#include "tlbmc/configs/blocklist_parser.h"

#include <cstddef>
#include <filesystem>
#include <fstream>
#include <optional>
#include <string>

#include "absl/container/flat_hash_map.h"
#include "absl/container/flat_hash_set.h"
#include "absl/log/log.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/numbers.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include <nlohmann/json.hpp>
#include "json_utils.h"

namespace milotic_tlbmc {

using ::milotic::authz::GetValueAsArray;
using ::milotic::authz::GetValueAsUintFromStringOrInteger;

absl::StatusOr<BusBlocklist> GetBusBlocklist(absl::string_view blocklist_path) {
  milotic_tlbmc::BusBlocklist bus_block_list;
  auto blocklist_file = std::filesystem::directory_entry(blocklist_path);

  if (!std::filesystem::exists(blocklist_path) ||
      !blocklist_file.is_regular_file()) {
    LOG(INFO) << "No blocklist found! Continuing...";
    return bus_block_list;
  }

  LOG(INFO) << "Blocklist found!";
  std::string json_file_path = blocklist_file.path().string();
  std::ifstream blocklist_json(json_file_path);
  if (!blocklist_json.is_open()) {
    return absl::InvalidArgumentError(
        absl::StrCat("Failed to open blocklist file: ", json_file_path));
  }

  nlohmann::json parsed_config =
      nlohmann::json::parse(blocklist_json, nullptr, /*allow_exceptions=*/false,
                            /*ignore_comments=*/true);
  if (parsed_config.is_discarded()) {
    return absl::InvalidArgumentError(absl::StrCat(
        "Failed to parse blocklist file: ", json_file_path, " is illformed."));
  }

  const nlohmann::json::array_t* buses =
      GetValueAsArray(parsed_config, "buses");
  if (buses == nullptr) {
    LOG(INFO) << "No buses found in the blocklist file.";
    return bus_block_list;
  }

  for (const auto& bus : *buses) {
    if (bus.is_number_unsigned()) {
      // Single integer bus, we skip all addresses for this bus.
      bus_block_list[bus.get<size_t>()] = std::nullopt;
      continue;
    }
    if (!bus.is_object()) {
      LOG(INFO) << "Invalid bus entry in the blocklist: " << bus.dump();
      continue;
    }
    std::optional<size_t> bus_value =
        GetValueAsUintFromStringOrInteger(bus, "bus");
    const nlohmann::json::array_t* addresses =
        GetValueAsArray(bus, "addresses");
    if (!bus_value.has_value() || addresses == nullptr) {
      LOG(INFO) << "Invalid bus entry in the blocklist: " << bus.dump();
      continue;
    }
    auto& bus_block_list_ref = bus_block_list[*bus_value];
    for (const auto& address : *addresses) {
      int address_value;
      if (address.is_string() &&
          absl::SimpleHexAtoi(address.get<std::string>(), &address_value)) {
        if (!bus_block_list_ref.has_value()) {
          bus_block_list_ref = absl::flat_hash_set<size_t>();
        }
        bus_block_list_ref->insert(address_value);
      }
    }
  }
  return bus_block_list;
}

}  // namespace milotic_tlbmc