import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:webview_flutter/webview_flutter.dart';

import '../../../core/theme/halo_tokens.dart';

/// Embedded WebView host for the Xendit hosted checkout page.
///
/// Why embedded (vs `LaunchMode.inAppBrowserView` / Custom Tab):
///   1. We get full control over `NavigationDelegate`, so we can short-circuit
///      the `halobestie://` deeplink + the backend's `/payment/return/*` HTML
///      pages without round-tripping through the system browser intent
///      handler.
///   2. Pop result tells the parent (`WaitingPaymentScreen`) to trigger an
///      immediate poll instead of waiting up to 3s for the next tick.
///
/// Pop results:
///   - `'success'`  — URL matched `/payment/return/success`
///   - `'failure'`  — URL matched `/payment/return/failure`
///   - `'deeplink'` — `halobestie://` scheme was followed (typically from the
///                    return page's button; the existing intent-filter in
///                    AndroidManifest would also handle it, but we intercept
///                    here so the WebView host pops cleanly)
///   - `null`       — user tapped the close (X) button manually
///
/// iOS NOTE: when shipping iOS, the dev backend at `http://192.168.88.247:3000`
/// will be blocked by ATS. Add an `NSAppTransportSecurity > NSAllowsArbitraryLoads`
/// (or per-domain `NSExceptionDomains`) entry to `ios/Runner/Info.plist` before
/// the iOS dev build will let the WebView load any /payment/return/* page from
/// the dev backend. Production (`api.halobestie.com`) is HTTPS so no exception
/// is needed there. Not touching Info.plist now — Android-only session.
class XenditCheckoutScreen extends ConsumerStatefulWidget {
  final String invoiceUrl;
  final String paymentId;

  const XenditCheckoutScreen({
    super.key,
    required this.invoiceUrl,
    required this.paymentId,
  });

  @override
  ConsumerState<XenditCheckoutScreen> createState() =>
      _XenditCheckoutScreenState();
}

class _XenditCheckoutScreenState extends ConsumerState<XenditCheckoutScreen> {
  late final WebViewController _controller;
  int _progress = 0;

  // Pre-compiled regexes for the backend's return pages. The route is defined
  // in backend `routes/payment.return.js` as `GET /payment/return/:status`
  // where :status is 'success' or 'failure'. Match anywhere in the URL so we
  // don't have to care about query strings, host, or scheme.
  static final RegExp _successPattern =
      RegExp(r'/payment/return/success(\?|$|/)');
  static final RegExp _failurePattern =
      RegExp(r'/payment/return/failure(\?|$|/)');

  @override
  void initState() {
    super.initState();
    _controller = WebViewController()
      ..setJavaScriptMode(JavaScriptMode.unrestricted)
      ..setBackgroundColor(HaloTokens.surface)
      ..setNavigationDelegate(
        NavigationDelegate(
          onProgress: (p) {
            if (!mounted) return;
            setState(() => _progress = p);
          },
          onNavigationRequest: _handleNavigationRequest,
          onWebResourceError: (error) {
            // Log only — Xendit pages routinely emit non-fatal resource errors
            // (favicons, third-party trackers blocked by adblock-style rules,
            // etc). Surfacing those as snackbars would be noisy.
            if (kDebugMode) {
              debugPrint(
                '[XenditCheckoutScreen] WebResourceError '
                'code=${error.errorCode} type=${error.errorType} '
                'desc=${error.description} url=${error.url}',
              );
            }
          },
        ),
      )
      ..loadRequest(Uri.parse(widget.invoiceUrl));
  }

  NavigationDecision _handleNavigationRequest(NavigationRequest request) {
    final url = request.url;

    // 1. Deeplink scheme — pop with informational result. The Android intent
    //    filter would also catch this from a system-browser context, but
    //    inside a WebView the engine surfaces it here as a navigation, and
    //    if we don't block it the WebView shows an `ERR_UNKNOWN_URL_SCHEME`
    //    error page.
    if (url.startsWith('halobestie://')) {
      _popWith('deeplink');
      return NavigationDecision.prevent;
    }

    // 2. Backend's success return page.
    if (_successPattern.hasMatch(url)) {
      _popWith('success');
      return NavigationDecision.prevent;
    }

    // 3. Backend's failure return page.
    if (_failurePattern.hasMatch(url)) {
      _popWith('failure');
      return NavigationDecision.prevent;
    }

    return NavigationDecision.navigate;
  }

  void _popWith(String result) {
    if (!mounted) return;
    Navigator.of(context).pop(result);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: HaloTokens.surface,
      appBar: AppBar(
        backgroundColor: HaloTokens.surface,
        elevation: 0,
        leading: IconButton(
          icon: const Icon(Icons.close, color: HaloTokens.brandDark),
          tooltip: 'Tutup',
          onPressed: () => Navigator.of(context).pop(),
        ),
        title: const Text(
          'Pembayaran Xendit',
          style: TextStyle(
            fontFamily: HaloTokens.fontDisplay,
            fontSize: 16,
            fontWeight: FontWeight.w700,
            color: HaloTokens.brandDark,
          ),
        ),
        centerTitle: true,
        bottom: _progress < 100
            ? PreferredSize(
                preferredSize: const Size.fromHeight(2),
                child: LinearProgressIndicator(
                  value: _progress / 100.0,
                  minHeight: 2,
                  backgroundColor: HaloTokens.brandSofter,
                  valueColor: const AlwaysStoppedAnimation<Color>(
                    HaloTokens.brand,
                  ),
                ),
              )
            : null,
      ),
      body: WebViewWidget(controller: _controller),
    );
  }
}