<?php

if (!defined('ABSPATH')) {
	exit;
}

function leexport_settings_key(): string {
	return 'leexport_settings';
}

function leexport_default_settings(): array {
	return [
		'post_types' => ['post'],
		'fields' => [
			'id' => 1,
			'title' => 1,
			'url' => 1,
			'categories' => 1,
			'category_urls' => 1,
			'tags' => 1,
			'tag_urls' => 1,
			'topics' => 0,
			'topic_urls' => 0,
			'published_date' => 1,
		],
		'export' => [
			// 0 = single file (no split). Default 10000 rows per file.
			'split_rows' => 10000,
		],
		'filters' => [
			'date_from' => '',
			'date_to' => '',
			'id_min' => 0,
			'id_max' => 0,
			'category_ids' => [],
			'topic_taxonomy' => '',
			'topic_ids' => [],
		],
		'link_check' => [
			'enabled' => 1,
			'max_items' => 50,
			'batch_posts' => 10,
			'batch_urls' => 25,
			'include_internal' => 0,
			'include_external' => 1,
			'max_links' => 500,
			'allow_private_targets' => 0,
			'timeout' => 8,
			'user_agent' => 'LeExport/' . (defined('LEEXPORT_VERSION') ? LEEXPORT_VERSION : 'dev'),
		],
	];
}

function leexport_get_settings(): array {
	$defaults = leexport_default_settings();
	$stored = get_option(leexport_settings_key(), []);
	if (!is_array($stored)) {
		$stored = [];
	}

	// Shallow merge, then per-group merge where needed.
	$settings = array_merge($defaults, $stored);

	if (!isset($settings['fields']) || !is_array($settings['fields'])) {
		$settings['fields'] = $defaults['fields'];
	} else {
		$settings['fields'] = array_merge($defaults['fields'], $settings['fields']);
	}

	if (!isset($settings['export']) || !is_array($settings['export'])) {
		$settings['export'] = $defaults['export'];
	} else {
		$settings['export'] = array_merge($defaults['export'], $settings['export']);
	}

	if (!isset($settings['filters']) || !is_array($settings['filters'])) {
		$settings['filters'] = $defaults['filters'];
	} else {
		$settings['filters'] = array_merge($defaults['filters'], $settings['filters']);
		if (!isset($settings['filters']['category_ids']) || !is_array($settings['filters']['category_ids'])) {
			$settings['filters']['category_ids'] = [];
		}
		if (!isset($settings['filters']['topic_ids']) || !is_array($settings['filters']['topic_ids'])) {
			$settings['filters']['topic_ids'] = [];
		}
		if (!isset($settings['filters']['topic_taxonomy'])) {
			$settings['filters']['topic_taxonomy'] = '';
		}
	}

	if (!isset($settings['link_check']) || !is_array($settings['link_check'])) {
		$settings['link_check'] = $defaults['link_check'];
	} else {
		$settings['link_check'] = array_merge($defaults['link_check'], $settings['link_check']);
	}

	if (!isset($settings['post_types']) || !is_array($settings['post_types']) || $settings['post_types'] === []) {
		$settings['post_types'] = $defaults['post_types'];
	}

	return $settings;
}

function leexport_update_settings(array $settings): bool {
	return update_option(leexport_settings_key(), $settings, false);
}

function leexport_bool_int($value): int {
	return empty($value) ? 0 : 1;
}

function leexport_sanitize_int($value, int $min = 0, ?int $max = null): int {
	$v = is_numeric($value) ? (int)$value : 0;
	if ($v < $min) {
		$v = $min;
	}
	if ($max !== null && $v > $max) {
		$v = $max;
	}
	return $v;
}

/**
 * Checks whether an URL is safe for outbound HTTP checks.
 *
 * Blocks localhost/private/reserved targets to reduce SSRF risk.
 */
function leexport_is_safe_remote_url(string $url, bool $allow_private_targets = false): bool {
	$url = trim($url);
	if ($url === '' || !wp_http_validate_url($url)) {
		return false;
	}
	if ($allow_private_targets) {
		return true;
	}

	$host = wp_parse_url($url, PHP_URL_HOST);
	if (!is_string($host) || $host === '') {
		return false;
	}

	// Block obvious local targets quickly.
	if (strtolower($host) === 'localhost') {
		return false;
	}

	$is_public_ip = static function (string $ip): bool {
		return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE) !== false;
	};

	// IP literal host.
	if (filter_var($host, FILTER_VALIDATE_IP)) {
		return $is_public_ip($host);
	}

	// Resolve host and ensure all resolved IPs are public.
	$resolved_ips = [];
	$ipv4 = gethostbynamel($host);
	if (is_array($ipv4)) {
		$resolved_ips = array_merge($resolved_ips, $ipv4);
	}
	if (function_exists('dns_get_record')) {
		$aaaa = @dns_get_record($host, DNS_AAAA);
		if (is_array($aaaa)) {
			foreach ($aaaa as $rec) {
				if (!empty($rec['ipv6']) && is_string($rec['ipv6'])) {
					$resolved_ips[] = $rec['ipv6'];
				}
			}
		}
	}

