<?php
/**
 * Module B: Manual Registration Validation & Ingestion Engine (Email Explicitly Required)
 * Target Path: htdocs/api/v1/accounts/register.php
 */

require_once __DIR__ . '/../../../config.php';

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    http_response_code(405);
    die(json_encode(["status" => "fail", "message" => "Method not allowed."]));
}

$db = getDB();

// Gather parameter arrays pushed out by the registration wizard forms
$email    = trim($_POST['email'] ?? '');
$username = trim($_POST['username'] ?? '');
$password = $_POST['password'] ?? '';
$fullName = trim($_POST['first_name'] ?? $_POST['username'] ?? '');

// Enforce safety constraint: Throw error if email or username inputs are missing
if (empty($email) || empty($username) || empty($password)) {
    http_response_code(400);
    die(json_encode(["status" => "fail", "message" => "An email, username, and password are required to sign up."]));
}

try {
    // 1. Conflict Prevention: Make sure username or email choices aren't duplicated in the matrix
    $stmt = $db->prepare("SELECT id, username, email FROM users WHERE username = ? OR email = ?");
    $stmt->execute([$username, $email]);
    $conflict = $stmt->fetch();
    
    if ($conflict) {
        http_response_code(400);
        $msg = ($conflict['username'] === $username) ? "That username is occupied." : "That email is already registered.";
        die(json_encode(["status" => "fail", "message" => $msg]));
    }
    
    // 2. Commit account parameters to data storage blocks
    $hashedPassword = password_hash($password, PASSWORD_BCRYPT);
    $cleanFullName  = !empty($fullName) ? $fullName : ucfirst($username) . " (NostolgaGram)";
    
    $insertStmt = $db->prepare("INSERT INTO users (username, email, password_hash, full_name) VALUES (?, ?, ?, ?)");
    $insertStmt->execute([$username, $email, $hashedPassword, $cleanFullName]);
    
    $stmt = $db->prepare("SELECT * FROM users WHERE id = ?");
    $stmt->execute([$db->lastInsertId()]);
    $user = $stmt->fetch();
    
} catch (PDOException $e) {
    http_response_code(500);
    die(json_encode(["status" => "fail", "message" => "Critical system allocation error during signup processing."]));
}

// 3. Authenticate and dispatch session payload configuration
http_response_code(200);
header("Set-Cookie: sessionid=nostolga_sess_" . $user['id'] . "; Path=/; HttpOnly");

echo json_encode([
    "created_user" => [
        "pk"              => (int)$user['id'],
        "username"        => $user['username'],
        "email"           => $user['email'],
        "full_name"       => $user['full_name'],
        "profile_pic_url" => $user['profile_pic'] ?? 'https://picsum.photos/150/150',
        "is_private"      => false
    ],
    "status" => "ok"
]);
exit;