<?php
/**
 * @package AKSRT
 */

namespace AKSRT\Auth;

defined('ABSPATH') || exit;

final class OAuth {

	private const BIND_PASS_KIND = 'oauth_bind_pass';
	private const BIND_PASS_TTL = 5 * MINUTE_IN_SECONDS;

	private static $instance = null;
	private OAuthProviderBroker $broker;

	private function __construct() {
		$this->broker = new OAuthProviderBroker();
	}

	public static function get_instance(): self {
		if (null === self::$instance) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	public function init(): void {
		add_action('init', [$this, 'add_rewrite_rules']);
		add_action('init', [$this, 'maybe_flush_rewrite_rules'], 20);
		add_action('init', static function (): void {
			if (wp_rand(1, 100) === 1) {
				OAuthTransactionStore::cleanup();
			}
		}, 30);
		add_action('template_redirect', [$this, 'handle_routes'], 8);
		add_action('rest_api_init', [$this, 'register_rest_routes']);
		add_action('wp_ajax_aksrt_oauth_unbind', [$this, 'ajax_unbind']);
	}

	public function add_rewrite_rules(): void {
		add_rewrite_rule('^oauth/start/([a-z0-9_-]+)/?$', 'index.php?aksrt_oauth=start&aksrt_oauth_provider=$matches[1]', 'top');
		add_rewrite_rule('^oauth/callback/?$', 'index.php?aksrt_oauth=callback', 'top');
		add_rewrite_rule('^oauth/clogin/?$', 'index.php?aksrt_oauth=clogin', 'top');
		add_rewrite_rule('^oauth/clogin/callback/?$', 'index.php?aksrt_oauth=clogin_callback', 'top');
		add_filter('query_vars', static function (array $vars): array {
			$vars[] = 'aksrt_oauth';
			$vars[] = 'aksrt_oauth_provider';
			return $vars;
		});
	}

	public function register_rest_routes(): void {
		register_rest_route('aksrt/v1', '/oauth/bind-pass', [
			'methods'             => 'POST',
			'callback'            => [$this, 'rest_issue_bind_pass'],
			'permission_callback' => static function (): bool {
				return is_user_logged_in();
			},
		]);
	}

	public function rest_issue_bind_pass(\WP_REST_Request $request): \WP_REST_Response {
		$user_id = get_current_user_id();
		$nonce = sanitize_text_field((string) $request->get_header('X-WP-Nonce'));
		if ($user_id <= 0 || $nonce === '' || !wp_verify_nonce($nonce, 'wp_rest')) {
			return new \WP_REST_Response([
				'success' => false,
				'code'    => 'oauth_bind_nonce_invalid',
				'message' => __('安全验证失败，请刷新页面重试', 'aksrt'),
			], 403);
		}

		$payload = $request->get_json_params();
		$payload = is_array($payload) ? $payload : [];
		$provider = sanitize_key((string) ($payload['provider'] ?? ''));
		if (!in_array($provider, OAuthProviderCatalog::enabled_login_keys(), true)) {
			return new \WP_REST_Response([
				'success' => false,
				'code'    => 'oauth_bind_provider_invalid',
				'message' => __('该第三方登录方式不可用', 'aksrt'),
			], 400);
		}

		$url = $this->get_auth_url($provider, 'bind');
		if ($url === '') {
			return new \WP_REST_Response([
				'success' => false,
				'code'    => 'oauth_bind_provider_invalid',
				'message' => __('该第三方登录方式不可用', 'aksrt'),
			], 400);
		}
		$redirect = OAuthUrlPolicy::validated_redirect((string) ($payload['redirect_to'] ?? ''), home_url('/'));
		$url = add_query_arg('redirect_to', $redirect, $url);

		if (!aksrt_is_captcha_enabled_for('bind')) {
			return new \WP_REST_Response([
				'success' => true,
				'data'    => ['url' => $url],
			], 200);
		}

		$result = aksrt_require_captcha('bind', $payload);
		if ($result !== true) {
			return new \WP_REST_Response([
				'success' => false,
				'code'    => is_wp_error($result) ? $result->get_error_code() : 'aksrt_captcha_failed',
				'message' => is_wp_error($result) ? $result->get_error_message() : __('人机验证失败，请重试', 'aksrt'),
			], 400);
		}

		try {
			$pass = OAuthTransactionStore::issue(self::BIND_PASS_KIND, [
				'user_id'  => $user_id,
				'provider' => $provider,
			], self::BIND_PASS_TTL, true);
		} catch (\Throwable $e) {
			return new \WP_REST_Response([
				'success' => false,
				'code'    => 'oauth_bind_pass_issue_failed',
				'message' => __('无法创建绑定会话，请稍后重试', 'aksrt'),
			], 500);
		}

