Reshape a list

# title: Reshape a list
# category: Vibescript Showcase
# difficulty: Showcase
# summary: Paginate, window, and sample a flat list with each_slice, each_cons, take, drop, and values_at.
# description: The 1.0 array library adds the Ruby slicing vocabulary, so turning a stream of records into pages or rolling windows no longer needs manual index bookkeeping.
# tags: collections, arrays, enumerable
# vibe: 0.4

def paginate(items, per_page)
  pages = []
  items.each_slice(per_page) do |page|
    pages.push(page)
  end
  pages
end

def rolling_totals(values, window)
  totals = []
  values.each_cons(window) do |group|
    totals.push(group.sum)
  end
  totals
end

def run
  ids = [101, 102, 103, 104, 105, 106, 107]
  readings = [3, 5, 4, 8, 6]

  {
    pages: paginate(ids, 3),
    first_three: ids.take(3),
    rest: ids.drop(3),
    endpoints: ids.values_at(0, -1),
    rolling_totals: rolling_totals(readings, 2)
  }
end