<?php
declare(strict_types=1);

header('Content-Type: application/json');

require_once 'db/config.php';
require_once 'includes/helpers.php';

session_start();

$response = ['success' => false, 'match' => false, 'error' => null];

if (!isset($_SESSION['user_id'])) {
    $response['error'] = 'User not authenticated.';
    echo json_encode($response);
    exit;
}

$current_user_id = $_SESSION['user_id'];
$data = json_decode(file_get_contents('php://input'), true);

$swiped_user_id = $data['swiped_user_id'] ?? null;
$action = $data['action'] ?? null; // 'like' or 'dislike'

if (!$swiped_user_id || !in_array($action, ['like', 'dislike'])) {
    $response['error'] = 'Invalid input.';
    echo json_encode($response);
    exit;
}

try {
    $pdo = db();

    // 1. Record the swipe action
    $stmt = $pdo->prepare(
        "INSERT INTO swipes (swiper_user_id, swiped_user_id, swipe_type)
        VALUES (:swiper_user_id, :swiped_user_id, :swipe_type)"
    );
    $stmt->execute([
        ':swiper_user_id' => $current_user_id,
        ':swiped_user_id' => $swiped_user_id,
        ':swipe_type' => $action
    ]);

    // 2. If it was a 'like', check for a mutual match
    if ($action === 'like') {
        $stmt = $pdo->prepare(
            "SELECT COUNT(*) FROM swipes
            WHERE swiper_user_id = :swiped_user_id AND swiped_user_id = :current_user_id AND swipe_type = 'like'"
        );
        $stmt->execute([
            ':swiped_user_id' => $swiped_user_id,
            ':current_user_id' => $current_user_id
        ]);
        $is_mutual = (int)$stmt->fetchColumn() > 0;

        if ($is_mutual) {
            // 3. It's a match! Insert into matches table.
            $user1 = min($current_user_id, $swiped_user_id);
            $user2 = max($current_user_id, $swiped_user_id);

            $stmt = $pdo->prepare(
                "INSERT INTO matches (user1_id, user2_id)
                SELECT :user1_id, :user2_id
                WHERE NOT EXISTS (
                    SELECT 1 FROM matches 
                    WHERE (user1_id = :user1_id AND user2_id = :user2_id) OR (user1_id = :user2_id AND user2_id = :user1_id)
                )"
            );
            $stmt->execute([
                ':user1_id' => $user1,
                ':user2_id' => $user2
            ]);

            $response['match'] = true;
            
            // Fetch the matched user's name for the notification
            $stmt = $pdo->prepare("SELECT name FROM user_profiles WHERE user_id = :swiped_user_id");
            $stmt->execute(['swiped_user_id' => $swiped_user_id]);
            $matched_user = $stmt->fetch(PDO::FETCH_ASSOC);
            $response['matched_user_name'] = $matched_user['name'] ?? 'Someone';
        }
    }

    $response['success'] = true;

} catch (PDOException $e) {
    $response['error'] = "Database error: " . $e->getMessage();
}

// Finally, get the next companion to show
$stmt = $pdo->prepare(
    "SELECT p.* 
    FROM user_profiles p 
    JOIN users u ON p.user_id = u.id
    WHERE u.role = 'companion'
      AND p.user_id != :current_user_id
      AND p.user_id NOT IN (
          SELECT swiped_user_id FROM swipes WHERE swiper_user_id = :current_user_id
      )
    ORDER BY RAND()
    LIMIT 1"
);
$stmt->execute(['current_user_id' => $current_user_id]);
$next_companion = $stmt->fetch(PDO::FETCH_ASSOC);

$response['next_companion_html'] = render_companion_card($next_companion);

echo json_encode($response);