		$url = add_query_arg('bind_pass', $pass, $url);

		return new \WP_REST_Response([
			'success' => true,
			'data'    => ['url' => $url],
		], 200);
	}

	public static function validate_bind_pass(string $token, string $provider, int $user_id, bool $consume = true): bool {
		if (!aksrt_is_captcha_enabled_for('bind')) {
			return true;
		}
		if ($token === '' || $user_id <= 0) {
			return false;
		}
		$matches = static function (?array $row) use ($provider, $user_id): bool {
			$payload = is_array($row['payload'] ?? null) ? $row['payload'] : [];
			return $row !== null
				&& (int) ($payload['user_id'] ?? 0) === $user_id
				&& hash_equals(sanitize_key($provider), sanitize_key((string) ($payload['provider'] ?? '')));
		};
		$row = OAuthTransactionStore::peek($token, self::BIND_PASS_KIND, true);
		if (!$matches($row)) {
			return false;
		}
		if (!$consume) {
			return true;
		}
		return $matches(OAuthTransactionStore::claim($token, self::BIND_PASS_KIND, true));
	}

	public function maybe_flush_rewrite_rules(): void {
		$version = defined('AKSRT_VERSION') ? AKSRT_VERSION . ':oauth-v2' : 'oauth-v2';
		if (get_option('aksrt_oauth_routes_flushed') !== $version) {
			flush_rewrite_rules(false);
			update_option('aksrt_oauth_routes_flushed', $version, false);
		}
	}

	public function handle_routes(): void {
		$route = sanitize_key((string) get_query_var('aksrt_oauth'));
		if ($route === '') {
			return;
		}
		switch ($route) {
			case 'start':
				$this->handle_start();
				break;
			case 'callback':
				$this->handle_callback();
				break;
			case 'clogin':
				$this->handle_clogin_start();
				break;
			case 'clogin_callback':
				$this->handle_clogin_callback();
				break;
		}
	}

	public function get_auth_url(string $provider, string $action = 'login'): string {
		$provider = sanitize_key($provider);
		$action = $action === 'bind' ? 'bind' : 'login';
		if (!in_array($provider, OAuthProviderCatalog::enabled_login_keys(), true)) {
			return '';
		}
		$redirect = isset($_GET['redirect_to'])
			? OAuthUrlPolicy::validated_redirect((string) wp_unslash($_GET['redirect_to']), home_url('/'))
			: '';
		if ($provider === 'weixingzh') {
			$url = function_exists('aksrt_get_sign_page_url') ? aksrt_get_sign_page_url('oauth') : home_url('/sign/?tab=oauth');
			$url = add_query_arg('oauth_intent', $action, $url);
			return $redirect !== '' ? add_query_arg('redirect_to', $redirect, $url) : $url;
		}
		if (str_starts_with($provider, 'clogin_')) {
			$url = add_query_arg([
				'type' => substr($provider, 7),
				'action' => $action,
			], home_url('/oauth/clogin/'));
			return $redirect !== '' ? add_query_arg('redirect_to', $redirect, $url) : $url;
		}
		$url = add_query_arg('action', $action, home_url('/oauth/start/' . $provider . '/'));
		return $redirect !== '' ? add_query_arg('redirect_to', $redirect, $url) : $url;
	}

	public function get_auth_providers_data(): array {
		$result = [];
		foreach (OAuthProviderCatalog::enabled_login_keys() as $provider) {
			$url = $this->get_auth_url($provider);
			if ($url === '') {
				continue;
			}
			$result[] = [
				'name' => $provider,
				'label' => OAuthProviderCatalog::label($provider),
				'icon' => function_exists('aksrt_brand_icon') ? aksrt_brand_icon(OAuthProviderCatalog::icon_key($provider)) : '',
				'url' => esc_url($url),
			];
		}
		return $result;
	}

