<?php

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

// The chatbot's inbox inside wp-admin: its conversations, the requests for a
// person and its figures, read from Rayachat with the site key «Connect to
// Rayachat» issued. The key stays on this server: the admin's browser talks
// only to admin-ajax.php, which asks Rayachat on its behalf.

define('RAYACHAT_INBOX_OPTION', 'rayachat_inbox');
// Each admin's unread marks: conversation id → Rayachat's time of the last customer message they saw.
define('RAYACHAT_INBOX_SEEN_META', 'rayachat_inbox_seen');
// A conversation an admin never opened is unread only this long, as in Rayachat's inbox.
define('RAYACHAT_INBOX_NEW_SECONDS', 2 * DAY_IN_SECONDS);
// The menu's count is refreshed at most this often, from WordPress's heartbeat.
define('RAYACHAT_INBOX_BADGE_SECONDS', 60);
// The dashboard widget's figures are kept this long between visits.
define('RAYACHAT_SUMMARY_SECONDS', 60);

add_action('wp_ajax_rayachat_inbox_list', 'rayachat_ajax_inbox_list');
add_action('wp_ajax_rayachat_inbox_thread', 'rayachat_ajax_inbox_thread');
add_action('wp_ajax_rayachat_inbox_reply', 'rayachat_ajax_inbox_reply');
add_action('wp_ajax_rayachat_inbox_update', 'rayachat_ajax_inbox_update');
add_action('wp_ajax_rayachat_inbox_correct', 'rayachat_ajax_inbox_correct');
add_action('wp_ajax_rayachat_inbox_canned', 'rayachat_ajax_inbox_canned');
add_action('wp_ajax_rayachat_inbox_file', 'rayachat_ajax_inbox_file');
add_action('wp_ajax_rayachat_inbox_summary', 'rayachat_ajax_inbox_summary');
add_filter('heartbeat_received', 'rayachat_inbox_heartbeat', 10, 2);

/**
 * `count` and `newest` are what the menu shows until the next refresh;
 * `rejected` is set once Rayachat refuses the key, until a reconnect.
 */
function rayachat_inbox_settings()
{
    $defaults = array(
        'token'    => '',
        'rejected' => false,
        'count'    => 0,
        'newest'   => '',
        'checked'  => 0,
    );
    $saved = get_option(RAYACHAT_INBOX_OPTION, array());

    return array_merge($defaults, is_array($saved) ? $saved : array());
}

// Autoloaded: the menu reads it on every admin page.
function rayachat_inbox_update(array $changes)
{
    update_option(RAYACHAT_INBOX_OPTION, array_merge(rayachat_inbox_settings(), $changes), true);
}

function rayachat_inbox_key_valid($token)
{
    return is_string($token) && preg_match('/^rwp_[a-f0-9]{12}_[A-Za-z0-9_-]{40,}$/', $token) === 1;
}

function rayachat_inbox_active()
{
    $inbox = rayachat_inbox_settings();

    return $inbox['token'] !== '' && !$inbox['rejected'];
}

/**
 * Who sees the inbox and the dashboard widget. On a store, shop managers
 * answer the customers too; elsewhere, administrators. A site can change it
 * with the `rayachat_inbox_capability` filter.
 */
function rayachat_inbox_capability()
{
    return (string) apply_filters('rayachat_inbox_capability', class_exists('WooCommerce') ? 'manage_woocommerce' : 'manage_options');
}

function rayachat_inbox_can()
{
    return current_user_can(rayachat_inbox_capability());
}

// Teaching the bot changes what it tells every customer, so it asks for more
// than answering does: in Rayachat an operator replies but can't correct.
function rayachat_inbox_correction_capability()
{
    return (string) apply_filters('rayachat_inbox_correction_capability', 'manage_options');
}

function rayachat_inbox_url($conversation = '')
{
    $url = admin_url('admin.php?page=rayachat-inbox');

    return $conversation !== '' ? add_query_arg('conversation', rawurlencode($conversation), $url) : $url;
}

