<?php
/**
 * Live AI visibility / citation tracking (Dev-plan task #5).
 *
 * Sends each tracked prompt to every AI engine that has an API key, inspects
 * the answer (and returned sources, when available) for the site's domain, and
 * records the citation position. Modular: each engine runs only if configured.
 * Triggered manually from the dashboard or by a weekly cron.
 *
 * @package AICitare
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class AICitare_Visibility {

	/** Engine id => display label. Column order in the citations table. */
	const ENGINES = array(
		'openai'     => 'ChatGPT',
		'perplexity' => 'Perplexity',
		'google'     => 'Gemini',
		'anthropic'  => 'Claude',
		'grok'       => 'Grok',
		'ollama'     => 'Ollama',
	);

	const OPT_RESULTS = 'aicitare_citations_live';
	const OPT_CHECKED = 'aicitare_vis_checked';
	const OPT_STATUS  = 'aicitare_engine_status';
	const OPT_ANSWERS = 'aicitare_answers';
	const OPT_PROMPTS = 'aicitare_prompts';
	const OPT_HISTORY = 'aicitare_vis_history';
	const OPT_COMPETITORS = 'aicitare_competitors';
	const OPT_SHARE = 'aicitare_share';
	const OPT_DISCOVERED = 'aicitare_discovered';

	/** Domains to ignore when auto-discovering competitors. */
	const NOISE = array(
		'schema.org', 'w3.org', 'wordpress.org', 'gravatar.com', 'gstatic.com', 'googleapis.com',
		'google.com', 'bing.com', 'youtube.com', 'facebook.com', 'twitter.com', 'x.com', 'instagram.com',
		'openai.com', 'perplexity.ai', 'anthropic.com', 'x.ai', 'reddit.com', 'wikipedia.org', 'amazon.com',
	);

	public function hooks() {
		add_action( 'aicitare_weekly_visibility', array( $this, 'run' ) );
	}

	/** Tracked prompts (default: the seed questions; filterable). */
	public static function prompts() {
		$stored = get_option( self::OPT_PROMPTS );
		if ( is_array( $stored ) && $stored ) {
			return $stored;
		}
		// No prompts saved yet: the pillow demo prompts only in Demo mode,
		// otherwise start empty so the user adds their own.
		$settings = AICitare_Data::get_settings();
		$qs = array();
		if ( ! empty( $settings['demo_mode'] ) ) {
			foreach ( AICitare_Data::citations() as $c ) {
				$qs[] = $c['q'];
			}
		}
		return apply_filters( 'aicitare_prompts', $qs );
	}

	/** Save the tracked-prompts list (empty array reverts to defaults). */
	public static function save_prompts( $list ) {
		$clean = array();
		foreach ( (array) $list as $p ) {
			$p = sanitize_text_field( $p );
			if ( '' !== trim( $p ) ) {
				$clean[] = $p;
			}
		}
		$clean = array_values( array_unique( $clean ) );
		if ( empty( $clean ) ) {
			delete_option( self::OPT_PROMPTS );
		} else {
			update_option( self::OPT_PROMPTS, $clean );
		}
		return self::prompts();
	}

	/** Citation-trend history (totals & avg position per check). */
	public static function vis_history() {
		$h = get_option( self::OPT_HISTORY );
		return is_array( $h ) ? $h : array();
	}

	/** Tracked competitors [{ name, domain }] (default: common pillow-review sites). */
	public static function competitors_list() {
		$stored = get_option( self::OPT_COMPETITORS );
		if ( is_array( $stored ) && $stored ) {
			return $stored;
		}
		return array(
			array( 'name' => 'Sleep Foundation', 'domain' => 'sleepfoundation.org' ),
			array( 'name' => 'Wirecutter', 'domain' => 'nytimes.com/wirecutter' ),
			array( 'name' => 'Sleepopolis', 'domain' => 'sleepopolis.com' ),
			array( 'name' => "Tom's Guide", 'domain' => 'tomsguide.com' ),
		);
	}

	/** Save competitor list (empty reverts to defaults). */
	public static function save_competitors( $list ) {
		$clean = array();
		foreach ( (array) $list as $c ) {
			$name   = isset( $c['name'] ) ? sanitize_text_field( $c['name'] ) : '';
			$domain = isset( $c['domain'] ) ? sanitize_text_field( $c['domain'] ) : '';
			$domain = preg_replace( '#^https?://#', '', trim( $domain ) );
			$domain = preg_replace( '#^www\.#', '', $domain );
			if ( '' !== $name && '' !== $domain ) {
				$clean[] = array( 'name' => $name, 'domain' => $domain );
			}
		}
		if ( empty( $clean ) ) {
			delete_option( self::OPT_COMPETITORS );
		} else {
			update_option( self::OPT_COMPETITORS, $clean );
		}
		return self::competitors_list();
	}

	/**
	 * Share-of-voice for the dashboard:
	 *  - computed live data if a visibility check has produced it; else
	 *  - the demo dataset when Demo mode is on (illustrative); else
	 *  - the user's tracked competitors at 0% (so additions show immediately,
	 *    pending a real check).
	 */
	/** Auto-discovered competitor suggestions from the last check. */
	public static function discovered() {
		$d = get_option( self::OPT_DISCOVERED );
		return is_array( $d ) ? $d : array();
	}