	$resolved_ips = array_values(array_unique(array_filter($resolved_ips, static fn($ip) => is_string($ip) && $ip !== '')));
	if ($resolved_ips === []) {
		// If DNS cannot be resolved, treat as unsafe for scanner.
		return false;
	}

	foreach ($resolved_ips as $ip) {
		if (!$is_public_ip($ip)) {
			return false;
		}
	}

	return true;
}

/**
 * Max rows per export file. 0 disables splitting (single file).
 */
function leexport_split_rows_limit(array $settings): int {
	$export = isset($settings['export']) && is_array($settings['export']) ? $settings['export'] : [];
	$limit = leexport_sanitize_int($export['split_rows'] ?? 10000, 0, 100000);
	return $limit;
}

/**
 * Sanitize Y-m-d date string for export filters.
 */
function leexport_sanitize_date_ymd($value): string {
	$value = trim((string)$value);
	if ($value === '') {
		return '';
	}
	$dt = DateTime::createFromFormat('Y-m-d', $value);
	if ($dt instanceof DateTime && $dt->format('Y-m-d') === $value) {
		return $value;
	}
	return '';
}

/**
 * Common taxonomy slugs used for “专题” on Chinese WordPress sites.
 *
 * @return string[]
 */
function leexport_common_topic_taxonomy_slugs(): array {
	return ['topic', 'topics', 'zhuanti', 'special', 'post_topic', 'series', 'special_topic'];
}

/**
 * @return array<string, string> taxonomy slug => label
 */
function leexport_get_topic_taxonomy_options(): array {
	$options = [];
	$skip = ['category', 'post_tag', 'post_format', 'nav_menu', 'link_category'];

	foreach (leexport_common_topic_taxonomy_slugs() as $slug) {
		if (!taxonomy_exists($slug)) {
			continue;
		}
		$tax = get_taxonomy($slug);
		if ($tax) {
			$options[$slug] = (string)($tax->labels->name ?? $slug);
		}
	}

	foreach (get_taxonomies(['public' => true], 'objects') as $tax) {
		if (in_array($tax->name, $skip, true) || isset($options[$tax->name])) {
			continue;
		}
		$label = (string)($tax->labels->singular_name ?? $tax->label ?? $tax->name);
		$name = (string)$tax->name;
		if (
			strpos($label, '专题') !== false
			|| stripos($name, 'topic') !== false
			|| stripos($name, 'zhuanti') !== false
			|| stripos($name, 'special') !== false
		) {
			$options[$tax->name] = $label;
		}
	}

	return $options;
}

/**
 * Resolve which taxonomy powers topic filter/export columns.
 */
function leexport_resolve_topic_taxonomy(array $settings): string {
	$filters = isset($settings['filters']) && is_array($settings['filters']) ? $settings['filters'] : [];
	$chosen = sanitize_key((string)($filters['topic_taxonomy'] ?? ''));
	$options = leexport_get_topic_taxonomy_options();

	if ($chosen !== '' && isset($options[$chosen]) && taxonomy_exists($chosen)) {
		return $chosen;
	}

	if ($options !== []) {
		return (string)array_key_first($options);
	}

	return '';
}

/**
 * @param array $raw_ids
 * @return int[]
 */
function leexport_sanitize_term_ids_for_taxonomy(array $raw_ids, string $taxonomy): array {
	if ($taxonomy === '' || !taxonomy_exists($taxonomy)) {
		return [];
	}

	$ids = [];
	foreach ($raw_ids as $id) {
		$tid = (int)$id;
		if ($tid <= 0) {
			continue;
		}
		$term = get_term($tid, $taxonomy);
		if ($term instanceof WP_Term && !is_wp_error($term)) {
			$ids[] = $tid;
		}
	}

	return array_values(array_unique($ids));
}

/**
 * @param array $raw filters array from form
 * @return array{date_from:string,date_to:string,id_min:int,id_max:int,category_ids:int[],topic_taxonomy:string,topic_ids:int[]}
 */
function leexport_sanitize_filters(array $raw): array {
	$date_from = leexport_sanitize_date_ymd($raw['date_from'] ?? '');
	$date_to = leexport_sanitize_date_ymd($raw['date_to'] ?? '');
	if ($date_from !== '' && $date_to !== '' && $date_from > $date_to) {
		$tmp = $date_from;
		$date_from = $date_to;
		$date_to = $tmp;
	}

	$id_min = leexport_sanitize_int($raw['id_min'] ?? 0, 0);
	$id_max = leexport_sanitize_int($raw['id_max'] ?? 0, 0);
	if ($id_min > 0 && $id_max > 0 && $id_min > $id_max) {
		$tmp = $id_min;
		$id_min = $id_max;
		$id_max = $tmp;
	}

