<?php
// ─── Users: lookup, registration, password reset ─────────────────────────────
// This install owns its identity — passwords live in `users.password_hash` —
// but auditoria 2026-09-24 ponto 1.3 moved credential verification and
// session establishment to shared/platform-tools/functions_auth.php
// (auth_attempt()/auth_login(), wired in config/db.php). What is left here is
// fitme-specific: registration, backoffice user creation, password reset
// tokens and their emails — none of which has a shared equivalent.
//
// parse_user_agent() lives in config/functions.php; db_get_user() /
// db_get_all_staff() / db_get_active_admins() live in config/functions_db.php
// — not redefined here.

// ─── Lookup ──────────────────────────────────────────────────────────────────

// Active user by email, or false. Used by the login and reset-request flows,
// which must never act on a deactivated account.
function user_find_by_email(PDO $pdo, string $email): array|false {
    $stmt = $pdo->prepare("SELECT * FROM users WHERE email = ? AND is_active = 1 LIMIT 1");
    $stmt->execute([strtolower(trim($email))]);
    return $stmt->fetch(PDO::FETCH_ASSOC);
}

// True once any sysadmin/admin row exists — gates views/auth/setup.php.
function admin_exists(PDO $pdo): bool {
    return (bool) $pdo->query(
        "SELECT 1 FROM users WHERE role IN ('sysadmin','admin') LIMIT 1"
    )->fetchColumn();
}

// ─── Authentication ──────────────────────────────────────────────────────────
//
// Credential verification is now auth_attempt($pdo, $email, $password) from
// shared/platform-tools/functions_auth.php — same account-enumeration timing
// defence and transparent rehash, one implementation instead of two. Login
// itself (session + audit "auth.login" + last_login_at/ip stamp) is
// auth_login($pdo, $user) from the same file. See views/auth/login.php.
//
// last_login_ua has no shared equivalent (functions_auth.php only tracks
// last_login/last_ip) and is still fitme's own — stamped separately, right
// after auth_login(), by fit_stamp_login_ua() below.

// Stamps the user-agent of the browser that just logged in. Best-effort:
// shown in views/user/index.php ("last seen from …") but never worth failing
// a login over.
function fit_stamp_login_ua(PDO $pdo, int $userId): void {
    $ua = substr($_SERVER['HTTP_USER_AGENT'] ?? '', 0, 512) ?: null;
    try {
        $pdo->prepare("UPDATE users SET last_login_ua = ? WHERE id = ?")
            ->execute([$ua, $userId]);
    } catch (Throwable $e) {
        error_log('[auth] last_login_ua stamp failed: ' . $e->getMessage());
    }
}

// Writes a new password hash. Shared by the reset flow, the profile page and
// the admin override in views/user/set_password.php. Any outstanding reset
// token is burned so an old "set your password" email can't be replayed to
// take the account back.
function auth_set_password(PDO $pdo, int $userId, string $password): void {
    $pdo->prepare("UPDATE users SET password_hash = ? WHERE id = ?")
        ->execute([auth_password_hash($password), $userId]);
    // Uma password nova invalida qualquer «manter sessão iniciada» antigo —
    // sem isto, um cookie roubado antes da mudança continuava a entrar depois.
    auth_remember_forget_user($pdo, $userId);
    $self = (int) ($_SESSION['user_id'] ?? 0) === $userId;
    audit($self ? 'auth.password_change' : 'user.password_set', [
        'target_type' => 'user', 'target_id' => $userId,
        'summary' => $self ? 'O próprio alterou a palavra-passe' : 'Palavra-passe definida por outra pessoa ou por link de recuperação',
    ]);

    // Best-effort: the password itself is already saved, so a missing
    // `password_resets` table (migration not applied yet) must not turn a
    // successful change into a 500 that makes the caller think it failed.
    try {
        $pdo->prepare("UPDATE password_resets SET used_at = NOW() WHERE user_id = ? AND used_at IS NULL")
            ->execute([$userId]);
    } catch (PDOException $e) {
        error_log('[auth] could not burn reset tokens (run migration_20260913_local_auth.sql?): ' . $e->getMessage());
    }
}

