package user

import (
	"bytes"
	"image"
	_ "image/jpeg"
	_ "image/png"
	"log/slog"
	"regexp"
	"strings"
)

type Validator struct {
	emailRegex *regexp.Regexp
	loginRegex *regexp.Regexp
}

func NewValidator() (*Validator, error) {
	emailRegexp := regexp.MustCompile(`^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$`)
	loginRegex := regexp.MustCompile(`^[a-zA-Z0-9_-]+$`)

	return &Validator{emailRegex: emailRegexp, loginRegex: loginRegex}, nil
}

func (v *Validator) VerifyEmail(email string) bool {
	if len(email) < 3 || len(email) > 254 {
		return false
	}

	return v.emailRegex.MatchString(email)
}

func (v *Validator) VerifyLogin(login string) bool {
	username := strings.TrimSpace(login)
	if len(username) < 3 || len(username) > 30 {
		return false
	}
	if !v.loginRegex.MatchString(username) {
		return false
	}

	return true
}

func (v *Validator) VerifyPassword(password string) bool {
	if len(password) < 8 || len(password) > 72 {
		return false
	}
	return true
}

func (v *Validator) VerifyImage(data []byte) error {
	r := bytes.NewReader(data)
	cfg, format, err := image.DecodeConfig(r)
	if err != nil {
		slog.Error("decode image config", slog.String("op", "validator.VerifyImage"), slog.Any("error", err))
		return err
	}

	switch format {
	case "jpeg", "png":
	default:
		return ErrUnsupportedFormat
	}

	if cfg.Width > MaxImageWidth || cfg.Height > MaxImageHeight {
		return ErrExceedDimensions
	}

	return nil
}