	/** Domains referenced in a response (from sources + text), normalized & unique. */
	private function extract_domains( $resp ) {
		$hosts = array();
		foreach ( (array) ( isset( $resp['sources'] ) ? $resp['sources'] : array() ) as $u ) {
			$h = self::norm_host( $u );
			if ( $h ) {
				$hosts[] = $h;
			}
		}
		$txt = isset( $resp['text'] ) ? $resp['text'] : '';
		if ( $txt && preg_match_all( '#\b((?:[a-z0-9-]+\.)+(?:com|org|net|io|co|ai|gov|edu|guide|shop|store|blog))\b#i', $txt, $m ) ) {
			foreach ( $m[1] as $d ) {
				$h = self::norm_host( $d );
				if ( $h ) {
					$hosts[] = $h;
				}
			}
		}
		return array_values( array_unique( $hosts ) );
	}

	/** Normalize a URL/host to a bare lowercase host (no scheme, no www, no path). */
	private static function norm_host( $u ) {
		$u = trim( (string) $u );
		if ( '' === $u ) {
			return '';
		}
		if ( ! preg_match( '#^https?://#i', $u ) ) {
			$u = 'http://' . $u;
		}
		$h = wp_parse_url( $u, PHP_URL_HOST );
		return $h ? preg_replace( '#^www\.#', '', strtolower( $h ) ) : '';
	}

	/** Human-friendly name from a domain (sleepopolis.com -> Sleepopolis). */
	private static function nice_name( $domain ) {
		$parts = explode( '.', $domain );
		return ucfirst( $parts[0] );
	}

	public static function get_share() {
		$live = get_option( self::OPT_SHARE );
		if ( is_array( $live ) && $live ) {
			return $live;
		}
		$settings = AICitare_Data::get_settings();
		if ( ! empty( $settings['demo_mode'] ) ) {
			return AICitare_Data::competitors();
		}
		$out = array( array( 'name' => get_bloginfo( 'name' ), 'share' => 0, 'me' => true ) );
		foreach ( self::competitors_list() as $c ) {
			$out[] = array( 'name' => $c['name'], 'share' => 0 );
		}
		return $out;
	}

	/** Which engines are usable now (API key configured, or Ollama enabled). */
	public static function active_engines() {
		$keys     = AICitare_Data::get_keys_plain();
		$settings = AICitare_Data::get_settings();
		$active   = array();
		foreach ( array_keys( self::ENGINES ) as $eng ) {
			if ( 'ollama' === $eng ) {
				$active[ $eng ] = ! empty( $settings['ollama_enabled'] ) && ! empty( $settings['ollama_url'] );
			} else {
				$active[ $eng ] = ! empty( $keys[ $eng ] );
			}
		}
		return $active;
	}

	/** Run the full check across prompts × engines. */
	public function run() {
		$keys     = AICitare_Data::get_keys_plain();
		$settings = AICitare_Data::get_settings();
		$host     = self::host();
		$name     = self::site_name();
		$comps    = self::competitors_list();
		$results  = array();
		$counts   = array(); // mention tally for share-of-voice.
		$status   = array(); // per-engine: ok count + last error, for diagnostics.
		$answers  = array(); // raw model answers per prompt, for inspection.
		$disc     = array(); // auto-discovered domain tally.

		// Domains to exclude from discovery: our own + already-tracked + noise.
		$exclude = array_merge( array( self::norm_host( $host ) ), self::NOISE );
		foreach ( $comps as $c ) {
			$h = self::norm_host( $c['domain'] );
			if ( $h ) {
				$exclude[] = $h;
			}
		}

		foreach ( self::prompts() as $q ) {
			$row  = array();
			$arow = array();
			foreach ( array_keys( self::ENGINES ) as $eng ) {
				if ( 'ollama' === $eng ) {
					if ( empty( $settings['ollama_enabled'] ) || empty( $settings['ollama_url'] ) ) {
						$row[] = null;
						continue;
					}
					$resp = $this->ollama( $settings['ollama_url'], isset( $settings['ollama_model'] ) ? $settings['ollama_model'] : '', $q );
				} else {
					$key = isset( $keys[ $eng ] ) ? $keys[ $eng ] : '';
					if ( '' === $key ) {
						$row[] = null;
						continue;
					}
					$resp = $this->ask( $eng, $key, $q );
				}
				if ( ! isset( $status[ $eng ] ) ) {
					$status[ $eng ] = array( 'ok' => 0, 'err' => '' );
				}
				if ( is_wp_error( $resp ) ) {
					$status[ $eng ]['err'] = $resp->get_error_message();
					$arow[ $eng ]          = '⚠ ' . $resp->get_error_message();
					$row[] = null;
					continue;
				}
				$status[ $eng ]['ok']++;
				$text          = isset( $resp['text'] ) ? $resp['text'] : '';
				$arow[ $eng ]  = function_exists( 'mb_substr' ) ? mb_substr( $text, 0, 1200 ) : substr( $text, 0, 1200 );
				$row[] = $this->position( $resp, $host, $name );
				foreach ( $this->mentions( $resp, $host, $name, $comps ) as $k ) {
					$counts[ $k ] = ( isset( $counts[ $k ] ) ? $counts[ $k ] : 0 ) + 1;
				}
				foreach ( $this->extract_domains( $resp ) as $d ) {
					if ( in_array( $d, $exclude, true ) ) {
						continue;
					}
					$disc[ $d ] = ( isset( $disc[ $d ] ) ? $disc[ $d ] : 0 ) + 1;
				}
			}
			$results[]  = array( 'q' => $q, 'e' => $row );
			$answers[]  = array( 'q' => $q, 'a' => $arow );
		}

		update_option( self::OPT_ANSWERS, $answers );
		update_option( self::OPT_RESULTS, $results );
		update_option( self::OPT_CHECKED, current_time( 'mysql' ) );
		update_option( self::OPT_SHARE, $this->compute_share( $counts, $comps ) );
		update_option( self::OPT_STATUS, $status );

