<?php
/*
    praktrack - tracking the parts of a portfolio review
    Copyright (C) 2026  Friedrich Beckmann <friedrich.beckmann@tha.de>

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

function db_student_new($matrikelnummer,$student) {
    date_default_timezone_set("UTC");
    $json_student_add = array (
        "time" => date('Y-m-d H:i:s', time()),
        "cmd" => "student_new",
        "matrikelnummer" => $matrikelnummer,
        "vorname" => $student["vorname"],
        "nachname" => $student["nachname"],
        "noten" => $student["noten"]
    );
    $json_string = json_encode($json_student_add, JSON_UNESCAPED_UNICODE)."\n";
    $fh = fopen("database.json", "a");
    fwrite($fh,$json_string);
    fclose($fh);

    //echo $json_string;
}

function db_student_add_fach($matrikelnummer,$fach) {
    date_default_timezone_set("UTC");
    $cmd = array (
        "time" => date('Y-m-d H:i:s', time()),
        "cmd" => "student_add_fach",
        "matrikelnummer" => $matrikelnummer,
        "fach" => $fach
    );
    $json_string = json_encode($cmd, JSON_UNESCAPED_UNICODE)."\n";
    $fh = fopen("database.json", "a");
    fwrite($fh,$json_string);
    fclose($fh);   
}

function db_student_update_note($matrikelnummer,$fach,$teilpruefung,$note) {
    date_default_timezone_set("UTC");
    $cmd = array (
        "time" => date('Y-m-d H:i:s', time()),
        "cmd" => "note_upd",
        "fach" => $fach,
        "teilpruefung" => $teilpruefung,
        "note" => $note,
        "matrikelnummer" => $matrikelnummer
    );
    $json_string = json_encode($cmd, JSON_UNESCAPED_UNICODE)."\n";
    $fh = fopen("database.json", "a");
    fwrite($fh,$json_string);
    fclose($fh);  
}

function db_group_new($semester,$fach,$gname,$teilnehmerarray) {
    date_default_timezone_set("UTC");
    $cmd = array (
        "time" => date('Y-m-d H:i:s', time()),
        "cmd" => "group_new",
        "semester" => $semester,
        "fach" => $fach,
        "name" => $gname,
        "teilnehmer" => $teilnehmerarray
    );
    $json_string = json_encode($cmd, JSON_UNESCAPED_UNICODE)."\n";
    $fh = fopen("database.json", "a");
    fwrite($fh,$json_string);
    fclose($fh);
    //echo $json_string;
}

function db_read () {
    global $students,$groups,$pfp;
    $fh = fopen("database.json", "r");
    if ($fh === FALSE) {
        echo "<p>Cannot open database.json</p>";
        return FALSE;
    }
    while ($line = fgets($fh)) {
        $cmd = json_decode($line,JSON_UNESCAPED_UNICODE);
        switch ($cmd["cmd"]) {
            case "student_new" :
                $matrikelnummer = $cmd["matrikelnummer"];
                if (empty($students[$matrikelnummer])) {
                    $students[$matrikelnummer]["vorname"] = $cmd["vorname"];
                    $students[$matrikelnummer]["nachname"] = $cmd["nachname"];
                    $students[$matrikelnummer]["noten"] = $cmd["noten"];
                    $fach = array_key_first($cmd["noten"]);
                    $students[$matrikelnummer]["history"][] = $cmd["time"]." student new with ".$fach;
                } else {
                    echo "<p>ERROR: Student ",$matrikelnummer," is already in database.</p>";
                }
                break;
            case "student_add_fach" :
                $matrikelnummer = $cmd["matrikelnummer"];
                $fach = $cmd["fach"];
                if (empty($students[$matrikelnummer])) {
                    echo "<p>ERROR: Cannot add $fach to $matrikelnummer as student is not in database.</p>";
                } elseif (array_key_exists($fach,$students[$matrikelnummer]["noten"])) {
                    echo "<p>ERROR: $fach already exists for $matrikelnummer in database.</p>";
                } else {
                    $students[$matrikelnummer]["noten"][$fach] = [];
                    $students[$matrikelnummer]["history"][] = $cmd["time"]." add ".$fach;
                }
                break;
            case "group_new" :
                $semester = $cmd["semester"];
                $fach = $cmd["fach"];
                $gname = $cmd["name"];
                if (empty($groups[$semester][$fach][$gname])) {
                    $groups[$semester][$fach][$gname] = $cmd["teilnehmer"];
                } else {
                    echo "<p>ERROR: Group $gname for $fach in $semester is already in database.</p>";
                }
                break;
            case "note_upd":
                $fach = $cmd["fach"];
                $teilpruefung = $cmd["teilpruefung"];
                $matrikelnummer = $cmd["matrikelnummer"];
                $note = $cmd["note"];
                $students[$matrikelnummer]["noten"][$fach][$teilpruefung] = $note;
                $students[$matrikelnummer]["history"][] = $cmd["time"]." ".$fach."/".$teilpruefung.": ".$note;
                break;
            default :
                echo "<p>ERROR: database cmd ", $cmd["cmd"],"is unknown.</p>";
        }
    }
    fclose($fh);
}

// Search user with name and return matrikelnummer if found
function db_find_user($vorname,$nachname) {
    global $students;
    foreach ($students as $matrikelnummer => $student) {
        if ($student["vorname"] === $vorname and $student["nachname"] === $nachname) {
            return $matrikelnummer;
            break;
        }
    }
    return FALSE;
}
?>