<?php

namespace OCA\Gestion\Helpers;

use DateTime;
use DateTimeZone;
use Exception;

class VCalendarHelpers
{

    public static function GetValueFromKeyInVCalendarString(string $key, string $vCalendarString): string
    {
        $value = "";
        preg_match("/$key:(.*)\r\n/", $vCalendarString, $matches);
        if (isset($matches[1])) {
            $value = trim($matches[1]);
        }
        return $value;
    }

    public static function GetDateStartOrDateEndFromVCalendarString(string $key, string $vCalendarString)
    {
        preg_match("/$key;TZID=([^:]+):(\d+T\d+)/", $vCalendarString, $matches);
        if (!$matches) {
            return null;
        }
        try {
            $dateTz = $matches[1];
            $datetimeString = $matches[2];
            $datetimeValue = new DateTime($datetimeString, new DateTimeZone($dateTz));
            return $datetimeValue;
        } catch (Exception $e) {
            return null;
        }
    }

    public static function GetStartAndEndTimeFromVCalendarString(string $vCalendarString)
    {
        $startTimeValue = "";
        $endTimeValue = "";
        if ($vCalendarString != "") {
            $dateStart = self::GetDateStartOrDateEndFromVCalendarString("DTSTART", $vCalendarString);
            if ($dateStart != null) {
                $startTimeValue = $dateStart->format("H") . "h";
            }
            $dateEnd = self::GetDateStartOrDateEndFromVCalendarString("DTEND", $vCalendarString);
            if ($dateEnd != null) {
                $endTimeValue = $dateEnd->format("H") . "h";
            }
        }
        return [
            "startTime" => $startTimeValue,
            "endTime" => $endTimeValue
        ];
    }

    public static function ReadVCalendarDataBlob($vCalendarData)
    {
        if (is_resource($vCalendarData)) {
            return stream_get_contents($vCalendarData);
        }
        return $vCalendarData;
    }

    public static function hasAttachment(string $vCalendarString): bool
    {
        return str_contains($vCalendarString, 'ATTACH;FMTTYPE');
    }
    public static function extractAttachments(string $vCalendarString): array
    {
        $attachments = [];
        $vCalendarString = preg_replace("/\r\n|\n|\r/", "\n", $vCalendarString);
        $vCalendarString = preg_replace("/\n[ \t]/", "", $vCalendarString); 
        preg_match_all('/ATTACH;FMTTYPE=([^;]+);FILENAME=([^;]+);X-NC-FILE-ID=(\d+)/', $vCalendarString, $matches, PREG_SET_ORDER);
        foreach ($matches as $match) {
            $attachments[] = [
                'type' => explode("/", $match[1])[0],
                'mime_type' => $match[1],
                'name' => trim($match[2], '/'),
                'file_id' => (int) $match[3],
            ];
        }
        return $attachments;
    }

}