/**
 * Keeps the key «Connect to Rayachat» returned, or forgets the old one when
 * the owner didn't give this site the inbox this time. A key it replaces is
 * revoked on Rayachat, best-effort.
 */
function rayachat_inbox_adopt($token)
{
    $old = rayachat_inbox_settings()['token'];
    if ($old !== '' && $old !== $token) {
        rayachat_inbox_request('POST', 'disconnect', array(), array(), $old);
    }
    delete_transient('rayachat_summary');
    update_option(RAYACHAT_INBOX_OPTION, array(
        'token'    => rayachat_inbox_key_valid($token) ? $token : '',
        'rejected' => false,
        'count'    => 0,
        'newest'   => '',
        'checked'  => 0,
    ), true);
    // The menu's count right away, rather than after the first heartbeat.
    if (rayachat_inbox_active()) {
        rayachat_inbox_refresh_badge();
    }
}

/** Asks Rayachat how many customers wait for a person, and keeps the answer for the menu. */
function rayachat_inbox_refresh_badge()
{
    rayachat_inbox_update(array('checked' => time()));
    $result = rayachat_inbox_request('GET', 'inbox/waiting');
    if (!is_wp_error($result) && $result['code'] === 200 && is_array($result['body'])) {
        rayachat_inbox_update(array(
            'count'  => absint($result['body']['count'] ?? 0),
            'newest' => sanitize_text_field((string) ($result['body']['newestAt'] ?? '')),
        ));
    }
}

/**
 * One call to the inbox API. Returns array('code' => int, 'body' => array|null,
 * 'response' => array), or a WP_Error when the request never got an answer.
 */
function rayachat_inbox_request($method, $path, array $query = array(), $body = null, $token = null)
{
    $stored = $token === null;
    $token = $stored ? rayachat_inbox_settings()['token'] : $token;
    if ($token === '') {
        return new WP_Error('rayachat_inbox_off', __('This site isn’t allowed to show the inbox yet.', 'raya-ai'));
    }
    $url = RAYACHAT_ORIGIN . '/api/integrations/wordpress/' . $path;
    if ($query) {
        $url .= '?' . http_build_query($query, '', '&', PHP_QUERY_RFC3986);
    }
    $args = array(
        'method'     => $method,
        'timeout'    => 15,
        'user-agent' => 'Rayachat-WordPress/' . RAYACHAT_VERSION,
        'headers'    => array(
            'Authorization' => 'Bearer ' . $token,
            'Accept'        => 'application/json',
        ),
    );
    if ($body !== null) {
        $args['headers']['Content-Type'] = 'application/json';
        $args['body'] = wp_json_encode($body, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
    }
    $response = wp_remote_request($url, $args);
    if (is_wp_error($response)) {
        return $response;
    }
    $code = (int) wp_remote_retrieve_response_code($response);
    // Revoked from the dashboard or replaced by a newer connection: say so
    // until the next «Connect to Rayachat», instead of asking again each time.
    if ($code === 401 && $stored) {
        rayachat_inbox_update(array('rejected' => true, 'count' => 0));
    }
    $decoded = json_decode(wp_remote_retrieve_body($response), true);

    return array('code' => $code, 'body' => is_array($decoded) ? $decoded : null, 'response' => $response);
}

// Every AJAX call: this admin's nonce and capability, and a site that has the inbox.
function rayachat_inbox_ajax_guard()
{
    check_ajax_referer('rayachat_inbox');
    if (!rayachat_inbox_can()) {
        wp_send_json(array('error' => __('You are not allowed to see Rayachat’s inbox.', 'raya-ai')), 403);
    }
    if (!rayachat_inbox_active()) {
        wp_send_json(array('error' => rayachat_inbox_reconnect_text(), 'reconnect' => true), 409);
    }
}

function rayachat_inbox_reconnect_text()
{
    return rayachat_inbox_settings()['rejected']
        ? __('Rayachat no longer accepts this site’s key, so the inbox is off. An administrator can turn it back on: Rayachat → Settings → “Change chatbot or reconnect”.', 'raya-ai')
        : __('To see the chatbot’s conversations here, an administrator connects once more: Rayachat → Settings → “Change chatbot or reconnect”, keeping “Inbox and figures in WordPress” ticked.', 'raya-ai');
}

