package auth

import (
	"crypto/subtle"
	"encoding/base64"
	"fmt"
	"strings"

	"golang.org/x/crypto/argon2"
)

func VerifyPassword(hashedPassword, password string) bool {
	// Parse the Argon2 hash format: $argon2id$v=19$m=65536,t=3,p=4$salt$hash
	parts := strings.Split(hashedPassword, "$")
	if len(parts) != 6 {
		return false
	}

	// Extract parameters
	var memory, time, threads uint32
	var version int

	fmt.Sscanf(parts[2], "v=%d", &version)
	fmt.Sscanf(parts[3], "m=%d,t=%d,p=%d", &memory, &time, &threads)

	salt, err := base64.RawStdEncoding.DecodeString(parts[4])
	if err != nil {
		return false
	}

	hash, err := base64.RawStdEncoding.DecodeString(parts[5])
	if err != nil {
		return false
	}

	// Generate hash with the same parameters
	derivedKey := argon2.IDKey([]byte(password), salt, time, memory, uint8(threads), uint32(len(hash)))

	// Compare hashes using constant time comparison
	return subtle.ConstantTimeCompare(hash, derivedKey) == 1
}