<?php
/**
 * AI Snippet SEO Helper — Helper Functions
 * Version: 1.0.0
 * 
 * Provides:
 * - Snippet score calculation
 * - RankPilot AI API calls via HTTP helper
 * - Token info fetch/reduce with transient caching
 * - Developer hooks, sanitization, and lightweight logging
 *
 * Notes:
 * - Executable logic is untouched; only comments and wording were cleaned up.
 * - Keep constants like AISH_OPT_KEY / AISH_RP_API consistent with the main plugin.
 */

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

/** Minimal multibyte polyfill (for environments without mbstring) */
if ( ! function_exists( 'mb_strlen' ) ) {
	function mb_strlen( $s, $enc = '' ) { return strlen( $s ); }
}

/** Debug logger (active only when WP_DEBUG is true) */
if ( ! function_exists( 'aish_log' ) ) {
	function aish_log( $msg, array $ctx = [] ) : void {
		if ( defined('WP_DEBUG') && WP_DEBUG ) {
			$line = '[AISH] ' . ( is_string($msg) ? $msg : wp_json_encode($msg) );
			if ( $ctx ) $line .= ' ' . wp_json_encode($ctx);
			error_log( $line );
		}
	}
}

/** Sanitize API snippet response fields */
if ( ! function_exists( 'aish_sanitize_snippet_response' ) ) {
	function aish_sanitize_snippet_response( array $res ) : array {
		foreach ( ['keyword','title','description','slug'] as $k ) {
			if ( isset( $res[$k] ) ) {
				$res[$k] = wp_strip_all_tags( (string) $res[$k] );
			}
		}
		return $res;
	}
}

/** Token-info cache helpers */
if ( ! function_exists( 'aish_token_cache_key' ) ) {
	function aish_token_cache_key( string $site_token ) : string {
		return 'aish_tok_' . wp_hash( home_url() . '|' . $site_token );
	}
}
if ( ! function_exists( 'aish_flush_token_cache' ) ) {
	function aish_flush_token_cache( string $site_token ) : void {
		delete_transient( aish_token_cache_key( $site_token ) );
	}
}

/** Normalize "global remaining" from token-info response */
if ( ! function_exists( 'aish_status_remaining' ) ) {
	function aish_status_remaining( array $st ) : int {

		// Prefer explicit global remaining fields
		if ( isset($st['remaining_total']) )  return (int)$st['remaining_total'];
		if ( isset($st['remaining_all']) )    return (int)$st['remaining_all'];
		if ( isset($st['global_remaining']) ) return (int)$st['global_remaining'];

		// Sum balances if present
		$fb = (int)($st['free_balance']   ?? 0);
		$pr = (int)($st['plan_remaining'] ?? 0);
		$pb = (int)($st['pack_balance']   ?? 0);
		$sum_bal = $fb + $pr + $pb;
		if ( $sum_bal > 0 ) return $sum_bal;

		// Legacy field names
		$free    = (int)($st['free']              ?? 0);
		$monthly = (int)($st['monthly_remaining'] ?? 0);
		$pack    = (int)($st['token_pack']        ?? 0);
		$sum_legacy = $free + $monthly + $pack;
		if ( $sum_legacy > 0 ) return $sum_legacy;

		// Generic "remaining"
		if ( isset($st['remaining']) ) {
			return max(0, (int)$st['remaining']);
		}

		// Fallback: limit - usage
		$limit = (int)($st['plan_limit_total'] ?? $st['plan_limit'] ?? $st['token_limit'] ?? 0);
		$usage = null;
		foreach ( ['usage_total','all_usage','total_usage','token_usage','usage'] as $k ) {
			if ( isset($st[$k]) ) { $usage = (int)$st[$k]; break; }
		}
		if ( $usage === null ) $usage = (int)($st['site_usage'] ?? 0);

		return max(0, $limit - (int)$usage);
	}
}

/* =========================================================
 *  1)  Snippet Score Calculation
 *  Simple 3-rule check: keyword found in normalized Title, Description, and Slug.
 * ======================================================= */
if ( ! function_exists( 'aish_calc_score' ) ) {
    function aish_calc_score( $fw, $ti, $de, $slug ) {
        $norm_text = function( $s ){
            $s = strtolower( (string) $s );
            if ( function_exists('remove_accents') ) $s = remove_accents($s);
            return trim( preg_replace('/[^a-z0-9]+/',' ', $s ) );
        };
        $norm_slug = function( $s ){
            $s = strtolower( (string) $s );
            if ( function_exists('remove_accents') ) $s = remove_accents($s);
            return trim( preg_replace('/[^a-z0-9]+/','-', $s ), '-' );
        };

        $arr = array_map( 'trim', explode( ',', (string) $fw ) );
        $kw  = strtolower( $arr[0] ?? '' );

        if ( $kw === '' ) {
            return [ 'score' => 0, 'color' => '#e74c3c' ];
        }

