claude.php

<?php
/**
 * Plugin Name: Claude 3.x Chat Interface
 * Description: Adds a Claude AI chat interface to your WordPress site using a shortcode.
 * Version: 1.4
 * Author: Volkan Kücükbudak
 * Enhancements: TurtleEngr
 */


// Define the available models
define('CLAUDE_MODELS', [
    'claude-3-haiku-20240307'      => 'Claude 3.0 Haiku',
    'claude-3-5-haiku-20241022'    => 'Claude 3.5 Haiku',
    'claude-haiku-4-5-20251001'    => 'Claude 4.5 Haiku',
    'claude-3-5-sonnet-20241022'   => 'Claude 3.5 Sonnet',
    'claude-3-7-sonnet-20250219'   => 'Claude 3.7 Sonnet',
    'claude-sonnet-4-5-20250929'   => 'Claude 4.5 Sonnet',
]);

// Register settings
function claude_chat_register_settings() {
    register_setting('claude_chat_options', 'claude_chat_api_key');
    register_setting('claude_chat_options', 'claude_chat_model');
    register_setting('claude_chat_options', 'claude_chat_temperature');
    register_setting('claude_chat_options', 'claude_chat_max_tokens');
    register_setting('claude_chat_options', 'claude_chat_prefix_prompt', [
            'sanitize_callback' => 'sanitize_textarea_field',
        ]);

    // Additional prompt settings
    register_setting('claude_chat_options', 'claude_chat_addon_prompt_enabled');
    register_setting('claude_chat_options', 'claude_chat_addon_prompt_label', [
            'sanitize_callback' => 'sanitize_text_field',
        ]);
    register_setting('claude_chat_options', 'claude_chat_addon_prompt_text', [
            'sanitize_callback' => 'sanitize_textarea_field',
        ]);
}
add_action('admin_init', 'claude_chat_register_settings');

// Enqueue necessary scripts and styles
function claude_chat_enqueue_scripts() {
    wp_enqueue_style('claude-chat-style', plugin_dir_url(__FILE__) . 'css/claude-chat.css');
    wp_enqueue_script('claude-chat-script', plugin_dir_url(__FILE__) . 'js/claude-chat.js', array('jquery'), '1.4', true);
    wp_localize_script('claude-chat-script', 'claudeChat', array(
            'ajax_url'      => admin_url('admin-ajax.php'),
            'nonce'         => wp_create_nonce('claude-chat-nonce'),
            // FIX: Only expose a boolean flag — never the prompt text itself.
            // The actual prompt text is appended server-side in claude_chat_ajax_handler().
            'addon_enabled' => get_option('claude_chat_addon_prompt_enabled', '0') === '1',
        ));
}
add_action('wp_enqueue_scripts', 'claude_chat_enqueue_scripts');

// Shortcode to display the chat interface
function claude_chat_shortcode() {
    $addon_enabled = get_option('claude_chat_addon_prompt_enabled', '0');
    $addon_label   = get_option('claude_chat_addon_prompt_label', '');

    ob_start();
    ?>
    <div id="claude-chat-interface">
        <div id="claude-chat-messages"></div>
        <?php if ( $addon_enabled === '1' ) : ?>
        <div id="claude-chat-addon">
            <label>
                <input type="checkbox" id="claude-chat-addon-checkbox">
                <?php echo esc_html( $addon_label ); ?>
            </label>
        </div>
        <?php endif; ?>
        <textarea id="claude-chat-input" placeholder="Ask Claude something..." rows="3"></textarea>        
        <button id="claude-chat-submit">Send</button>
    </div>
    <?php
    return ob_get_clean();
}
add_shortcode('claude_chat', 'claude_chat_shortcode');

// ---------------------------------------------------------------------------
// FIX: Transient-based rate limiter — max 10 requests per minute per IP.
// Returns true when the request is allowed, false when the limit is exceeded.
// ---------------------------------------------------------------------------
function claude_chat_check_rate_limit() {
    $ip            = isset($_SERVER['REMOTE_ADDR']) ? $_SERVER['REMOTE_ADDR'] : 'unknown';
    $transient_key = 'claude_chat_rate_' . md5($ip);
    $count         = get_transient($transient_key);

    if ($count === false) {
        // First request in this window — start the counter with a 60-second TTL.
        set_transient($transient_key, 1, 60);
        return true;
    }

    if (intval($count) >= 10) {
        return false; // Rate limit exceeded.
    }

    // Increment without resetting the existing TTL by reusing the same key.
    set_transient($transient_key, intval($count) + 1, 60);
    return true;
}

