###
# ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0
# ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
###

module.exports.lib = lib = {}

class ValidationError
  constructor: (@parameter, @message, @value) ->

  toString: ->
    if typeof(@value) == 'string'
      "#{@parameter}: '#{@value}'; #{@message}"
    else if typeof(@value) == 'object'
      "#{@parameter}: #{JSON.stringify(@value)}; #{@message}"
    else
      "#{@parameter}: #{@value}; #{@message}"


formatParameter = (p) ->
  if p == ''
    return ''
  if typeof(p) == 'number'
    return "[#{p}]"
  p = '' + p
  if p.match /[\.\s]/g
    return "[\"#{p}\"]"
  return ".#{p}"


class lib.JSONValidator
  # This class is  designed to discover and record problems with a JSON object
  constructor: (@jsonObject) ->
    @reset()

  reset: ->
    @prefix = ''
    @prefixStack = []
    @errors = []

  push: (prefix, subRoutine) ->
    @prefixStack.push prefix
    @prefix = ( formatParameter(p) for p in @prefixStack ).join ''
    newValue = @getValue('')[1]
    if newValue
      subRoutine()
    else
      @fail prefix, "missing required object"
    @prefixStack.pop()
    @prefix = ( formatParameter(p) for p in @prefixStack ).join ''

  fail: (parameter, message) ->
    loc = "#{@prefix}#{formatParameter parameter}"
    try
      value = eval("this.jsonObject#{loc}")
    catch
      value = undefined
    @errors.push new ValidationError loc, message, value

  failNoValue: (parameter, message) ->
    loc = "#{@prefix}#{formatParameter parameter}"
    @errors.push new ValidationError loc, message, null

  badKey: (parameter, key, message) ->
    loc = "this.jsonObject#{@prefix}#{formatParameter parameter}]"
    @errors.push new ValidationError loc, message, "'#{key}'"

  strictlyOnly: (parameters) ->
    @require parameters
    @allowOnly parameters

  require: (parameters) ->
    [loc, value] = @getValue('')
    unless value
      @errors.push new ValidationError loc, "expected an object with parameters [#{parameters.join ', '}]"
      return
    if typeof(parameters) == 'string'
      unless parameters of value
        @fail parameters, "missing required parameter"
    else
      for p in parameters
        unless p of value
          @fail p, "missing required parameter"

  whiteList: (parameters) ->
    # note, this function will be deprecated eventually, please use `allowOnly` instead
    console.warn("The JSON validator function `whiteList` has been renamed `allowOnly`, please adjust this code.")
    @allowOnly(parameters)

  allowOnly: (parameters) ->
    [loc, value] = @getValue('')
    for k, v of value
      unless k in parameters
        @errors.push new ValidationError "#{loc}.#{k}", 'unsupported parameter'

  integerBounds: (parameter, min, max) ->
    [loc, value] = @getValue(parameter)
    unless value? and typeof(value) == 'number' and Math.floor(value) == value
      @errors.push new ValidationError loc, "should be an integer between #{min} and #{max}, inclusive", value
      return
    unless min <= value <= max
      @errors.push new ValidationError loc, "should be between #{min} and #{max}, inclusive", value
      return

  oneOf: (parameter, choices) ->
    [loc, value] = @getValue(parameter)
    unless value?
      @errors.push new ValidationError loc, 'missing parameter'
      return
    unless value in choices
      @errors.push new ValidationError loc, "should only be one of #{JSON.stringify(choices)}", value

  boolean: (parameter) ->
    [loc, value] = @getValue(parameter)
    unless typeof(value) == 'boolean'
      @errors.push new ValidationError loc, "should be true or false", value

  getValue: (parameter) ->
    loc = "#{@prefix}#{formatParameter parameter}"
    if loc == ''
      return ['', @jsonObject]
    try
      value = eval("this.jsonObject" + loc)
    catch
      value = undefined
    [loc, value]

  length: ->
    @errors.length

  toString: ->
    @errors.join '\n'