        $has_title = strpos( ' ' . $norm_text($ti) . ' ', ' ' . $norm_text($kw) . ' ' ) !== false;
        $has_desc  = strpos( ' ' . $norm_text($de) . ' ', ' ' . $norm_text($kw) . ' ' ) !== false;
        $has_slug  = strpos( $norm_slug($slug), $norm_slug($kw) ) !== false;

        $hit   = (int)$has_title + (int)$has_desc + (int)$has_slug;
        $score = ($hit === 0) ? 0 : (($hit === 1) ? 33 : (($hit === 2) ? 66 : 100));
        $color = ($score >= 100) ? '#2980b9' : (($score >= 66) ? '#f39c12' : '#e74c3c');

        return [ 'score' => $score, 'color' => $color ];
    }
}

/** Minimal post payload for bulk operations */
function aish_prepare_snippet_item_for_post( int $post_id, array $opts = [] ) : array {
	$title   = get_the_title( $post_id );
	$excerpt = get_the_excerpt( $post_id );
	$ptype   = get_post_type( $post_id );
	$fw      = get_post_meta( $post_id, 'rank_math_focus_keyword', true );

	return [
		'id'            => (int) $post_id,
		'context_type'  => 'post',
		'post_title'    => $title,
		'post_excerpt'  => $excerpt,
		'post_type'     => $ptype,
		'focus_keyword' => $fw,
		'slug'          => get_post_field( 'post_name', $post_id ),
	];
}

/* =========================================================
 *  2)  RankPilot AI — /snippet
 * ======================================================= */
if ( ! function_exists( 'aish_call_rankpilot_api' ) ) {
	function aish_call_rankpilot_api( string $site_token, array $payload ) : array {

		if ( empty( $site_token ) ) {
			throw new Exception( 'Site token missing.' );
		}

		$payload = array_merge(
			$payload,
			[
				'site_token' => $site_token,
				'plugin'     => 'ai-snippet-seo-helper',
				'site_url'   => home_url(),
			]
		);

		// Allow plugins/themes to adjust payload
		$payload = apply_filters( 'aish/snippet_payload', $payload, $site_token );

		$r = aish_http_json( AISH_RP_API . '/snippet', $payload, 'POST', ['timeout'=>30] );
		if ( is_wp_error( $r ) ) {
			aish_log('API request error', ['err'=>$r->get_error_message()]);
			throw new Exception( 'API request error: ' . $r->get_error_message() );
		}
		$code = wp_remote_retrieve_response_code( $r );
		$body = wp_remote_retrieve_body( $r );

		if ( (int)$code !== 200 ) {
			aish_log('RankPilotAI API HTTP error', ['code'=>$code,'body'=>substr((string)$body,0,300)]);
			throw new Exception( 'RankPilotAI API Error (HTTP ' . $code . '): ' . $body );
		}

		$j = json_decode( (string)$body, true );
		if ( ! is_array( $j ) ) {
			aish_log('Invalid JSON response', ['body'=>substr((string)$body,0,300)]);
			throw new Exception( 'Invalid JSON response.' );
		}

		$j = aish_sanitize_snippet_response( $j );

		// Usage changed → bust token-info cache immediately
		aish_flush_token_cache( $site_token );

		// Allow plugins/themes to inspect/adjust response
		$j = apply_filters( 'aish/snippet_response', $j, $site_token );

		return $j;
	}
}

/**
 * Try /snippet-bulk; if it fails, fall back to single /snippet calls.
 */
function aish_call_rankpilot_api_bulk( string $site_token, array $items, string $model_sel, array $opts = [] ) : array {
	if ( empty( $site_token ) ) { throw new Exception('Site token missing.'); }
	if ( empty( $items ) )      { return [ 'items' => [] ]; }

	$endpoint = AISH_RP_API . '/snippet-bulk';
	$payload = [
		'site_token'    => $site_token,
		'plugin'        => 'ai-snippet-seo-helper',
		'site_url'      => home_url(),
		'domain'        => parse_url( home_url(), PHP_URL_HOST ),
		'model'         => strtolower( $model_sel ?: 'gpt-4-turbo' ),
		'custom_prompt' => $opts['custom_prompt'] ?? '',
		'auto_slug'     => ( $opts['auto_slug'] ?? 'no' ) === 'yes',
		'items'         => array_values( $items ),
	];

	$res = aish_http_json( $endpoint, $payload, 'POST', [ 'timeout' => 120 ] );
	if ( ! is_wp_error( $res ) ) {
		$code = (int) wp_remote_retrieve_response_code( $res );
		$body = wp_remote_retrieve_body( $res );
		if ( $code === 200 ) {
			$json = json_decode( (string)$body, true );
			if ( is_array($json) ) {
				if ( empty($json['items']) ) $json['items'] = $json;
				return $json;
			}
		}
	}

