docs: begin to setup main structure and write BlockSS

backend/src/main.cpp

@@ -1 +1,60 @@
-int main() { return 0; }
+#include <iostream>
+#include <string>
+
+#include "bs-utility.h"
+#include "builtin-cli.h"
+#include "clipp/clipp.h"
+void test() {
+  BlockingStringStream bss;
+
+  std::thread writer([&bss]() {
+    for (int i = 1; i <= 5; ++i) {
+      bss << "Data " << i << '\n';
+      std::this_thread::sleep_for(std::chrono::seconds(1));
+    }
+  });
+
+  std::thread reader([&bss]() {
+    std::string data;
+    for (int i = 1; i <= 5; ++i) {
+      // Use getline with string delimiter
+      bss.getline(data, '\n');
+      std::cout << "Received: " << data << std::endl;
+    }
+  });
+  reader.join();
+  writer.join();
+}
+int main(int argc, char **argv) {
+  test();
+  return 0;
+  bool is_server = false;
+  std::string config_dir = "";
+  bool custom_config_dir = false;
+  auto cli =
+      (clipp::option("-s", "--server").set(is_server).doc("run as server"),
+       clipp::option("-c", "--config")
+               .set(custom_config_dir)
+               .doc("use config directory") &
+           clipp::value("config directory", config_dir));
+  if (!clipp::parse(argc, argv, cli)) {
+    std::cout << clipp::make_man_page(cli, argv[0]);
+    return 0;
+  }
+  if (!custom_config_dir) config_dir = "./";
+  try {
+    BookStoreMain(is_server, config_dir);
+  } catch (const FatalError &e) {
+    std::cerr << "\e[7m\e[31m[Fatal Error] " << e.GetCode() << " : " << e.what()
+              << "\e[0m" << std::endl;
+    return e.GetCode();
+  } catch (const std::exception &e) {
+    std::cerr << "\e[7m\e[31m[other std::exception] " << e.what() << "\e[0m"
+              << std::endl;
+    return 255;
+  } catch (...) {
+    std::cerr << "\e[7m\e[31m[Unknown Exception]\e[0m" << std::endl;
+    return 255;
+  }
+  return 0;
+}