		// Build auto-discovered competitor suggestions (most-cited first).
		arsort( $disc );
		$discovered = array();
		$k          = 0;
		foreach ( $disc as $dom => $cnt ) {
			if ( $cnt < 2 ) {
				continue; // only suggest domains seen more than once.
			}
			$discovered[] = array( 'domain' => $dom, 'name' => self::nice_name( $dom ), 'count' => (int) $cnt );
			if ( ++$k >= 12 ) {
				break;
			}
		}
		update_option( self::OPT_DISCOVERED, $discovered );

		// Append to the citation-trend history.
		$total = 0;
		$pos   = array();
		foreach ( $results as $r ) {
			foreach ( $r['e'] as $v ) {
				if ( null !== $v ) {
					$total++;
					$pos[] = $v;
				}
			}
		}
		$hist   = self::vis_history();
		$hist[] = array(
			'date'  => current_time( 'Y-m-d' ),
			'total' => $total,
			'avg'   => $pos ? round( array_sum( $pos ) / count( $pos ), 1 ) : 0,
		);
		if ( count( $hist ) > 24 ) {
			$hist = array_slice( $hist, -24 );
		}
		update_option( self::OPT_HISTORY, $hist );

		$active = count( array_filter( self::active_engines() ) );
		AICitare_Log::add( 'visibility', sprintf( 'Visibility check — %d prompts, %d engine(s), %d citations', count( self::prompts() ), $active, $total ) );

		return $results;
	}

	/** Which tracked entities (our site + competitors) are mentioned in a response. */
	private function mentions( $resp, $host, $name, $comps ) {
		$hay = strtolower( ( isset( $resp['text'] ) ? $resp['text'] : '' ) . ' ' . implode( ' ', (array) ( isset( $resp['sources'] ) ? $resp['sources'] : array() ) ) );
		$out = array();
		if ( self::hay_has( $hay, $host, $name ) ) {
			$out[] = '__me__';
		}
		foreach ( $comps as $c ) {
			if ( self::hay_has( $hay, trim( $c['domain'] ), $c['name'] ) ) {
				$out[] = 'c:' . $c['name'];
			}
		}
		return array_unique( $out );
	}

	/** True if the haystack contains the domain, or the brand name (>=4 chars). */
	private static function hay_has( $hay, $domain, $name ) {
		$domain = strtolower( (string) $domain );
		if ( '' !== $domain && false !== strpos( $hay, $domain ) ) {
			return true;
		}
		$name = strtolower( trim( (string) $name ) );
		if ( strlen( $name ) >= 4 && false !== strpos( $hay, $name ) ) {
			return true;
		}
		return false;
	}

	/** Lowercased site/brand name for text matching. */
	private static function site_name() {
		return strtolower( trim( (string) get_bloginfo( 'name' ) ) );
	}

	/** Turn a mention tally into share-of-voice percentages. */
	private function compute_share( $counts, $comps ) {
		$total = array_sum( $counts );
		if ( $total <= 0 ) {
			return array(); // nothing detected → keep demo data.
		}
		$share = array();
		if ( ! empty( $counts['__me__'] ) ) {
			$share[] = array( 'name' => get_bloginfo( 'name' ), 'share' => (int) round( $counts['__me__'] / $total * 100 ), 'me' => true );
		}
		foreach ( $comps as $c ) {
			$k = 'c:' . $c['name'];
			if ( ! empty( $counts[ $k ] ) ) {
				$share[] = array( 'name' => $c['name'], 'share' => (int) round( $counts[ $k ] / $total * 100 ) );
			}
		}
		usort( $share, function ( $a, $b ) { return $b['share'] - $a['share']; } );
		return $share;
	}

	/** Determine citation position from an engine response (by domain in sources, or domain/brand in text). */
	private function position( $resp, $host, $name = '' ) {
		if ( $host && ! empty( $resp['sources'] ) ) {
			$pos = 1;
			foreach ( $resp['sources'] as $url ) {
				if ( false !== stripos( (string) $url, $host ) ) {
					return $pos;
				}
				$pos++;
			}
		}
		$text = isset( $resp['text'] ) ? strtolower( $resp['text'] ) : '';
		if ( '' === $text ) {
			return null;
		}
		// Domain or brand-name mention in the answer text counts as cited.
		if ( $host && false !== strpos( $text, strtolower( $host ) ) ) {
			return 1;
		}
		$name = strtolower( trim( (string) $name ) );
		if ( strlen( $name ) >= 4 && false !== strpos( $text, $name ) ) {
			return 1;
		}
		return null;
	}

	/** Recommended default model per engine. */
	public static function recommended( $eng ) {
		$map = array(
			'openai'     => 'gpt-4o-mini',
			'perplexity' => 'sonar',
			'google'     => 'gemini-2.0-flash',
			'anthropic'  => 'claude-3-5-haiku-latest',
			'grok'       => 'grok-3',
			'ollama'     => 'llama3.2',
		);
		return isset( $map[ $eng ] ) ? $map[ $eng ] : '';
	}