	public function render_social_buttons(string $title = ''): string {
		$items = $this->get_auth_providers_data();
		if ($items === []) {
			return '';
		}
		ob_start();
		?>
<div class="social-login-divider">
	<span><?php echo esc_html($title) ?: esc_html__('or', 'aksrt'); ?></span>
</div>
<div class="oauth-row">
	<?php foreach ($items as $item) : ?>
	<a href="<?php echo esc_url((string) $item['url']); ?>"
	   class="oauth-btn oauth-btn--<?php echo esc_attr((string) $item['name']); ?>"
	   data-provider="<?php echo esc_attr((string) $item['name']); ?>"
	   aria-label="<?php echo esc_attr((string) $item['label']); ?>"
	   title="<?php echo esc_attr((string) $item['label']); ?>">
		<?php echo $item['icon']; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped ?>
	</a>
	<?php endforeach; ?>
</div>
		<?php
		return (string) ob_get_clean();
	}

	public function get_frontend_bindings_data(int $user_id): array {
		$bound = OAuthAccountService::bindings($user_id);
		$bindings = [];
		foreach ($bound as $provider) {
			$bindings[] = $this->binding_row($provider, true);
		}
		$available = [];
		foreach (OAuthProviderCatalog::enabled_login_keys() as $provider) {
			if (in_array($provider, $bound, true)) {
				continue;
			}
			$url = $this->get_auth_url($provider, 'bind');
			if ($url !== '') {
				$row = $this->binding_row($provider, false);
				$row['url'] = $url;
				$available[] = $row;
			}
		}
		return ['bindings' => $bindings, 'available' => $available];
	}

	public function ajax_unbind(): void {
		check_ajax_referer('aksrt_oauth_unbind', 'nonce');
		$provider = sanitize_key((string) ($_POST['provider'] ?? ''));
		$user_id = isset($_POST['userId']) ? (int) $_POST['userId'] : 0;
		$current_id = get_current_user_id();
		if ($current_id <= 0 || $current_id !== $user_id || !current_user_can('read')) {
			wp_send_json_error(['message' => __('无权执行此操作', 'aksrt')], 403);
		}
		$result = OAuthAccountService::unbind($current_id, $provider);
		if (is_wp_error($result)) {
			$status = $result->get_error_code() === 'oauth_last_login_method' ? 409 : 400;
			wp_send_json_error(['message' => $result->get_error_message()], $status);
		}
		wp_send_json_success(['unbound' => true, 'message' => __('解除绑定成功', 'aksrt')]);
	}

	private function handle_start(): void {
		$provider = sanitize_key((string) get_query_var('aksrt_oauth_provider'));
		$action = isset($_GET['action']) && sanitize_key((string) $_GET['action']) === 'bind' ? 'bind' : 'login';
		if (!OAuthProviderCatalog::master_enabled() || !in_array($provider, OAuthProviderCatalog::enabled_login_keys(), true)) {
			$this->redirect_error('provider_disabled', $provider, $action);
		}
		$user_id = get_current_user_id();
		if ($action === 'bind' && $user_id <= 0) {
			wp_safe_redirect(function_exists('aksrt_get_login_url') ? aksrt_get_login_url() : wp_login_url());
			exit;
		}
		if ($action === 'bind') {
			$bind_pass = sanitize_text_field((string) ($_GET['bind_pass'] ?? ''));
			if (!self::validate_bind_pass($bind_pass, $provider, $user_id, true)) {
				$this->redirect_error('bind_verification_required', $provider, $action);
			}
		}
		if (OAuthProviderCatalog::proxy_mode() === 'client') {
			$url = OAuthProxyClient::get_instance()->get_proxy_auth_url($provider, $action);
			if ($url === '') {
				$this->redirect_error('proxy_config', $provider, $action);
			}
			wp_redirect($url); // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect
			exit;
		}
		$redirect = isset($_GET['redirect_to']) ? OAuthUrlPolicy::validated_redirect((string) $_GET['redirect_to'], home_url('/')) : home_url('/');
		$redirect_uri = home_url('/oauth/callback/');
		try {
			$state = OAuthTransactionStore::issue('direct', [
				'provider' => $provider,
				'action' => $action,
				'user_id' => $user_id,
				'redirect_to' => $redirect,
				'redirect_uri' => $redirect_uri,
			], 10 * MINUTE_IN_SECONDS);
			wp_redirect($this->broker->auth_url($provider, $redirect_uri, $state)); // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect
			exit;
		} catch (\Throwable $e) {
			$this->redirect_error('provider_unavailable', $provider, $action);
		}
	}

