'use strict'

// hoisted due to circular dependency on command. module.exports = argsert const command = require('./command')() const YError = require('./yerror')

const positionName = ['first', 'second', 'third', 'fourth', 'fifth', 'sixth'] function argsert (expected, callerArguments, length) {

// TODO: should this eventually raise an exception.
try {
  // preface the argument description with "cmd", so
  // that we can run it through yargs' command parser.
  let position = 0
  let parsed = { demanded: [], optional: [] }
  if (typeof expected === 'object') {
    length = callerArguments
    callerArguments = expected
  } else {
    parsed = command.parseCommand(`cmd ${expected}`)
  }
  const args = [].slice.call(callerArguments)

  while (args.length && args[args.length - 1] === undefined) args.pop()
  length = length || args.length

  if (length < parsed.demanded.length) {
    throw new YError(`Not enough arguments provided. Expected ${parsed.demanded.length} but received ${args.length}.`)
  }

  const totalCommands = parsed.demanded.length + parsed.optional.length
  if (length > totalCommands) {
    throw new YError(`Too many arguments provided. Expected max ${totalCommands} but received ${length}.`)
  }

  parsed.demanded.forEach((demanded) => {
    const arg = args.shift()
    const observedType = guessType(arg)
    const matchingTypes = demanded.cmd.filter(type => type === observedType || type === '*')
    if (matchingTypes.length === 0) argumentTypeError(observedType, demanded.cmd, position, false)
    position += 1
  })

  parsed.optional.forEach((optional) => {
    if (args.length === 0) return
    const arg = args.shift()
    const observedType = guessType(arg)
    const matchingTypes = optional.cmd.filter(type => type === observedType || type === '*')
    if (matchingTypes.length === 0) argumentTypeError(observedType, optional.cmd, position, true)
    position += 1
  })
} catch (err) {
  console.warn(err.stack)
}

}

function guessType (arg) {

if (Array.isArray(arg)) {
  return 'array'
} else if (arg === null) {
  return 'null'
}
return typeof arg

}

function argumentTypeError (observedType, allowedTypes, position, optional) {

throw new YError(`Invalid ${positionName[position] || 'manyith'} argument. Expected ${allowedTypes.join(' or ')} but received ${observedType}.`)

}