<?php
/**
 * The llms.txt screen (design board 3p) and the per-post controls.
 *
 * A free local feature, same standing as the crawler log: everything here
 * works with the API stopped. The screen shows the file exactly as served,
 * says plainly when something needs attention, and carries the honesty
 * footer — llms.txt is a proposed standard and publishing it guarantees
 * nothing.
 *
 * @package Citolume
 */

defined( 'ABSPATH' ) || exit;

add_action( 'admin_init', 'citolume_handle_llms_post' );
/**
 * The screen's mutations, nonce-checked: regenerate, site context, and the
 * custom-sections editor.
 *
 * @return void
 */
function citolume_handle_llms_post() {
	if ( ! isset( $_POST['citolume_llms_action'] ) || ! current_user_can( 'manage_options' ) ) {
		return;
	}

	check_admin_referer( 'citolume_llms' );

	$action = sanitize_key( wp_unslash( $_POST['citolume_llms_action'] ) );

	if ( 'regenerate' === $action ) {
		citolume_clear_llms_cache();
		citolume_get_llms_txt();
		add_settings_error( 'citolume', 'citolume_llms_regen', __( 'File regenerated.', 'citolume' ), 'success' );
	}

	if ( 'context' === $action && isset( $_POST['citolume_llms_context'] ) ) {
		update_option( 'citolume_llms_context', sanitize_textarea_field( wp_unslash( $_POST['citolume_llms_context'] ) ), false );
		citolume_clear_llms_cache();
		add_settings_error( 'citolume', 'citolume_llms_context', __( 'Context saved and the file rebuilt.', 'citolume' ), 'success' );
	}

	if ( 'custom' === $action && isset( $_POST['citolume_llms_custom'] ) ) {
		update_option( 'citolume_llms_custom', sanitize_textarea_field( wp_unslash( $_POST['citolume_llms_custom'] ) ), false );
		citolume_clear_llms_cache();
		add_settings_error( 'citolume', 'citolume_llms_custom', __( 'Sections saved and the file rebuilt.', 'citolume' ), 'success' );
	}
}

/**
 * The checks behind the attention notice. Empty array means all is well.
 *
 * @return array<int, string> Plain sentences, one per failing check.
 */
function citolume_llms_attention() {
	$problems = array();

	if ( ! citolume_llms_enabled() ) {
		$problems[] = __( 'llms.txt is switched off, so /llms.txt answers 404. Turn it on under Settings → Site features.', 'citolume' );
	}

	if ( ! citolume_permalinks_support_llms() ) {
		$problems[] = __( 'Plain permalinks are active, so WordPress never routes /llms.txt to this plugin. Pick any other structure under Settings → Permalinks.', 'citolume' );
	}

	if ( file_exists( ABSPATH . 'llms.txt' ) ) {
		$problems[] = __( 'A physical llms.txt file exists in the web root and wins over this generated one — on purpose, so nothing you placed there is silently overridden.', 'citolume' );
	}

	// A missing tagline is NOT here any more. It is a content finding, not a
	// delivery one, and Review below says the same thing in the standard's
	// own words ("add a one-line summary as a blockquote"). Two bands saying
	// it from different angles taught the reader to skim both.

	return $problems;
}

/**
 * The platform's `reviewLlms()`, in PHP, run on the file we generate.
 *
 * Two different things used to be conflated and only one of them existed
 * here. `citolume_llms_attention()` above is about **delivery** — is the file
 * switched on, does the permalink structure route to it, is a physical file
 * shadowing it. This is about **content**: does the file say what the
 * standard asks for, so an AI tool can read it as intended.
 *
 * Run **locally**, not through the API. The rules are pure text analysis, the
 * plugin already holds the file it generated, and llms.txt is a free feature
 * that must keep working with the service completely absent. Sending the file
 * away to be read would break that for no gain.
 *
 * Kept rule-for-rule with the platform so the two surfaces cannot disagree
 * about the same file. If a rule changes there, change it here.
 *
 * @param string $content The file's content.
 * @param string $domain  The site's host, for the foreign-link check.
 * @return array<int, array{level: string, text: string}>
 */
function citolume_review_llms( $content, $domain ) {
	$findings = array();
	$lines    = preg_split( '/\r?\n/', $content );