	/** Fetch the list of available models for an engine from its API. */
	public static function list_models( $eng ) {
		$rec = self::recommended( $eng );

		if ( 'ollama' === $eng ) {
			$s = AICitare_Data::get_settings();
			if ( empty( $s['ollama_enabled'] ) || empty( $s['ollama_url'] ) ) {
				return array( 'ok' => false, 'msg' => 'Ollama is not enabled' );
			}
			$r = wp_remote_get( rtrim( $s['ollama_url'], '/' ) . '/api/tags', array( 'timeout' => 15 ) );
			if ( is_wp_error( $r ) ) {
				return array( 'ok' => false, 'msg' => $r->get_error_message() );
			}
			$models = array();
			$j      = json_decode( wp_remote_retrieve_body( $r ), true );
			if ( isset( $j['models'] ) ) {
				foreach ( $j['models'] as $m ) {
					if ( ! empty( $m['name'] ) ) {
						$models[] = $m['name'];
					}
				}
			}
			sort( $models );
			return array( 'ok' => true, 'models' => $models, 'recommended' => $rec );
		}

		if ( 'perplexity' === $eng ) {
			// Perplexity has no public models endpoint — curated list.
			return array( 'ok' => true, 'models' => array( 'sonar', 'sonar-pro', 'sonar-reasoning', 'sonar-reasoning-pro', 'sonar-deep-research' ), 'recommended' => $rec );
		}

		$keys = AICitare_Data::get_keys_plain();
		$key  = isset( $keys[ $eng ] ) ? $keys[ $eng ] : '';
		if ( '' === $key ) {
			return array( 'ok' => false, 'msg' => 'No key set' );
		}

		$models = array();
		if ( 'openai' === $eng || 'grok' === $eng ) {
			$url = 'openai' === $eng ? 'https://api.openai.com/v1/models' : 'https://api.x.ai/v1/models';
			$r   = wp_remote_get( $url, array( 'timeout' => 20, 'headers' => array( 'Authorization' => 'Bearer ' . $key ) ) );
			$models = self::ids_from_data( $r );
		} elseif ( 'anthropic' === $eng ) {
			$r = wp_remote_get( 'https://api.anthropic.com/v1/models', array( 'timeout' => 20, 'headers' => array( 'x-api-key' => $key, 'anthropic-version' => '2023-06-01' ) ) );
			$models = self::ids_from_data( $r );
		} elseif ( 'google' === $eng ) {
			$r = wp_remote_get( 'https://generativelanguage.googleapis.com/v1beta/models?key=' . rawurlencode( $key ), array( 'timeout' => 20 ) );
			if ( ! is_wp_error( $r ) && (int) wp_remote_retrieve_response_code( $r ) < 400 ) {
				$j = json_decode( wp_remote_retrieve_body( $r ), true );
				if ( isset( $j['models'] ) ) {
					foreach ( $j['models'] as $m ) {
						$methods = isset( $m['supportedGenerationMethods'] ) ? $m['supportedGenerationMethods'] : array();
						if ( in_array( 'generateContent', $methods, true ) && ! empty( $m['name'] ) ) {
							$models[] = preg_replace( '#^models/#', '', $m['name'] );
						}
					}
				}
			}
		} else {
			return array( 'ok' => false, 'msg' => 'Unsupported engine' );
		}

		if ( is_wp_error( $r ) ) {
			return array( 'ok' => false, 'msg' => $r->get_error_message() );
		}
		$code = (int) wp_remote_retrieve_response_code( $r );
		if ( $code >= 400 ) {
			$b = json_decode( wp_remote_retrieve_body( $r ), true );
			return array( 'ok' => false, 'msg' => 'HTTP ' . $code . ( isset( $b['error']['message'] ) ? ': ' . $b['error']['message'] : '' ) );
		}
		sort( $models );
		return array( 'ok' => true, 'models' => array_values( array_unique( $models ) ), 'recommended' => $rec );
	}

	private static function ids_from_data( $r ) {
		if ( is_wp_error( $r ) ) {
			return array();
		}
		$j   = json_decode( wp_remote_retrieve_body( $r ), true );
		$out = array();
		if ( isset( $j['data'] ) ) {
			foreach ( $j['data'] as $m ) {
				if ( ! empty( $m['id'] ) ) {
					$out[] = $m['id'];
				}
			}
		}
		return $out;
	}

	/** Test a single engine with a trivial prompt. Returns ['ok'=>bool,'msg'=>string]. */
	public static function test( $eng ) {
		$self = new self();
		$q    = 'Reply with the single word OK.';
		if ( 'ollama' === $eng ) {
			$s = AICitare_Data::get_settings();
			if ( empty( $s['ollama_enabled'] ) || empty( $s['ollama_url'] ) ) {
				return array( 'ok' => false, 'msg' => 'Ollama is not enabled' );
			}
			$r = $self->ollama( $s['ollama_url'], isset( $s['ollama_model'] ) ? $s['ollama_model'] : '', $q );
		} else {
			$keys = AICitare_Data::get_keys_plain();
			$key  = isset( $keys[ $eng ] ) ? $keys[ $eng ] : '';
			if ( '' === $key ) {
				return array( 'ok' => false, 'msg' => 'No key set' );
			}
			$r = $self->ask( $eng, $key, $q );
		}
		if ( is_wp_error( $r ) ) {
			return array( 'ok' => false, 'msg' => $r->get_error_message() );
		}
		$txt = isset( $r['text'] ) ? trim( $r['text'] ) : '';
		$snip = '' !== $txt ? ( function_exists( 'mb_substr' ) ? mb_substr( $txt, 0, 60 ) : substr( $txt, 0, 60 ) ) : '';
		return array( 'ok' => true, 'msg' => $snip ? ( 'Responded: ' . $snip ) : 'Responded' );
	}

	/**
	 * Produce GEO-optimized rephrasings of a piece of text.
	 * Returns [ 'ok'=>true, 'engine'=>slug, 'variants'=>[..] ] or WP_Error.
	 */
	public static function rephrase( $text, $engine = '', $n = 3 ) {
		$text = trim( (string) $text );
		if ( '' === $text ) {
			return new WP_Error( 'empty', 'Please provide some text to rephrase.' );
		}
		if ( strlen( $text ) > 6000 ) {
			$text = substr( $text, 0, 6000 );
		}
		$n      = max( 1, min( 5, (int) $n ) );
		$active = self::active_engines();
		if ( '' === $engine || empty( $active[ $engine ] ) ) {
			$engine = '';
			foreach ( $active as $e => $on ) {
				if ( $on ) {
					$engine = $e;
					break;
				}
			}
		}
		if ( '' === $engine ) {
			return new WP_Error( 'no_engine', 'No LLM is configured. Add an API key (or enable Ollama) in Settings.' );
		}