// Rayachat's answer, passed to the browser as it came, or why there is none.
function rayachat_inbox_relay($result)
{
    if (is_wp_error($result)) {
        wp_send_json(array('error' => sprintf(
            /* translators: %s: the network error. */
            __('This site could not reach Rayachat: %s', 'raya-ai'),
            $result->get_error_message()
        )), 502);
    }
    if ($result['code'] === 401) {
        wp_send_json(array('error' => rayachat_inbox_reconnect_text(), 'reconnect' => true), 409);
    }
    if (!is_array($result['body'])) {
        wp_send_json(array('error' => __('Rayachat sent an answer this plugin can’t read. Please try again in a minute.', 'raya-ai')), 502);
    }
    wp_send_json($result['body'], $result['code'] > 0 ? $result['code'] : 502);
}

// A conversation or message id as Rayachat issues them.
function rayachat_inbox_id($value)
{
    $value = is_string($value) ? strtolower(trim($value)) : '';

    return preg_match('/^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$/', $value) ? $value : '';
}

/**
 * A reply as the admin typed it. Not sanitize_textarea_field(): that drops
 * percent-encoded bytes, which turns a pasted Persian product link into a
 * broken one, and anything that looks like a tag. The text goes to Rayachat
 * as plain text and WordPress never prints it.
 */
function rayachat_inbox_text($raw)
{
    $text = wp_check_invalid_utf8(is_string($raw) ? $raw : '');
    $text = str_replace(array("\r\n", "\r"), "\n", $text);
    $text = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', '', $text);

    return trim(function_exists('mb_substr') ? mb_substr($text, 0, 4096) : substr($text, 0, 4096));
}

// The WordPress user a reply or a change is signed with, as Rayachat shows it.
function rayachat_inbox_author()
{
    $user = wp_get_current_user();
    $name = trim(wp_strip_all_tags($user->display_name !== '' ? $user->display_name : $user->user_login));

    return function_exists('mb_substr') ? mb_substr($name, 0, 80) : substr($name, 0, 80);
}

function rayachat_ajax_inbox_list()
{
    rayachat_inbox_ajax_guard();
    // phpcs:disable WordPress.Security.NonceVerification.Recommended -- checked in rayachat_inbox_ajax_guard().
    $filter = isset($_GET['filter']) ? sanitize_key(wp_unslash($_GET['filter'])) : 'all';
    $query = isset($_GET['q']) ? sanitize_text_field(wp_unslash($_GET['q'])) : '';
    // phpcs:enable
    $result = rayachat_inbox_request('GET', 'inbox/conversations', array_filter(array(
        'filter' => $filter,
        'q'      => $query,
    )));
    if (!is_wp_error($result) && $result['code'] === 200 && isset($result['body']['rows']) && is_array($result['body']['rows'])) {
        $result['body']['rows'] = rayachat_inbox_mark_unread($result['body']['rows']);
    }
    rayachat_inbox_relay($result);
}

/**
 * Sets `unread` on rows Rayachat sent: the customer wrote last, after this
 * admin last opened the conversation here. Kept per WordPress user, since
 * WordPress users aren't on the Rayachat team and share one key.
 */
function rayachat_inbox_mark_unread(array $rows)
{
    $seen = rayachat_inbox_seen();
    $since = gmdate('Y-m-d\TH:i:s', time() - RAYACHAT_INBOX_NEW_SECONDS);
    foreach ($rows as $index => $row) {
        $at = is_array($row) && is_string($row['customerAt'] ?? null) ? $row['customerAt'] : '';
        $id = is_array($row) && is_string($row['id'] ?? null) ? $row['id'] : '';
        // Both are Rayachat's ISO times, so they compare as strings.
        $rows[$index]['unread'] = $at !== '' && $at > ($seen[$id] ?? $since);
    }