// AJAX handler for chat requests
function claude_chat_ajax_handler() {
    check_ajax_referer('claude-chat-nonce', 'nonce');

    // FIX: Enforce rate limit before doing any further work.
    if ( ! claude_chat_check_rate_limit() ) {
        wp_send_json_error('Rate limit exceeded. Please wait a moment before sending another message.');
        return;
    }

    // FIX: Use sanitize_textarea_field so newlines in multi-line messages
    // are preserved (sanitize_text_field strips them).
    $message = sanitize_textarea_field($_POST['message']);

    // FIX: The addon prompt text never travels to the browser.
    // The JS sends only a boolean flag; we append the stored prompt server-side.
    $addon_checked = ! empty($_POST['addon_enabled']) && $_POST['addon_enabled'] === '1';
    if ($addon_checked && get_option('claude_chat_addon_prompt_enabled', '0') === '1') {
        $addon_text = get_option('claude_chat_addon_prompt_text', '');
        if ($addon_text !== '') {
            $message = $message . "\n" . $addon_text;
        }
    }

    $response = claude_chat_api_request($message);
    if ($response) {
        wp_send_json_success($response);
    } else {
        wp_send_json_error('Error: No response from API');
    }
}
add_action('wp_ajax_claude_chat',        'claude_chat_ajax_handler');
add_action('wp_ajax_nopriv_claude_chat', 'claude_chat_ajax_handler');

// Claude API request function with logging
function claude_chat_api_request($message) {
    $api_key       = get_option('claude_chat_api_key');
    $model         = get_option('claude_chat_model');
    $temperature   = get_option('claude_chat_temperature');
    $max_tokens    = get_option('claude_chat_max_tokens');
    $prefix_prompt = trim(get_option('claude_chat_prefix_prompt', ''));

    // Use the correct API-Endpoint.
    $url = 'https://api.anthropic.com/v1/messages';

    $headers = array(
        'Content-Type'      => 'application/json',
        'x-api-key'         => $api_key,
        'anthropic-version' => '2023-06-01',
        // Required to enable cache_control on system/content blocks.
        'anthropic-beta'    => 'prompt-caching-2024-07-31',
    );

    // -----------------------------------------------------------------------
    // FIX: Move the prefix prompt to the dedicated `system` parameter.
    //
    // Placing it in `system` gives it architectural separation from the
    // conversation turn — it cannot be overridden by "Ignore previous
    // instructions…" style user inputs and benefits from Claude's distinct
    // system-prompt handling.
    //
    // The array form is used (rather than a plain string) so that
    // cache_control can be set on the block, preserving the prompt-caching
    // benefit of the original implementation.
    // -----------------------------------------------------------------------
    $body = array(
        'model'      => $model,
        'max_tokens' => intval($max_tokens),
        'messages'   => array(
            array(
                'role'    => 'user',
                'content' => $message,   // plain string — no prefix bundled in here
            ),
        ),
    );

    if ($prefix_prompt !== '') {
        $body['system'] = array(
            array(
                'type'          => 'text',
                'text'          => $prefix_prompt,
                'cache_control' => array('type' => 'ephemeral'),
            ),
        );
    }

    // Only include temperature when set (0 is falsy but valid, so check !== '')
    if ($temperature !== '') {
        $body['temperature'] = floatval($temperature);
    }

    $response = wp_remote_post($url, array(
            'headers' => $headers,
            'body'    => json_encode($body),
            'timeout' => 60,
        ));

    if (is_wp_error($response)) {
        claude_chat_log_error('HTTP Error', $response->get_error_message());
        return 'Error: ' . $response->get_error_message();
    }

    $body = wp_remote_retrieve_body($response);
    $data = json_decode($body, true);

    if (isset($data['content'][0]['text'])) {
        return $data['content'][0]['text'];

