<?php
/**
 * AITemplateProcessor - Handles AI-based email template generation.
 * 
 * Orchestrates the flow:
 *   1. Load system prompt from email_template_prompt.txt
 *   2. Call AI providers via the plugin's own AICallerBase factory
 *   3. Return raw AI response + updated history to the frontend
 * 
 * Self-contained within the email plugin — no dependency on any other plugin.
 */

namespace rnadvanceemailingwc\api;

class AITemplateProcessor {

    /** @var string The API key */
    private $apiKey;

    /** @var string The model to use */
    private $model;

    /** @var array Files attached to the message */
    private $files;

    public function __construct() {
        $this->apiKey = '';
        $this->model  = '';
        $this->files  = [];
    }

    /**
     * Process an AI message and generate an email template.
     * 
     * @param string $message    The user's message describing the desired template
     * @param array  $history    Previous conversation history for context
     * @param string $model      The AI model to use (e.g., 'gemini25pro', 'deepseek')
     * @param string $apiKey     The API key for the selected model
     * @param array  $files      Attached files [{name, mimeType, base64Data}, ...]
     * @param string $promptName Prompt filename without extension (default: 'email_template_prompt')
     * @return array Response with HTML, message, and updated history
     */
    public function process($message, $history = [], $model = '', $apiKey = '', $files = [], $promptName = 'email_template_prompt') {
        $this->model  = $model;
        $this->apiKey = $apiKey;
        $this->files  = $files;

        if (empty($this->apiKey)) {
            return [
                'error' => __('AI API key is not configured. Please set it in Settings > AI.', 'advanced-emailing-for-woocommerce')
            ];
        }

        // Load the system prompt from the text file
        $systemPrompt = $this->loadSystemPrompt($promptName);
        if ($systemPrompt === false) {
            return [
                'error' => __('Could not load AI prompt template file.', 'advanced-emailing-for-woocommerce')
            ];
        }

        // Build conversation messages
        $messages = [];
        if (!empty($history)) {
            foreach ($history as $historyItem) {
                // History items arrive as stdClass from json_decode — use object access
                $role = is_array($historyItem) ? $historyItem['role'] : $historyItem->role;
                $content = is_array($historyItem) ? $historyItem['content'] : $historyItem->content;
                $messages[] = [
                    'role'    => $role,
                    'content' => $content
                ];
            }
        }
        $messages[] = ['role' => 'user', 'content' => $message];

        // Call the AI via the appropriate provider
        try {
            require_once __DIR__ . '/ai_callers/AICallerBase.php';
            $caller = AICallerBase::create($this->model, $this->apiKey);
            $aiResponse = $caller->callAI($systemPrompt, $messages, $this->files);
        } catch (\Exception $e) {
            return ['error' => $e->getMessage()];
        }

        // Log the raw AI response for debugging
        \rnadvanceemailingwc\Managers\LogManager::LogDebug("=== AI RAW RESPONSE START ===\r\n" . $aiResponse . "\r\n=== AI RAW RESPONSE END ===");

        // Update conversation history
        $updatedHistory   = $history;
        $updatedHistory[] = ['role' => 'user', 'content' => $message];
        $updatedHistory[] = ['role' => 'assistant', 'content' => $aiResponse];

        return [
            'response' => $aiResponse,
            'history'  => $updatedHistory
        ];
    }

    /**
     * Public accessor for the compiled system prompt.
     * Used by the external chat feature to give users the prompt they need.
     *
     * @param string $promptName Prompt filename without extension
     * @return string|false The prompt text, or false on failure
     */
    public function getSystemPrompt($promptName = 'email_template_prompt') {
        return $this->loadSystemPrompt($promptName);
    }

    /**
     * Public accessor for HTML extraction from AI response text.
     * Used by the external chat feature to process manually-pasted AI responses.
     *
     * @param string $response The raw AI response text
     * @return string The extracted HTML
     */
    public function extractHtml($response) {
        return $this->extractHtmlFromResponse($response);
    }

    /**
     * Loads the system prompt from the template file.
     * 
     * @param string $promptName Prompt filename without extension (sanitized to [a-zA-Z0-9_] only)
     * @return string|false The prompt text, or false on failure
     */
    private function loadSystemPrompt($promptName = 'email_template_prompt') {
        // Sanitize: only allow alphanumeric and underscores to prevent directory traversal
        if (!preg_match('/^[a-zA-Z0-9_]+$/', $promptName)) {
            return false;
        }

        $promptFile = __DIR__ . '/prompts/' . $promptName . '.txt';
        
        if (!file_exists($promptFile)) {
            return false;
        }

        $prompt = file_get_contents($promptFile);
        if ($prompt === false) {
            return false;
        }

        return $prompt;
    }

    /**
     * Extracts the HTML content from the AI response.
     * 
     * The AI should return raw HTML, but sometimes it wraps it in
     * ```html code blocks or adds commentary. This method handles
     * all cases and extracts the clean HTML.
     * 
     * @param string $response The raw AI response text
     * @return string The extracted HTML
     */
    private function extractHtmlFromResponse($response) {
        $response = trim($response);

        // Case 1: AI wrapped the HTML in ```html ... ``` code blocks
        if (preg_match('/```(?:html)?\s*\n([\s\S]*?)\n```/', $response, $matches)) {
            return trim($matches[1]);
        }

        // Case 2: Response starts with a tag — it's already raw HTML
        if (preg_match('/^\s*</', $response)) {
            return $response;
        }

        // Case 3: There's text before the HTML (AI added commentary despite instructions)
        $firstTagPos = strpos($response, '<');
        if ($firstTagPos !== false) {
            return trim(substr($response, $firstTagPos));
        }

        // Fallback: return as-is
        return $response;
    }
}