	$first = '';
	foreach ( $lines as $line ) {
		if ( '' !== trim( $line ) ) {
			$first = $line;
			break;
		}
	}

	if ( ! preg_match( '/^# \S/', $first ) ) {
		$findings[] = array(
			'level' => 'problem',
			'text'  => __( 'The file should open with an H1 title ("# Your site name") — it is the first thing an AI reads.', 'citolume' ),
		);
	}

	$has = static function ( $pattern ) use ( $lines ) {
		foreach ( $lines as $line ) {
			if ( preg_match( $pattern, $line ) ) {
				return true;
			}
		}
		return false;
	};

	if ( ! $has( '/^> \S/' ) ) {
		$findings[] = array(
			'level' => 'suggestion',
			'text'  => __( 'Add a one-line summary as a blockquote ("> what the site is") right under the title.', 'citolume' ),
		);
	}

	if ( ! $has( '/^## \S/' ) ) {
		$findings[] = array(
			'level' => 'problem',
			'text'  => __( 'No "## Section" headings. Group your important pages into sections — the lists are what AI tools actually read.', 'citolume' ),
		);
	}

	preg_match_all( '/\[[^\]]*\]\(([^)\s]+)\)/', $content, $matches );
	$links = (array) ( $matches[1] ?? array() );

	if ( ! $links ) {
		$findings[] = array(
			'level' => 'problem',
			'text'  => __( 'No linked pages. Each section should list pages as "- [Title](URL)".', 'citolume' ),
		);
	} else {
		$relative = 0;
		$foreign  = 0;
		// Host comparison, never substrings — the product's own rule.
		$own = strtolower( (string) preg_replace( '/:.*$/', '', $domain ) );

		foreach ( $links as $url ) {
			if ( ! preg_match( '#^https?://#i', $url ) ) {
				++$relative;
				continue;
			}

			$host = strtolower( (string) wp_parse_url( $url, PHP_URL_HOST ) );

			if ( '' !== $host && $host !== $own && substr( $host, -strlen( '.' . $own ) ) !== '.' . $own ) {
				++$foreign;
			}
		}

		if ( $relative ) {
			$findings[] = array(
				'level' => 'suggestion',
				'text'  => sprintf(
					/* translators: %d: number of relative links. */
					_n( '%d link is relative — use absolute URLs so the file works wherever it is read from.', '%d links are relative — use absolute URLs so the file works wherever it is read from.', $relative, 'citolume' ),
					$relative
				),
			);
		}

		if ( $foreign ) {
			$findings[] = array(
				'level' => 'suggestion',
				'text'  => sprintf(
					/* translators: %d: number of links pointing at other domains. */
					_n( '%d link points at another domain. llms.txt is for your own pages — outbound links dilute it.', '%d links point at other domains. llms.txt is for your own pages — outbound links dilute it.', $foreign, 'citolume' ),
					$foreign
				),
			);
		}
	}

	if ( strlen( $content ) > 100 * 1024 ) {
		$findings[] = array(
			'level' => 'suggestion',
			'text'  => __( 'The file is over 100KB. Shorter files are read whole; trim to the pages that matter.', 'citolume' ),
		);
	}

	return $findings;
}

/**
 * Renders the llms.txt screen.
 *
 * @return void
 */
function citolume_render_llms_screen() {
	if ( ! current_user_can( 'manage_options' ) ) {
		return;
	}