	// Fallback: single /snippet loop
	$out = [];
	foreach ( $items as $it ) {
		$single = array_merge( $it, [
			'model'         => strtolower( $model_sel ?: 'gpt-4-turbo' ),
			'auto_slug'     => ( $opts['auto_slug'] ?? 'no' ) === 'yes',
			'custom_prompt' => $opts['custom_prompt'] ?? '',
		] );

		try {
			$resp = aish_call_rankpilot_api( $site_token, $single );
			$resp['id'] = (int) ($it['id'] ?? 0);
			$out[ (int)$it['id'] ] = $resp;
		} catch ( \Exception $ex ) {
			$out[ (int)$it['id'] ] = [ 'id'=>(int)$it['id'], 'error'=>$ex->getMessage() ];
		}

		usleep( 50000 ); // 50ms backoff
	}

	return [ 'items' => $out, 'fallback' => 'single' ];
}

/** Apply a generated snippet to Rank Math fields for a given post */
function aish_apply_snippet_result_for_post( int $post_id, array $data, array $opts = [] ) : bool {
	if ( ! empty($data['error']) ) return false;

	$kw   = $data['keyword']     ?? '';
	$ti   = $data['title']       ?? '';
	$desc = $data['description'] ?? '';
	$slug = $data['slug']        ?? '';

	// Rank Math fields
	if ( $kw )   update_post_meta( $post_id, 'rank_math_focus_keyword', $kw );
	if ( $ti )   update_post_meta( $post_id, 'rank_math_title',         $ti );
	if ( $desc ) update_post_meta( $post_id, 'rank_math_description',   $desc );

	// Slug (optional)
	if ( ( $opts['auto_slug'] ?? 'no' ) === 'yes' && $slug ) {
		$san = sanitize_title( $slug );
		$cur = get_post_field( 'post_name', $post_id );
		if ( $san && $san !== $cur ) {
			add_post_meta( $post_id, '_wp_old_slug', $cur );
			wp_update_post( [ 'ID' => $post_id, 'post_name' => $san ] );
		}
	}

	$final_slug = get_post_field( 'post_name', $post_id );
	$sc         = aish_calc_score( $kw, $ti, $desc, $final_slug );

	update_post_meta( $post_id, '_aish_snippet_score', $sc['score'] );
	update_post_meta( $post_id, '_aish_score',         $sc['score'] ); // legacy

	return true;
}

/* =========================================================
 *  3)  /token-info
 * ======================================================= */
if ( ! function_exists( 'aish_check_token_status' ) ) {
	function aish_check_token_status( string $site_token, bool $force_refresh = false ) : array {

		$cache_key = aish_token_cache_key( $site_token );

		// Soft cache with optional bypass
		if ( $force_refresh ) {
			delete_transient( $cache_key );
		} else {
			$cached = get_transient( $cache_key );
			if ( is_array( $cached ) ) {
				return $cached;
			}
		}

		if ( empty($site_token) ) {
			return [ 'error' => 'No token provided' ];
		}

		$body = [
			'site_token' => $site_token,
			'plugin'     => 'ai-snippet-seo-helper',
			'site_url'   => home_url(),
			'cache_bust' => time(),
			'include'    => 'balances,usage,limits',
		];

		$r = aish_http_json(
			AISH_RP_API . '/token-info',
			$body,
			'POST',
			[ 'timeout' => 20, 'headers' => [ 'Cache-Control' => 'no-cache' ] ]
		);

		if ( is_wp_error( $r ) ) {
			aish_log('Token-info connection error', ['err'=>$r->get_error_message()]);
			return [ 'error' => 'Connection Error' ];
		}

		$resp = wp_remote_retrieve_body( $r );
		$data = json_decode( (string)$resp, true );

		if ( ! is_array($data) ) {
			aish_log('Invalid token-info response', ['body'=>substr((string)$resp,0,300)]);
			return [ 'error' => 'Invalid token-info response' ];
		}

		// Ensure at least one allowed model is present
		if ( empty($data['allowed_models']) ) {
			$data['allowed_models'] = [ 'gpt-4-turbo' ];
		}

		set_transient( $cache_key, $data, 30 );
		return $data;
	}
}

/* =========================================================
 *  4)  /token-reduce
 * ======================================================= */
if ( ! function_exists( 'aish_reduce_rankpilot_token' ) ) {
	function aish_reduce_rankpilot_token( string $site_token, string $model = 'gpt-4-turbo' ) : array {
		$body = [
			'site_token' => $site_token,
			'plugin'     => 'ai-snippet-seo-helper',
			'model'      => strtolower( $model ),
			'site_url'   => home_url(),
		];
		$r = aish_http_json( AISH_RP_API . '/token-reduce', $body, 'POST', ['timeout'=>20] );
		if ( is_wp_error( $r ) ) {
			aish_log('Token-reduce connection error', ['err'=>$r->get_error_message()]);
			return [ 'error' => 'Connection Error' ];
		}
		$data = json_decode( (string) wp_remote_retrieve_body( $r ), true );
		if ( is_array( $data ) && empty( $data['error'] ) ) {
			aish_flush_token_cache( $site_token );
		}
		return is_array( $data ) ? $data : [];
	}
}