-- cc.expect

local _expect = {}

local function checkType(index, valueType, value, ...)
  local expected = table.pack(...)
  local isType = false

  for i=1, expected.n, 1 do
    if type(value) == expected[i] then
      isType = true
      break
    end
  end

  if not isType then
    error(string.format("bad %s %s (%s expected, got %s)", valueType,
      index, table.concat(expected, " or "), type(value)), 3)
  end

  return value
end

function _expect.expect(index, value, ...)
  return checkType(("#%d"):format(index), "argument", value, ...)
end

function _expect.field(tbl, index, ...)
  _expect.expect(1, tbl, "table")
  _expect.expect(2, index, "string")
  return checkType(("%q"):format(index), "field", tbl[index], ...)
end

function _expect.range(num, min, max)
  _expect.expect(1, num, "number")
  _expect.expect(2, min, "number", "nil")
  _expect.expect(3, max, "number", "nil")
  min = min or -math.huge
  max = max or math.huge
  if num < min or num > max then
    error(("number outside of range (expected %d to be within %d and %d")
      :format(num, min, max), 2)
  end
end

setmetatable(_expect, {__call = function(_, ...)
  return _expect.expect(...)
end})

return _expect