#include "StaticFiles.hpp"

#include <cstdio>
#include <fstream>
#include <sstream>

namespace molo::example::fw {

bool path_is_safe(const std::string& request_path) {
  if (request_path.find("..") != std::string::npos) return false;
  if (request_path.find('\\') != std::string::npos) return false;
  if (request_path.empty() || request_path.front() != '/') return false;
  return true;
}

namespace {

std::string content_type_for(const std::string& name) {
  auto ends = [&](const char* ext) {
    std::string e(ext);
    return name.size() >= e.size() &&
           name.compare(name.size() - e.size(), e.size(), e) == 0;
  };
  if (ends(".html")) return "text/html; charset=utf-8";
  if (ends(".css")) return "text/css; charset=utf-8";
  if (ends(".js")) return "text/javascript; charset=utf-8";
  if (ends(".json")) return "application/json";
  if (ends(".svg")) return "image/svg+xml";
  if (ends(".png")) return "image/png";
  return "application/octet-stream";
}

}  // namespace

std::string etag_for(const std::string& body) {
  unsigned long long h = 1469598103934665603ULL;
  for (unsigned char c : body) {
    h ^= c;
    h *= 1099511628211ULL;
  }
  char buf[32];
  std::snprintf(buf, sizeof(buf), "\"%llx-%zu\"",
                (unsigned long long)h, body.size());
  return buf;
}

Response serve_disk_file(const std::string& root,
                         const std::string& subpath) {
  std::string full = "/" + subpath;
  if (!path_is_safe(full)) return TextResponse("unsafe path", 403);
  std::ifstream in(root + full, std::ios::binary);
  if (!in) return TextResponse("not found", 404);
  std::ostringstream ss;
  ss << in.rdbuf();
  Response res(200, ss.str(), content_type_for(full));
  res.headers.set("ETag", etag_for(res.body));
  res.headers.set("Cache-Control", "public, max-age=3600");
  return res;
}

Response serve_embedded(const std::map<std::string, std::string>& assets,
                        const std::string& subpath) {
  std::string full = "/" + subpath;
  if (!path_is_safe(full)) return TextResponse("unsafe path", 403);
  auto it = assets.find(full);
  if (it == assets.end()) return TextResponse("not found", 404);
  Response res(200, it->second, content_type_for(full));
  res.headers.set("ETag", etag_for(res.body));
  res.headers.set("Cache-Control", "public, max-age=3600");
  res.headers.set("X-Asset-Source", "embedded");
  return res;
}

}  // namespace molo::example::fw