<?php
defined( 'ABSPATH' ) || exit;

/**
 * Bing Webmaster Tools Integration - FREE feature.
 *
 * Unlike Google Search Console, Bing Webmaster Tools doesn't use OAuth -
 * the user generates a personal API key from their Bing Webmaster account
 * (Settings → API Access) and pastes it in. We verify it once by asking
 * Bing for the sites it can see, then store the key and the matching
 * property (if any) for this site.
 */
class AWBSEO_Bing {

    const OPTION_API_KEY   = 'awbseo_bing_api_key';
    const OPTION_PROPERTY  = 'awbseo_bing_property';
    const OPTION_ALL_SITES = 'awbseo_bing_all_sites';
    const OPTION_OWNER     = 'awbseo_bing_owner_user_id';
    const API_BASE         = 'https://ssl.bing.com/webmaster/api.svc/json/';

    private static $instance = null;

    public static function get_instance() {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    public static function init() {
        add_action( 'admin_post_awbseo_bing_connect',         [ __CLASS__, 'handle_connect' ] );
        add_action( 'admin_post_awbseo_bing_disconnect',      [ __CLASS__, 'handle_disconnect' ] );
        add_action( 'admin_post_awbseo_bing_change_property', [ __CLASS__, 'handle_change_property' ] );
        add_action( 'admin_post_awbseo_bing_claim_owner',     [ __CLASS__, 'handle_claim_owner' ] );
    }

    // ── Connection Status ─────────────────────────────────────────────────────

    public function is_connected() {
        return (bool) get_option( self::OPTION_API_KEY );
    }

    public function get_property() {
        return get_option( self::OPTION_PROPERTY, '' );
    }

    public function get_all_sites() {
        return get_option( self::OPTION_ALL_SITES, [] );
    }

    private function get_api_key() {
        return get_option( self::OPTION_API_KEY, '' );
    }

    // ── Ownership (prevents the client seeing other clients' sites) ───────────

    /**
     * True when the current WP user is the one who connected Bing. Only the
     * owner sees the full list of sites tied to the pasted API key; other
     * admins (e.g. a client sharing this WordPress install) just see the
     * single active property, so they can never browse the agency's other
     * client sites through this dropdown.
     *
     * An unclaimed connection (owner_id === 0, e.g. one made before this
     * check existed) never auto-grants ownership to whoever loads Settings
     * first -- see needs_owner_claim() / handle_claim_owner().
     */
    public static function is_bing_owner(): bool {
        $owner_id = (int) get_option( self::OPTION_OWNER, 0 );
        $current  = get_current_user_id();

        return $owner_id > 0 && $current > 0 && $current === $owner_id;
    }

    /** True when Bing is connected but no owner has been recorded yet. */
    public static function needs_owner_claim(): bool {
        return self::get_instance()->is_connected() && 0 === (int) get_option( self::OPTION_OWNER, 0 );
    }

    /**
     * Lets the current admin explicitly claim an unclaimed Bing connection.
     * Requires a deliberate click (nonce + manage_options).
     */
    public static function handle_claim_owner() {
        check_admin_referer( 'awbseo_bing_claim_owner' );
        if ( ! current_user_can( 'manage_options' ) ) wp_die( 'Forbidden' );

        if ( 0 === (int) get_option( self::OPTION_OWNER, 0 ) ) {
            update_option( self::OPTION_OWNER, get_current_user_id(), false );
        }

        wp_redirect( admin_url( 'admin.php?page=awbseo-settings#bing' ) );
        exit;
    }

    // ── Connect / Disconnect ──────────────────────────────────────────────────

    public static function handle_connect() {
        check_admin_referer( 'awbseo_bing_connect' );
        if ( ! current_user_can( 'manage_options' ) ) wp_die( 'Forbidden' );

        $api_key = sanitize_text_field( $_POST['awb_bing_api_key'] ?? '' );
        if ( ! $api_key ) {
            wp_redirect( admin_url( 'admin.php?page=awbseo-settings&bing_error=no_key' ) );
            exit;
        }

        // Verify the key works before storing it.
        $sites = self::api_call( 'GetUserSites', $api_key );
        if ( null === $sites || isset( $sites['ErrorCode'] ) ) {
            wp_redirect( admin_url( 'admin.php?page=awbseo-settings&bing_error=invalid_key' ) );
            exit;
        }

        update_option( self::OPTION_API_KEY, $api_key, false );
        update_option( self::OPTION_OWNER, get_current_user_id(), false );

        $sites_list = $sites['d'] ?? $sites ?? [];
        // Store full list so the property dropdown can show all sites.
        $urls = [];
        foreach ( $sites_list as $s ) {
            $url = $s['Url'] ?? $s['url'] ?? '';
            if ( $url ) {
                $urls[] = $url;
            }
        }
        update_option( self::OPTION_ALL_SITES, $urls, false );

