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: 1.2
 * 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'), '1.1', true);
    wp_localize_script('claude-chat-script', 'claudeChat', array(
            'ajax_url'      => admin_url('admin-ajax.php'),
            'nonce'         => wp_create_nonce('claude-chat-nonce'),
            // Pass addon prompt text so JS can append it when the user ticks the box.
            // An empty string is sent when the feature is disabled, which is harmless.
            'addon_prompt'  => get_option('claude_chat_addon_prompt_text', ''),
        ));
}
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');

// AJAX handler for chat requests
function claude_chat_ajax_handler() {
    check_ajax_referer('claude-chat-nonce', 'nonce');
    $message = sanitize_text_field($_POST['message']);
    $response = claude_chat_api_request($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 = get_option('claude_chat_prefix_prompt', '');

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

    // -----------------------------------------------------------------------
    // Build the messages array.
    //
    // When a prefix prompt is configured it is sent as the first content block
    // of the user message with cache_control set to "ephemeral" so that
    // Anthropic's prompt-caching feature can cache that block across requests.
    // The user's actual question follows as a second content block without
    // cache_control, ensuring only the stable prefix is cached.
    //
    // If no prefix prompt is set the message is sent as a plain string.
    // -----------------------------------------------------------------------

    $prefix_prompt = trim($prefix_prompt);

    if ($prefix_prompt !== '') {
        // Multi-block content with cached prefix
        $content = array(
            array(
                'type'          => 'text',
                'text'          => $prefix_prompt,
                'cache_control' => array('type' => 'ephemeral'),
            ),
            array(
                'type' => 'text',
                'text' => $message,
            ),
        );
    } else {
        // Original single-string content
        $content = $message;
    }

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

    $body = array(
        'model'       => $model,
        'max_tokens'  => intval($max_tokens),
        'messages'    => array(
            array(
                'role'    => 'user',
                'content' => $content,
            ),
        ),
    );

    // 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'])) {
        $reply = $data['content'][0]['text'];

        // ------------------------------------------------------------------
        // Strip the prefix prompt from the returned response.
        //
        // Claude will not normally echo the prefix back, but if it does (e.g.
        // because the prefix instructed it to repeat instructions, or due to
        // an unexpected model behavior) we remove it here so the end-user
        // only ever sees the genuine answer.
        // ------------------------------------------------------------------
        if ($prefix_prompt !== '') {
            $reply = claude_chat_strip_prefix($reply, $prefix_prompt);
        }

        return $reply;

    } 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.';
    }
}

// ---------------------------------------------------------------------------
// Helper: strip prefix from response text
//
// Removes the prefix prompt text from the very beginning of $response if it
// appears there (case-insensitively, ignoring leading/trailing whitespace).
// Also removes any leading whitespace that remains after stripping.
// ---------------------------------------------------------------------------
function claude_chat_strip_prefix($response, $prefix) {
    $response_trimmed = ltrim($response);
    $prefix_len       = strlen($prefix);

    if (strncasecmp($response_trimmed, $prefix, $prefix_len) === 0) {
        return ltrim(substr($response_trimmed, $prefix_len));
    }

    return $response;
}

// 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_text_field_callback',
        '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. This text is prepended to every user message before it is sent to the Claude API. It is sent with <code>cache_control</code> (ephemeral) so the block is eligible for prompt caching, reducing latency and cost on repeated requests. 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>';
}


function claude_chat_text_field_callback($args) {
    $option = get_option($args['label_for']);
    echo '<input type="text" id="'   . esc_attr($args['label_for'])
        . '" name="'                  . esc_attr($args['label_for'])
        . '" value="'                 . esc_attr($option)
        . '" class="regular-text">';
    if ( ! empty($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, the prompt text in this textarea is appended to their message.'
        . '</p>';
}