<?php

require_once "globals.php";

if (!file_exists(INSTALL_INDICATOR)) {
    exit();
}

if (!isset($_REQUEST["action"])) {
    exit();
}

require_once "common_func.php";

// load databases only if something meaningful have arrived
require_once "usermgr.php";
require_once "groupmgr.php";
require_once "gamemgr.php";
require_once "testmgr.php";

$action = $_REQUEST["action"];

$result = "";

// no-login accessible actions
switch ($action) {
    case "login":
        {
            $nickname = $_REQUEST["nickname"];
            $password = $_REQUEST["password"];
            if (check_user_credentials($nickname, $password)) {
                session_start();
                $_SESSION["nickname"] = $nickname;
                $result = "OK";
            } else {
                $result = "FAIL";
            }
        }
        break;
}

// exit script if there's no live session or nickname is missing or the referenced user is non-existent
if ((session_status() != PHP_SESSION_ACTIVE) || (!isset($_SESSION["nickname"])) || (count(get_user($_SESSION["nickname"])) == 0)) {
    goto print_result;
}

$user_data = get_user($_SESSION["nickname"]);
$nickname = $user_data["nickname"];
$privilege = $user_data["privilege"];

// login-requiring actions
switch ($action) {
    case "logout":
        {
            $_SESSION = []; // clean up session data
            setcookie(SESSION_NAME, "", -1); // invalidate cookie
        }
        break;
    case "get_user_info":
        {
            $user_data_filtered = $user_data;
            unset($user_data_filtered["password"]);
            $result = json_encode($user_data_filtered);
        }
        break;
    case "get_available_games":
        {
            $games_by_groups = [];
            $groupids = $user_data["groups"];
            foreach ($groupids as $groupid) {
                $group_data = get_group($groupid);
                $game_collection = [
                    "groupname" => $group_data["groupname"],
                    "description" => $group_data["description"],
                    "games" => []
                ];
                $gameids = $group_data["games"];
                foreach ($gameids as $gameid) {
                    $game = get_game($gameid);
                    $game_collection["games"][] = $game;
                }
                $games_by_groups[] = $game_collection;
            }
            $result = json_encode($games_by_groups);
        }
        break;
    case "start_or_continue_test":
        {
            $gameid = trim($_REQUEST["gameid"] ?: "");
            $testid = create_or_continue_test($gameid, $nickname);
            $result = $testid;
        }
        break;
    case "get_results_overview":
        {
            $gameid = trim($_REQUEST["gameid"] ?: "");
            $concluded_tests = get_concluded_tests($gameid, $nickname);
            $overviews = [];
            foreach ($concluded_tests as $ct) {
                $overview = [
                    "testid" => $ct["_id"],
                    "start_time" => $ct["start_time"],
                    "end_time" => $ct["end_time"],
                    ...$ct["summary"]
                ];
                $overviews[] = $overview;
            }
            $result = json_encode($overviews);
        }
        break;
}

// test-related queries
if ((($testid = trim($_REQUEST["testid"] ?: "")) !== "") &&
    ((count($test_data = get_test($testid))) > 0) &&
    ($test_data["nickname"] === $nickname)) {

    // update the test if timed
    update_timed_tests([ $test_data ]);

    switch ($action) {
        case "get_test":
            {
                $test_data_with_current_time = $test_data;
                $test_data_with_current_time["current_time"] = time();
                $result = json_encode($test_data_with_current_time);
            }
            break;
        case "save_answer":
            {
                $chidx = $_REQUEST["challenge_index"];
                $answeridx = $_REQUEST["answer_index"];
                save_answer($testid, $chidx, $answeridx);
            }
            break;
        case "submit_test":
            {
                conclude_test($testid);
            }
            break;
    }
}

