/*
	Copyright (C) 2024  Pagefault Games

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Affero General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Affero General Public License for more details.

	You should have received a copy of the GNU Affero General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package api

import (
	"hash/crc32"
	"math"
)

func CheckFeatureFlagEnabled(accountId []byte, flag string, percent int) bool {
	if percent <= 0 {
		return false
	} else if percent >= 100 {
		return true
	}

	pct := math.Max(0, math.Min(100, float64(percent)))
	flagBytes := []byte(flag)

	// hash key is [...accountId, ...flagBytes]
	hashKey := make([]byte, len(accountId)+len(flagBytes))
	copy(hashKey, accountId)
	copy(hashKey[len(accountId):], flagBytes)

	boundary := float64(math.MaxUint32) * (pct / float64(100))
	hash := float64(crc32.ChecksumIEEE(hashKey))

	return hash >= boundary
}