From 1ffe5fffb44e60abcd9600943ef2fef2e7b6c4b0 Mon Sep 17 00:00:00 2001
From: mrkubax10 <mrkubax10@onet.pl>
Date: Wed, 6 Sep 2023 20:09:20 +0200
Subject: [PATCH] Frontend: Add support for HTML templates

---
 frontend.pl          | 152 ++++++++++++++++++++++++++++++++++++++-----
 static/index.html    |   1 +
 templates/index.html |   2 +-
 3 files changed, 138 insertions(+), 17 deletions(-)
 create mode 100644 static/index.html

diff --git a/frontend.pl b/frontend.pl
index 7d6e9c3..3e8b3b4 100644
--- a/frontend.pl
+++ b/frontend.pl
@@ -25,6 +25,16 @@ use feature qw(switch);
 use strict;
 use warnings;
 
+sub readFullFile {
+	my $aFile = $_[0];
+
+	my $content = "";
+	while(!eof($aFile)) {
+		$content.=readline($aFile);
+	}
+	return $content;
+}
+
 use constant {
 	HTTP_METHOD_UNKNOWN => 0,
 	HTTP_METHOD_GET => 1,
@@ -132,6 +142,123 @@ sub sendNotImplemented {
 	$aClient->send($response);
 }
 
+sub sendNotFound {
+	my $aClient = $_[0];
+
+	my $content = "<h1>404 Not Found</h1><h6>irclogger_web</h6>";
+	my $response = getBaseResponse(404, "Not Found");
+	$response.="Content-Type: text/html, charset=utf-8\r\n";
+	$response.="Content-Length: ".length($content)."\r\n\r\n";
+	$response.=$content;
+	$aClient->send($response);
+}
+
+use constant {
+	PREPROCESSOR_STATE_TEXT => 0,
+	PREPROCESSOR_STATE_VAR => 1,
+	PREPROCESSOR_STATE_INC => 2
+};
+sub preprocessHTML {
+	my $aContent = $_[0];
+	my $aVariables = $_[1];
+
+	my $contentLength = length($aContent);
+	my $state = PREPROCESSOR_STATE_TEXT;
+	my $currentString = "";
+	my $index = 0;
+	my $output = "";
+	while($index<$contentLength) {
+		my $char = substr($aContent, $index++, 1);
+		given($state) {
+		when(PREPROCESSOR_STATE_TEXT) {
+			if($char eq "{" && $index<$contentLength) {
+				my $nextChar = substr($aContent, $index, 1);
+				if($nextChar eq "{") {
+					$index++;
+					$state = PREPROCESSOR_STATE_VAR;
+					next;
+				}
+			}
+			if($char eq "[" && $index<$contentLength) {
+				my $nextChar = substr($aContent, $index, 1);
+				if($nextChar eq "[") {
+					$index++;
+					$state = PREPROCESSOR_STATE_INC;
+					next;
+				}
+			}
+			$output.=$char;
+		}
+		when(PREPROCESSOR_STATE_VAR) {
+			if($char eq "}" && $index<$contentLength) {
+				my $nextChar = substr($aContent, $index, 1);
+				if($nextChar eq "}") {
+					$index++;
+					$output.=$aVariables->{$currentString};
+					$currentString = "";
+					$state = PREPROCESSOR_STATE_TEXT;
+					next;
+				}
+			}
+			$currentString.=$char;
+		}
+		when(PREPROCESSOR_STATE_INC) {
+			if($char eq "]" && $index<$contentLength) {
+				my $nextChar = substr($aContent, $index, 1);
+				if($nextChar eq "]") {
+					$index++;
+					if(open(my $file, "<", $currentString)) {
+						$output.=readFullFile($file);
+						close($file);
+					}
+					else {
+						$output.="[[Include file not found]";
+					}
+					$currentString = "";
+					$state = PREPROCESSOR_STATE_TEXT;
+					next;
+				}
+			}
+			$currentString.=$char;
+		}
+		}
+	}
+	return $output;
+}
+
+sub sendTemplate {
+	my $aFilePath = $_[0];
+	my $aClient = $_[1];
+	my $aVariables = $_[2];
+
+	my $result = open(my $file, "<", $aFilePath);
+	if(!$result) {
+		sendNotFound($aClient);
+		return 0;
+	}
+	my $content = preprocessHTML(readFullFile($file), $aVariables);
+	close($file);
+	my $length = length($content);
+	my $response = getBaseResponse(200, "OK");
+	$response.="Content-Length: $length\r\n\r\n";
+	$response.=$content;
+	$aClient->send($response);
+}
+
+sub handlePath {
+	my $aClient = $_[0];
+	my $aPath = $_[1];
+	my $aRequest = $_[2];
+
+	given($aPath) {
+	when("/") {
+		sendTemplate("templates/index.html", $aClient, {"var"=>"value"});
+		return 1;
+	}
+	}
+	return 0;
+}
+
 sub sendResponse {
 	my $aClient = $_[0];
 	my $aRequest = $_[1];
@@ -144,25 +271,19 @@ sub sendResponse {
 	given($aRequest->{"method"}) {
 	when(HTTP_METHOD_GET) {
 		my $path = File::Spec->canonpath($aRequest->{"path"});
-		if($path eq "/") {
-			$path = "/index.html";
+		if($path eq "/index.html" || $path eq "/index.htm") {
+			$path = "/";
 		}
-		my $filePath = "templates".$path;
-		my $result = open(my $file, "<", $filePath);
-		print($filePath);
-		if(!$result) {
-			my $content = "<h1>404 Not Found</h1><h6>irclogger_web</h6>";
-			my $response = getBaseResponse(404, "Not Found");
-			$response.="Content-Type: text/html, charset=utf-8\r\n";
-			$response.="Content-Length: ".length($content)."\r\n\r\n";
-			$response.=$content;
-			$aClient->send($response);
+		if(handlePath($aClient, $path, $aRequest)) {
 			return;
 		}
-		my $content = "";
-		while(!eof($file)) {
-			$content.=readline($file);
+		my $filePath = "static".$path;
+		my $result = open(my $file, "<", $filePath);
+		if(!$result) {
+			sendNotFound($aClient);
+			return;
 		}
+		my $content = readFullFile($file);
 		close($file);
 		my $response = getBaseResponse(200, "OK");
 		# TODO
@@ -170,7 +291,6 @@ sub sendResponse {
 		#$response.="Content-Type: $mime\r\n";
 		$response.="Content-Length: ".length($content)."\r\n\r\n";
 		$response.=$content;
-		print($response);
 		$aClient->send($response);
 	}
 	default {
diff --git a/static/index.html b/static/index.html
new file mode 100644
index 0000000..32f7201
--- /dev/null
+++ b/static/index.html
@@ -0,0 +1 @@
+<h1>Hi!</h1>
diff --git a/templates/index.html b/templates/index.html
index 32f7201..b12ef73 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -1 +1 @@
-<h1>Hi!</h1>
+<h1>{{var}}</h1>