	$status    = '' !== citolume_license_key() ? citolume_site_status() : null;
	$body      = citolume_get_llms_txt();
	$generated = (int) get_option( 'citolume_llms_generated_at', 0 );
	$context   = (string) get_option( 'citolume_llms_context', '' );
	$custom    = (string) get_option( 'citolume_llms_custom', '' );
	$problems  = citolume_llms_attention();
	$findings  = citolume_review_llms( (string) $body, citolume_site_host() );
	?>
	<div class="wrap citolume-wrap">
		<?php citolume_render_screen_head( __( 'llms.txt', 'citolume' ), __( 'A machine-readable index of your best content, served at /llms.txt', 'citolume' ) ); ?>

		<?php settings_errors( 'citolume' ); ?>

		<div class="citolume-llms-bar">
			<span class="citolume-llms-bar__file">
				<a href="<?php echo esc_url( citolume_llms_url() ); ?>" target="_blank" rel="noopener">
					<?php echo esc_html( preg_replace( '#^https?://#', '', citolume_llms_url() ) ); ?> ↗
				</a>
				<?php if ( $generated ) : ?>
					<span class="citolume-muted">
						<?php
						printf(
							/* translators: %s: date and time the file was last generated. */
							esc_html__( 'Regenerated %s', 'citolume' ),
							esc_html( wp_date( get_option( 'date_format' ) . ', ' . get_option( 'time_format' ), $generated ) )
						);
						?>
					</span>
				<?php endif; ?>
			</span>
			<span class="citolume-llms-bar__actions">
				<button type="button" class="button citolume-llms-copy" data-copied="<?php esc_attr_e( 'Copied', 'citolume' ); ?>">
					<?php esc_html_e( 'Copy', 'citolume' ); ?>
				</button>
				<form method="post">
					<?php wp_nonce_field( 'citolume_llms' ); ?>
					<input type="hidden" name="citolume_llms_action" value="regenerate" />
					<button type="submit" class="button button-primary"><?php esc_html_e( 'Regenerate', 'citolume' ); ?></button>
				</form>
			</span>
		</div>

		<?php if ( $problems ) : ?>
			<?php // Delivery: is the file reachable at all. Content findings are the Review card below. ?>
			<div class="citolume-llms-attention">
				<strong><?php esc_html_e( 'The file needs attention', 'citolume' ); ?></strong>
				<?php foreach ( $problems as $problem ) : ?>
					<p><?php echo esc_html( $problem ); ?></p>
				<?php endforeach; ?>
			</div>
		<?php endif; ?>

		<?php
		/*
		 * Review — the platform's card, run on the file we generate rather
		 * than on one fetched from the live site. Same rules, same two
		 * levels, so the two surfaces cannot disagree about the same file.
		 */
		?>
		<div class="citolume-card citolume-llms-review">
			<h2><?php esc_html_e( 'Review', 'citolume' ); ?></h2>
			<?php if ( $findings ) : ?>
				<?php foreach ( $findings as $finding ) : ?>
					<div class="citolume-finding">
						<span class="citolume-lvl is-<?php echo esc_attr( $finding['level'] ); ?>">
							<?php
							echo esc_html(
								'problem' === $finding['level']
									? __( 'Problem', 'citolume' )
									: __( 'Suggestion', 'citolume' )
							);
							?>
						</span>
						<span><?php echo esc_html( $finding['text'] ); ?></span>
					</div>
				<?php endforeach; ?>
			<?php else : ?>
				<p class="citolume-muted">
					<?php esc_html_e( 'Nothing to fix — the file has a title, a summary and linked sections. AI tools can read it as intended.', 'citolume' ); ?>
				</p>
			<?php endif; ?>
			<p class="citolume-muted citolume-llms-review__how">
				<?php esc_html_e( 'This plugin writes the file, so a fix here is an edit below — the generated sections keep updating, and anything you write by hand is left alone. The one-line summary comes from your tagline, under Settings → General.', 'citolume' ); ?>
			</p>
		</div>

