From 4c40aa6b388b4de08b8daad53c2248249860cef1 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Mon, 5 Jun 2023 01:42:57 +0300
Subject: [PATCH] Userspace: Start work on proper shell

---
 userspace/Shell/main.cpp | 128 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 123 insertions(+), 5 deletions(-)

diff --git a/userspace/Shell/main.cpp b/userspace/Shell/main.cpp
index a0eaf2ee..0de2a8fd 100644
--- a/userspace/Shell/main.cpp
+++ b/userspace/Shell/main.cpp
@@ -1,25 +1,143 @@
+#include <BAN/ScopeGuard.h>
+#include <BAN/String.h>
+#include <BAN/Vector.h>
 #include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
 #include <termios.h>
+#include <unistd.h>
 
 struct termios old_termios, new_termios;
 
+BAN::Vector<char*> parse_command(BAN::StringView command)
+{
+	auto args = MUST(command.split(' '));
+	BAN::Vector<char*> result;
+	for (auto arg : args)
+	{
+		char* carg = new char[arg.size() + 1];
+		memcpy(carg, arg.data(), arg.size());
+		carg[arg.size()] = '\0';
+		MUST(result.push_back(carg));
+	}
+	return result;
+}
+
+int execute_command(BAN::StringView command)
+{
+	auto args = parse_command(command);
+	if (args.empty())
+		return 0;
+
+	BAN::ScopeGuard deleter([&args] {
+		for (char* arg : args)
+			delete[] arg;
+	});
+	
+	if (args.front() == "clear"sv)
+	{
+		fprintf(stdout, "\e[H\e[J");
+		fflush(stdout);
+		return 0;
+	}
+	else
+	{
+		pid_t pid = fork();
+		if (pid == 0)
+		{
+			MUST(args.push_back(nullptr));
+			execv(args.front(), args.data());
+			perror("execv");
+			exit(1);
+		}
+		if (pid == -1)
+		{
+			perror("fork()");
+			return 1;
+		}
+		int status;
+		if (waitpid(pid, &status, 0) == -1)
+			perror("waitpid");
+	}
+
+	return 0;
+}
+
 int main(int argc, char** argv)
 {
-	for (int i = 0; i < argc; i++)
-		printf("%s\n", argv[i]);
-
 	tcgetattr(0, &old_termios);
 
 	new_termios = old_termios;
 	new_termios.c_lflag &= ~(ECHO | ICANON);
 	tcsetattr(0, TCSANOW, &new_termios);
 
+	BAN::Vector<BAN::String> buffers, history;
+	MUST(buffers.emplace_back(""sv));
+	size_t index = 0;
+	size_t col = 0;
+
+	bool got_csi = false;
+
+	BAN::String prompt("\e[32muser@host\e[m:\e[34m/\e[m$ "sv);
+	fprintf(stdout, "%s", prompt.data());
+	fflush(stdout);
+
 	while (true)
 	{
 		char c;
 		fread(&c, 1, sizeof(char), stdin);
-		fputc(c, stdout);
-		fflush(stdout);
+
+		if (got_csi)
+		{
+			
+			continue;
+		}
+
+		switch (c)
+		{
+		case '\e':
+			fread(&c, 1, sizeof(char), stdin);
+			if (c != '[')
+				break;
+			fread(&c, 1, sizeof(char), stdin);
+			switch (c)
+			{
+				case 'A': if (index > 0)					{ index--; col = buffers[index].size(); fprintf(stdout, "\e[G%s\e[K", buffers[index].data()); fflush(stdout); } break;
+				case 'B': if (index < buffers.size() - 1)	{ index++; col = buffers[index].size(); fprintf(stdout, "\e[G%s\e[K", buffers[index].data()); fflush(stdout); } break;
+				case 'C': break;
+				case 'D': break;
+			}
+			break;
+		case '\b':
+			if (col > 0)
+			{
+				buffers[index].pop_back();
+				fprintf(stdout, "\b \b");
+				fflush(stdout);
+				col--;
+			}
+			break;
+		case '\n':
+			fputc('\n', stdout);
+			if (!buffers[index].empty())
+			{
+				execute_command(buffers[index]);
+				MUST(history.push_back(buffers[index]));
+				buffers = history;
+				MUST(buffers.emplace_back(""sv));
+			}
+			fprintf(stdout, "%s", prompt.data());
+			fflush(stdout);
+			index = buffers.size() - 1;
+			col = 0;
+			break;
+		default:
+			MUST(buffers[index].push_back(c));
+			fprintf(stdout, "%s \b", buffers[index].data() + col);
+			fflush(stdout);
+			col++;
+			break;
+		}
 	}
 
 	tcsetattr(0, TCSANOW, &old_termios);