package wire

import (
	"crypto/md5"
	"io"
)

// WeakMD5PasswordHash hashes password and authKey for AIM v3.5-v4.7.
//
//goland:noinspection ALL
func WeakMD5PasswordHash(pass, authKey string) []byte {
	hash := md5.New()
	io.WriteString(hash, authKey)
	io.WriteString(hash, pass)
	io.WriteString(hash, "AOL Instant Messenger (SM)")
	return hash.Sum(nil)
}

// StrongMD5PasswordHash hashes password and authKey for AIM v4.8+.
//
//goland:noinspection ALL
func StrongMD5PasswordHash(pass, authKey string) []byte {
	top := md5.New()
	io.WriteString(top, pass)
	bottom := md5.New()
	io.WriteString(bottom, authKey)
	bottom.Write(top.Sum(nil))
	io.WriteString(bottom, "AOL Instant Messenger (SM)")
	return bottom.Sum(nil)
}

// RoastPassword toggles password obfuscation using a roasting algorithm for
// AIM v1.0-v3.0 auth. The first call obfuscates the password, and the second
// call de-obfuscates the password, and so on.
func RoastPassword(roastedPass []byte) []byte {
	var roastTable = [16]byte{
		0xF3, 0x26, 0x81, 0xC4, 0x39, 0x86, 0xDB, 0x92,
		0x71, 0xA3, 0xB9, 0xE6, 0x53, 0x7A, 0x95, 0x7C,
	}
	clearPass := make([]byte, len(roastedPass))
	for i := range roastedPass {
		clearPass[i] = roastedPass[i] ^ roastTable[i%len(roastTable)]
	}
	return clearPass
}