<?php

// Cron replacement: the periodic manage-client tasks, triggered by admin
// activity instead of a scheduler.
//
// This deployment usually has no cron, so the two jobs that would otherwise run
// from manage-client/bin/manage-client.php happen when an admin loads the
// dashboard: the automatic backup once its interval has passed, and the status
// report to the manage server once its own, much shorter interval has passed.
//
// Both are throttled and neither may break the page it runs on, so nothing in
// here throws.

require_once __DIR__ . "/../manage-client/lib/client.php";

// How long an admin session may pass without the manage server hearing from
// this instance. Short enough that the server dashboard stays meaningful,
// long enough that it is not one request per admin page view.
if (!defined("MANAGE_ACTIVITY_HEARTBEAT_INTERVAL")) {
    define("MANAGE_ACTIVITY_HEARTBEAT_INTERVAL", 3600);
}

function manageActivityStateFile(): string
{
    // Next to the client's own log, in data/manage/ - gitignored and blocked
    // from the web by the .htaccess in the project root.
    return dirname((string) MANAGE_LOG_FILE) . "/activity.json";
}

function manageActivityReadState(): array
{
    $file = manageActivityStateFile();
    if (!is_file($file) || !is_readable($file)) {
        return [];
    }

    $decoded = json_decode((string) file_get_contents($file), true);

    return is_array($decoded) ? $decoded : [];
}

function manageActivityWriteState(array $state): void
{
    $file = manageActivityStateFile();
    $dir = dirname($file);

    if (!is_dir($dir) && !mkdir($dir, 02775, true) && !is_dir($dir)) {
        return;
    }

    @file_put_contents($file, json_encode($state, JSON_PRETTY_PRINT), LOCK_EX);
}

/**
 * Sends the status report if the interval has passed.
 *
 * The timestamp is written before the request, not after: a manage server that
 * hangs must not turn every following page load into another attempt.
 *
 * @return bool whether a heartbeat was attempted
 */
function manageActivityHeartbeatIfDue(bool $force = false): bool
{
    $interval = (int) MANAGE_ACTIVITY_HEARTBEAT_INTERVAL;
    if (!$force && $interval <= 0) {
        return false;
    }

    if (!manageClientConfigured()) {
        return false;
    }

    $state = manageActivityReadState();
    $last = (int) ($state["last_heartbeat_at"] ?? 0);

    if (!$force && $last > 0 && time() - $last < $interval) {
        return false;
    }

    $state["last_heartbeat_at"] = time();
    manageActivityWriteState($state);

    manageHeartbeatSendQuietly();

    return true;
}

/**
 * Runs the due jobs for one admin page view.
 *
 * @return array{message: string, type: string} empty message when nothing happened
 */
function manageActivityRunDueTasks(): array
{
    $result = ["message" => "", "type" => ""];
    $backup = null;

    try {
        $backup = manageBackupCreateAutomaticIfDue();
        if ($backup !== null) {
            $result = [
                "message" => "Automatisches Backup wurde erstellt: " . $backup["filename"] . ".",
                "type" => "success",
            ];
        }
    } catch (Throwable $exception) {
        $result = [
            "message" => "Automatisches Backup konnte nicht erstellt werden: " .
                $exception->getMessage(),
            "type" => "warning",
        ];
    }

    // A fresh backup is worth reporting right away, so the server dashboard
    // does not show a stale "last backup" for up to another interval.
    manageActivityHeartbeatIfDue($backup !== null);

    return $result;
}