package auth

import (
	"addrss/pkg/repo"
	"fmt"
	"math/rand"
	"time"

	"golang.org/x/crypto/bcrypt"
)

type NewPassword struct {
	Password string `json:"-"`
	Hash     string `json:"-"`
}

type PasswordChange struct {
	UserId          int64  `json:"userId"`
	OldPassword     string `json:"oldPassword"`
	NewPassword     string `json:"newPassword"`
	ConfirmPassword string `json:"confirmPassword"`
}

func ChangePassword(pc PasswordChange) error {
	u, err := repo.GetUserById(pc.UserId)
	if err != nil {
		return fmt.Errorf("could not get user for user id %d: %v", pc.UserId, err)
	}

	if err = bcrypt.CompareHashAndPassword([]byte(u.Password), []byte(pc.OldPassword)); err != nil {
		return fmt.Errorf("incorrect password for user id %d", pc.UserId)
	}

	h, err := bcrypt.GenerateFromPassword([]byte(pc.NewPassword), bcrypt.DefaultCost)
	if err != nil {
		return fmt.Errorf("bcrypt error: %v", err)
	}

	u.Password = string(h)
	if err = repo.UpdateUserPassword(u); err != nil {
		return fmt.Errorf("failed to update password for user id %d: %v", u.Id, err)
	}

	return nil
}

func GetRandomPassword(length int) (NewPassword, error) {
	p := GetRandomString(length)

	h, err := bcrypt.GenerateFromPassword([]byte(p), bcrypt.DefaultCost)
	if err != nil {
		return NewPassword{}, err
	}

	np := NewPassword{
		Password: p,
		Hash:     string(h),
	}

	return np, nil
}

// GetRandomString Keep as a separate function in case this becomes useful for some other purpose
func GetRandomString(length int) string {
	const chars = "!@#$%?abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))

	b := make([]byte, length)
	for i := range b {
		b[i] = chars[rnd.Intn(len(chars))]
	}

	return string(b)
}