Improve Template engine

lib/src/http/controller/controller_handler.dart

@@ -1,5 +1,6 @@
 import 'package:vania/src/exception/validation_exception.dart';
 import 'package:vania/src/route/route_data.dart';
+import 'package:vania/src/route/route_history.dart';
 import 'package:vania/vania.dart';
 
 class ControllerHandler {
@@ -28,9 +29,14 @@ class ControllerHandler {
 
       response.makeResponse(request.response);
     } on ValidationException catch (error) {
-      error
-          .response(request.headers['accept'].toString().contains('html'))
-          .makeResponse(request.response);
+      bool isHtml =
+          request.request.headers.value('accept').toString().contains('html');
+      if (isHtml) {
+        Response.redirect(RouteHistory().previousRoute)
+            .makeResponse(request.response);
+      } else {
+        error.response(false).makeResponse(request.response);
+      }
     } catch (error) {
       _response(request, error.toString());
     }

lib/src/http/request/request.dart

@@ -4,6 +4,7 @@ import 'package:vania/src/exception/validation_exception.dart';
 import 'package:vania/src/http/request/request_body.dart';
 import 'package:vania/src/http/validation/validator.dart';
 import 'package:vania/src/route/route_data.dart';
+import 'package:vania/src/view_engine/template_engine.dart';
 import 'package:vania/vania.dart';
 
 class Request {
@@ -321,6 +322,7 @@ class Request {
       [Map<String, String> messages = const <String, String>{}]) {
     assert(rules is Map<String, String> || rules is List<Validation>,
         'Rules must be either Map<String, String> or List<Validation>.');
+    TemplateEngine().sessionErrors.clear();
     if (rules is Map<String, String>) {
       _validate(rules, messages);
     } else {
@@ -336,6 +338,10 @@ class Request {
     }
     validator.validate(rules);
     if (validator.hasError) {
+      bool isHtml = request.headers.value('accept').toString().contains('html');
+      if (isHtml) {
+        TemplateEngine().sessionErrors.addAll(validator.errors);
+      }
       throw ValidationException(message: validator.errors);
     }
   }
@@ -354,6 +360,10 @@ class Request {
       }
     }
     if (errors.isNotEmpty) {
+      bool isHtml = request.headers.value('accept').toString().contains('html');
+      if (isHtml) {
+        TemplateEngine().sessionErrors.addAll(errors);
+      }
       throw ValidationException(message: errors);
     }
   }

lib/src/http/request/request_handler.dart

@@ -9,6 +9,8 @@ import 'package:vania/src/http/controller/controller_handler.dart';
 import 'package:vania/src/http/middleware/middleware_handler.dart';
 import 'package:vania/src/route/route_data.dart';
 import 'package:vania/src/route/route_handler.dart';
+import 'package:vania/src/route/route_history.dart';
+import 'package:vania/src/view_engine/template_engine.dart';
 import 'package:vania/src/websocket/web_socket_handler.dart';
 import 'package:vania/vania.dart';
 
@@ -36,6 +38,8 @@ Future httpRequestHandler(HttpRequest req) async {
     String requestUri = req.uri.path;
     String starteRequest = startTime.format();
 
+    bool isHtml = req.headers.value('accept').toString().contains('html');
+
     try {
       /// Check if cors is enabled
       HttpCors(req);
@@ -44,6 +48,12 @@ Future httpRequestHandler(HttpRequest req) async {
       await request.extractBody();
       if (route == null) return;
 
+      RouteHistory().updateRouteHistory(req);
+
+      if (isHtml) {
+        TemplateEngine().formData.addAll(request.all());
+      }
+
       /// check if pre middleware exist and call it
       if (route.preMiddleware.isNotEmpty) {
         await middlewareHandler(route.preMiddleware, request);
@@ -55,7 +65,6 @@ Future httpRequestHandler(HttpRequest req) async {
         request: request,
       );
     } on BaseHttpResponseException catch (error) {
-      bool isHtml = req.headers.value('accept').toString().contains('html');
       if (error is NotFoundException && isHtml) {
         if (File('lib/view/template/errors/404.html').existsSync()) {
           return view('errors/404').makeResponse(req.response);

lib/src/http/response/response.dart

@@ -3,6 +3,8 @@ import 'dart:io';
 import 'dart:typed_data';
 import 'package:meta/meta.dart';
 import 'package:vania/src/http/response/stream_file.dart';
+import 'package:vania/src/route/route_history.dart';
+import 'package:vania/src/view_engine/template_engine.dart';
 
