#include "backend.cpp"
#include <filesystem>

class file_backend : public backend {
private:
  unordered_map<string, string> file_cache;
  bool cache_enabled;

  http_response handle_request_nocache(http_request req) {
     string filename = req.path() == "/" ? "index.html" : req.path();
     filename = "./www/" + filename;
     ifstream stream(filename);

     int status = 200;
     if (!stream.is_open()) {
         status = 404;
         filename = "./error_pages/404.html";
         stream = ifstream(filename);
     }

     stringstream buffer;
     buffer << stream.rdbuf();
     return { buffer.str(), status };
  }

  http_response handle_request_cache(http_request req) {
     string filename = req.path() == "/" ? "/index.html" : req.path();
     filename = "./www" + filename;
     auto file_info = file_cache.find(filename);

     int status = 200;
     if (file_info == file_cache.end()) {
         status = 404;
         filename = "./error_pages/404.html";
         file_info = file_cache.find(filename);
     }

     return { file_info->second, status };
  }

  void populate_cache_dir(string dir) {
    filesystem::recursive_directory_iterator cur = begin(filesystem::recursive_directory_iterator(dir));
    filesystem::recursive_directory_iterator fin = end(filesystem::recursive_directory_iterator(dir));

    while (cur != fin) {
        auto p = cur->path();
        string filename = p.string();
        stringstream buffer;
        ifstream stream(filename);
        buffer << stream.rdbuf();
        file_cache[filename] = buffer.str();
        cout << "File at " << filename << " cached (" << file_cache[filename].size() << " bytes)" << endl;
        ++cur;
    }
  }

  void populate_cache() {
    populate_cache_dir("./www/");
    populate_cache_dir("./error_pages/");
  }

public:
  file_backend(bool enable_cache) : cache_enabled(enable_cache) {
    if(cache_enabled) {
      populate_cache(); 
    }
  }

  http_response handle_request(http_request req) override {
    return cache_enabled ? handle_request_cache(req) : handle_request_nocache(req);
  }
};