	private function handle_callback(): void {
		$state = sanitize_text_field((string) ($_GET['state'] ?? ''));
		$row = $state !== '' ? OAuthTransactionStore::claim($state, 'direct') : null;
		$payload = is_array($row['payload'] ?? null) ? $row['payload'] : [];
		$provider = sanitize_key((string) ($payload['provider'] ?? ''));
		$action = (string) ($payload['action'] ?? 'login');
		if (!$row || !OAuthProviderCatalog::is_direct($provider)) {
			$this->redirect_error('state_invalid', $provider, $action);
		}
		if ($action === 'bind' && (int) ($payload['user_id'] ?? 0) !== get_current_user_id()) {
			$this->redirect_error('state_user_mismatch', $provider, $action);
		}
		if (!empty($_GET['error'])) {
			$this->redirect_error('provider_cancelled', $provider, $action);
		}
		$code = sanitize_text_field((string) ($_GET['code'] ?? ''));
		if ($code === '') {
			$this->redirect_error('code_missing', $provider, $action);
		}
		try {
			$identity = $this->broker->identity($provider, $code, (string) $payload['redirect_uri'], $state);
			if (empty($identity['provider_id'])) {
				throw new \RuntimeException('missing_provider_id');
			}
			if ($action === 'bind') {
				$result = OAuthAccountService::bind(get_current_user_id(), $provider, $identity);
				if (is_wp_error($result)) {
					throw new \RuntimeException($result->get_error_code());
				}
				$this->redirect_success('bind', $provider, function_exists('aksrt_get_user_center_url') ? aksrt_get_user_center_url('settings') : home_url('/'));
			}
			$this->complete_identity_login($provider, $identity, (string) ($payload['redirect_to'] ?? home_url('/')));
		} catch (\Throwable $e) {
			$this->redirect_error($e->getMessage() === 'oauth_binding_conflict' ? 'binding_conflict' : 'callback_failed', $provider, $action);
		}
	}

	private function handle_clogin_start(): void {
		$config = OAuthProviderCatalog::clogin_settings();
		$type = sanitize_key((string) ($_GET['type'] ?? ''));
		$action = sanitize_key((string) ($_GET['action'] ?? '')) === 'bind' ? 'bind' : 'login';
		if (!$config['enabled'] || !in_array($type, $config['types'], true)) {
			$this->redirect_error('provider_disabled', 'clogin_' . $type, $action);
		}
		if ($action === 'bind' && !is_user_logged_in()) {
			wp_safe_redirect(function_exists('aksrt_get_login_url') ? aksrt_get_login_url() : wp_login_url());
			exit;
		}
		if ($action === 'bind') {
			$bind_pass = sanitize_text_field((string) ($_GET['bind_pass'] ?? ''));
			if (!self::validate_bind_pass($bind_pass, 'clogin_' . $type, get_current_user_id(), true)) {
				$this->redirect_error('bind_verification_required', 'clogin_' . $type, $action);
			}
		}
		$redirect = isset($_GET['redirect_to']) ? OAuthUrlPolicy::validated_redirect((string) $_GET['redirect_to'], home_url('/')) : home_url('/');
		try {
			$state = OAuthTransactionStore::issue('clogin', [
				'type' => $type,
				'action' => $action,
				'user_id' => get_current_user_id(),
				'redirect_to' => $redirect,
			], 10 * MINUTE_IN_SECONDS);
			$client = new CLoginClient([
				'apiurl' => $config['url'],
				'appid' => $config['id'],
				'appkey' => $config['key'],
				'callback' => home_url('/oauth/clogin/callback/'),
			]);
			$response = $client->login($type, $state);
			if (!empty($response['code']) || empty($response['url'])) {
				throw new \RuntimeException('clogin_unavailable');
			}
			wp_redirect((string) $response['url']); // phpcs:ignore WordPress.Security.SafeRedirect.wp_redirect_wp_redirect
			exit;
		} catch (\Throwable $e) {
			$this->redirect_error('provider_unavailable', 'clogin_' . $type, $action);
		}
	}