    return $rows;
}

function rayachat_inbox_seen()
{
    $seen = get_user_meta(get_current_user_id(), RAYACHAT_INBOX_SEEN_META, true);

    return is_array($seen) ? $seen : array();
}

/**
 * Remembers the newest customer message a thread showed this admin. Only
 * moves forward, so a poll that brings nothing new writes nothing.
 */
function rayachat_inbox_remember_seen(array $body)
{
    $id = rayachat_inbox_id($body['conversation']['id'] ?? '');
    $latest = '';
    foreach ((array) ($body['messages'] ?? array()) as $message) {
        if (is_array($message) && ($message['from'] ?? '') === 'customer' && is_string($message['at'] ?? null) && $message['at'] > $latest) {
            $latest = $message['at'];
        }
    }
    $seen = rayachat_inbox_seen();
    if ($id === '' || $latest === '' || ($seen[$id] ?? '') >= $latest) {
        return;
    }
    $seen[$id] = $latest;
    // The oldest marks go first: a conversation that old reads as read anyway.
    arsort($seen);
    update_user_meta(get_current_user_id(), RAYACHAT_INBOX_SEEN_META, array_slice($seen, 0, 300, true));
}

function rayachat_ajax_inbox_thread()
{
    rayachat_inbox_ajax_guard();
    // phpcs:disable WordPress.Security.NonceVerification.Recommended -- checked in rayachat_inbox_ajax_guard().
    $id = rayachat_inbox_id(isset($_GET['id']) ? sanitize_text_field(wp_unslash($_GET['id'])) : '');
    $before = rayachat_inbox_id(isset($_GET['before']) ? sanitize_text_field(wp_unslash($_GET['before'])) : '');
    $after = isset($_GET['after']) ? sanitize_text_field(wp_unslash($_GET['after'])) : '';
    // phpcs:enable
    if ($id === '') {
        wp_send_json(array('error' => 'not found'), 404);
    }
    $query = array();
    if ($before !== '') {
        $query['before'] = $before;
    } elseif (preg_match('/^\d{4}-\d{2}-\d{2}T[\d:.]+Z$/', $after)) {
        $query['after'] = $after;
    }
    $result = rayachat_inbox_request('GET', 'inbox/conversations/' . $id, $query);
    if ($before === '' && !is_wp_error($result) && $result['code'] === 200 && is_array($result['body'])) {
        rayachat_inbox_remember_seen($result['body']);
    }
    rayachat_inbox_relay($result);
}

function rayachat_ajax_inbox_reply()
{
    rayachat_inbox_ajax_guard();
    // phpcs:disable WordPress.Security.NonceVerification.Missing -- checked in rayachat_inbox_ajax_guard().
    $id = rayachat_inbox_id(isset($_POST['id']) ? sanitize_text_field(wp_unslash($_POST['id'])) : '');
    $seen = rayachat_inbox_id(isset($_POST['seen']) ? sanitize_text_field(wp_unslash($_POST['seen'])) : '');
    // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- sanitized by rayachat_inbox_text().
    $message = rayachat_inbox_text(isset($_POST['message']) ? wp_unslash($_POST['message']) : '');
    // phpcs:enable
    if ($id === '' || $message === '') {
        wp_send_json(array('error' => __('Write a reply first.', 'raya-ai')), 400);
    }
    $body = array('message' => $message, 'by' => rayachat_inbox_author());
    if ($seen !== '') {
        $body['seenAssigneeId'] = $seen;
    }
    rayachat_inbox_relay(rayachat_inbox_request('POST', 'inbox/conversations/' . $id . '/reply', array(), $body));
}