        $property = self::match_property( $sites_list );
        if ( $property ) {
            update_option( self::OPTION_PROPERTY, $property );
        } else {
            delete_option( self::OPTION_PROPERTY );
        }

        self::flush_transients();
        wp_redirect( admin_url( 'admin.php?page=awbseo-settings&bing_connected=1' ) );
        exit;
    }

    public static function handle_change_property() {
        check_admin_referer( 'awbseo_bing_change_property' );
        if ( ! current_user_can( 'manage_options' ) ) wp_die( 'Forbidden' );

        $property = sanitize_text_field( $_POST['awb_bing_property'] ?? '' );
        if ( $property ) {
            update_option( self::OPTION_PROPERTY, $property );
        } else {
            delete_option( self::OPTION_PROPERTY );
        }

        self::flush_transients();
        wp_redirect( admin_url( 'admin.php?page=awbseo-settings&bing_connected=1' ) );
        exit;
    }

    public static function handle_disconnect() {
        check_admin_referer( 'awbseo_bing_disconnect' );
        if ( ! current_user_can( 'manage_options' ) ) wp_die( 'Forbidden' );
        delete_option( self::OPTION_API_KEY );
        delete_option( self::OPTION_PROPERTY );
        delete_option( self::OPTION_ALL_SITES );
        delete_option( self::OPTION_OWNER );
        self::flush_transients();
        wp_redirect( admin_url( 'admin.php?page=awbseo-settings&bing_disconnected=1' ) );
        exit;
    }

    /**
     * Picks the site entry that matches this WordPress install's home URL,
     * falling back to the first verified site Bing returns for this key.
     */
    private static function match_property( $sites ) {
        if ( ! is_array( $sites ) || empty( $sites ) ) {
            return '';
        }

        $home      = rtrim( home_url(), '/' );
        $home_bare = self::bare_host( home_url() );

        foreach ( $sites as $site ) {
            $url = $site['Url'] ?? $site['url'] ?? '';
            if ( $url && rtrim( $url, '/' ) === $home ) {
                return $url;
            }
        }

        // Loosen to a bare-host match (scheme/www/trailing-path differences)
        // before giving up entirely.
        if ( $home_bare ) {
            foreach ( $sites as $site ) {
                $url = $site['Url'] ?? $site['url'] ?? '';
                if ( $url && self::bare_host( $url ) === $home_bare ) {
                    return $url;
                }
            }
        }

        // IMPORTANT: never fall back to "the first site" here. The pasted
        // API key is often an agency's own Bing Webmaster account with
        // access to many unrelated clients' verified sites -- silently
        // assigning properties[0] previously meant a site with no exact
        // domain match could end up auto-connected to a completely
        // different client's Bing property with no indication anything
        // was wrong.
        return '';
    }

    /** Lowercase hostname with a leading "www." stripped, for loose domain comparisons. */
    private static function bare_host( $url ) {
        $host = (string) wp_parse_url( $url, PHP_URL_HOST );
        return strtolower( preg_replace( '/^www\\./i', '', $host ) );
    }

    /**
     * Same list as get_all_sites(), filtered down to entries whose host
     * matches this WordPress install's own domain. The pasted API key is
     * frequently an agency's Bing Webmaster account with access to every
     * client site it manages -- never let one client's property picker
     * browse every other client's site through this dropdown.
     */
    public function get_all_sites_for_this_domain() {
        $home_bare = self::bare_host( home_url() );
        if ( ! $home_bare ) {
            return [];
        }

        $matches = [];
        foreach ( $this->get_all_sites() as $site_url ) {
            if ( self::bare_host( $site_url ) === $home_bare ) {
                $matches[] = $site_url;
            }
        }
        return $matches;
    }

    // ── API Calls ─────────────────────────────────────────────────────────────

    private static function api_call( $endpoint, $api_key, $args = [] ) {
        if ( ! $api_key ) {
            return null;
        }

        $args['apikey'] = $api_key;
        $url = add_query_arg( $args, self::API_BASE . $endpoint );

        $response = wp_remote_get( $url, [ 'timeout' => 15 ] );
        if ( is_wp_error( $response ) ) {
            return null;
        }

        return json_decode( wp_remote_retrieve_body( $response ), true );
    }

    private function api_get( $endpoint, $args = [] ) {
        return self::api_call( $endpoint, $this->get_api_key(), $args );
    }

    /**
     * Bing returns dates as legacy ASP.NET AJAX strings, e.g.
     * "/Date(1316156400000-0700)/". The numeric portion is already a
     * UTC millisecond epoch, so we can parse it directly into Y-m-d.
     */
    private static function parse_bing_date( $value ) {
        if ( ! $value || ! preg_match( '/-?\d+/', $value, $m ) ) {
            return '';
        }
        return gmdate( 'Y-m-d', intdiv( (int) $m[0], 1000 ) );
    }