    } elseif (isset($data['error'])) {
        claude_chat_log_error('API Error', print_r($data, true));
        return 'API Error: ' . $data['error']['message'];
    } else {
        claude_chat_log_error('Unknown Error', 'Unable to get a response from Claude API. Response: ' . print_r($data, true));
        return 'Error: Unable to get a response from Claude API.';
    }
}

// Logging function
function claude_chat_log_error($error_type, $error_message) {
    $log_message = date('Y-m-d H:i:s') . " - $error_type: $error_message\n";
    $log_file    = plugin_dir_path(__FILE__) . 'claude-chat-error.log';
    error_log($log_message, 3, $log_file);
}

// Add settings page
function claude_chat_settings_page() {
    add_options_page(
        'Claude Chat Settings',
        'Claude Chat',
        'manage_options',
        'claude-chat-settings',
        'claude_chat_settings_page_html'
    );
}
add_action('admin_menu', 'claude_chat_settings_page');

// Settings page HTML
function claude_chat_settings_page_html() {
    ?>
    <div class="wrap">
        <h1><?php echo esc_html(get_admin_page_title()); ?></h1>
        <form action="options.php" method="post">
            <?php
            settings_fields('claude_chat_options');
            do_settings_sections('claude-chat-settings');
            submit_button('Save Settings');
            ?>
        </form>
    </div>
    <?php
}

// Initialize settings
function claude_chat_settings_init() {
    add_settings_section(
        'claude_chat_settings_section',
        'Claude API Settings',
        'claude_chat_settings_section_callback',
        'claude-chat-settings'
    );

    add_settings_field(
        'claude_chat_api_key',
        'API Key',
        'claude_chat_api_key_field_callback',   // FIX: dedicated callback uses type="password"
        'claude-chat-settings',
        'claude_chat_settings_section',
        array('label_for' => 'claude_chat_api_key')
    );

    add_settings_field(
        'claude_chat_model',
        'Model',
        'claude_chat_model_dropdown_callback',
        'claude-chat-settings',
        'claude_chat_settings_section',
        array('label_for' => 'claude_chat_model')
    );

    add_settings_field(
        'claude_chat_temperature',
        'Temperature',
        'claude_chat_number_field_callback',
        'claude-chat-settings',
        'claude_chat_settings_section',
        array(
            'label_for' => 'claude_chat_temperature',
            'description' => 'Range: 0 to 1',
            'min' => 0,
            'max' => 1,
            'step' => 0.1,
        )
    );

    add_settings_field(
        'claude_chat_max_tokens',
        'Max Tokens',
        'claude_chat_number_field_callback',
        'claude-chat-settings',
        'claude_chat_settings_section',
        array(
            'label_for' => 'claude_chat_max_tokens',
            'description' => 'Range: 1 to 8096',
            'min' => 1,
            'max' => 8096,
        )
    );

    add_settings_field(
        'claude_chat_prefix_prompt',
        'Prefix Prompt',
        'claude_chat_textarea_field_callback',
        'claude-chat-settings',
        'claude_chat_settings_section',
        array(
            'label_for'   => 'claude_chat_prefix_prompt',
            'description' => 'Optional. Sent as the <code>system</code> prompt on every request, keeping it architecturally separate from the conversation. Uses <code>cache_control</code> (ephemeral) for prompt-caching eligibility. Leave blank to disable.',
        )
    );

    // -----------------------------------------------------------------------
    // Additional prompt field — a single settings row that groups together:
    //   1. An enable/disable checkbox
    //   2. A text input for the checkbox label shown in the user form
    //   3. A textarea for the prompt text that gets appended to the message
    // -----------------------------------------------------------------------
    add_settings_field(
        'claude_chat_addon_prompt',
        'Additional Prompt',
        'claude_chat_addon_prompt_callback',
        'claude-chat-settings',
        'claude_chat_settings_section'
    );
}
add_action('admin_init', 'claude_chat_settings_init');

// Field render callbacks
function claude_chat_settings_section_callback($args) {
    echo '<p>Enter your Claude API settings below:</p>';
}