// creator or quizmaster actions
if (($privilege !== PRIVILEGE_CREATOR) && ($privilege !== PRIVILEGE_QUIZMASTER)) {
    goto print_result;
}

switch ($action) {
    case "create_game":
    case "update_game":
        {
            $update = $action === "update_game";
            $data = json_decode($_REQUEST["data"], true) ?: [];
            if (($data === []) || (trim($data["name"] ?: "") === "")) { // no further processing
                goto print_result; // ~exit...
            }
            $gameid = $data["_id"];
            $name = $data["name"];
            $description = $data["description"];
            $contributors = explode_list($data["contributors"] ?: "");
            $owner = $update ? trim($data["owner"] ?: $nickname) : $nickname;
            $groups = explode_list($data["groups"] ?: "");

            $groupids = get_groupids_by_compounds($groups); // convert group compounds to _ids

            // remove group ID's this user cannot edit
            $groupids_with_editor_access = [];
            foreach ($groupids as $groupid) {
                if (is_user_editor_to_group($groupid, $nickname)) {
                    $groupids_with_editor_access[] = $groupid;
                }
            }
            $groupids_with_editor_access = $groupid;

            if (!$update) {
                create_game($name, $owner, $description);
            } else if (is_user_contributor_to_game($gameid, $nickname)) {
                $game_data = get_game($gameid);
                if (count($game_data) !== 0) {
                    // group management
                    $old_groupids = $game_data["groups"]; // retain old groupids
                    $new_groupids = $groupids; // get new groupids
                    $groupids_add = array_diff($new_groupids, $old_groupids); // groups this user needs to be added to
                    $groupids_remove = array_diff($old_groupids, $new_groupids); // groups this user need to be removed from
                    foreach ($groupids_add as $groupid) { // execute insertion and removal
                        change_group_game_assignments($groupid, $gameid, null);
                    }
                    foreach ($groupids_remove as $groupid) {
                        change_group_game_assignments($groupid, null, $gameid);
                    }

                    // re-fetch game data
                    $game_data = get_game($gameid);

                    // update game header data
                    $game_data["name"] = $name;
                    $game_data["description"] = $description;
                    if (($game_data["owner"] === $nickname) || ($privilege === PRIVILEGE_QUIZMASTER)) {
                        $game_data["owner"] = $owner;
                    }
                    $game_data["contributors"] = array_intersect($contributors, get_all_nicknames());
                    update_game($game_data);

                    // update game file if supplied
                    if (isset($_FILES["game_file"])) {
                        import_challenges_from_csv($_FILES["game_file"]["tmp_name"], $data["_id"]);
                    }
                }
            }
        }
        break;
    case "get_all_game_headers":
        {
            $requester_nickname = ($privilege === PRIVILEGE_QUIZMASTER) ? "*" : $nickname; // "*" means every game
            $game_headers = get_all_game_data_by_contributor_nickname($requester_nickname);
            foreach ($game_headers as &$game_header) {
                resolve_groupids($game_header["groups"]);
            }
            $result = json_encode($game_headers);
        }
        break;
    case "delete_games":
        {
            $gameids = explode_list(trim($_REQUEST["ids"] ?: ""));
            foreach ($gameids as $gameid) {
                if (($gameid !== "") && (is_user_owner_of_the_game($gameid, $nickname))) { // only the owner may delete a game
                    delete_game($gameid);
                }
            }
        }
        break;
    case "export_game_file_csv":
        {
            $gameid = trim($_REQUEST["gameid"] ?: "");
            if (($gameid !== "") && is_user_contributor_to_game($gameid, $nickname)) {
                $f = tmpfile();
                header("Content-Type: text/csv");
                header("Content-Disposition: attachment; filename=\"challenges_$gameid.csv\"\r\n");
                export_challenges_to_csv($f, $gameid);
                fseek($f, 0);
                fpassthru($f);
            }
        }
        break;
}