    /**
     * Reshapes a raw Bing row ({Query|PageURL, Clicks, Impressions,
     * AvgClickPosition, Date, ...}) into the same shape AWBSEO_GSC rows
     * use ({keys, clicks, impressions, ctr, position}) so dashboard
     * rendering code can treat both sources identically. Bing has no
     * native CTR field, so it's derived from clicks / impressions.
     */
    private static function normalize_rows( $rows, $key_field ) {
        if ( ! is_array( $rows ) ) {
            return [];
        }

        $out = [];
        foreach ( $rows as $row ) {
            $clicks      = (int) ( $row['Clicks'] ?? 0 );
            $impressions = (int) ( $row['Impressions'] ?? 0 );
            $out[]       = [
                'keys'        => [ $row[ $key_field ] ?? '' ],
                'clicks'      => $clicks,
                'impressions' => $impressions,
                'position'    => (float) ( $row['AvgClickPosition'] ?? $row['AvgImpressionPosition'] ?? 0 ),
                'ctr'         => $impressions > 0 ? $clicks / $impressions : 0,
                'date'        => self::parse_bing_date( $row['Date'] ?? '' ),
            ];
        }
        return $out;
    }

    /**
     * Resolves a requested range into concrete start/end dates - mirrors
     * AWBSEO_GSC::resolve_range() so the dashboard's date picker works the
     * same way against both sources. Bing has no fixed reporting lag, so
     * $end just clamps to today.
     *
     * @return array [ $start, $end, $days ]
     */
    private function resolve_range( $days = 28, $start = null, $end = null ) {
        $today = gmdate( 'Y-m-d' );

        if ( $start && $end ) {
            $end = min( $end, $today );
            if ( $start > $end ) $start = $end;
            $days = max( 1, (int) ( ( strtotime( $end ) - strtotime( $start ) ) / DAY_IN_SECONDS ) + 1 );
            return [ $start, $end, $days ];
        }

        $days = max( 1, (int) $days );
        return [ gmdate( 'Y-m-d', strtotime( "-{$days} days" ) ), $today, $days ];
    }

    /**
     * Bing's GetQueryStats/GetPageStats return one row per key per date
     * rather than a single date-ranged total, so we fetch everything Bing
     * has, drop rows outside the requested window, then group by key and
     * sum. Note: Bing's own data refreshes weekly, not daily like GSC.
     */
    private function get_aggregated( $endpoint, $key_field, $days, $limit, $cache_prefix, $start = null, $end = null ) {
        $property = $this->get_property();
        if ( ! $property ) {
            return [];
        }

        list( $start, $end, $days ) = $this->resolve_range( $days, $start, $end );

        $cache_key = $cache_prefix . md5( $property . '_' . $start . '_' . $end . '_' . $limit );
        $cached    = get_transient( $cache_key );
        if ( false !== $cached ) {
            return $cached;
        }

        $data = $this->api_get( $endpoint, [ 'siteUrl' => $property ] );
        $rows = self::normalize_rows( $data['d'] ?? [], $key_field );

        $rows = array_filter( $rows, function ( $row ) use ( $start, $end ) {
            return $row['date'] >= $start && $row['date'] <= $end;
        } );

        $grouped = [];
        foreach ( $rows as $row ) {
            $key = $row['keys'][0];
            if ( ! isset( $grouped[ $key ] ) ) {
                $grouped[ $key ] = [
                    'keys'         => [ $key ],
                    'clicks'       => 0,
                    'impressions'  => 0,
                    'position_sum' => 0,
                    'position_n'   => 0,
                ];
            }
            $grouped[ $key ]['clicks']       += $row['clicks'];
            $grouped[ $key ]['impressions']  += $row['impressions'];
            $grouped[ $key ]['position_sum'] += $row['position'];
            $grouped[ $key ]['position_n']++;
        }

        $result = [];
        foreach ( $grouped as $g ) {
            $result[] = [
                'keys'        => $g['keys'],
                'clicks'      => $g['clicks'],
                'impressions' => $g['impressions'],
                'position'    => $g['position_n'] ? $g['position_sum'] / $g['position_n'] : 0,
                'ctr'         => $g['impressions'] > 0 ? $g['clicks'] / $g['impressions'] : 0,
            ];
        }

        usort( $result, function ( $a, $b ) {
            return $b['clicks'] <=> $a['clicks'];
        } );
        $result = array_slice( $result, 0, $limit );

        set_transient( $cache_key, $result, HOUR_IN_SECONDS );
        return $result;
    }

