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

/**
 * Leaf↔Root Link — v0.8.0 MVP
 *
 * Two halves in one class, ship together in every install:
 *
 *   ROOT half — REST endpoint /sa-orch/v1/root/assignments
 *               Returns Fluent Boards tasks where the authenticated user is
 *               an assignee (via fbs_relations object_type='task_assignee').
 *               Auth: WP application password (Basic auth) or session nonce.
 *
 *   LEAF half — Admin page (SA-Orchestration → Remote Roots)
 *               Stores ONE remote root config in wp_options (URL + app
 *               password). Manual "Fetch Now" button calls the configured
 *               root's /assignments endpoint and renders results in a
 *               table on the same admin page.
 *
 * MVP scope (locked):
 *   - One root per leaf (multi-root deferred to post-MVP)
 *   - No new tables — single wp_option for config
 *   - Manual fetch only; no cadence, heartbeat, or cron
 *   - No Fluent Support ticket creation; just list assignments on screen
 *   - No outbound curated updates; bidirectional sync is post-MVP
 *
 * The closed loop: developer self-assigns on Fluent Boards on the dev root
 * → leaf admin clicks "Fetch Now" → assignment appears in the leaf's
 * Remote Roots admin page.
 *
 * Doctrine: leaf-initiated, always up; the dev root never reaches into
 * the leaf. Per Board #40 invariants.
 */
class SA_Orch_Leaf_Link {

    const SUBMENU_SLUG  = 'sa-orchestration-remote-roots';
    const OPTION_KEY    = 'sa_orch_remote_root';   // single-root MVP storage
    const REST_TIMEOUT  = 15;

    /* ===================================================================
     * Hooks
     * =================================================================== */

    public static function register_routes() {
        // ROOT half — serves assignments to authenticated callers.
        register_rest_route( 'sa-orch/v1', '/root/assignments', [
            'methods'             => 'GET',
            'callback'            => [ __CLASS__, 'rest_assignments' ],
            'permission_callback' => function () {
                return current_user_can( 'read' );  // any logged-in user; the
                                                    // join filters by their id
            },
            'args' => [
                'since' => [ 'type' => 'string', 'required' => false ],
            ],
        ] );

        // LEAF half — manual fetch trigger (callable by admin from the page).
        register_rest_route( 'sa-orch/v1', '/leaf/fetch-now', [
            'methods'             => 'POST',
            'callback'            => [ __CLASS__, 'rest_fetch_now' ],
            'permission_callback' => function () {
                return current_user_can( 'manage_options' );
            },
        ] );
    }

    public static function register_menu() {
        add_submenu_page(
            SA_Orch_Admin::PARENT_SLUG,
            'Remote Roots',
            'Remote Roots',
            SA_Orch_Admin::CAP,
            self::SUBMENU_SLUG,
            [ __CLASS__, 'render_page' ]
        );
    }

    /* ===================================================================
     * ROOT HALF — assignments endpoint
     * =================================================================== */

    public static function rest_assignments( WP_REST_Request $req ) {
        global $wpdb;

        $user_id = get_current_user_id();
        if ( $user_id <= 0 ) {
            return new WP_REST_Response( [
                'error'   => 'unauthenticated',
                'message' => 'No authenticated user resolved.',
            ], 401 );
        }

        // Filter by 'since' (last_modified > since); optional.
        $since = $req->get_param( 'since' );
        $where_since = '';
        $params      = [ $user_id ];
        if ( $since && preg_match( '/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z?$/', (string) $since ) ) {
            $where_since = " AND t.updated_at > %s";
            $params[]    = str_replace( 'T', ' ', rtrim( (string) $since, 'Z' ) );
        }

        // Fluent Boards assignment join: fbs_relations.object_type = 'task_assignee',
        // object_id = task_id, foreign_id = wp user_id.
        $sql = "
            SELECT
                t.id           AS root_task_id,
                t.board_id,
                t.title,
                t.description,
                t.stage_id,
                t.status,
                t.priority,
                t.created_at,
                t.updated_at,
                t.last_completed_at,
                b.title        AS board_title,
                bt.title       AS stage_title
            FROM {$wpdb->prefix}fbs_relations r
            JOIN {$wpdb->prefix}fbs_tasks t      ON r.object_id = t.id
            LEFT JOIN {$wpdb->prefix}fbs_boards b ON t.board_id = b.id
            LEFT JOIN {$wpdb->prefix}fbs_board_terms bt ON t.stage_id = bt.id
            WHERE r.object_type = 'task_assignee'
              AND r.foreign_id  = %d
              AND t.archived_at IS NULL
              {$where_since}
            ORDER BY t.updated_at DESC
            LIMIT 100
        ";

        $rows = $wpdb->get_results( $wpdb->prepare( $sql, $params ), ARRAY_A );
        if ( $rows === null ) {
            return new WP_REST_Response( [
                'error'   => 'query_failed',
                'message' => 'Database query failed: ' . $wpdb->last_error,
            ], 500 );
        }