// quizmaster actions
if ($privilege !== PRIVILEGE_QUIZMASTER) {
    goto print_result;
}

switch ($action) {
    case "create_group":
    case "update_group":
        {
            $update = $action === "update_group";
            $groupname = trim($_REQUEST["groupname"] ?: "");
            $description = trim($_REQUEST["description"] ?: "");
            $editors = explode_list(trim($_REQUEST["editors"] ?: ""));
            $owner = (!$update) ? $user_data["nickname"] : trim($_REQUEST["owner"]);
            if ($owner === "") {
                $owner = $user_data["nickname"];
            }
            if ($groupname != "") {
                switch ($action) {
                    case "create_group":
                        create_group($groupname, $owner, $description, $editors);
                        break;
                    case "update_group":
                        {
                            $gid = $_REQUEST["id"];
                            $group = get_group($gid);
                            if (count($group) !== 0) {
                                $group["unique"] = clear_unique_in_siblings($groupname); // manage unique flag in case of renaming
                                $group["groupname"] = $groupname;
                                $group["description"] = $description;
                                $group["editors"] = array_intersect($editors, $group["users"]); // a user cannot be an editor if not part of the group
                                $group["owner"] = $owner;
                                update_group($group);
                            }
                        }
                        break;
                }

            }
        }
        break;
    case "delete_groups":
        {
            $groups = explode_list($_REQUEST["ids"] ?: "");
            foreach ($groups as $g) {
                delete_group($g);
            }
        }
        break;
    case "get_all_groups":
        $result = json_encode(get_all_groups());
        break;
    case "search_groups":
        {
            $needle = $_REQUEST["needle"] ?: "";
            $result = json_encode(search_groups($needle));
        }
        break;
    case "create_user":
    case "update_user":
        {
            $update = $action === "update_user";
            $target_nickname = trim($_REQUEST["nickname"] ?: "");
            $password = trim($_REQUEST["password"] ?: "");
            $groups = explode_list($_REQUEST["groups"] ?: "");
            $realname = trim($_REQUEST["realname"] ?: "");
            $privilege = trim($_REQUEST["privilege"] ?: PRIVILEGE_PLAYER);

            $groupids = get_groupids_by_compounds($groups); // convert group compounds to _ids

            if (($target_nickname !== "")) {
                if ((!$update) && ($password !== "")) { // CREATE
                    add_user($target_nickname, $password, $realname, $groupids, $privilege);
                } else if ($update) { // UPDATE
                    $user_data = get_user($target_nickname); // load user data

                    // group management
                    $old_groupids = $user_data["groups"]; // retain old groupids
                    $new_groupids = $groupids; // get new groupids
                    $groupids_add = array_diff($new_groupids, $old_groupids); // groups this user needs to be added to
                    $groupids_remove = array_diff($old_groupids, $new_groupids); // groups this user need to be removed from
                    foreach ($groupids_add as $groupid) { // execute insertion and removal
                        change_group_user_assignments($groupid, $target_nickname, null);
                    }
                    foreach ($groupids_remove as $groupid) {
                        change_group_user_assignments($groupid, null, $target_nickname);
                    }

                    // re-fetch user
                    $user_data = get_user($target_nickname); // load user data

                    // further field update
                    $user_data["realname"] = $realname;
                    $user_data["privilege"] = $privilege;

                    // password replacement, if requested
                    if ($password !== "") {
                        $user_data["password"] = password_hash($password, PASSWORD_DEFAULT);
                    }

                    update_user($user_data);
                }
            }

        }
        break;
    case "delete_users":
        {
            $users = explode_list($_REQUEST["users"] ?: "");
            foreach ($users as $g) {
                delete_user($g);
            }
        }
        break;
    case "get_all_users":
        {
            $user_data_filtered = get_all_users();
            for ($i = 0; $i < count($user_data_filtered); $i++) {
                unset($user_data_filtered[$i]["password"]); // remove password from records
                resolve_groupids($user_data_filtered[$i]["groups"]);  // resolve group IDs
            }
            $result = json_encode($user_data_filtered);
        }
        break;
}

// ----------

print_result:

if ($result !== "") {
    echo $result;
}