    /**
     * Top queries by clicks over the last N days - mirrors
     * AWBSEO_GSC::get_top_queries(). FREE.
     */
    public function get_top_queries( $days = 28, $limit = 10, $start = null, $end = null ) {
        return $this->get_aggregated( 'GetQueryStats', 'Query', $days, $limit, 'awbseo_bing_top_queries_', $start, $end );
    }

    /**
     * Top pages by clicks over the last N days - mirrors
     * AWBSEO_GSC::get_top_pages(). FREE.
     */
    public function get_top_pages( $days = 28, $limit = 10, $start = null, $end = null ) {
        return $this->get_aggregated( 'GetPageStats', 'PageURL', $days, $limit, 'awbseo_bing_top_pages_', $start, $end );
    }

    /**
     * Daily clicks/impressions series for the last N days, plus the prior
     * N-day window's totals for period-over-period deltas - mirrors
     * AWBSEO_GSC::get_site_stats() so the dashboard can reuse the same
     * rendering code for both sources. Built from page-level stats since
     * that's the closest thing Bing offers to a site-wide breakdown.
     * Note: Bing updates this data weekly, so day-to-day movement within
     * the series will look "steppy" compared to GSC's daily granularity.
     */
    public function get_site_stats( $days = 28, $start = null, $end = null ) {
        $property = $this->get_property();
        if ( ! $property ) {
            return null;
        }

        list( $start, $end, $days ) = $this->resolve_range( $days, $start, $end );

        $cache_key = 'awbseo_bing_site_stats_' . md5( $property . '_' . $start . '_' . $end );
        $cached    = get_transient( $cache_key );
        if ( false !== $cached ) {
            return $cached;
        }

        $data = $this->api_get( 'GetPageStats', [ 'siteUrl' => $property ] );
        $rows = self::normalize_rows( $data['d'] ?? [], 'PageURL' );

        $prev_end   = gmdate( 'Y-m-d', strtotime( $start . ' -1 day' ) );
        $prev_start = gmdate( 'Y-m-d', strtotime( $prev_end . " -{$days} days" ) );

        $by_date      = [];
        $prev_clicks  = 0;
        $prev_impr    = 0;
        $prev_ctr_sum = 0;
        $prev_pos_sum = 0;
        $prev_days    = 0;

        foreach ( $rows as $row ) {
            if ( ! $row['date'] ) {
                continue;
            }
            if ( $row['date'] >= $start && $row['date'] <= $end ) {
                if ( ! isset( $by_date[ $row['date'] ] ) ) {
                    $by_date[ $row['date'] ] = [ 'clicks' => 0, 'impressions' => 0, 'position_sum' => 0, 'position_n' => 0 ];
                }
                $by_date[ $row['date'] ]['clicks']       += $row['clicks'];
                $by_date[ $row['date'] ]['impressions']  += $row['impressions'];
                $by_date[ $row['date'] ]['position_sum'] += $row['position'];
                $by_date[ $row['date'] ]['position_n']++;
            } elseif ( $row['date'] >= $prev_start && $row['date'] <= $prev_end ) {
                $prev_clicks  += $row['clicks'];
                $prev_impr    += $row['impressions'];
                $prev_ctr_sum += $row['impressions'] > 0 ? $row['clicks'] / $row['impressions'] : 0;
                $prev_pos_sum += $row['position'];
                $prev_days++;
            }
        }

        ksort( $by_date );

        $daily = [];
        foreach ( $by_date as $date => $vals ) {
            $daily[] = [
                'keys'        => [ $date ],
                'clicks'      => $vals['clicks'],
                'impressions' => $vals['impressions'],
                'position'    => $vals['position_n'] ? $vals['position_sum'] / $vals['position_n'] : 0,
                'ctr'         => $vals['impressions'] > 0 ? $vals['clicks'] / $vals['impressions'] : 0,
            ];
        }

        $result = [
            'daily'    => $daily,
            'prev_sum' => [
                'clicks'      => $prev_clicks,
                'impressions' => $prev_impr,
                'ctr'         => $prev_days ? round( ( $prev_ctr_sum / $prev_days ) * 100, 1 ) : 0,
                'position'    => $prev_days ? round( $prev_pos_sum / $prev_days, 1 ) : 0,
            ],
        ];

        set_transient( $cache_key, $result, HOUR_IN_SECONDS );
        return $result;
    }

    /**
     * Deletes all cached Bing API results from the options table.
     * Called on connect and disconnect so stale cached data is cleared.
     */
    public static function flush_transients() {
        global $wpdb;
        $wpdb->query(
            "DELETE FROM {$wpdb->options}
             WHERE option_name LIKE '\_transient\_awbseo\_bing\_%'
                OR option_name LIKE '\_transient\_timeout\_awbseo\_bing\_%'"
        );
    }
}