<?php

require_once "globals.php";
require_once "common_func.php";

$gamedb = new \SleekDB\Store(GAMEDB, DATADIR, ["timeout" => false]);

const DEFAULT_GAME_PROPERTIES = [
    "forward_only" => false, // player may traverse back and forth between challenges
    "time_limit" => 0, // no time limit; otherwise, this field indicates time limit in seconds
    "repeatable" => false // this test can be taken multiple times
];

function create_game(string $name, string $owner, string $description = "", array $properties = DEFAULT_GAME_PROPERTIES, array $contributors = [], array $challenges = []): bool
{
    global $gamedb;
    $game_data = [
        "name" => $name,
        "owner" => $owner,
        "contributors" => $contributors,
        "description" => $description,
        "game_file_present" => false,
        "properties" => $properties,
        "groups" => [],
        "public" => false,
        "public_id" => uniqid("p"),
    ];
    $game_data = $gamedb->insert($game_data);

    // prepare game context
    $id = $game_data["_id"];
    $current_game_media_dir = get_game_dir_by_gameid($id);
    mkdir($current_game_media_dir);
    save_challenges($id, []);
    return true;
}

function get_game(string $gameid): array
{
    global $gamedb;
    return $gamedb->findById($gameid);
}

function update_game(array $game_data)
{
    global $gamedb;
    $gamedb->update($game_data);
}

function delete_game(string $gameid)
{
    global $gamedb;
    $game_data = get_game($gameid);
    if (count($game_data) != 0) {
        foreach ($game_data["groups"] as $groupid) {
            change_group_game_assignments($groupid, null, $gameid);
        }
        $gamedb->deleteById($gameid);
    }
}

function change_game_group_assignments(string $gid, $groupname_add, $groupname_remove)
{
    $game_data = get_game($gid);
    if (count($game_data) != 0) {
        alter_array_contents($game_data["groups"], $groupname_add, $groupname_remove);
        update_game($game_data); // update user
    }
}

function get_all_games()
{
    global $gamedb;
    return $gamedb->findAll();
}

function get_all_game_data_by_contributor_nickname(string $nickname): array
{
    global $gamedb;
    $game_headers = [];
    if ($nickname !== "*") {
        $game_data_array = $gamedb->findBy([["owner", "=", $nickname], "OR", ["contributors", "CONTAINS", $nickname]]);
    } else {
        $game_data_array = $gamedb->findAll();
    }
    foreach ($game_data_array as $game_data) {
        $game_headers[] = $game_data;
    }
    return $game_headers;
}

const CSV_ENCODINGS = ["UTF-8", "Windows-1252"];

function import_challenges_from_csv(string $csv_path, string $gameid): array
{
    $game_data = get_game($gameid);
    $game_dir = get_game_dir_by_gameid($gameid);
    if (count($game_data) === []) {
        return ["n" => 0, "encoding" => ""];
    }

    // convert text encoding into UTF-8
    $data = file_get_contents($csv_path);
    $encoding = "UNKNOWN";
    foreach (CSV_ENCODINGS as $enc) { // detect encoding
        if (mb_check_encoding($data, $enc)) {
            $encoding = $enc;
            break;
        }
    }

    if ($encoding !== "UNKNOWN") { // if encoding has been detected successfully
        $data = mb_convert_encoding($data, "UTF-8", $encoding);
        file_put_contents($csv_path, $data);
    }

    // load challenges
    $challenges = [];

    // load filled CSV file
    $f = fopen($csv_path, "r");
    if (!$f) { // failed to open file
        return ["n" => 0, "encoding" => $encoding];
    }
    while ($csvline = fgetcsv($f)) {
        // skip empty lines
        if (trim(implode("", $csvline)) === "") {
            continue;
        }
        if (count($csvline) >= 3) {
            // construct challenge record
            $ch = [
                "question" => trim($csvline[0]),
                "image_url" => trim($csvline[1]),
                "correct_answer" => trim($csvline[2]),
                "answers" => array_filter(array_slice($csvline, 2), function ($v) {
                    return trim($v) !== "";
                })
            ];

            // if image is attached to the challenge, then give a random name to the image
            if ($ch["image_url"] !== "") {
                $old_img_name = $ch["image_url"];
                $ext = pathinfo($old_img_name, PATHINFO_EXTENSION);
                $ext = ($ext !== "") ? ("." . $ext) : $ext;
                $new_img_name = uniqid("img_", true) . $ext;
                $ch["image_url"] = $new_img_name;

                // rename the actual file
                $old_img_path = $game_dir . DIRECTORY_SEPARATOR . $old_img_name;
                $new_img_path = $game_dir . DIRECTORY_SEPARATOR . $new_img_name;
                rename($old_img_path, $new_img_path);
            }

            // store the challenge
            $challenges[] = $ch;
        }
    }
    fclose($f);

    // save challenges
    save_challenges($gameid, $challenges);

    // update game with game file present
    $game_data["game_file_present"] = true;
    update_game($game_data);

    return ["n" => count($challenges), "encoding" => $encoding];
}

function is_user_contributor_to_game(string $gameid, string $nickname): bool
{
    $game_data = get_game($gameid);
    if (count($game_data) === 0) {
        return false;
    }

    return in_array($nickname, $game_data["contributors"]) || ($game_data["owner"] === $nickname);
}

function is_user_owner_of_the_game(string $gameid, string $nickname): bool
{
    $game_data = get_game($gameid);
    if (count($game_data) === 0) {
        return false;
    }
    return $game_data["owner"] === $nickname;
}

function save_challenges(string $gameid, array $challenges)
{
    file_put_contents(get_game_file_by_gameid($gameid), json_encode($challenges));     // store challenges in JSON-format
}

function load_challenges(string $gameid)
{
    return json_decode(file_get_contents(get_game_file_by_gameid($gameid)), true);
}

function export_challenges_to_csv($f, string $gameid)
{
    $game_data = get_game($gameid);
    if ((count($game_data) === []) || (!$game_data["game_file_present"])) {
        return;
    }

    // load challenges
    $challenges = load_challenges($gameid);

    // populate CSV file
    foreach ($challenges as $ch) {
        $csvline = [
            $ch["question"],
            $ch["image_url"],
        ];
        $csvline = array_merge($csvline, $ch["answers"]);
        fputcsv($f, $csvline);
    }
}

function get_contributors(string $gameid): array
{
    $game_data = get_game($gameid);
    return $game_data["contributors"];
}

function get_game_file_by_gameid(string $gameid)
{
    return GAMEMEDIA_DIR . DIRECTORY_SEPARATOR . $gameid . DIRECTORY_SEPARATOR . GAME_FILE;
}

function get_game_dir_by_gameid(string $gameid)
{
    return GAMEMEDIA_DIR . DIRECTORY_SEPARATOR . $gameid;
}