		$prompt = "You are a GEO (Generative Engine Optimization) copy editor. Rewrite the text below so AI assistants (ChatGPT, Perplexity, Google AI Overviews, Gemini, Claude) are more likely to quote and cite it.\n\n"
			. "Each rewrite should: lead with a direct, self-contained answer; state clear, verifiable facts; use a natural, confident, non-spammy tone; stay roughly the same length; and keep the SAME language as the input.\n\n"
			. "Give exactly {$n} DISTINCT alternatives that differ in phrasing and structure.\n"
			. "Return ONLY a JSON array of {$n} strings — no markdown fences, no numbering, no commentary.\n\n"
			. "TEXT:\n\"\"\"\n{$text}\n\"\"\"";

		$self = new self();
		if ( 'ollama' === $engine ) {
			$s = AICitare_Data::get_settings();
			$r = $self->ollama( $s['ollama_url'], isset( $s['ollama_model'] ) ? $s['ollama_model'] : '', $prompt );
		} else {
			$keys = AICitare_Data::get_keys_plain();
			$r    = $self->ask( $engine, isset( $keys[ $engine ] ) ? $keys[ $engine ] : '', $prompt );
		}
		if ( is_wp_error( $r ) ) {
			return $r;
		}
		$variants = self::parse_variants( isset( $r['text'] ) ? $r['text'] : '', $n );
		if ( empty( $variants ) ) {
			return new WP_Error( 'parse', 'The model did not return usable suggestions. Please try again.' );
		}
		AICitare_Log::add( 'rephrase', 'Generated ' . count( $variants ) . ' GEO rephrasings via ' . $engine . '.' );
		return array( 'ok' => true, 'engine' => $engine, 'variants' => $variants );
	}

	/**
	 * Generate FAQ question/answer pairs from article text via the active LLM.
	 * Returns [ 'ok'=>true, 'engine'=>slug, 'faqs'=>[ {q,a}, ... ] ] or WP_Error.
	 */
	public static function generate_faq( $text, $engine = '', $n = 5 ) {
		$text = trim( wp_strip_all_tags( (string) $text ) );
		if ( '' === $text ) {
			return new WP_Error( 'empty', 'There is no content to build a FAQ from.' );
		}
		if ( strlen( $text ) > 8000 ) {
			$text = substr( $text, 0, 8000 );
		}
		$n      = max( 3, min( 8, (int) $n ) );
		$active = self::active_engines();
		if ( '' === $engine || empty( $active[ $engine ] ) ) {
			$engine = '';
			foreach ( $active as $e => $on ) {
				if ( $on ) {
					$engine = $e;
					break;
				}
			}
		}
		if ( '' === $engine ) {
			return new WP_Error( 'no_engine', 'No LLM is configured. Add an API key (or enable Ollama) in Settings.' );
		}

		$prompt = "You are an SEO/GEO editor. From the article below, write {$n} frequently-asked question-and-answer pairs that real readers would ask and that are answerable from the article.\n\n"
			. "Each answer must be 1–3 sentences, factual, and in the SAME language as the article. Do not invent facts not supported by the text.\n"
			. "Return ONLY a JSON array of objects, each with keys \"q\" (question) and \"a\" (answer). No markdown, no commentary.\n\n"
			. "ARTICLE:\n\"\"\"\n{$text}\n\"\"\"";

		$self = new self();
		if ( 'ollama' === $engine ) {
			$s = AICitare_Data::get_settings();
			$r = $self->ollama( $s['ollama_url'], isset( $s['ollama_model'] ) ? $s['ollama_model'] : '', $prompt );
		} else {
			$keys = AICitare_Data::get_keys_plain();
			$r    = $self->ask( $engine, isset( $keys[ $engine ] ) ? $keys[ $engine ] : '', $prompt );
		}
		if ( is_wp_error( $r ) ) {
			return $r;
		}
		$faqs = self::parse_faq( isset( $r['text'] ) ? $r['text'] : '', $n );
		if ( empty( $faqs ) ) {
			return new WP_Error( 'parse', 'The model did not return usable FAQ pairs. Please try again.' );
		}
		AICitare_Log::add( 'faq', 'Generated ' . count( $faqs ) . ' FAQ pairs via ' . $engine . '.' );
		return array( 'ok' => true, 'engine' => $engine, 'faqs' => $faqs );
	}

	/** Parse model output into a list of { q, a } FAQ pairs. */
	private static function parse_faq( $text, $n ) {
		$text = trim( (string) $text );
		$text = preg_replace( '#^```[a-z]*\s*#i', '', $text );
		$text = preg_replace( '#\s*```$#', '', $text );
		$start = strpos( $text, '[' );
		$end   = strrpos( $text, ']' );
		$out   = array();
		if ( false !== $start && false !== $end && $end > $start ) {
			$arr = json_decode( substr( $text, $start, $end - $start + 1 ), true );
			if ( is_array( $arr ) ) {
				foreach ( $arr as $row ) {
					if ( ! is_array( $row ) ) {
						continue;
					}
					$q = isset( $row['q'] ) ? trim( (string) $row['q'] ) : ( isset( $row['question'] ) ? trim( (string) $row['question'] ) : '' );
					$a = isset( $row['a'] ) ? trim( (string) $row['a'] ) : ( isset( $row['answer'] ) ? trim( (string) $row['answer'] ) : '' );
					if ( '' !== $q && '' !== $a ) {
						$out[] = array( 'q' => $q, 'a' => $a );
					}
				}
			}
		}
		return array_slice( $out, 0, $n );
	}