		<div class="citolume-card citolume-llms-row">
			<div>
				<h2><?php esc_html_e( 'Optional site context', 'citolume' ); ?></h2>
				<p class="citolume-muted">
					<?php esc_html_e( 'Add facts that are not clear from your page titles, such as who you help, your location, or pricing.', 'citolume' ); ?>
				</p>
			</div>
			<button type="button" class="button citolume-reveal" aria-expanded="false" data-target="citolume-llms-context-form">
				<?php echo esc_html( '' === trim( $context ) ? __( 'Add context', 'citolume' ) : __( 'Edit context', 'citolume' ) ); ?>
			</button>
			<form method="post" class="citolume-llms-form" id="citolume-llms-context-form">
				<?php wp_nonce_field( 'citolume_llms' ); ?>
				<input type="hidden" name="citolume_llms_action" value="context" />
				<label class="screen-reader-text" for="citolume-llms-context"><?php esc_html_e( 'Site context', 'citolume' ); ?></label>
				<textarea id="citolume-llms-context" name="citolume_llms_context" rows="3"
					placeholder="<?php esc_attr_e( 'e.g. A family bakery in Brighton teaching home sourdough baking. Classes from £40.', 'citolume' ); ?>"><?php echo esc_textarea( $context ); ?></textarea>
				<p><button type="submit" class="button button-primary"><?php esc_html_e( 'Save context', 'citolume' ); ?></button></p>
			</form>
		</div>

		<div class="citolume-card">
			<div class="citolume-llms-edit-head">
				<h2><?php esc_html_e( 'Edit the file', 'citolume' ); ?></h2>
				<span class="citolume-automatic-pill"><?php esc_html_e( 'AUTOMATIC', 'citolume' ); ?></span>
			</div>
			<p class="citolume-muted">
				<?php esc_html_e( 'Add a custom section or change a generated one. Sections you leave alone keep updating.', 'citolume' ); ?>
			</p>
			<button type="button" class="button citolume-reveal" aria-expanded="false" data-target="citolume-llms-custom-form">
				<?php esc_html_e( 'Edit this file', 'citolume' ); ?>
			</button>
			<form method="post" class="citolume-llms-form" id="citolume-llms-custom-form">
				<?php wp_nonce_field( 'citolume_llms' ); ?>
				<input type="hidden" name="citolume_llms_action" value="custom" />
				<label class="screen-reader-text" for="citolume-llms-custom"><?php esc_html_e( 'Custom sections', 'citolume' ); ?></label>
				<textarea id="citolume-llms-custom" name="citolume_llms_custom" rows="10"
					placeholder="<?php echo esc_attr( "## Guides\n\n- [Sourdough Starter Guide](https://example.com/sourdough-starter/)" ); ?>"><?php echo esc_textarea( $custom ); ?></textarea>
				<p class="description">
					<?php esc_html_e( 'Start each section with “## Heading”. A section named like a generated one (Pages, Posts, Optional…) replaces it; any other is added. Delete a section here to hand it back to the generator.', 'citolume' ); ?>
				</p>
				<p><button type="submit" class="button button-primary"><?php esc_html_e( 'Save sections', 'citolume' ); ?></button></p>
			</form>
		</div>

		<div class="citolume-card">
			<h2><?php esc_html_e( 'Live preview', 'citolume' ); ?></h2>
			<pre class="citolume-llms-preview" id="citolume-llms-preview"><?php echo esc_html( $body ); ?></pre>
		</div>

