<?php
// Log all incoming requests to a temporary file for debugging
file_put_contents('whatsapp_log.txt', print_r($_REQUEST, true), FILE_APPEND);

require_once 'db/config.php';

// --- Placeholder for a function to send a reply via WhatsApp API ---
// You will need to replace this with the actual API call from your provider (e.g., Twilio)
function send_whatsapp_reply($to, $message) {
    // In a real application, you would make an HTTP request to the WhatsApp API provider here.
    // For now, we will just log the message that would be sent.
    $log_message = "-----
" . "TO: $to
" . "MESSAGE: $message
" . "-----
";
    file_put_contents('whatsapp_sent_messages.txt', $log_message, FILE_APPEND);
}

// Get the sender's phone number and the message they sent
// The field names might be different depending on your API provider (e.g., 'From', 'Body' for Twilio)
$from = $_REQUEST['From'] ?? null;
$body = $_REQUEST['Body'] ?? null;

// Basic validation
if (!$from || !$body) {
    http_response_code(400);
    echo 'Missing From or Body parameter';
    exit;
}

// Sanitize the input
$from = htmlspecialchars($from);
$body = trim($body);

// --- Conversation Logic ---

// We'll use a simple session system based on files to keep track of the conversation state for each user.
$session_file = 'session_' . md5($from) . '.txt';

// Get the user's current state, or start a new conversation
$session_data = file_exists($session_file) ? json_decode(file_get_contents($session_file), true) : [];
$state = $session_data['state'] ?? 'new';


// --- State Machine for the conversation ---
switch ($state) {
    case 'new':
        // New conversation
        $session_data['state'] = 'waiting_for_name';
        file_put_contents($session_file, json_encode($session_data));
        send_whatsapp_reply($from, "Welcome to our service booking bot! What is your full name?");
        break;

    case 'waiting_for_name':
        // User sent their name
        $session_data['name'] = $body;
        $session_data['state'] = 'waiting_for_email';
        file_put_contents($session_file, json_encode($session_data));
        send_whatsapp_reply($from, "Thanks, {$body}! What is your email address?");
        break;

    case 'waiting_for_email':
        // User sent their email
        if (!filter_var($body, FILTER_VALIDATE_EMAIL)) {
            send_whatsapp_reply($from, "That doesn't look like a valid email. Please provide a correct email address.");
            break;
        }
        $session_data['email'] = $body;
        $session_data['state'] = 'waiting_for_description';
        file_put_contents($session_file, json_encode($session_data));
        send_whatsapp_reply($from, "Got it. Please describe the service you need.");
        break;

    case 'waiting_for_description':
        // User sent the service description
        $session_data['description'] = $body;

        // Save to database
        try {
            $stmt = db()->prepare("INSERT INTO service_requests (name, email, description, status) VALUES (?, ?, ?, 'New')");
            $stmt->execute([
                $session_data['name'],
                $session_data['email'],
                $session_data['description']
            ]);
            send_whatsapp_reply($from, "Thank you! Your service request has been booked. We will contact you shortly.");
            // End of conversation, so delete the session file
            unlink($session_file);

        } catch (PDOException $e) {
            error_log("Database Error: " . $e->getMessage());
            send_whatsapp_reply($from, "Sorry, there was a problem booking your service. Please try again later.");
        }
        
        // Reset state for the next conversation
        $session_data = ['state' => 'new'];
        file_put_contents($session_file, json_encode($session_data));
        break;
    
    default:
        send_whatsapp_reply($from, "Sorry, I'm not sure how to respond. Let's start over. What is your full name?");
        // Reset state
        $session_data = ['state' => 'waiting_for_name'];
        file_put_contents($session_file, json_encode($session_data));
        break;
}

echo "OK";