require "#{File.dirname(__FILE__)}/spec_setup"
require 'rack/cache/core'

class MockCore
  include Rack::Cache::Core
  alias_method :initialize, :initialize_core
  public :transition, :trigger, :events
end

describe 'Rack::Cache::Core' do
  before :each do
    @core = MockCore.new
  end

  it 'has events after instantiation' do
    @core.events.should.respond_to :[]
  end
  it 'defines and triggers event handlers' do
    executed = false
    @core.on(:foo) { executed = true }
    @core.trigger :foo
    executed.should.be true
  end
  it 'executes multiple handlers in LIFO order' do
    x = 'nothing executed'
    @core.on :foo do
      x.should.equal 'bottom executed'
      x = 'top executed'
    end
    @core.on :foo do
      x.should.equal 'nothing executed'
      x = 'bottom executed'
    end
    @core.trigger :foo
    x.should.equal 'top executed'
  end
  it 'records event execution history' do
    @core.on(:foo) {}
    @core.trigger :foo
    @core.should.a.performed :foo
  end
  it 'raises an exception when asked to perform an unknown event' do
    assert_raises NameError do
      @core.trigger :foo
    end
  end
  it 'raises an exception when asked to transition to an unknown event' do
    @core.on(:bling) {}
    @core.on(:foo) { throw(:transition, [:bling]) }
    lambda { @core.transition(from=:foo, to=[:bar, :baz]) }.
      should.raise Rack::Cache::IllegalTransition
  end
  it 'passes transition arguments to handlers' do
    passed = nil
    @core.meta_def(:perform_bar) do |*args|
      passed = args
      'hi'
    end
    @core.on(:bar) {}
    @core.on(:foo) { throw(:transition, [:bar, 1, 2, 3]) }
    result = @core.transition(from=:foo, to=[:bar])
    passed.should.equal [1,2,3]
    result.should.equal 'hi'
  end
  it 'fully transitions out of handlers when the next event is invoked' do
    x = []
    @core.on(:foo) {
      x << 'in foo, before transitioning to bar'
      throw(:transition, [:bar])
      x << 'in foo, after transitioning to bar'
    }
    @core.on(:bar) { x << 'in bar' }
    @core.trigger(:foo).should.equal [:bar]
    @core.trigger(:bar).should.be.nil
    x.should.equal [
      'in foo, before transitioning to bar',
      'in bar'
    ]
  end
  it 'returns the transition event name' do
    @core.on(:foo) { throw(:transition, [:bar]) }
    @core.trigger(:foo).should.equal [:bar]
  end
end