// ─── Registration ────────────────────────────────────────────────────────────

// Self-registration for clients (views/auth/register.php).
//
// Returns ['id' => int] on success, or ['error' => 'email_taken'].
//
// A row with no password — left behind by an admin who created the account, or
// by the SSO era, when client rows were provisioned from the hub with
// password_hash NULL — is *claimable* by whoever registers with that address,
// but only when it is a plain client. A passwordless admin/staff/sysadmin row
// must not be claimable through the public form: that would let anyone who
// knows a staff email self-assign the role. Those report as taken and have to
// be set up from the backoffice.
function auth_register_client(PDO $pdo, array $data): array {
    $email = strtolower(trim($data['email']));
    $name  = trim($data['name']);
    $phone = trim($data['phone'] ?? '') ?: null;

    $stmt = $pdo->prepare("SELECT id, role, password_hash FROM users WHERE email = ? LIMIT 1");
    $stmt->execute([$email]);
    $row = $stmt->fetch(PDO::FETCH_ASSOC);

    if ($row) {
        if (!empty($row['password_hash']) || $row['role'] !== 'client') {
            return ['error' => 'email_taken'];
        }
        $pdo->prepare(
            "UPDATE users SET name = ?, phone = COALESCE(?, phone), password_hash = ?, is_active = 1 WHERE id = ?"
        )->execute([$name, $phone, auth_password_hash($data['password']), $row['id']]);
        audit('user.register', ['target_type' => 'user', 'target_id' => (int) $row['id'], 'target_label' => $name,
                                'summary' => 'Registo que reclamou uma conta de cliente sem palavra-passe', 'actor' => null]);
        return ['id' => (int) $row['id']];
    }

    // UNIQUE(email) is the real guard — the SELECT above can lose a race with a
    // concurrent signup, so the insert is what decides.
    try {
        $pdo->prepare("
            INSERT INTO users (name, email, phone, password_hash, role, marketing_consent, is_active)
            VALUES (?, ?, ?, ?, 'client', ?, 1)
        ")->execute([
            $name,
            $email,
            $phone,
            auth_password_hash($data['password']),
            !empty($data['marketing_consent']) ? 1 : 0,
        ]);
    } catch (PDOException $e) {
        if ((int) ($e->errorInfo[1] ?? 0) === 1062) return ['error' => 'email_taken'];
        throw $e;
    }
    $newId = (int) $pdo->lastInsertId();
    audit('user.register', ['target_type' => 'user', 'target_id' => $newId, 'target_label' => $name,
                            'summary' => 'Novo cliente registado no site', 'actor' => null]);
    return ['id' => $newId];
}

// ─── Backoffice user creation ────────────────────────────────────────────────

// Creates a sysadmin (full access incl. backups + platform update). Used once,
// by views/auth/setup.php, on a fresh install.
function auth_create_sysadmin(PDO $pdo, string $name, string $email, string $password): int {
    $stmt = $pdo->prepare("
        INSERT INTO users (name, email, password_hash, role)
        VALUES (?, ?, ?, 'sysadmin')
    ");
    $stmt->execute([
        $name,
        strtolower(trim($email)),
        auth_password_hash($password),
    ]);
    $id = (int) $pdo->lastInsertId();
    audit('user.create', ['target_type' => 'user', 'target_id' => $id, 'target_label' => $name,
                          'summary' => 'Sysadmin criado pelo setup inicial', 'actor' => null]);
    return $id;
}

// Returns ['id' => int] on success, or ['error' => 'email_taken'].
function auth_create_admin(PDO $pdo, string $name, string $email, string $phone, string $password): array {
    return _create_backoffice_user($pdo, 'admin', $name, $email, $phone, $password);
}

function auth_create_staff(PDO $pdo, string $name, string $email, string $phone, string $password): array {
    return _create_backoffice_user($pdo, 'staff', $name, $email, $phone, $password);
}

function _create_backoffice_user(PDO $pdo, string $role, string $name, string $email, string $phone, string $password): array {
    if (!in_array($role, ['admin', 'staff'], true)) {
        throw new InvalidArgumentException("Invalid backoffice role: {$role}");
    }
    try {
        $pdo->prepare("
            INSERT INTO users (name, email, phone, password_hash, role)
            VALUES (?, ?, ?, ?, ?)
        ")->execute([
            $name,
            strtolower(trim($email)),
            $phone ?: null,
            auth_password_hash($password),
            $role,
        ]);
    } catch (PDOException $e) {
        if ((int) ($e->errorInfo[1] ?? 0) === 1062) return ['error' => 'email_taken'];
        throw $e;
    }
    $id = (int) $pdo->lastInsertId();
    audit('user.create', ['target_type' => 'user', 'target_id' => $id, 'target_label' => $name,
                          'changes' => ['role' => ['antes' => null, 'depois' => $role]]]);
    return ['id' => $id];
}

