require 'spec_helper'
require 'support/heredoc_helper'

RSpec.describe SLOCCountScanner, type: :process do
  # For safety and speed: disable the system calls by default
  before do
    stub_const('SystemSLOCCount', double)
  end

  describe ".scan" do
    it "returns a SLOCCount object when sloccount is successful" do
      stub_dir_exists
      system_sloccount = fake_system_sloccount(
        result: "The thing worked. Your sloccount was lots",
        process_status: successful_process_status
      )
      expect(SLOCCountScanner.new(system_sloccount).scan("my_directory")).to be_a(SLOCCount)
    end

    it "returns a null SLOCCount object when sloccount gives a zero sloc result" do
      stub_dir_exists
      system_sloccount = fake_system_sloccount(
        result: ZERO_SLOCCOUNT_OUTPUT,
        process_status: failed_process_status
      )
      expect(SLOCCountScanner.new(system_sloccount).scan("my_directory")).to be_a(NullSLOCCount)
    end

    # EXCEPTION HANDLING:
    #####################

    it "raises an error when no directory is passed" do
      expect{ SLOCCountScanner.new(anything).scan(nil) }
        .to raise_error SLOCCountScanner::ArgumentError
    end

    it "raises an error when the directory doesn't exist" do
      system_sloccount = fake_system_sloccount(available: true)
      expect{ SLOCCountScanner.new(system_sloccount).scan("my_directory") }
        .to raise_error SLOCCountScanner::NoDirectory
    end

    it "raises an error when sloccount was not available" do
      stub_dir_exists
      system_sloccount = fake_system_sloccount(available: false)
      expect{ SLOCCountScanner.new(system_sloccount).scan("my_directory") }
        .to raise_error SLOCCountScanner::Unavailable
    end

    it 'raises an error when sloccount returns an unrecognised error' do
      stub_dir_exists
      system_sloccount = fake_system_sloccount(
        result: "Some nonsense",
        process_status: failed_process_status
      )
      expect{ SLOCCountScanner.new(system_sloccount).scan("my_directory") }
        .to raise_error SLOCCountScanner::Exception
    end

    it 'raises an error when sloccount returns a `no input` error' do
      stub_dir_exists
      # In reality this should never happen because we check for this case
      system_sloccount = fake_system_sloccount(
        result: NO_INPUT_SLOCCOUNT_OUTPUT,
        process_status: failed_process_status
      )
      expect{ SLOCCountScanner.new(system_sloccount).scan("my_directory") }
        .to raise_error SLOCCountScanner::NoInput
    end

    def fake_system_sloccount(result: nil, process_status: successful_process_status, available: true)
      instance_double('SystemSLOCCount').tap do |fake|
        allow(fake).to receive(:call).and_return [result, process_status]
        allow(fake).to receive(:available?).and_return(available)
      end
    end

    def stub_dir_exists
      allow(Dir).to receive(:exist?).and_return(true)
    end

    ZERO_SLOCCOUNT_OUTPUT = <<-EOS.heredoc_unindent
      filelist for tmp
      Categorizing files.
      Computing results.


      SLOC Directory SLOC-by-Language (Sorted)
      0       tmp             (none)
      SLOC total is zero, no further analysis performed.
    EOS

    NO_INPUT_SLOCCOUNT_OUTPUT = "Error: You must provide a directory or directories of source code.\n".freeze
  end
end