package routes

import (
	"bssapp-backend/models"
	"bssapp-backend/queries"
	"database/sql"
	"encoding/json"
	"net/http"
	"sort"
	"strconv"
	"strings"

	"github.com/gorilla/mux"
)

type MarketMailSavePayload struct {
	MailIDs []string `json:"mail_ids"`
}

type MarketMailLookupResponse struct {
	Markets []models.MarketOption `json:"markets"`
	Mails   []models.MailOption   `json:"mails"`
}

func GetMarketMailMappingLookupsHandler(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		markets := make([]models.MarketOption, 0, 64)
		mails := make([]models.MailOption, 0, 128)

		marketRows, err := db.Query(queries.GetActiveMarketsForMapping)
		if err != nil {
			http.Error(w, "markets lookup error", http.StatusInternalServerError)
			return
		}
		defer marketRows.Close()

		for marketRows.Next() {
			var item models.MarketOption
			if err := marketRows.Scan(&item.ID, &item.Code, &item.Title); err != nil {
				http.Error(w, "markets scan error", http.StatusInternalServerError)
				return
			}
			markets = append(markets, item)
		}
		if err := marketRows.Err(); err != nil {
			http.Error(w, "markets rows error", http.StatusInternalServerError)
			return
		}

		mailRows, err := db.Query(queries.GetActiveMailsForMapping)
		if err != nil {
			http.Error(w, "mails lookup error", http.StatusInternalServerError)
			return
		}
		defer mailRows.Close()

		for mailRows.Next() {
			var item models.MailOption
			if err := mailRows.Scan(&item.ID, &item.Email, &item.DisplayName); err != nil {
				http.Error(w, "mails scan error", http.StatusInternalServerError)
				return
			}
			mails = append(mails, item)
		}
		if err := mailRows.Err(); err != nil {
			http.Error(w, "mails rows error", http.StatusInternalServerError)
			return
		}

		_ = json.NewEncoder(w).Encode(MarketMailLookupResponse{
			Markets: markets,
			Mails:   mails,
		})
	}
}

func GetMarketMailMappingsHandler(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		rows, err := db.Query(queries.GetMarketMailMappingRows)
		if err != nil {
			http.Error(w, "mapping query error", http.StatusInternalServerError)
			return
		}
		defer rows.Close()

		byMarket := make(map[int64]*models.MarketMailMappingRow, 64)
		order := make([]int64, 0, 64)

		for rows.Next() {
			var marketID int64
			var marketCode, marketTitle string
			var mailID sql.NullString
			var email sql.NullString
			var displayName sql.NullString

			if err := rows.Scan(
				&marketID,
				&marketCode,
				&marketTitle,
				&mailID,
				&email,
				&displayName,
			); err != nil {
				http.Error(w, "mapping scan error", http.StatusInternalServerError)
				return
			}

			row, ok := byMarket[marketID]
			if !ok {
				row = &models.MarketMailMappingRow{
					MarketID:    marketID,
					MarketCode:  marketCode,
					MarketTitle: marketTitle,
					MailIDs:     make([]string, 0, 8),
					Mails:       make([]models.MarketMailOption, 0, 8),
				}
				byMarket[marketID] = row
				order = append(order, marketID)
			}

			if mailID.Valid && strings.TrimSpace(mailID.String) != "" {
				id := strings.TrimSpace(mailID.String)
				row.MailIDs = append(row.MailIDs, id)

				label := strings.TrimSpace(displayName.String)
				if label == "" {
					label = strings.TrimSpace(email.String)
				}

				row.Mails = append(row.Mails, models.MarketMailOption{
					ID:    id,
					Label: label,
				})
			}
		}
		if err := rows.Err(); err != nil {
			http.Error(w, "mapping rows error", http.StatusInternalServerError)
			return
		}

		list := make([]models.MarketMailMappingRow, 0, len(order))
		for _, marketID := range order {
			list = append(list, *byMarket[marketID])
		}

		_ = json.NewEncoder(w).Encode(list)
	}
}

func SaveMarketMailMappingHandler(db *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		marketIDStr := mux.Vars(r)["marketId"]
		marketID, err := strconv.ParseInt(marketIDStr, 10, 64)
		if err != nil || marketID <= 0 {
			http.Error(w, "invalid market id", http.StatusBadRequest)
			return
		}

		var payload MarketMailSavePayload
		if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
			http.Error(w, "invalid payload", http.StatusBadRequest)
			return
		}

		var marketExists bool
		if err := db.QueryRow(queries.ExistsActiveMarketByID, marketID).Scan(&marketExists); err != nil {
			http.Error(w, "market validate error", http.StatusInternalServerError)
			return
		}
		if !marketExists {
			http.Error(w, "market not found", http.StatusNotFound)
			return
		}

		mailIDs := normalizeIDList(payload.MailIDs)
		for _, mailID := range mailIDs {
			var mailExists bool
			if err := db.QueryRow(queries.ExistsActiveMailByID, mailID).Scan(&mailExists); err != nil {
				http.Error(w, "mail validate error", http.StatusInternalServerError)
				return
			}
			if !mailExists {
				http.Error(w, "mail not found: "+mailID, http.StatusBadRequest)
				return
			}
		}

		tx, err := db.Begin()
		if err != nil {
			http.Error(w, "transaction start error", http.StatusInternalServerError)
			return
		}
		defer tx.Rollback()

		if _, err := tx.Exec(queries.DeleteMarketMailsByMarketID, marketID); err != nil {
			http.Error(w, "mapping delete error", http.StatusInternalServerError)
			return
		}

		for _, mailID := range mailIDs {
			if _, err := tx.Exec(queries.InsertMarketMailMapping, marketID, mailID); err != nil {
				http.Error(w, "mapping insert error", http.StatusInternalServerError)
				return
			}
		}

		if err := tx.Commit(); err != nil {
			http.Error(w, "transaction commit error", http.StatusInternalServerError)
			return
		}

		_ = json.NewEncoder(w).Encode(map[string]any{
			"success":   true,
			"market_id": marketID,
			"mail_ids":  mailIDs,
		})
	}
}

func normalizeIDList(ids []string) []string {
	seen := make(map[string]struct{}, len(ids))
	out := make([]string, 0, len(ids))

	for _, raw := range ids {
		id := strings.TrimSpace(raw)
		if id == "" {
			continue
		}
		if _, ok := seen[id]; ok {
			continue
		}
		seen[id] = struct{}{}
		out = append(out, id)
	}

	sort.Strings(out)
	return out
}