// FIX: Render the API key as a password field so it is masked in the browser.
function claude_chat_api_key_field_callback($args) {
    $option = get_option($args['label_for']);
    echo '<input type="password" id="'  . esc_attr($args['label_for'])
        . '" name="'                     . esc_attr($args['label_for'])
        . '" value="'                    . esc_attr($option)
        . '" class="regular-text"'
        . ' autocomplete="new-password">';
    if ( ! empty($args['description'])) {
       echo '<p class="description">' . wp_kses($args['description'], array('code' => array())) . '</p>';
    }
}

function claude_chat_number_field_callback($args) {
    $option = get_option($args['label_for']);
    echo '<input type="number" id="' . esc_attr($args['label_for'])
        . '" name="'                  . esc_attr($args['label_for'])
        . '" value="'                 . esc_attr($option)
        . '" class="regular-text"'
        . ' min="'                    . esc_attr($args['min'])
        . '" max="'                   . esc_attr($args['max'])
        . '" step="'                  . (isset($args['step']) ? esc_attr($args['step']) : '1')
        . '">';
    if ( ! empty($args['description'])) {
       echo '<p class="description">' . wp_kses($args['description'], array('code' => array())) . '</p>';
    }
}


function claude_chat_model_dropdown_callback($args) {
    $selected_model = get_option($args['label_for']);
    echo '<select id="'   . esc_attr($args['label_for'])
        . '" name="'       . esc_attr($args['label_for'])
        . '" class="regular-text">';
    foreach (CLAUDE_MODELS as $model_key => $model_name) {
        $selected = ($selected_model == $model_key) ? 'selected="selected"' : '';
        echo '<option value="' . esc_attr($model_key) . '" ' . $selected . '>'
            . esc_html($model_name) . '</option>';
    }
    echo '</select>';
    if ( ! empty($args['description'])) {
       echo '<p class="description">' . wp_kses($args['description'], array('code' => array())) . '</p>';
    }
}


function claude_chat_textarea_field_callback($args) {
    $option = get_option($args['label_for'], '');
    echo '<textarea id="'   . esc_attr($args['label_for'])
        . '" name="'         . esc_attr($args['label_for'])
        . '" rows="6" cols="60" class="large-text code">'
        . esc_textarea($option)
        . '</textarea>';
    if ( ! empty($args['description'])) {
        echo '<p class="description">' . wp_kses($args['description'], array('code' => array())) . '</p>';
    }
}


// ---------------------------------------------------------------------------
// Callback for the "Additional Prompt" settings row.
//
// Renders three controls in one table row:
//   Row 1 — Enable checkbox + label text input (inline)
//   Row 2 — Prompt textarea
// ---------------------------------------------------------------------------
function claude_chat_addon_prompt_callback() {
    $enabled = get_option('claude_chat_addon_prompt_enabled', '0');
    $label   = get_option('claude_chat_addon_prompt_label', '');
    $text    = get_option('claude_chat_addon_prompt_text', '');

    // ---- Enable checkbox + label input (same line) ----
    echo '<label style="display:inline-flex; align-items:center; gap:6px;">';
    echo '<input type="checkbox"'
        . ' id="claude_chat_addon_prompt_enabled"'
        . ' name="claude_chat_addon_prompt_enabled"'
        . ' value="1"'
        . checked('1', $enabled, false)
        . '>';
    echo '<strong>Enable</strong>';
    echo '</label>';

    echo '&nbsp;&nbsp;';

    echo '<label for="claude_chat_addon_prompt_label" style="font-weight:normal;">Checkbox label:&nbsp;</label>';
    echo '<input type="text"'
        . ' id="claude_chat_addon_prompt_label"'
        . ' name="claude_chat_addon_prompt_label"'
        . ' value="' . esc_attr($label) . '"'
        . ' class="regular-text"'
        . ' placeholder="e.g. Include extra context">';

    // ---- Prompt textarea ----
    echo '<br><br>';
    echo '<textarea'
        . ' id="claude_chat_addon_prompt_text"'
        . ' name="claude_chat_addon_prompt_text"'
        . ' rows="4" cols="60" class="large-text code">'
        . esc_textarea($text)
        . '</textarea>';

    echo '<p class="description">'
        . 'When <strong>Enable</strong> is checked, a checkbox labelled with the text above '
        . 'is shown in the user chat form (before the message input). '
        . 'If the user ticks that checkbox, a boolean flag is sent to the server and '
        . 'the prompt text is appended to their message <strong>server-side</strong> — '
        . 'the prompt text is never exposed to the browser.'
        . '</p>';
}