 enum ResponseType {
   json,
@@ -191,4 +193,23 @@ class Response {
         responseType: ResponseType.download,
         headers: headers,
       );
+
+  static back([String? key, String? message]) {
+    String previousRoute = RouteHistory().previousRoute;
+    if (key != null && message != null) {
+      TemplateEngine().sessions[key] = message;
+    }
+    if (previousRoute.isNotEmpty) {
+      return Response(
+        responseType: ResponseType.redirect,
+        data: previousRoute,
+        httpStatusCode: HttpStatus.found,
+      );
+    }
+    return Response(
+      responseType: ResponseType.redirect,
+      data: RouteHistory().currentRoute,
+      httpStatusCode: HttpStatus.found,
+    );
+  }
 }

lib/src/route/route_handler.dart

@@ -6,6 +6,20 @@ import 'package:vania/src/route/set_static_path.dart';
 import 'package:vania/src/utils/functions.dart';
 import 'package:vania/vania.dart';
 
+/// Find the matched route from the given request and return the
+/// [RouteData] for the matched route.
+///
+/// The function first checks if the request is an OPTIONS request. If it is,
+/// the request is closed and null is returned. If the request is not an
+/// OPTIONS request, the function checks if the request path matches a static
+/// file. If it does, the function returns null. If it doesn't, the function
+/// throws a [NotFoundException].
+///
+/// If the request is not an OPTIONS request and the request path doesn't match
+/// a static file, the function returns the matched [RouteData].
+///
+/// Throws a [NotFoundException] if the request is not an OPTIONS request and
+/// the request path doesn't match a static file.
 RouteData? httpRouteHandler(HttpRequest req) {
   final route = _getMatchRoute(
     Uri.decodeComponent(
@@ -36,7 +50,6 @@ RouteData? httpRouteHandler(HttpRequest req) {
   return route;
 }
 
-/// Exctract the domain from the url
 String _extractDomain(String domain, String path) {
   String firstPart = domain.split('.').first.toLowerCase();
   final RegExp domainRegex = RegExp(r'\{[^}]*\}');
@@ -48,8 +61,6 @@ String _extractDomain(String domain, String path) {
   return domainUri;
 }
 
-/// Exctarct username from {username}
-/// Or any string between {}
 String? _extractDomainPlaceholder(String input) {
   final RegExp regex = RegExp(r'\{([^}]*)\}');
   final match = regex.firstMatch(input);

lib/src/route/route_history.dart

@@ -0,0 +1,24 @@
+import 'dart:io';
+
+class RouteHistory {
+  static final RouteHistory _instance = RouteHistory._internal();
+  factory RouteHistory() => _instance;
+  RouteHistory._internal();
+
+  String _currentRoute = '';
+  String _previousRoute = '';
+
+  String get currentRoute => _currentRoute;
+  String get previousRoute => _previousRoute;
+
+  Future<void> updateRouteHistory(HttpRequest req) async {
+    if (req.headers.value('accept').toString().contains('html')) {
+      if (_currentRoute.isEmpty) {
+        _currentRoute = req.uri.path;
+      } else {
+        _previousRoute = _currentRoute;
+        _currentRoute = req.uri.path;
+      }
+    }
+  }
+}

lib/src/utils/helper.dart

@@ -59,7 +59,7 @@ Response view(String template, [Map<String, dynamic>? context]) =>
 Future<void> setSession(String key, dynamic value) async =>
     await SessionManager().setSession(key, value);
 Future<T> getSession<T>(String key) async =>
-    await SessionManager().getSession<T>(key);
+    TemplateEngine().sessions[key] ?? await SessionManager().getSession<T>(key);
 Future<Map<String, dynamic>?> allSessions() async =>
     await SessionManager().allSessions();
 Future<void> deleteSession(String key) async =>

lib/src/view_engine/processor_engine/error_processor.dart

@@ -0,0 +1,29 @@
+import 'package:vania/src/view_engine/template_engine.dart';
+
+import 'abs_processor.dart';
+
+class ErrorProcessor extends AbsProcessor {
+  @override
+  String parse(String content, [Map<String, dynamic>? context]) {
+    final hasErrorPattern = RegExp(
+      r"hasError\(\s*'([^']*)'\s*\)",
+      dotAll: true,
+    );
+    content = content.replaceAllMapped(hasErrorPattern, (match) {
+      final errorKey = match.group(1);
+      return TemplateEngine().sessionErrors.containsKey(errorKey).toString();
+    });
+
+    final errorPattern = RegExp(
+      r"\{@\s*error\(\s*'([^']*)'\s*\)\s*@\}",
+      dotAll: true,
+    );
+
+    content = content.replaceAllMapped(errorPattern, (error) {
+      final errorKey = error.group(1);
+      return TemplateEngine().sessionErrors[errorKey] ?? '';
+    });
+
+    return content;
+  }
+}

