require "rails_helper"

describe UprnClient do
  let(:client) { described_class.new("123") }

  let(:valid_response) do
    { results: [{ DPA: { postcode: "12345" } }] }.to_json
  end

  def stub_api_request(body:, status: 200)
    stub_request(:get, "https://api.os.uk/search/places/v1/uprn?dataset=DPA,LPI&key=OS_DATA_KEY&uprn=123")
    .to_return(status:, body:, headers: {})
  end

  describe "call" do
    context "when json parse error" do
      before do
        stub_api_request(body: "{", status: 200)

        client.call
      end

      it "returns error" do
        expect(client.error).to eq("UPRN is not recognised. Check the number, or enter the address.")
      end
    end

    context "when http error" do
      before do
        stub_api_request(body: valid_response, status: 500)

        client.call
      end

      it "returns error" do
        expect(client.error).to eq("UPRN is not recognised. Check the number, or enter the address.")
      end
    end

    context "when DPA results empty" do
      context "and LPI result is present" do
        let(:valid_lpi_response) do
          { results: [{ LPI: { postcode_locator: "LPI postcode", LPI_KEY: "123" } }] }.to_json
        end

        before do
          stub_api_request(body: valid_lpi_response, status: 200)

          client.call
        end

        it "returns result" do
          expect(client.result).to eq({ "postcode_locator" => "LPI postcode", "LPI_KEY" => "123" })
        end

        it "returns no error" do
          expect(client.error).to be_nil
        end
      end

      context "and LPI results empty" do
        before do
          stub_api_request(body: {}.to_json)

          client.call
        end

        it "returns error" do
          expect(client.error).to eq("UPRN is not recognised. Check the number, or enter the address.")
        end
      end
    end

    context "with results" do
      before do
        stub_api_request(body: valid_response)

        client.call
      end

      it "returns result" do
        expect(client.result).to eq({ "postcode" => "12345" })
      end

      it "returns no error" do
        expect(client.error).to be_nil
      end
    end

    describe "result" do
      context "when response is successful" do
        before do
          stub_api_request(body: valid_response)

          client.call
        end

        it "returns parsed result" do
          expect(client.result).to eq({ "postcode" => "12345" })
          expect(client.send(:response).code.to_i).to eq(200)
        end
      end

      context "when response is not successful" do
        before do
          stub_api_request(body: valid_response, status: 500)

          client.call
        end

        it "returns nil" do
          expect(client.result).to be_nil
          expect(client.error).to eq("UPRN client failed to return a valid result, try again later.")
        end
      end
    end
  end
end