signup_process.php

<?php
session_start();
require 'db.php';

if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $fullname = trim($_POST['fullname'] ?? '');
    $email = trim($_POST['email'] ?? '');
    $password = trim($_POST['password'] ?? '');

    // Validate
    if (empty($fullname) || empty($email) || empty($password)) {
        http_response_code(400);
        echo json_encode(['success' => false, 'message' => 'All fields required']);
        exit();
    }

    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
        http_response_code(400);
        echo json_encode(['success' => false, 'message' => 'Invalid email']);
        exit();
    }

    if (strlen($password) < 6) {
        http_response_code(400);
        echo json_encode(['success' => false, 'message' => 'Password must be 6+ characters']);
        exit();
    }

    // Check if email exists
    $check = $conn->prepare("SELECT id FROM users WHERE email = ?");
    $check->bind_param("s", $email);
    $check->execute();
    if ($check->get_result()->num_rows > 0) {
        http_response_code(409);
        echo json_encode(['success' => false, 'message' => 'Email already exists']);
        exit();
    }

    // Insert user
    $hashed_password = password_hash($password, PASSWORD_DEFAULT);
    $stmt = $conn->prepare("INSERT INTO users (fullname, email, password) VALUES (?, ?, ?)");
    $stmt->bind_param("sss", $fullname, $email, $hashed_password);

    if ($stmt->execute()) {
        $_SESSION['user_id'] = $conn->insert_id;
        $_SESSION['user'] = $fullname;
        $_SESSION['email'] = $email;
        
        echo json_encode([
            'success' => true,
            'message' => 'Signup successful',
            'user' => [
                'fullname' => $fullname,
                'email' => $email,
                'role' => 'user'
            ]
        ]);
    } else {
        http_response_code(500);
        echo json_encode(['success' => false, 'message' => 'Signup failed']);
    }
}
?>