	/**
	 * Return the real post body of a dashboard page, split into paragraphs.
	 * Dashboard page ids are 'wp{ID}' for real posts; demo pages return a WP_Error.
	 */
	public static function page_paragraphs( $page_id ) {
		$page_id = (string) $page_id;
		$pid     = 0;
		if ( preg_match( '#^wp(\d+)$#', $page_id, $m ) ) {
			$pid = (int) $m[1];
		}
		if ( ! $pid ) {
			return new WP_Error( 'demo', 'This is a demo page — there is no WordPress post to load. Paste text below instead.' );
		}
		$post = get_post( $pid );
		if ( ! $post ) {
			return new WP_Error( 'notfound', 'Post not found.' );
		}
		$html  = do_shortcode( $post->post_content );
		$paras = self::html_paragraphs( $html );
		if ( empty( $paras ) ) {
			$paras = self::html_paragraphs( wpautop( $post->post_content ) );
		}
		if ( empty( $paras ) ) {
			return new WP_Error( 'nocontent', 'This post has no readable paragraphs to rephrase.' );
		}
		return array(
			'ok'         => true,
			'postId'     => $pid,
			'title'      => get_the_title( $pid ),
			'paragraphs' => $paras,
			'editUrl'    => admin_url( 'post.php?post=' . $pid . '&action=edit' ),
		);
	}

	/** Extract block-level text chunks (paragraphs, headings, list items) from HTML. */
	private static function html_paragraphs( $html ) {
		$out = array();
		if ( preg_match_all( '#<(p|h[1-6]|li)\b[^>]*>(.*?)</\1>#is', (string) $html, $m, PREG_SET_ORDER ) ) {
			foreach ( $m as $mm ) {
				$txt = self::block_text( $mm[2] );
				if ( ( function_exists( 'mb_strlen' ) ? mb_strlen( $txt ) : strlen( $txt ) ) < 15 ) {
					continue;
				}
				$out[] = array( 'text' => $txt, 'tag' => strtolower( $mm[1] ) );
				if ( count( $out ) >= 40 ) {
					break;
				}
			}
		}
		return $out;
	}

	/** Normalize a block's inner HTML to plain text (shared by extraction and replacement). */
	private static function block_text( $inner ) {
		return trim( preg_replace( '#\s+#', ' ', html_entity_decode( wp_strip_all_tags( $inner ), ENT_QUOTES ) ) );
	}

	/**
	 * Apply chosen paragraph rephrasings and save the result as a DRAFT copy
	 * awaiting approval, leaving the live post untouched.
	 * $changes = [ [ 'i' => blockIndex, 'text' => newText ], ... ].
	 */
	public static function create_rephrase_draft( $page_id, $changes ) {
		$page_id = (string) $page_id;
		if ( ! preg_match( '#^wp(\d+)$#', $page_id, $m ) ) {
			return new WP_Error( 'demo', 'Only real WordPress posts can be saved as drafts.' );
		}
		$post = get_post( (int) $m[1] );
		if ( ! $post ) {
			return new WP_Error( 'notfound', 'Post not found.' );
		}
		$repl = array();
		if ( is_array( $changes ) ) {
			foreach ( $changes as $c ) {
				if ( isset( $c['i'] ) && isset( $c['text'] ) && '' !== trim( (string) $c['text'] ) ) {
					$repl[ (int) $c['i'] ] = (string) $c['text'];
				}
			}
		}
		if ( empty( $repl ) ) {
			return new WP_Error( 'empty', 'No paragraph changes were selected.' );
		}

		$html    = do_shortcode( $post->post_content );
		$kept    = -1;
		$applied = 0;
		$new     = preg_replace_callback( '#<(p|h[1-6]|li)\b[^>]*>(.*?)</\1>#is', function ( $mm ) use ( &$kept, &$applied, $repl ) {
			$txt = self::block_text( $mm[2] );
			if ( ( function_exists( 'mb_strlen' ) ? mb_strlen( $txt ) : strlen( $txt ) ) < 15 ) {
				return $mm[0]; // Skipped block — not counted (matches extraction).
			}
			$kept++;
			if ( $kept < 40 && isset( $repl[ $kept ] ) ) {
				$applied++;
				return '<' . strtolower( $mm[1] ) . '>' . esc_html( $repl[ $kept ] ) . '</' . strtolower( $mm[1] ) . '>';
			}
			return $mm[0];
		}, $html );

		if ( ! $applied ) {
			return new WP_Error( 'nomatch', 'Could not locate the selected paragraphs in the post.' );
		}

		$pid = wp_insert_post( array(
			'post_title'   => get_the_title( $post ) . ' (GEO draft)',
			'post_content' => wp_kses_post( $new ),
			'post_status'  => 'draft',
			'post_type'    => $post->post_type,
			'post_excerpt' => $post->post_excerpt,
		), true );
		if ( is_wp_error( $pid ) ) {
			return $pid;
		}
		update_post_meta( $pid, '_aicitare_rephrase_source', $post->ID );
		AICitare_Log::add( 'rephrase', 'Created GEO draft #' . $pid . ' from post #' . $post->ID . ' (' . $applied . ' paragraphs).' );

		return array(
			'ok'      => true,
			'draftId' => (int) $pid,
			'applied' => $applied,
			'editUrl' => admin_url( 'post.php?post=' . $pid . '&action=edit' ),
		);
	}

