defmodule Towerops.Geocoding do
  @moduledoc """
  Service for geocoding addresses using Google Maps Geocoding API.

  Supports both system-wide API keys and organization-specific encrypted API keys.
  """

  alias Towerops.HTTP

  require Logger

  @google_geocoding_url "https://maps.googleapis.com/maps/api/geocode/json"

  @doc """
  Geocode an address to latitude/longitude coordinates.

  ## Parameters

  - `address`: The address string to geocode

  ## Returns

  - `{:ok, %{latitude: float, longitude: float, formatted_address: string}}` on success
  - `{:error, reason}` on failure
  """
  def geocode(address) when is_binary(address) do
    with {:ok, api_key} <- get_api_key(),
         {:ok, response} <- make_geocoding_request(address, api_key) do
      parse_geocoding_response(response)
    end
  end

  defp get_api_key do
    api_key = get_system_api_key()

    if api_key && String.trim(api_key) != "" do
      {:ok, String.trim(api_key)}
    else
      {:error, :no_api_key}
    end
  end

  defp get_system_api_key do
    Application.get_env(:towerops, :google_maps_api_key) ||
      System.get_env("GOOGLE_MAPS_API_KEY")
  end

  defp make_geocoding_request(address, api_key) do
    params = %{
      "address" => address,
      "key" => api_key
    }

    case HTTP.get(__MODULE__, @google_geocoding_url, params: params, timeout: 10_000) do
      {:ok, %Req.Response{status: 200, body: body}} ->
        {:ok, body}

      {:ok, %Req.Response{status: status_code, body: body}} ->
        Logger.warning("Geocoding API returned status #{status_code}: #{inspect(body)}")
        {:error, "Geocoding API error (status #{status_code})"}

      {:error, reason} ->
        Logger.error("Failed to make geocoding request: #{inspect(reason)}")
        {:error, "Network error: #{inspect(reason)}"}
    end
  end

  defp parse_geocoding_response(%{"status" => "OK", "results" => [result | _]}) do
    with %{"geometry" => %{"location" => %{"lat" => lat, "lng" => lng}}} <- result,
         %{"formatted_address" => formatted_address} <- result do
      {:ok,
       %{
         latitude: lat,
         longitude: lng,
         formatted_address: formatted_address
       }}
    else
      _ -> {:error, "Invalid response format from Google Maps API"}
    end
  end

  defp parse_geocoding_response(%{"status" => "ZERO_RESULTS"}) do
    {:error, "No results found for the given address"}
  end

  defp parse_geocoding_response(%{"status" => "OVER_QUERY_LIMIT"}) do
    {:error, "API quota exceeded. Please check your Google Maps API usage."}
  end

  defp parse_geocoding_response(%{"status" => "REQUEST_DENIED", "error_message" => message}) do
    {:error, "API request denied: #{message}"}
  end

  defp parse_geocoding_response(%{"status" => "INVALID_REQUEST"}) do
    {:error, "Invalid request. Please check the address format."}
  end

  defp parse_geocoding_response(%{"status" => status}) do
    {:error, "Geocoding failed with status: #{status}"}
  end

  defp parse_geocoding_response(_response) do
    {:error, "Unexpected response format from Google Maps API"}
  end
end