package service

import (
	"Portifolio/internal/model"
	"database/sql"
	"encoding/json"
	"net/http"

	_ "github.com/mattn/go-sqlite3"
)

type Service struct {
	db *sql.DB
}

func (s *Service) AddCurrencyHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var input model.CurrencyInput
		if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
			http.Error(w, "invalid json", http.StatusBadRequest)
			return
		}

		id, err := s.InsertCurrency(input)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(http.StatusCreated)
		json.NewEncoder(w).Encode(map[string]any{"status": "created", "id": id})
	}
}

func (s *Service) GetCurrenciesHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		currencies, err := s.GetAllCurrencies()
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

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

func (s *Service) InsertCurrency(input model.CurrencyInput) (int, error) {
	res, err := s.db.Exec(
		`INSERT INTO currencies (code, name) VALUES (?, ?)`,
		input.Code, input.Name,
	)
	if err != nil {
		return 0, err
	}
	id, err := res.LastInsertId()
	return int(id), err
}

func (s *Service) GetCurrencyByCode(code string) (*model.Currency, error) {
	c := &model.Currency{}
	err := s.db.QueryRow(
		`SELECT id, code, name FROM currencies WHERE code = ?`, code,
	).Scan(&c.ID, &c.Code, &c.Name)
	if err == sql.ErrNoRows {
		return nil, nil
	}
	return c, err
}

func (s *Service) GetAllCurrencies() ([]model.Currency, error) {
	rows, err := s.db.Query(`SELECT id, code, name FROM currencies ORDER BY code`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var currencies []model.Currency
	for rows.Next() {
		var c model.Currency
		if err := rows.Scan(&c.ID, &c.Code, &c.Name); err != nil {
			return nil, err
		}
		currencies = append(currencies, c)
	}
	return currencies, rows.Err()
}