == "" {
			apn.Status = "1"
		}
		if apn.DiagnosisStatus == "" {
			apn.DiagnosisStatus = diagnosisStatus(apn.Status)
		}
		if apn.ModifyTime == "" {
			apn.ModifyTime = diagnosticTime(now)
		}
		if apn.ServiceUsageState == "" {
			apn.ServiceUsageState = "1"
		}
		if len(apn.PCCs) == 0 {
			apn.PCCs = []PCC{{ServiceCode: "default", Name: "APN 缺省流量", PolicyStatus: "2", ServiceUsageState: "1", ModifyTime: apn.ModifyTime}}
		}
		for j := range apn.PCCs {
			if apn.PCCs[j].ServiceCode == "" {
				apn.PCCs[j].ServiceCode = "default"
			}
			if apn.PCCs[j].Name == "" {
				apn.PCCs[j].Name = "APN 缺省流量"
			}
			if apn.PCCs[j].PolicyStatus == "" {
				apn.PCCs[j].PolicyStatus = "2"
			}
			if apn.PCCs[j].ServiceUsageState == "" {
				apn.PCCs[j].ServiceUsageState = "1"
			}
			if apn.PCCs[j].ModifyTime == "" {
				apn.PCCs[j].ModifyTime = apn.ModifyTime
			}
		}
	}
}

func diagnosticTime(value time.Time) string { return value.Format("20060102150405") }

func defaultStopReason(cardStatus string) string {
	if cardStatus == "4" {
		return "000020000000"
	}
	return "000000000000"
}

func diagnosisStatus(status string) string {
	switch status {
	case "0":
		return "4"
	case "1":
		return "2"
	default:
		return status
	}
}