<?php
if (!defined('ABSPATH')) { exit; }

/** Serialize database mutations. Never automatically steal an old lock: a slow
 * worker may still be writing. The token makes release ownership-specific. */
function wplocation_acquire_database_lock() {
    $token = time() . ':' . wp_generate_uuid4();
    global $wpdb;
    // add_option() uses an upsert and can overwrite a simultaneous acquisition.
    $previous_suppression = $wpdb->suppress_errors(true);
    // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- A plain INSERT is required for an atomic, single-owner database lock; add_option() can upsert.
    $inserted = $wpdb->query($wpdb->prepare("INSERT INTO {$wpdb->options} (option_name, option_value, autoload) VALUES (%s, %s, %s)", 'wplocation_update_lock', $token, 'no'));
    $wpdb->suppress_errors($previous_suppression);
    if ($inserted !== 1) { return false; }
    wp_cache_delete('wplocation_update_lock', 'options');
    wp_cache_delete('notoptions', 'options');
    // Another request may have changed these options while this request waited.
    foreach (array('wplocation_db_path', 'wplocation_managed_database', 'wplocation_managed_files', 'wplocation_updates_enabled', 'wplocation_maxmind_account_id', 'wplocation_maxmind_license_key') as $name) { wp_cache_delete($name, 'options'); }
    wp_cache_delete('alloptions', 'options');
    return $token;
}
function wplocation_database_lock_value() {
    global $wpdb;
    // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Read the lock from the database, not a potentially stale object cache.
    return $wpdb->get_var($wpdb->prepare("SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1", 'wplocation_update_lock'));
}
function wplocation_release_database_lock($token) {
    if (!is_string($token) || $token === '') { return false; }
    global $wpdb;
    // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery -- Conditional DELETE ensures only the lock holder can release its token.
    $removed = $wpdb->query($wpdb->prepare("DELETE FROM {$wpdb->options} WHERE option_name = %s AND BINARY option_value = BINARY %s", 'wplocation_update_lock', $token));
    if ($removed !== 1) { return false; }
    wp_cache_delete('wplocation_update_lock', 'options');
    wp_cache_delete('alloptions', 'options');
    wp_cache_delete('notoptions', 'options');
    return true;
}
function wplocation_database_lock_is_old($value) {
    return is_string($value) && preg_match('/^(\d+)(?::[a-f0-9-]+)?$/', $value, $match) && (int) $match[1] > 0 && (int) $match[1] <= time() - HOUR_IN_SECONDS;
}

/** Validate a writable private directory for first database downloads. */
function wplocation_private_database_directory($directory, $filesystem = null) {
    $dir = is_string($directory) ? realpath($directory) : false;
    if (!$dir || !is_dir($dir) || ($filesystem && !$filesystem->is_writable($dir))) { return false; }
    $roots = array(realpath(ABSPATH), realpath(WP_CONTENT_DIR), realpath(WP_PLUGIN_DIR));
    if (!empty($_SERVER['DOCUMENT_ROOT']) && is_string($_SERVER['DOCUMENT_ROOT'])) {
        $roots[] = realpath(sanitize_text_field(wp_unslash($_SERVER['DOCUMENT_ROOT'])));
    }
    foreach ($roots as $root) {
        if ($root && ($dir === $root || strpos($dir, rtrim($root, DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR) === 0)) { return false; }
    }
    return $dir;
}

/** Select a previously validated managed copy only for the configured source. */
function wplocation_configured_database_path() {
    return defined('WPLOCATION_GEOIP_DB_PATH') ? WPLOCATION_GEOIP_DB_PATH : get_option('wplocation_db_path', '');
}
function wplocation_active_database_path() {
    $source = wplocation_configured_database_path();
    $selected = get_option('wplocation_managed_database', array());
    if (!is_string($source) || !is_array($selected) || ($selected['source'] ?? null) !== $source || !isset($selected['file']) || !is_string($selected['file'])) { return $source; }
    $source_dir = realpath(dirname($source)); $file = $selected['file']; $resolved = realpath($file);
    if (!$source_dir || !$resolved || is_link($file) || !is_file($resolved) || dirname($resolved) !== $source_dir || !preg_match('/^\.wplocation-[a-f0-9-]+\.mmdb$/', basename($resolved))) { return $source; }
    return $resolved;
}
/** Resolve per site on each request, including after switch_to_blog().
 * Preserve the legacy constant if another integration explicitly defined it. */
function wplocation_database_path() {
    // Respect an explicit legacy constant, but do not define a global alias
    // ourselves. The active path can change after a validated database update.
    $path = defined('WPLOCATION_GEOIP_DB_PATH') ? wplocation_active_database_path() : (defined('GEOIPDBFILE') ? GEOIPDBFILE : wplocation_active_database_path());
    return is_string($path) ? $path : '';
}
/** Re-read the stored option rather than trusting a request-local cache after a
 * long download; another administrator may have changed the source meanwhile. */
function wplocation_source_matches($expected) {
    if (!is_string($expected)) { return false; }
    if (defined('WPLOCATION_GEOIP_DB_PATH')) { return WPLOCATION_GEOIP_DB_PATH === $expected; }
    global $wpdb;
    // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Re-read after a long download to reject a concurrent source switch.
    $stored = $wpdb->get_var($wpdb->prepare("SELECT option_value FROM {$wpdb->options} WHERE option_name = %s LIMIT 1", 'wplocation_db_path'));
    return is_string($stored) && $stored === $expected;
}

