package lishwist

import (
	"fmt"

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

type ErrorInvalidCredentials error

func Login(username, password string) (*Session, error) {
	user, err := getUserByName(username)
	if err != nil {
		return nil, ErrorInvalidCredentials(fmt.Errorf("Failed to fetch user: %w", err))
	}
	if user == nil {
		return nil, ErrorInvalidCredentials(fmt.Errorf("User not found by name: %s", username))
	}

	passHash, err := user.getPassHash()
	if err != nil {
		return nil, fmt.Errorf("Failed to get password hash: %w", err)
	}

	err = bcrypt.CompareHashAndPassword(passHash, []byte(password))
	if err != nil {
		return nil, ErrorInvalidCredentials(fmt.Errorf("Password compare failed: %w", err))
	}

	return &Session{*user}, nil
}