<?php
    require_once "$PROJECT_ROOT/php/servers/known-servers.php";

    /**
     * Return local path to room icon.
     * @param string $room_id Id of room to locate icon for.
     */
    function room_icon_path(string $room_id): string {
        global $ROOM_ICONS_CACHE;
        return "$ROOM_ICONS_CACHE/$room_id";
    }

    /**
     * Return local path to resized room icon.
     * @param string $room_id Id of room to locate icon for.
     * @param string $size Image dimensions.
     */
    function room_icon_path_resized(string $room_id, string $size): string {
        global $ROOM_ICONS;
        return "$ROOM_ICONS/$room_id-$size";
    }

    /**
     * Return server path to room icon.
     * @param string $room_id Id of room to locate icon for.
     * @param string $size Image dimensions.
     */
    function room_icon_path_relative(string $room_id, string $size): string {
        global $ROOM_ICONS_RELATIVE;
        return "$ROOM_ICONS_RELATIVE/$room_id-$size";
    }

    /**
     * @return \Generator<int,CurlHandle,CurlHandle|false,void>
     */
    function fetch_room_icon_coroutine(\CommunityRoom $room): Generator {
        if (room_icon_safety($room) < 0) {
            return;
        }

        $room_id = $room->get_room_identifier();
        $icon_cached = room_icon_path($room_id);
        $icon_expired = file_exists($icon_cached) && filemtime($icon_cached) < strtotime("-1 day");

        // Re-fetch icons periodically.
        if (!file_exists($icon_cached) || $icon_expired) {
            $icon_url = $room->get_icon_url();
            if (empty($icon_url)) {
                return null;
            }
            log_debug("Fetching icon for $room_id.");
            $icon_response = yield from FetchingCoroutine::from_url($icon_url)->run();
            $icon = $icon_response ? curl_multi_getcontent($icon_response) : null;
            if (empty($icon)) {
                log_info("$room_id returned an empty icon.");
            }
            // Never overwrite with an empty file.
            if (!(file_exists($icon_cached) && filesize($icon_cached) > 0 && empty($icon))) {
                file_put_contents($icon_cached, $icon);
            }
        }
    }

    /**
     * Fetch the icon of the given room and return its relative path.
     * @param \CommunityRoom $room
     * @param string $size Image dimensions.
     * @return string Relative path or null if icon is absent.
     */
    function room_icon(\CommunityRoom $room, string $size): ?string {
        list($width, $height) = explode("x", $size);
        $width = intval($width);
        $height = intval($height);
        assert(!empty($width) && !empty($height));

        if (room_icon_safety($room) < 0) {
            return null;
        }

        $room_id = $room->get_room_identifier();
        $icon_cached = room_icon_path($room_id);
        $icon_resized = room_icon_path_resized($room_id, $size);
        $icon_expired = file_exists($icon_cached) && filemtime($icon_cached) < strtotime("-1 day");

        if (!file_exists($icon_cached)) {
            log_debug("Missing icon asset for $room_id");
            return "";
        }
        if (!file_exists($icon_resized) || $icon_expired) {
            $icon_cached_contents = file_get_contents($icon_cached);
            if (empty($icon_cached_contents)) {
                file_put_contents($icon_resized, "");
                return "";
            }
            // Resize image
            $gd_image = imagecreatefromstring($icon_cached_contents);
            $gd_resized = imagescale($gd_image, $width, $height);
            if (!imagewebp($gd_resized, $icon_resized)) {
                log_info("Converting image for $room_id to $size failed");
            }
        }
        if (filesize($icon_resized) == 0) {
            return "";
        }
        return room_icon_path_relative($room_id, $size);
    }

    function room_icon_safety(\CommunityRoom $room): int {
        global $ICON_ALLOWLIST, $ICON_BLOCKLIST;
        if (in_array($room->get_room_identifier(), $ICON_BLOCKLIST)) {
            return -1;
        }
        if (in_array($room->server->get_hostname(), $ICON_ALLOWLIST)) {
            return 1;
        }
        if (in_array($room->server->get_hostname(), $ICON_BLOCKLIST)) {
            return -1;
        }
        if ($room->has_nsfw_keywords()) {
            return -1;
        }
        return 0;
    }

    file_exists($ROOM_ICONS_CACHE) or mkdir($ROOM_ICONS_CACHE, 0755, true);
    file_exists($ROOM_ICONS) or mkdir($ROOM_ICONS, 0755, true);
?>