lib/src/view_engine/processor_engine/old_processor.dart

@@ -0,0 +1,20 @@
+import 'package:vania/src/view_engine/template_engine.dart';
+
+import 'abs_processor.dart';
+
+class OldProcessor extends AbsProcessor {
+  @override
+  String parse(String content, [Map<String, dynamic>? context]) {
+    final oldPattern = RegExp(
+      r"\{@\s*old\(\s*'([^']*)'\s*\)\s*@\}",
+      dotAll: true,
+    );
+
+    content = content.replaceAllMapped(oldPattern, (oldMatch) {
+      final oldKey = oldMatch.group(1);
+      return TemplateEngine().formData[oldKey] ?? '';
+    });
+
+    return content;
+  }
+}

lib/src/view_engine/processor_engine/session_processor.dart

@@ -0,0 +1,29 @@
+import 'package:vania/src/view_engine/processor_engine/abs_processor.dart';
+import 'package:vania/src/view_engine/template_engine.dart';
+
+class SessionProcessor implements AbsProcessor {
+  @override
+  String parse(String content, [Map<String, dynamic>? context]) {
+    final hasSessionPattern = RegExp(
+      r"hasSession\(\s*'([^']*)'\s*\)",
+      dotAll: true,
+    );
+
+    content = content.replaceAllMapped(hasSessionPattern, (match) {
+      final sessionKey = match.group(1);
+      return TemplateEngine().sessions.containsKey(sessionKey).toString();
+    });
+
+    final sessionPattern = RegExp(
+      r"\{@\s*session\(\s*'([^']*)'\s*\)\s*@\}",
+      dotAll: true,
+    );
+
+    content = content.replaceAllMapped(sessionPattern, (math) {
+      final sessionKey = math.group(1);
+      return TemplateEngine().sessions[sessionKey] ?? '';
+    });
+
+    return content;
+  }
+}

lib/src/view_engine/template_engine.dart

@@ -3,11 +3,14 @@ import 'package:vania/src/view_engine/processor_engine/variables_processor.dart'
 
 import 'processor_engine/csrf_processor.dart';
 import 'processor_engine/csrf_token_processor.dart';
+import 'processor_engine/error_processor.dart';
 import 'processor_engine/if_statement_processor.dart';
 import 'processor_engine/extends_processor.dart';
 import 'processor_engine/for_loop_processor.dart';
 import 'processor_engine/include_processor.dart';
+import 'processor_engine/old_processor.dart';
 import 'processor_engine/section_processor.dart';
+import 'processor_engine/session_processor.dart';
 import 'processor_engine/switch_cases_processor.dart';
 import 'template_reader.dart';
 
@@ -28,6 +31,7 @@ class TemplateEngine {
   static final TemplateEngine _singleton = TemplateEngine._internal();
   factory TemplateEngine() => _singleton;
   TemplateEngine._internal();
+
   final VariablesProcessor _variablesProcess = VariablesProcessor();
   final IfStatementProcessor _conditionalProcess = IfStatementProcessor();
   final SwitchCasesProcessor _switchCaseProcess = SwitchCasesProcessor();
@@ -36,11 +40,22 @@ class TemplateEngine {
   final ExtendsProcessor _extendsProcessor = ExtendsProcessor();
   final CsrfProcessor _csrfProcessor = CsrfProcessor();
   final CsrfTokenProcessor _csrfTokenProcessor = CsrfTokenProcessor();
+  final ErrorProcessor _errorProcessor = ErrorProcessor();
   final SectionProcessor _sectionProcessor = SectionProcessor();
+  final OldProcessor _oldProcessor = OldProcessor();
+  final SessionProcessor _sessionProcessor = SessionProcessor();
+
+  final Map<String, dynamic> sessionErrors = {};
+  final Map<String, dynamic> formData = {};
+  final Map<String, dynamic> sessions = {};
 
   String render(String template, [Map<String, dynamic>? data]) {
     String templateContent = FileTemplateReader().read(template);
-    return renderString(templateContent, data);
+    String renderedTemplate = renderString(templateContent, data);
+    sessionErrors.clear();
+    formData.clear();
+    sessions.clear();
+    return renderedTemplate;
   }
 
   /// Renders a template string with the provided data context.
@@ -69,12 +84,15 @@ class TemplateEngine {
       _extendsProcessor,
       _includeProcessor,
       _sectionProcessor,
+      _errorProcessor,
+      _sessionProcessor,
       _forLoopProcessor,
       _switchCaseProcess,
       _conditionalProcess,
       _variablesProcess,
       _csrfProcessor,
       _csrfTokenProcessor,
+      _oldProcessor
     ]);
 
     final renderedContent = pipeline.run(templateContent, data);