// «This answer was wrong»: the bot's reply and what it should have said, saved in Rayachat as an approved answer.
function rayachat_ajax_inbox_correct()
{
    rayachat_inbox_ajax_guard();
    if (!current_user_can(rayachat_inbox_correction_capability())) {
        wp_send_json(array('error' => __('Only an administrator can teach the bot.', 'raya-ai')), 403);
    }
    // phpcs:disable WordPress.Security.NonceVerification.Missing -- checked in rayachat_inbox_ajax_guard().
    $id = rayachat_inbox_id(isset($_POST['id']) ? sanitize_text_field(wp_unslash($_POST['id'])) : '');
    // phpcs:disable WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- sanitized by rayachat_inbox_text().
    $question = rayachat_inbox_text(isset($_POST['question']) ? wp_unslash($_POST['question']) : '');
    $answer = rayachat_inbox_text(isset($_POST['answer']) ? wp_unslash($_POST['answer']) : '');
    // phpcs:enable
    if ($id === '' || $question === '' || $answer === '') {
        wp_send_json(array('error' => __('Write the customer’s question and the right answer.', 'raya-ai')), 400);
    }
    rayachat_inbox_relay(rayachat_inbox_request('POST', 'inbox/corrections', array(), array(
        'messageId' => $id,
        'question'  => $question,
        'answer'    => $answer,
    )));
}

function rayachat_ajax_inbox_update()
{
    rayachat_inbox_ajax_guard();
    // phpcs:disable WordPress.Security.NonceVerification.Missing -- checked in rayachat_inbox_ajax_guard().
    $id = rayachat_inbox_id(isset($_POST['id']) ? sanitize_text_field(wp_unslash($_POST['id'])) : '');
    $status = isset($_POST['status']) ? sanitize_key(wp_unslash($_POST['status'])) : '';
    $paused = isset($_POST['botPaused']) ? sanitize_key(wp_unslash($_POST['botPaused'])) : '';
    // phpcs:enable
    $body = array('by' => rayachat_inbox_author());
    if (in_array($status, array('open', 'waiting', 'resolved'), true)) {
        $body['status'] = $status;
    }
    if ($paused === '1' || $paused === '0') {
        $body['botPaused'] = $paused === '1';
    }
    if ($id === '' || count($body) < 2) {
        wp_send_json(array('error' => 'nothing to change'), 400);
    }
    rayachat_inbox_relay(rayachat_inbox_request('PATCH', 'inbox/conversations/' . $id, array(), $body));
}

function rayachat_ajax_inbox_canned()
{
    rayachat_inbox_ajax_guard();
    rayachat_inbox_relay(rayachat_inbox_request('GET', 'inbox/canned-replies'));
}

function rayachat_ajax_inbox_summary()
{
    rayachat_inbox_ajax_guard();
    $summary = rayachat_inbox_summary();
    if (is_array($summary)) {
        wp_send_json(rayachat_inbox_summary_for_user($summary));
    }
    rayachat_inbox_relay($summary);
}

// The summary is kept for every admin alike; whether a row is unread is each admin's own.
function rayachat_inbox_summary_for_user(array $summary)
{
    if (isset($summary['waiting']['rows']) && is_array($summary['waiting']['rows'])) {
        $summary['waiting']['rows'] = rayachat_inbox_mark_unread($summary['waiting']['rows']);
    }
    if (isset($summary['recent']) && is_array($summary['recent'])) {
        $summary['recent'] = rayachat_inbox_mark_unread($summary['recent']);
    }

    return $summary;
}

/**
 * The dashboard widget's figures: kept a minute, so the dashboard opening
 * again draws them at once. Returns the summary, or what the request
 * returned when it isn't one.
 */
function rayachat_inbox_summary()
{
    $cached = get_transient('rayachat_summary');
    if (is_array($cached)) {
        return $cached;
    }
    $result = rayachat_inbox_request('GET', 'inbox/summary');
    if (is_wp_error($result) || $result['code'] !== 200 || !is_array($result['body'])) {
        return $result;
    }
    set_transient('rayachat_summary', $result['body'], RAYACHAT_SUMMARY_SECONDS);
    if (isset($result['body']['waiting']['count'])) {
        rayachat_inbox_update(array('count' => absint($result['body']['waiting']['count']), 'checked' => time()));
    }

