require 'fileutils'

describe Rscons do
  before(:all) do
    FileUtils.rm_rf('build_tests_run')
    @owd = Dir.pwd
  end

  after(:each) do
    Dir.chdir(@owd)
    FileUtils.rm_rf('build_tests_run')
  end

  def build_testdir
    if File.exists?("build.rb")
      system("ruby -I #{@owd}/lib -r rscons build.rb > build.out")
    end
    get_build_output
  end

  def test_dir(build_test_directory)
    FileUtils.cp_r("build_tests/#{build_test_directory}", 'build_tests_run')
    Dir.chdir("build_tests_run")
    build_testdir
  end

  def file_sub(fname)
    contents = File.read(fname)
    replaced = ''
    contents.each_line do |line|
      replaced += yield(line)
    end
    File.open(fname, 'w') do |fh|
      fh.write(replaced)
    end
  end

  def get_build_output
    File.read('build.out').lines.map(&:strip)
  end

  ###########################################################################
  # Tests
  ###########################################################################

  it 'builds a C program with one source file' do
    test_dir('simple')
    File.exists?('simple.o').should be_true
    `./simple`.should == "This is a simple C program\n"
  end

  it 'prints commands as they are executed' do
    lines = test_dir('simple')
    lines.should == [
      'gcc -c -o simple.o -MMD -MF simple.mf simple.c',
      'gcc -o simple simple.o',
    ]
  end

  it 'prints short representations of the commands being executed' do
    lines = test_dir('header')
    lines.should == [
      'CC header.o',
      'LD header',
    ]
  end

  it 'builds a C program with one source file and one header file' do
    test_dir('header')
    File.exists?('header.o').should be_true
    `./header`.should == "The value is 2\n"
  end

  it 'rebuilds a C module when a header it depends on changes' do
    test_dir('header')
    `./header`.should == "The value is 2\n"
    file_sub('header.h') {|line| line.sub(/2/, '5')}
    build_testdir
    `./header`.should == "The value is 5\n"
  end

  it 'does not rebuild a C module when its dependencies have not changed' do
    lines = test_dir('header')
    `./header`.should == "The value is 2\n"
    lines.should == [
      'CC header.o',
      'LD header',
    ]
    lines = build_testdir
    lines.should == []
  end

  it "does not rebuild a C module when only the file's timestampe has changed" do
    lines = test_dir('header')
    `./header`.should == "The value is 2\n"
    lines.should == [
      'CC header.o',
      'LD header',
    ]
    file_sub('header.c') {|line| line}
    lines = build_testdir
    lines.should == []
  end

  it 're-links a program when the link flags have changed' do
    lines = test_dir('simple')
    lines.should == [
      'gcc -c -o simple.o -MMD -MF simple.mf simple.c',
      'gcc -o simple simple.o',
    ]
    file_sub('build.rb') {|line| line.sub(/.*CHANGE.FLAGS.*/, '  env["LIBS"] += ["c"]')}
    lines = build_testdir
    lines.should == ['gcc -o simple simple.o -lc']
  end

  it 'builds object files in a different build directory' do
    lines = test_dir('build_dir')
    `./build_dir`.should == "Hello from two()\n"
    File.exists?('build/one/one.o').should be_true
    File.exists?('build/two/two.o').should be_true
  end

  it 'allows Ruby classes as custom builders to be used to construct files' do
    lines = test_dir('custom_builder')
    lines.should == ['CC program.o', 'LD program']
    File.exists?('inc.h').should be_true
    `./program`.should == "The value is 5678\n"
  end

  it 'allows cloning Environment objects' do
    lines = test_dir('clone_env')
    lines.should == [
      %q{gcc -c -o debug/program.o -MMD -MF debug/program.mf '-DSTRING="Debug Version"' -O2 src/program.c},
      %q{gcc -o program-debug debug/program.o},
      %q{gcc -c -o release/program.o -MMD -MF release/program.mf '-DSTRING="Release Version"' -O2 src/program.c},
      %q{gcc -o program-release release/program.o},
    ]
  end

  it 'builds a C++ program with one source file' do
    test_dir('simple_cc')
    File.exists?('simple.o').should be_true
    `./simple`.should == "This is a simple C++ program\n"
  end

end