package lib

import (
	"time"

	"github.com/google/uuid"
	"golang.org/x/crypto/bcrypt"
)

type User struct {
	ID           int
	Username     string
	PasswordHash string
}

// hash password
func HashPassword(password string) (string, error) {
	bytes, err := bcrypt.GenerateFromPassword([]byte(password), 14)
	return string(bytes), err
}

// check password
func CheckPasswordHash(password, hash string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
	return err == nil
}

// create new user
func CreateUser(username, password string) error {
	hash, err := HashPassword(password)
	if err != nil {
		return err
	}
	_, err = DB.Exec("INSERT INTO users (username, password_hash) VALUES (?, ?)", username, hash)
	return err
}

// get user by name
func GetUserByUsername(username string) (*User, error) {
	row := DB.QueryRow("SELECT id, username, password_hash FROM users WHERE username = ?", username)
	u := &User{}
	err := row.Scan(&u.ID, &u.Username, &u.PasswordHash)
	if err != nil {
		return nil, err
	}
	return u, nil
}

// create session token
func CreateSession(userID int) (string, error) {
	sessionID := uuid.New().String()
	expiresAt := time.Now().Add(24 * time.Hour)

	_, err := DB.Exec("INSERT INTO sessions (id, user_id, expires_at) VALUES (?, ?, ?)", sessionID, userID, expiresAt)
	if err != nil {
		return "", err
	}
	return sessionID, nil
}

// get user from session
func GetUserFromSession(sessionID string) (*User, error) {
	row := DB.QueryRow(`
		SELECT u.id, u.username, u.password_hash
		FROM users u
		JOIN sessions s ON u.id = s.user_id
		WHERE s.id = ? AND s.expires_at > ?
	`, sessionID, time.Now())

	u := &User{}
	err := row.Scan(&u.ID, &u.Username, &u.PasswordHash)
	if err != nil {
		return nil, err
	}
	return u, nil
}

// delete session
func DeleteSession(sessionID string) error {
	_, err := DB.Exec("DELETE FROM sessions WHERE id = ?", sessionID)
	return err
}