        // Trim description for transport efficiency. Full description fetched
        // on demand by leaf when dev clicks into a specific assignment.
        $out = [];
        foreach ( $rows as $r ) {
            $desc = (string) $r['description'];
            $desc_excerpt = function_exists( 'mb_substr' )
                ? mb_substr( wp_strip_all_tags( $desc ), 0, 800 )
                : substr( wp_strip_all_tags( $desc ), 0, 800 );
            $out[] = [
                'root_task_id'      => (int) $r['root_task_id'],
                'board_id'          => (int) $r['board_id'],
                'board_title'       => (string) $r['board_title'],
                'stage_id'          => (int) $r['stage_id'],
                'stage_title'       => (string) $r['stage_title'],
                'status'            => (string) $r['status'],
                'priority'          => (string) $r['priority'],
                'title'             => (string) $r['title'],
                'description_excerpt' => $desc_excerpt,
                'created_at'        => (string) $r['created_at'],
                'updated_at'        => (string) $r['updated_at'],
                'last_completed_at' => $r['last_completed_at'],
            ];
        }

        return new WP_REST_Response( [
            'actor'      => [
                'wp_user_id' => $user_id,
                'login'      => ( $u = get_user_by( 'id', $user_id ) ) ? $u->user_login : null,
            ],
            'count'      => count( $out ),
            'fetched_at' => current_time( 'mysql', true ),
            'assignments' => $out,
        ], 200 );
    }

    /* ===================================================================
     * LEAF HALF — fetch logic
     * =================================================================== */

    /**
     * Fetch assignments from the configured root.
     * Returns either a parsed payload or a WP_Error.
     */
    public static function fetch_remote_assignments() {
        $cfg = get_option( self::OPTION_KEY, [] );
        if ( empty( $cfg['url'] ) || empty( $cfg['app_user'] ) || empty( $cfg['app_password'] ) ) {
            return new WP_Error( 'not_configured', 'Remote root not configured. Set URL, username, and application password first.' );
        }

        $url = rtrim( (string) $cfg['url'], '/' ) . '/wp-json/sa-orch/v1/root/assignments';

        $auth_header = 'Basic ' . base64_encode( $cfg['app_user'] . ':' . str_replace( ' ', '', $cfg['app_password'] ) );

        $resp = wp_remote_get( $url, [
            'headers' => [ 'Authorization' => $auth_header ],
            'timeout' => self::REST_TIMEOUT,
        ] );

        if ( is_wp_error( $resp ) ) {
            return $resp;
        }
        $code = (int) wp_remote_retrieve_response_code( $resp );
        $body = (string) wp_remote_retrieve_body( $resp );
        if ( $code < 200 || $code >= 300 ) {
            return new WP_Error( 'remote_error', "HTTP $code from root: " . substr( $body, 0, 240 ) );
        }
        $payload = json_decode( $body, true );
        if ( ! is_array( $payload ) ) {
            return new WP_Error( 'parse_error', 'Root response was not valid JSON: ' . substr( $body, 0, 240 ) );
        }

        // Cache the last fetch in option for the admin page render.
        update_option( 'sa_orch_remote_root_last_fetch', [
            'at'      => current_time( 'mysql', true ),
            'payload' => $payload,
        ], false /* not autoloaded */ );

        return $payload;
    }

    public static function rest_fetch_now( WP_REST_Request $req ) {
        $r = self::fetch_remote_assignments();
        if ( is_wp_error( $r ) ) {
            return new WP_REST_Response( [
                'error'   => $r->get_error_code(),
                'message' => $r->get_error_message(),
            ], 502 );
        }
        return new WP_REST_Response( $r, 200 );
    }

    /* ===================================================================
     * LEAF HALF — admin page render
     * =================================================================== */

    public static function render_page() {
        if ( ! current_user_can( SA_Orch_Admin::CAP ) ) wp_die( 'Insufficient permissions.' );

        $error  = '';
        $notice = '';

        // Handle save
        if ( isset( $_POST['sa_orch_save_root'] ) && check_admin_referer( 'sa_orch_save_root' ) ) {
            $cfg = [
                'url'          => esc_url_raw( trim( wp_unslash( $_POST['root_url']     ?? '' ) ) ),
                'app_user'     => sanitize_text_field( wp_unslash( $_POST['app_user']     ?? '' ) ),
                'app_password' => trim( wp_unslash( $_POST['app_password'] ?? '' ) ),
            ];
            update_option( self::OPTION_KEY, $cfg, false );
            $notice = 'Remote root saved.';
        }

        // Handle fetch button
        if ( isset( $_POST['sa_orch_fetch_now'] ) && check_admin_referer( 'sa_orch_fetch_now' ) ) {
            $r = self::fetch_remote_assignments();
            if ( is_wp_error( $r ) ) {
                $error = 'Fetch failed: ' . $r->get_error_message();
            } else {
                $notice = 'Fetched ' . (int) $r['count'] . ' assignment(s).';
            }
        }

