// Available variables:
  // - Machine
  // - interpret
  // - assign
  // - send
  // - sendParent
  // - spawn
  // - raise
  // - actions
  // - XState (all XState exports)

const singlePage = 5;

const selectedMachine = Machine({
  id: "selected",
  initial: "empty",
  context: {
    cache: false
  },
  states: {
    empty: {
      on: {
        SELECTION_ADDED: "some"
      }
    },
    some: {
      on: {
        SELECTION_ADDED: [{
          target: "fetching",
          cond: "pageExistsInCache"
        },
        {
          target: "some"
        }],
        PAGE_REQUESTED: [{
          target: "fetching",
          cond: "pageExistsInCache"
        },
        {
          target: "some"
        }]
      }
    },
    fetching: {
      invoke: {
        src: () => new Promise(res => setTimeout(res, 500)),
        onDone: {
          target: "some",
          actions: "addToCache"
        }
      }
    }
  }
}, {
  actions: {
    addToCache: assign({
      cache: true
    })
  },
  guards: {
    pageExistsInCache: (ctx) => ctx.cache
  }
});