    return $result['body'];
}

/**
 * A customer's photo, voice note or PDF, passed through from Rayachat. Only
 * the types the inbox draws, each sent so the browser can't run it.
 */
function rayachat_ajax_inbox_file()
{
    rayachat_inbox_ajax_guard();
    // phpcs:disable WordPress.Security.NonceVerification.Recommended -- checked in rayachat_inbox_ajax_guard().
    $message = rayachat_inbox_id(isset($_GET['message']) ? sanitize_text_field(wp_unslash($_GET['message'])) : '');
    $index = isset($_GET['i']) ? absint(wp_unslash($_GET['i'])) : 0;
    // phpcs:enable
    if ($message === '') {
        status_header(404);
        exit;
    }
    $result = rayachat_inbox_request('GET', 'inbox/attachments/' . $message, array('i' => $index));
    $types = array('image/jpeg', 'image/png', 'image/webp', 'audio/ogg', 'audio/mpeg', 'audio/mp4', 'application/pdf');
    $type = is_wp_error($result) ? '' : strtolower(trim(explode(';', (string) wp_remote_retrieve_header($result['response'], 'content-type'))[0]));
    if (is_wp_error($result) || $result['code'] !== 200 || !in_array($type, $types, true)) {
        status_header(is_wp_error($result) ? 502 : 404);
        exit;
    }
    nocache_headers();
    header('Content-Type: ' . $type);
    header('Content-Disposition: ' . ($type === 'application/pdf' ? 'attachment; filename="file.pdf"' : 'inline'));
    header('X-Content-Type-Options: nosniff');
    header("Content-Security-Policy: default-src 'none'; sandbox");
    // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- the file's bytes, of a type checked above.
    echo wp_remote_retrieve_body($result['response']);
    exit;
}

/**
 * The menu's count, refreshed while any admin page is open: the page's
 * heartbeat asks, and Rayachat is asked at most once a minute however many
 * admins are on.
 */
function rayachat_inbox_heartbeat($response, $data)
{
    if (empty($data['rayachat_inbox']) || !rayachat_inbox_active() || !rayachat_inbox_can()) {
        return $response;
    }
    if ((int) rayachat_inbox_settings()['checked'] < time() - RAYACHAT_INBOX_BADGE_SECONDS) {
        // It marks the time first, so admins whose heartbeats arrive meanwhile don't ask too.
        rayachat_inbox_refresh_badge();
    }
    $inbox = rayachat_inbox_settings();
    $response['rayachat_inbox'] = array(
        'count'  => (int) $inbox['count'],
        'label'  => rayachat_digits(number_format_i18n((int) $inbox['count'])),
        'text'   => rayachat_inbox_waiting_text((int) $inbox['count']),
        'newest' => (string) $inbox['newest'],
    );

    return $response;
}

// What the bubble says to a screen reader.
function rayachat_inbox_waiting_text($count)
{
    /* translators: %s: number of customers. */
    return sprintf(_n('%s customer waiting for you', '%s customers waiting for you', $count, 'raya-ai'), rayachat_digits(number_format_i18n($count)));
}

// The count beside the menu items, in WordPress's own bubble.
function rayachat_inbox_bubble()
{
    $count = rayachat_inbox_active() ? (int) rayachat_inbox_settings()['count'] : 0;

    // WordPress hides a bubble whose class says count-0; the heartbeat changes both.
    return sprintf(
        ' <span class="awaiting-mod rayachat-inbox-count count-%1$d"><span class="pending-count" aria-hidden="true">%2$s</span><span class="screen-reader-text">%3$s</span></span>',
        $count,
        esc_html(rayachat_digits(number_format_i18n($count))),
        esc_html(rayachat_inbox_waiting_text($count))
    );
}