	/** Parse model output into a list of variant strings (JSON array preferred, then list/paragraph fallback). */
	private static function parse_variants( $text, $n ) {
		$text = trim( (string) $text );
		$text = preg_replace( '#^```[a-z]*\s*#i', '', $text );
		$text = preg_replace( '#\s*```$#', '', $text );
		$variants = array();

		$start = strpos( $text, '[' );
		$end   = strrpos( $text, ']' );
		if ( false !== $start && false !== $end && $end > $start ) {
			$arr = json_decode( substr( $text, $start, $end - $start + 1 ), true );
			if ( is_array( $arr ) ) {
				foreach ( $arr as $v ) {
					if ( is_string( $v ) && '' !== trim( $v ) ) {
						$variants[] = trim( $v );
					}
				}
			}
		}
		if ( empty( $variants ) ) {
			$parts = preg_split( '#\n\s*(?:\d+[\.\)]|[-*])\s+#', "\n" . $text );
			foreach ( $parts as $p ) {
				$p = trim( $p );
				if ( '' !== $p ) {
					$variants[] = $p;
				}
			}
		}
		if ( count( $variants ) < 2 ) {
			$variants = array();
			foreach ( preg_split( '#\n{2,}#', $text ) as $p ) {
				$p = trim( $p );
				if ( '' !== $p ) {
					$variants[] = $p;
				}
			}
		}
		// Strip surrounding quotes the model may add.
		$variants = array_map( function ( $v ) { return trim( $v, " \t\n\r\0\x0B\"'" ); }, $variants );
		return array_slice( array_values( array_filter( $variants ) ), 0, $n );
	}

	/** Dispatch to the right engine adapter. */
	private function ask( $eng, $key, $q ) {
		switch ( $eng ) {
			case 'openai':
				return $this->openai_compatible( 'https://api.openai.com/v1/chat/completions', $key, $q, self::model_for( 'openai', 'gpt-4o-mini' ) );
			case 'perplexity':
				return $this->openai_compatible( 'https://api.perplexity.ai/chat/completions', $key, $q, self::model_for( 'perplexity', 'sonar' ) );
			case 'grok':
				return $this->openai_compatible( 'https://api.x.ai/v1/chat/completions', $key, $q, self::model_for( 'grok', 'grok-3' ) );
			case 'anthropic':
				return $this->anthropic( $key, $q );
			case 'google':
				return $this->gemini( $key, $q );
		}
		return new WP_Error( 'unknown_engine', 'Unknown engine' );
	}

	/** Resolve the model for an engine: user setting > default (filterable). */
	private static function model_for( $eng, $default ) {
		$s = AICitare_Data::get_settings();
		$m = ( isset( $s['models'][ $eng ] ) && '' !== trim( $s['models'][ $eng ] ) ) ? trim( $s['models'][ $eng ] ) : $default;
		return apply_filters( 'aicitare_model_' . $eng, $m );
	}

	/** Build a descriptive WP_Error from an API error response (surfaces the provider's message). */
	private static function http_err( $res, $body, $code ) {
		$msg = '';
		if ( is_array( $body ) ) {
			if ( isset( $body['error']['message'] ) ) {
				$msg = $body['error']['message'];
			} elseif ( isset( $body['error'] ) && is_string( $body['error'] ) ) {
				$msg = $body['error'];
			} elseif ( isset( $body['message'] ) && is_string( $body['message'] ) ) {
				$msg = $body['message'];
			} elseif ( isset( $body['msg'] ) && is_string( $body['msg'] ) ) {
				$msg = $body['msg'];
			}
		}
		if ( '' === $msg ) {
			$raw = trim( (string) wp_remote_retrieve_body( $res ) );
			if ( '' !== $raw ) {
				$msg = function_exists( 'mb_substr' ) ? mb_substr( $raw, 0, 200 ) : substr( $raw, 0, 200 );
			}
		}
		return new WP_Error( 'api_error', 'HTTP ' . $code . ( '' !== $msg ? ': ' . $msg : '' ) );
	}

	/** OpenAI-compatible chat endpoint (OpenAI, Perplexity, Grok). */
	private function openai_compatible( $url, $key, $q, $model ) {
		$res = wp_remote_post( $url, array(
			'timeout' => 30,
			'headers' => array( 'Authorization' => 'Bearer ' . $key, 'Content-Type' => 'application/json' ),
			'body'    => wp_json_encode( array( 'model' => $model, 'messages' => array( array( 'role' => 'user', 'content' => $q ) ) ) ),
		) );
		if ( is_wp_error( $res ) ) {
			return $res;
		}
		$code = wp_remote_retrieve_response_code( $res );
		$body = json_decode( wp_remote_retrieve_body( $res ), true );
		if ( $code >= 400 ) {
			return self::http_err( $res, $body, $code );
		}
		$text    = isset( $body['choices'][0]['message']['content'] ) ? $body['choices'][0]['message']['content'] : '';
		$sources = ( isset( $body['citations'] ) && is_array( $body['citations'] ) ) ? $body['citations'] : array();
		return array( 'text' => $text, 'sources' => $sources );
	}

