//Calendar implementation for the HTWK Leipzig timetable. Evaluation and display of the individual dates in iCal format.
//Copyright (C) 2024 HTWKalender support@htwkalender.de

//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 <https://www.gnu.org/licenses/>.

package functions

import (
	"crypto/sha256"
	"encoding/hex"
	"strings"
)

// check if string is empty or contains only whitespaces
func OnlyWhitespace(word string) bool {
	return len(strings.TrimSpace(word)) == 0
}

// return function to check if rune is a separator
func IsSeparator(separator []rune) func(rune) bool {
	return func(character rune) bool {
		for _, sep := range separator {
			if sep == character {
				return true
			}
		}
		return false
	}
}

func Contains(s []string, e string) bool {
	for _, a := range s {
		if a == e {
			return true
		}
	}
	return false
}

func ReplaceEmptyString(word string, replacement string) string {
	if OnlyWhitespace(word) {
		return replacement
	}
	return word
}

func HashString(s string) string {
	hash := sha256.New()
	hash.Write([]byte(s))
	hashInBytes := hash.Sum(nil)
	return hex.EncodeToString(hashInBytes)
}

func SeperateRoomString(rooms string) []string {
	return strings.FieldsFunc(rooms, IsSeparator(
		[]rune{',', '\t', '\n', '\r', ';', ' ', '\u00A0'}),
	)
}