		<div class="citolume-card">
			<h2><?php esc_html_e( 'How llms.txt works', 'citolume' ); ?></h2>
			<p class="citolume-muted">
				<?php esc_html_e( 'llms.txt is a proposed plain-text guide to your website. An AI system may choose to read it, but publishing the file does not guarantee crawling, rankings, or citations.', 'citolume' ); ?>
			</p>
			<div class="citolume-llms-how">
				<div>
					<strong>✓ <?php esc_html_e( 'Organized automatically', 'citolume' ); ?></strong>
					<p><?php esc_html_e( 'Published Pages, Posts, Products, Downloads, and public custom content types receive their own sections.', 'citolume' ); ?></p>
				</div>
				<div>
					<strong>✓ <?php esc_html_e( 'Control every entry', 'citolume' ); ?></strong>
					<p><?php esc_html_e( 'Open a post or page to write its llms.txt description. Switch its entry off when you want it left out.', 'citolume' ); ?></p>
				</div>
				<div>
					<strong>✓ <?php esc_html_e( 'Add your own sections', 'citolume' ); ?></strong>
					<p><?php esc_html_e( 'Use Edit the file to add sections such as Guides or Resources. Your custom sections stay saved while generated ones keep updating.', 'citolume' ); ?></p>
				</div>
			</div>
		</div>
	</div>
	<?php
}

add_action( 'add_meta_boxes', 'citolume_add_llms_meta_box' );
/**
 * The per-post llms.txt controls: a deliberate description, and the off
 * switch (design 3p, "Control every entry").
 *
 * @return void
 */
function citolume_add_llms_meta_box() {
	$types = get_post_types( array( 'public' => true ) );
	unset( $types['attachment'] );

	add_meta_box(
		'citolume-llms',
		__( 'llms.txt', 'citolume' ),
		'citolume_render_llms_meta_box',
		array_values( $types ),
		'side'
	);
}

/**
 * Renders the meta box.
 *
 * @param WP_Post $post The post being edited.
 * @return void
 */
function citolume_render_llms_meta_box( $post ) {
	wp_nonce_field( 'citolume_llms_meta', 'citolume_llms_meta_nonce' );

	$description = (string) get_post_meta( $post->ID, '_citolume_description', true );
	$excluded    = ! empty( get_post_meta( $post->ID, '_citolume_exclude', true ) );
	?>
	<p>
		<label for="citolume-llms-description"><?php esc_html_e( 'Description in llms.txt', 'citolume' ); ?></label>
		<textarea id="citolume-llms-description" name="citolume_llms_description" rows="3" class="widefat"
			placeholder="<?php echo esc_attr( citolume_clean_text( citolume_post_summary( $post ) ) ); ?>"><?php echo esc_textarea( $description ); ?></textarea>
	</p>
	<p class="description"><?php esc_html_e( 'Optional one-liner after the link. Empty means the link stands alone.', 'citolume' ); ?></p>
	<p>
		<label>
			<input type="checkbox" name="citolume_llms_exclude" value="1" <?php checked( $excluded ); ?> />
			<?php esc_html_e( 'Leave this out of llms.txt', 'citolume' ); ?>
		</label>
	</p>
	<?php
}

add_action( 'save_post', 'citolume_save_llms_meta' );
/**
 * Saves the meta box, and only the meta box.
 *
 * @param int $post_id The post being saved.
 * @return void
 */
function citolume_save_llms_meta( $post_id ) {
	if ( ! isset( $_POST['citolume_llms_meta_nonce'] )
		|| ! wp_verify_nonce( sanitize_key( wp_unslash( $_POST['citolume_llms_meta_nonce'] ) ), 'citolume_llms_meta' )
		|| ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
		|| ! current_user_can( 'edit_post', $post_id ) ) {
		return;
	}

	$description = isset( $_POST['citolume_llms_description'] ) ? sanitize_textarea_field( wp_unslash( $_POST['citolume_llms_description'] ) ) : '';

	if ( '' === trim( $description ) ) {
		delete_post_meta( $post_id, '_citolume_description' );
	} else {
		update_post_meta( $post_id, '_citolume_description', $description );
	}

	if ( empty( $_POST['citolume_llms_exclude'] ) ) {
		delete_post_meta( $post_id, '_citolume_exclude' );
	} else {
		update_post_meta( $post_id, '_citolume_exclude', 1 );
	}

	// citolume_clear_llms_cache() already runs on save_post.
}