	private function handle_clogin_callback(): void {
		$state = sanitize_text_field((string) ($_GET['state'] ?? ''));
		$row = $state !== '' ? OAuthTransactionStore::claim($state, 'clogin') : null;
		$payload = is_array($row['payload'] ?? null) ? $row['payload'] : [];
		$type = sanitize_key((string) ($payload['type'] ?? ''));
		$provider = 'clogin_' . $type;
		$action = (string) ($payload['action'] ?? 'login');
		if (!$row || !in_array($type, OAuthProviderCatalog::clogin_settings()['types'], true)) {
			$this->redirect_error('state_invalid', $provider, $action);
		}
		if ($action === 'bind' && (int) ($payload['user_id'] ?? 0) !== get_current_user_id()) {
			$this->redirect_error('state_user_mismatch', $provider, $action);
		}
		$code = sanitize_text_field((string) ($_GET['code'] ?? ''));
		if ($code === '') {
			$this->redirect_error('code_missing', $provider, $action);
		}
		$config = OAuthProviderCatalog::clogin_settings();
		$client = new CLoginClient(['apiurl' => $config['url'], 'appid' => $config['id'], 'appkey' => $config['key']]);
		$info = $client->callback($code);
		$returned_type = $client->from_api_type((string) ($info['type'] ?? ''));
		if ((isset($info['code']) && (int) $info['code'] !== 0) || $returned_type !== $type || empty($info['social_uid'])) {
			$this->redirect_error('callback_failed', $provider, $action);
		}
		$identity = [
			'provider' => $provider,
			'provider_id' => (string) $info['social_uid'],
			'username' => sanitize_text_field((string) ($info['nickname'] ?? '')),
			'name' => sanitize_text_field((string) ($info['nickname'] ?? '')),
			'email' => '',
			'email_verified' => false,
			'avatar_url' => esc_url_raw((string) ($info['faceimg'] ?? '')),
		];
		if ($action === 'bind') {
			$result = OAuthAccountService::bind(get_current_user_id(), $provider, $identity);
			if (is_wp_error($result)) {
				$this->redirect_error('binding_conflict', $provider, $action);
			}
			$this->redirect_success('bind', $provider, function_exists('aksrt_get_user_center_url') ? aksrt_get_user_center_url('settings') : home_url('/'));
		}
		$this->complete_identity_login($provider, $identity, (string) ($payload['redirect_to'] ?? home_url('/')));
	}

	private function complete_identity_login(string $provider, array $identity, string $redirect): void {
		$user = OAuthAccountService::resolve($provider, $identity);
		if (is_wp_error($user) && $user->get_error_code() === 'oauth_no_match') {
			$obk = OAuthTransactionStore::issue('obk', [
				'provider' => $provider,
				'provider_id' => (string) ($identity['provider_id'] ?? ''),
				'user_data' => $identity,
				'redirect_to' => OAuthUrlPolicy::validated_redirect($redirect, home_url('/')),
			], 15 * MINUTE_IN_SECONDS);
			$url = function_exists('aksrt_get_bind_url') ? aksrt_get_bind_url($obk) : home_url('/sign/?tab=bind&obk=' . rawurlencode($obk));
			wp_safe_redirect($url);
			exit;
		}
		if (!$user instanceof \WP_User) {
			$this->redirect_error('account_match_failed', $provider, 'login');
		}
		OAuthAccountService::complete_login($user, true);
		$this->redirect_success('login', $provider, OAuthUrlPolicy::validated_redirect($redirect, home_url('/')));
	}

	private function binding_row(string $provider, bool $bound): array {
		return [
			'key' => $provider,
			'name' => OAuthProviderCatalog::label($provider),
			'icon' => function_exists('aksrt_brand_icon') ? aksrt_brand_icon(OAuthProviderCatalog::icon_key($provider)) : '',
			'is_bound' => $bound,
			'url' => '',
		];
	}

	private function redirect_success(string $action, string $provider, string $target): void {
		wp_safe_redirect(add_query_arg([
			'oauth_action' => $action,
			'oauth_provider' => $provider,
		], $target));
		exit;
	}

	private function redirect_error(string $code, string $provider = '', string $action = 'login'): void {
		$target = $action === 'bind' && is_user_logged_in() && function_exists('aksrt_get_user_center_url')
			? aksrt_get_user_center_url('settings')
			: (function_exists('aksrt_get_login_url') ? aksrt_get_login_url() : wp_login_url());
		wp_safe_redirect(add_query_arg([
			'oauth_action' => 'error',
			'oauth_provider' => sanitize_key($provider),
			'oauth_error' => sanitize_key($code),
		], $target));
		exit;
	}
}