	/** Anthropic Messages API. */
	private function anthropic( $key, $q ) {
		$res = wp_remote_post( 'https://api.anthropic.com/v1/messages', array(
			'timeout' => 30,
			'headers' => array( 'x-api-key' => $key, 'anthropic-version' => '2023-06-01', 'content-type' => 'application/json' ),
			'body'    => wp_json_encode( array(
				'model'      => self::model_for( 'anthropic', 'claude-3-5-haiku-latest' ),
				'max_tokens' => 1024,
				'messages'   => array( array( 'role' => 'user', 'content' => $q ) ),
			) ),
		) );
		if ( is_wp_error( $res ) ) {
			return $res;
		}
		$code = wp_remote_retrieve_response_code( $res );
		$body = json_decode( wp_remote_retrieve_body( $res ), true );
		if ( $code >= 400 ) {
			return self::http_err( $res, $body, $code );
		}
		return array( 'text' => isset( $body['content'][0]['text'] ) ? $body['content'][0]['text'] : '', 'sources' => array() );
	}

	/** Local Ollama (OpenAI-compatible endpoint, no API key). */
	private function ollama( $base, $model, $q ) {
		$base = rtrim( (string) $base, '/' );
		$url  = $base . '/v1/chat/completions';
		$res  = wp_remote_post( $url, array(
			'timeout' => 60, // local models can be slow.
			'headers' => array( 'Content-Type' => 'application/json' ),
			'body'    => wp_json_encode( array(
				'model'    => $model ? $model : 'llama3.2',
				'messages' => array( array( 'role' => 'user', 'content' => $q ) ),
				'stream'   => false,
			) ),
		) );
		if ( is_wp_error( $res ) ) {
			return $res;
		}
		$code = wp_remote_retrieve_response_code( $res );
		$body = json_decode( wp_remote_retrieve_body( $res ), true );
		if ( $code >= 400 ) {
			return self::http_err( $res, $body, $code );
		}
		return array( 'text' => isset( $body['choices'][0]['message']['content'] ) ? $body['choices'][0]['message']['content'] : '', 'sources' => array() );
	}

	/** Google Gemini generateContent. */
	private function gemini( $key, $q ) {
		$model = apply_filters( 'aicitare_model_google', 'gemini-2.0-flash' );
		$url   = 'https://generativelanguage.googleapis.com/v1beta/models/' . $model . ':generateContent?key=' . rawurlencode( $key );
		$res   = wp_remote_post( $url, array(
			'timeout' => 30,
			'headers' => array( 'Content-Type' => 'application/json' ),
			'body'    => wp_json_encode( array( 'contents' => array( array( 'parts' => array( array( 'text' => $q ) ) ) ) ) ),
		) );
		if ( is_wp_error( $res ) ) {
			return $res;
		}
		$code = wp_remote_retrieve_response_code( $res );
		$body = json_decode( wp_remote_retrieve_body( $res ), true );
		if ( $code >= 400 ) {
			return self::http_err( $res, $body, $code );
		}
		$text = isset( $body['candidates'][0]['content']['parts'][0]['text'] ) ? $body['candidates'][0]['content']['parts'][0]['text'] : '';
		return array( 'text' => $text, 'sources' => array() );
	}

	/** Live citations if a check has run; the demo dataset only in Demo mode; else empty. */
	public static function get_citations() {
		$live = get_option( self::OPT_RESULTS );
		if ( is_array( $live ) && $live ) {
			return $live;
		}
		$settings = AICitare_Data::get_settings();
		return ! empty( $settings['demo_mode'] ) ? AICitare_Data::citations() : array();
	}

	public static function last_checked() {
		return get_option( self::OPT_CHECKED, '' );
	}

	/** Per-engine status from the last check (ok count + last error). */
	public static function engine_status() {
		$s = get_option( self::OPT_STATUS );
		return is_array( $s ) ? $s : array();
	}

	/** Raw model answers from the last check, keyed by prompt. */
	public static function answers() {
		$a = get_option( self::OPT_ANSWERS );
		return is_array( $a ) ? $a : array();
	}

	private static function host() {
		$h = wp_parse_url( home_url(), PHP_URL_HOST );
		return preg_replace( '/^www\./', '', (string) $h );
	}

	/**
	 * Content gaps vs competitors: prompts where a tracked competitor is cited
	 * but this site is NOT. Requires a live visibility check to be meaningful.
	 * Returns [ { q, competitors:[names] }, ... ].
	 */
	public static function competitor_gaps() {
		$answers = self::answers();
		$results = get_option( self::OPT_RESULTS );
		$comps   = self::competitors_list();
		if ( empty( $answers ) || ! is_array( $results ) || empty( $comps ) ) {
			return array();
		}
		// Map prompt -> was our site cited on any engine?
		$cited = array();
		foreach ( $results as $r ) {
			$is = false;
			foreach ( (array) $r['e'] as $v ) {
				if ( null !== $v ) {
					$is = true;
					break;
				}
			}
			$cited[ $r['q'] ] = $is;
		}
		$gaps = array();
		foreach ( $answers as $row ) {
			$q = isset( $row['q'] ) ? $row['q'] : '';
			if ( '' === $q || ! empty( $cited[ $q ] ) ) {
				continue; // We are already cited → not a gap.
			}
			$hay     = strtolower( implode( ' ', array_map( 'strval', (array) ( isset( $row['a'] ) ? $row['a'] : array() ) ) ) );
			$winners = array();
			foreach ( $comps as $c ) {
				$dom = self::norm_host( $c['domain'] );
				$nm  = strtolower( trim( isset( $c['name'] ) ? $c['name'] : '' ) );
				$hit = ( $dom && false !== strpos( $hay, $dom ) ) || ( $nm && strlen( $nm ) >= 3 && false !== strpos( $hay, $nm ) );
				if ( $hit ) {
					$winners[] = ( isset( $c['name'] ) && '' !== $c['name'] ) ? $c['name'] : $dom;
				}
			}
			if ( $winners ) {
				$gaps[] = array( 'q' => $q, 'competitors' => array_values( array_unique( $winners ) ) );
			}
		}
		return $gaps;
	}
}