        $cfg        = get_option( self::OPTION_KEY, [] );
        $last_fetch = get_option( 'sa_orch_remote_root_last_fetch', [] );
        $payload    = $last_fetch['payload'] ?? null;
        $assignments = is_array( $payload ) ? ( $payload['assignments'] ?? [] ) : [];

        echo '<div class="wrap">';
        echo '<h1>Remote Roots</h1>';
        echo '<p>Pull assignments from a remote SA-Orchestration root (e.g., the dev root). Leaf-initiated; outbound HTTPS only.</p>';

        if ( $error  !== '' ) echo '<div class="notice notice-error"><p>' . esc_html( $error )  . '</p></div>';
        if ( $notice !== '' ) echo '<div class="notice notice-success"><p>' . esc_html( $notice ) . '</p></div>';

        // Configuration form
        echo '<h2>Configuration (single root, MVP)</h2>';
        echo '<form method="post">';
        wp_nonce_field( 'sa_orch_save_root' );
        echo '<table class="form-table">';
        echo '<tr><th>Root URL</th><td><input type="url" name="root_url" class="regular-text" placeholder="https://sleeperagendev.wpenginepowered.com" value="' . esc_attr( $cfg['url'] ?? '' ) . '" required></td></tr>';
        echo '<tr><th>App Username</th><td><input type="text" name="app_user" class="regular-text" placeholder="user@example.com" value="' . esc_attr( $cfg['app_user'] ?? '' ) . '" required></td></tr>';
        echo '<tr><th>App Password</th><td><input type="password" name="app_password" class="regular-text" placeholder="XXXX XXXX XXXX XXXX XXXX XXXX" value="' . esc_attr( $cfg['app_password'] ?? '' ) . '" required>';
        echo '<p class="description">Generate at <code>{root}/wp-admin/profile.php</code> → Application Passwords. Stored in wp_options (not autoloaded). Revoke from same page anytime.</p></td></tr>';
        echo '</table>';
        echo '<p><button type="submit" name="sa_orch_save_root" value="1" class="button">Save Remote Root</button></p>';
        echo '</form>';

        // Fetch button
        echo '<h2>Pull Assignments</h2>';
        echo '<form method="post">';
        wp_nonce_field( 'sa_orch_fetch_now' );
        echo '<p><button type="submit" name="sa_orch_fetch_now" value="1" class="button button-primary">Fetch Now</button>';
        if ( ! empty( $last_fetch['at'] ) ) {
            echo ' <span style="margin-left:1em;color:#666;">Last fetched: ' . esc_html( $last_fetch['at'] ) . ' UTC</span>';
        }
        echo '</p>';
        echo '</form>';

        // Render assignments
        if ( $payload && isset( $payload['count'] ) ) {
            $actor = $payload['actor'] ?? [];
            echo '<h2>Assignments (' . (int) $payload['count'] . ')</h2>';
            echo '<p style="color:#666;">Authenticated to root as: <code>' . esc_html( $actor['login'] ?? '' ) . '</code> (wp_user_id=' . (int) ( $actor['wp_user_id'] ?? 0 ) . ')</p>';

            if ( empty( $assignments ) ) {
                echo '<p>No assignments found for this user on the configured root.</p>';
            } else {
                echo '<table class="widefat striped"><thead><tr>';
                echo '<th>Root Task ID</th><th>Board</th><th>Stage</th><th>Status</th><th>Priority</th><th>Title</th><th>Updated</th>';
                echo '</tr></thead><tbody>';
                foreach ( $assignments as $a ) {
                    echo '<tr>';
                    echo '<td>' . (int) $a['root_task_id'] . '</td>';
                    echo '<td>' . esc_html( $a['board_title'] ) . ' (#' . (int) $a['board_id'] . ')</td>';
                    echo '<td>' . esc_html( $a['stage_title'] ) . '</td>';
                    echo '<td>' . esc_html( $a['status'] ) . '</td>';
                    echo '<td>' . esc_html( $a['priority'] ) . '</td>';
                    echo '<td>' . esc_html( $a['title'] ) . '</td>';
                    echo '<td>' . esc_html( $a['updated_at'] ) . '</td>';
                    echo '</tr>';
                    if ( ! empty( $a['description_excerpt'] ) ) {
                        echo '<tr><td colspan="7" style="background:#f8f8f8;font-size:11.5px;color:#444;padding:6px 12px;"><em>excerpt:</em> ' . esc_html( substr( $a['description_excerpt'], 0, 400 ) ) . ( strlen( $a['description_excerpt'] ) > 400 ? '...' : '' ) . '</td></tr>';
                    }
                }
                echo '</tbody></table>';
            }
        }

        echo '</div>';
    }
}