// ─── Password reset ──────────────────────────────────────────────────────────
// Single-use tokens in `password_resets`, valid for 2 hours. Minting a new one
// invalidates any outstanding token for that user.

function auth_create_reset_token(PDO $pdo, int $userId): string {
    $pdo->prepare("DELETE FROM password_resets WHERE user_id = ? AND used_at IS NULL")
        ->execute([$userId]);
    $token = bin2hex(random_bytes(32));
    $pdo->prepare(
        "INSERT INTO password_resets (user_id, token, expires_at)
         VALUES (?, ?, DATE_ADD(NOW(), INTERVAL 2 HOUR))"
    )->execute([$userId, $token]);
    return $token;
}

function auth_get_valid_reset_token(PDO $pdo, string $token): array|false {
    $stmt = $pdo->prepare("
        SELECT pr.user_id, pr.token, u.name, u.email, u.role
        FROM password_resets pr
        JOIN users u ON u.id = pr.user_id
        WHERE pr.token = ?
          AND pr.used_at IS NULL
          AND pr.expires_at > NOW()
          AND u.is_active = 1
        LIMIT 1
    ");
    $stmt->execute([$token]);
    return $stmt->fetch(PDO::FETCH_ASSOC);
}

function auth_consume_reset_token(PDO $pdo, string $token, string $newPassword): bool {
    $reset = auth_get_valid_reset_token($pdo, $token);
    if (!$reset) return false;
    // auth_set_password() burns every outstanding token for this user, this one
    // included, so the link can't be replayed.
    auth_set_password($pdo, (int) $reset['user_id'], $newPassword);
    return true;
}

// ─── Email: password reset / first-password invitation ───────────────────────
// Delivery is centralized at the hub's /notify endpoint — see
// config/functions_queue.php (enqueue_email + flush_message).

// $flush=false deixa a mensagem na fila para o cron (≤5 min). O pedido de
// recuperação usa-o: um envio SMTP síncrono só quando a conta existe fazia a
// resposta demorar segundos apenas nesse caso — um oráculo de contas.
function send_password_reset_email(string $name, string $email, string $resetUrl, ?int $userId = null, bool $flush = true): bool {
    $body = load_email_template('password_reset', [
        'user_name' => $name,
        'reset_url' => $resetUrl,
        'app_name'  => APP_NAME,
    ]);
    $id = enqueue_email([
        'to_user_id'   => $userId,
        'to_address'   => $email,
        'to_name'      => $name,
        'subject'      => 'Redefinir palavra-passe',
        'body'         => $body,
        'alt_body'     => "Olá {$name},\n\nPara definir uma nova palavra-passe aceda a:\n{$resetUrl}\n\nO link é válido durante 2 horas.",
        'context_type' => 'password_reset',
        'context_id'   => $userId,
    ]);
    return $flush ? flush_message($id) : $id > 0;
}

// An account created from the backoffice has no password, so the person has no
// way of knowing it exists. Invites them to set one, reusing the reset token —
// same mechanism, different copy.
function send_password_invite_email(PDO $pdo, array $user): bool {
    if (empty($user['email'])) return false;
    audit('user.invite', ['target_type' => 'user', 'target_id' => (int) $user['id'], 'target_label' => (string) ($user['name'] ?? '')]);
    $token = auth_create_reset_token($pdo, (int) $user['id']);
    $url   = base_url('views/auth/reset_password.php?token=' . $token);
    $name  = (string) ($user['name'] ?? '');

    $body = load_email_template('password_invite', [
        'user_name' => $name,
        'reset_url' => $url,
        'app_name'  => APP_NAME,
    ]);
    $id = enqueue_email([
        'to_user_id'   => (int) $user['id'],
        'to_address'   => $user['email'],
        'to_name'      => $name,
        'subject'      => 'A sua conta ' . APP_NAME,
        'body'         => $body,
        'alt_body'     => "Olá {$name},\n\nFoi criada uma conta para si em " . APP_NAME . ".\nDefina a sua palavra-passe em:\n{$url}\n\nO link é válido durante 2 horas.",
        'context_type' => 'password_invite',
        'context_id'   => (int) $user['id'],
    ]);
    return flush_message($id);
}