the-biergarten-app/pipeline/src/data_generation/data_downloader.cpp

#include "data_generation/data_downloader.h"

#include <spdlog/spdlog.h>

#include <filesystem>
#include <fstream>
#include <sstream>
#include <stdexcept>

#include "web_client/web_client.h"

DataDownloader::DataDownloader(std::shared_ptr<WebClient> web_client)
    : web_client_(std::move(web_client)) {}

DataDownloader::~DataDownloader() {}

bool DataDownloader::FileExists(const std::string& file_path) {
   return std::filesystem::exists(file_path);
}

std::string DataDownloader::DownloadCountriesDatabase(
    const std::string& cache_path, const std::string& commit) {
   if (FileExists(cache_path)) {
      spdlog::info("[DataDownloader] Cache hit: {}", cache_path);
      return cache_path;
   }

   std::string short_commit = commit;
   if (commit.length() > 7) {
      short_commit = commit.substr(0, 7);
   }

   std::string url =
       "https://raw.githubusercontent.com/dr5hn/"
       "countries-states-cities-database/" +
       short_commit + "/json/countries+states+cities.json";

   spdlog::info("[DataDownloader] Downloading: {}", url);

   web_client_->DownloadToFile(url, cache_path);

   std::ifstream file_check(cache_path, std::ios::binary | std::ios::ate);
   std::streamsize size = file_check.tellg();
   file_check.close();

   spdlog::info("[DataDownloader] OK: Download complete: {} ({:.2f} MB)",
                cache_path, (size / (1024.0 * 1024.0)));
   return cache_path;
}