package admin

import (
	"crussell/db"
	"encoding/json"
	"log"
	"net/http"
	"strconv"
)

type BusinessSettings struct {
	BusinessName          string   `json:"business_name"`
	BusinessAddress       string   `json:"business_address"`
	BusinessPhone         *string  `json:"business_phone,omitempty"`
	BusinessEmail         *string  `json:"business_email,omitempty"`
	VATRegistrationNumber *string  `json:"vat_registration_number,omitempty"`
	IsVATRegistered       bool     `json:"is_vat_registered"`
	DefaultVATRate        float64  `json:"default_vat_rate"`
	CurrencyCode          string   `json:"currency_code"`
	WebsiteURL            *string  `json:"website_url,omitempty"`
	GiftCardExpiryMonths  int      `json:"gift_card_expiry_months"`
	VoucherType           string   `json:"voucher_type"`
}

func GetBusinessSettings(w http.ResponseWriter, r *http.Request) {
	var s BusinessSettings
	err := db.DB.QueryRow(r.Context(), `
		SELECT business_name, business_address, business_phone, business_email,
		       vat_registration_number, is_vat_registered, default_vat_rate,
		       currency_code, website_url, gift_card_expiry_months, voucher_type
		FROM business_settings
		LIMIT 1
	`).Scan(
		&s.BusinessName, &s.BusinessAddress, &s.BusinessPhone, &s.BusinessEmail,
		&s.VATRegistrationNumber, &s.IsVATRegistered, &s.DefaultVATRate,
		&s.CurrencyCode, &s.WebsiteURL, &s.GiftCardExpiryMonths, &s.VoucherType,
	)
	if err != nil {
		log.Printf("Failed to fetch business settings: %v", err)
		http.Error(w, "Failed to fetch settings", http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(s)
}

type UpdateBusinessSettingsRequest struct {
	BusinessName          *string  `json:"business_name,omitempty"`
	BusinessAddress       *string  `json:"business_address,omitempty"`
	BusinessPhone         *string  `json:"business_phone,omitempty"`
	BusinessEmail         *string  `json:"business_email,omitempty"`
	VATRegistrationNumber *string  `json:"vat_registration_number,omitempty"`
	IsVATRegistered       *bool    `json:"is_vat_registered,omitempty"`
	DefaultVATRate        *float64 `json:"default_vat_rate,omitempty"`
	WebsiteURL            *string  `json:"website_url,omitempty"`
	GiftCardExpiryMonths  *int     `json:"gift_card_expiry_months,omitempty"`
	VoucherType           *string  `json:"voucher_type,omitempty"`
}

func UpdateBusinessSettings(w http.ResponseWriter, r *http.Request) {
	var req UpdateBusinessSettingsRequest
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Invalid request body", http.StatusBadRequest)
		return
	}

	if req.VoucherType != nil && *req.VoucherType != "SPV" && *req.VoucherType != "MPV" {
		http.Error(w, "voucher_type must be 'SPV' or 'MPV'", http.StatusBadRequest)
		return
	}

	if req.GiftCardExpiryMonths != nil && *req.GiftCardExpiryMonths < 1 {
		http.Error(w, "gift_card_expiry_months must be at least 1", http.StatusBadRequest)
		return
	}

	if req.DefaultVATRate != nil && (*req.DefaultVATRate < 0 || *req.DefaultVATRate > 100) {
		http.Error(w, "default_vat_rate must be between 0 and 100", http.StatusBadRequest)
		return
	}

	setClauses := []string{}
	args := []interface{}{}
	argIdx := 1

	if req.BusinessName != nil {
		setClauses = append(setClauses, "business_name = $"+strconv.Itoa(argIdx))
		args = append(args, *req.BusinessName)
		argIdx++
	}
	if req.BusinessAddress != nil {
		setClauses = append(setClauses, "business_address = $"+strconv.Itoa(argIdx))
		args = append(args, *req.BusinessAddress)
		argIdx++
	}
	if req.BusinessPhone != nil {
		setClauses = append(setClauses, "business_phone = $"+strconv.Itoa(argIdx))
		args = append(args, *req.BusinessPhone)
		argIdx++
	}
	if req.BusinessEmail != nil {
		setClauses = append(setClauses, "business_email = $"+strconv.Itoa(argIdx))
		args = append(args, *req.BusinessEmail)
		argIdx++
	}
	if req.VATRegistrationNumber != nil {
		setClauses = append(setClauses, "vat_registration_number = $"+strconv.Itoa(argIdx))
		args = append(args, *req.VATRegistrationNumber)
		argIdx++
	}
	if req.IsVATRegistered != nil {
		setClauses = append(setClauses, "is_vat_registered = $"+strconv.Itoa(argIdx))
		args = append(args, *req.IsVATRegistered)
		argIdx++
	}
	if req.DefaultVATRate != nil {
		setClauses = append(setClauses, "default_vat_rate = $"+strconv.Itoa(argIdx))
		args = append(args, *req.DefaultVATRate)
		argIdx++
	}
	if req.WebsiteURL != nil {
		setClauses = append(setClauses, "website_url = $"+strconv.Itoa(argIdx))
		args = append(args, *req.WebsiteURL)
		argIdx++
	}
	if req.GiftCardExpiryMonths != nil {
		setClauses = append(setClauses, "gift_card_expiry_months = $"+strconv.Itoa(argIdx))
		args = append(args, *req.GiftCardExpiryMonths)
		argIdx++
	}
	if req.VoucherType != nil {
		setClauses = append(setClauses, "voucher_type = $"+strconv.Itoa(argIdx))
		args = append(args, *req.VoucherType)
		argIdx++
	}

	if len(setClauses) == 0 {
		http.Error(w, "No fields to update", http.StatusBadRequest)
		return
	}

	query := "UPDATE business_settings SET "
	for i, clause := range setClauses {
		if i > 0 {
			query += ", "
		}
		query += clause
	}

	_, err := db.DB.Exec(r.Context(), query, args...)
	if err != nil {
		log.Printf("Failed to update business settings: %v", err)
		http.Error(w, "Failed to update settings", http.StatusInternalServerError)
		return
	}

	GetBusinessSettings(w, r)
}