	$category_ids = leexport_sanitize_term_ids_for_taxonomy(
		isset($raw['category_ids']) && is_array($raw['category_ids']) ? $raw['category_ids'] : [],
		'category'
	);

	$topic_taxonomy = sanitize_key((string)($raw['topic_taxonomy'] ?? ''));
	$topic_options = leexport_get_topic_taxonomy_options();
	if ($topic_taxonomy !== '' && !isset($topic_options[$topic_taxonomy])) {
		$topic_taxonomy = '';
	}

	$topic_tax_for_ids = $topic_taxonomy !== '' ? $topic_taxonomy : (leexport_resolve_topic_taxonomy(['filters' => ['topic_taxonomy' => '']]));
	$topic_ids = leexport_sanitize_term_ids_for_taxonomy(
		isset($raw['topic_ids']) && is_array($raw['topic_ids']) ? $raw['topic_ids'] : [],
		$topic_tax_for_ids
	);

	return [
		'date_from' => $date_from,
		'date_to' => $date_to,
		'id_min' => $id_min,
		'id_max' => $id_max,
		'category_ids' => $category_ids,
		'topic_taxonomy' => $topic_taxonomy,
		'topic_ids' => $topic_ids,
	];
}

/**
 * Build WP_Query / get_posts args for export (published posts only).
 *
 * @param array $settings leexport_get_settings()
 * @param array $overrides Extra query arguments.
 */
function leexport_build_export_query_args(array $settings, array $overrides = []): array {
	$post_types = isset($settings['post_types']) && is_array($settings['post_types']) ? array_values($settings['post_types']) : ['post'];
	$filters = isset($settings['filters']) && is_array($settings['filters']) ? $settings['filters'] : leexport_default_settings()['filters'];

	$args = [
		'post_type' => $post_types,
		'post_status' => 'publish',
		'orderby' => 'date',
		'order' => 'DESC',
		'ignore_sticky_posts' => true,
		'leexport_filtered' => true,
	];

	$date_from = leexport_sanitize_date_ymd($filters['date_from'] ?? '');
	$date_to = leexport_sanitize_date_ymd($filters['date_to'] ?? '');
	if ($date_from !== '' || $date_to !== '') {
		$date_query = [
			'inclusive' => true,
			'column' => 'post_date',
		];
		if ($date_from !== '') {
			$date_query['after'] = $date_from;
		}
		if ($date_to !== '') {
			$date_query['before'] = $date_to;
		}
		$args['date_query'] = [$date_query];
	}

	$id_min = leexport_sanitize_int($filters['id_min'] ?? 0, 0);
	$id_max = leexport_sanitize_int($filters['id_max'] ?? 0, 0);
	if ($id_min > 0) {
		$args['leexport_id_min'] = $id_min;
	}
	if ($id_max > 0) {
		$args['leexport_id_max'] = $id_max;
	}

	$tax_query = [];

	$category_ids = isset($filters['category_ids']) && is_array($filters['category_ids']) ? $filters['category_ids'] : [];
	$category_ids = array_values(array_filter(array_map('intval', $category_ids), static fn($id) => $id > 0));
	if ($category_ids !== []) {
		$tax_query[] = [
			'taxonomy' => 'category',
			'field' => 'term_id',
			'terms' => $category_ids,
			'operator' => 'IN',
		];
	}

	$topic_ids = isset($filters['topic_ids']) && is_array($filters['topic_ids']) ? $filters['topic_ids'] : [];
	$topic_ids = array_values(array_filter(array_map('intval', $topic_ids), static fn($id) => $id > 0));
	$topic_taxonomy = leexport_resolve_topic_taxonomy($settings);
	if ($topic_ids !== [] && $topic_taxonomy !== '') {
		$tax_query[] = [
			'taxonomy' => $topic_taxonomy,
			'field' => 'term_id',
			'terms' => $topic_ids,
			'operator' => 'IN',
		];
	}

	if (count($tax_query) === 1) {
		// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_tax_query -- Required for category/topic export filters.
		$args['tax_query'] = $tax_query;
	} elseif (count($tax_query) > 1) {
		// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_tax_query -- Required for category/topic export filters.
		$args['tax_query'] = array_merge(['relation' => 'AND'], $tax_query);
	}

	return array_merge($args, $overrides);
}

/**
 * @param WP_Query $query
 */
function leexport_posts_where_id_range(string $where, $query): string {
	if (!($query instanceof WP_Query) || !$query->get('leexport_filtered')) {
		return $where;
	}

	global $wpdb;
	$id_min = (int)$query->get('leexport_id_min');
	$id_max = (int)$query->get('leexport_id_max');
	if ($id_min > 0) {
		$where .= $wpdb->prepare(" AND {$wpdb->posts}.ID >= %d", $id_min);
	}
	if ($id_max > 0) {
		$where .= $wpdb->prepare(" AND {$wpdb->posts}.ID <= %d", $id_max);
	}

	return $where;
}

add_filter('posts_where', 'leexport_posts_where_id_range', 10, 2);