/** Install a new immutable file, then switch the database option in one write.
 * Existing readers and the original file remain available if anything fails. */
function wplocation_install_managed_database($candidate, $current, $filesystem, $expected_source) {
    $source = wplocation_configured_database_path();
    if (!is_string($expected_source) || $source !== $expected_source || !wplocation_source_matches($expected_source)) { return false; }
    $source_dir = is_string($source) ? realpath(dirname($source)) : false;
    if (!$source_dir || $source_dir !== dirname($current) || dirname($candidate) !== $source_dir) { return false; }
    $destination = $source_dir . DIRECTORY_SEPARATOR . '.wplocation-' . wp_generate_uuid4() . '.mmdb';
    if ($filesystem->exists($destination) || !$filesystem->move($candidate, $destination, false)) { return false; }
    $hash = hash_file('sha256', $destination);
    if (!is_string($hash)) { $filesystem->delete($destination); return false; }
    $owned = get_option('wplocation_managed_files', array());
    if (!is_array($owned)) { $owned = array(); }
    $owned[$destination] = array('source' => $source, 'created' => time(), 'sha256' => $hash);
    update_option('wplocation_managed_files', $owned, false);
    if (get_option('wplocation_managed_files') !== $owned) { $filesystem->delete($destination); return false; }
    $previous = get_option('wplocation_managed_database', array());
    $selection = array('source' => $source, 'file' => $destination);
    if (!wplocation_source_matches($expected_source)) {
        if ($filesystem->delete($destination)) { unset($owned[$destination]); update_option('wplocation_managed_files', $owned, false); }
        return false;
    }
    update_option('wplocation_managed_database', $selection, false);
    if (get_option('wplocation_managed_database') !== $selection) {
        if ($filesystem->delete($destination)) { unset($owned[$destination]); update_option('wplocation_managed_files', $owned, false); }
        return false;
    }
    if (is_array($previous) && ($previous['source'] ?? null) === $source && isset($previous['file']) && isset($owned[$previous['file']])) {
        $owned[$previous['file']]['retired'] = time();
        update_option('wplocation_managed_files', $owned, false);
    }
    return true;
}

/** Retire a recorded managed copy when the administrator selects another source. */
function wplocation_retire_selected_managed_database() {
    $selected = get_option('wplocation_managed_database', array());
    $owned = get_option('wplocation_managed_files', array());
    if (!is_array($selected) || !is_array($owned) || empty($selected['file']) || !is_string($selected['file'])) { return; }
    $file = $selected['file'];
    if (!isset($owned[$file]) || !is_array($owned[$file]) || ($owned[$file]['source'] ?? null) !== ($selected['source'] ?? null)) { return; }
    $owned[$file]['retired'] = time();
    update_option('wplocation_managed_files', $owned, false);
}

/** Remove only recorded, unchanged copies for the currently configured source.
 * Leave recent copies and the selected file intact; never scan or delete a
 * user-supplied database. Concurrent database updates use the same lock. */
function wplocation_cleanup_managed_databases() {
    $lock = wplocation_acquire_database_lock();
    if (!$lock) { return; }
    try {
        $owned = get_option('wplocation_managed_files', array());
        $selection = get_option('wplocation_managed_database', array());
        $active = is_array($selection) && isset($selection['file']) ? $selection['file'] : '';
        if (!is_array($owned)) { return; }
        require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-base.php';
        require_once ABSPATH . 'wp-admin/includes/class-wp-filesystem-direct.php';
        $filesystem = new WP_Filesystem_Direct(null); $changed = false;
        foreach ($owned as $path => $entry) {
            $dir = is_array($entry) && isset($entry['source']) && is_string($entry['source']) ? realpath(dirname($entry['source'])) : false;
            if (!is_string($path) || !is_array($entry) || !$dir || !isset($entry['retired'], $entry['sha256']) || !is_string($entry['sha256']) || !preg_match('/^[a-f0-9]{64}$/', $entry['sha256']) || (int) $entry['retired'] <= 0 || (int) $entry['retired'] > time() - 2 * DAY_IN_SECONDS || $path === $active || is_link($path) || dirname($path) !== $dir || !preg_match('/^\.wplocation-[a-f0-9-]+\.mmdb$/', basename($path))) { continue; }
            if (!$filesystem->exists($path)) { unset($owned[$path]); $changed = true; continue; }
            if (!is_file($path) || realpath($path) !== $path || !hash_equals($entry['sha256'], (string) hash_file('sha256', $path))) { continue; }
            if ($filesystem->delete($path)) { unset($owned[$path]); $changed = true; }
        }
        if ($changed) { update_option('wplocation_managed_files', $owned, false); }
    } finally { wplocation_release_database_lock($lock); }
}
add_action('wplocation_cleanup_managed_databases', 'wplocation_cleanup_managed_databases');
function wplocation_schedule_database_cleanup() {
    if (get_option('wplocation_managed_files') && !wp_next_scheduled('wplocation_cleanup_managed_databases')) { wp_schedule_event(time() + DAY_IN_SECONDS, 'daily', 'wplocation_cleanup_managed_databases'); }
}
add_action('init', 'wplocation_schedule_database_cleanup');
function wplocation_deactivate_database_cleanup() { wp_clear_scheduled_hook('wplocation_cleanup_managed_databases'); }
register_deactivation_hook(WPLOCATION_PLUGIN_FILE, 'wplocation_deactivate_database_cleanup');