'use strict'

var url = require('url')

, qs = require('qs')
, caseless = require('caseless')
, uuid = require('node-uuid')
, oauth = require('oauth-sign')
, crypto = require('crypto')

function OAuth (request) {

this.request = request
this.params = null

}

OAuth.prototype.buildParams = function (_oauth, uri, method, query, form, qsLib) {

var oa = {}
for (var i in _oauth) {
  oa['oauth_' + i] = _oauth[i]
}
if (!oa.oauth_version) {
  oa.oauth_version = '1.0'
}
if (!oa.oauth_timestamp) {
  oa.oauth_timestamp = Math.floor( Date.now() / 1000 ).toString()
}
if (!oa.oauth_nonce) {
  oa.oauth_nonce = uuid().replace(/-/g, '')
}
if (!oa.oauth_signature_method) {
  oa.oauth_signature_method = 'HMAC-SHA1'
}

var consumer_secret_or_private_key = oa.oauth_consumer_secret || oa.oauth_private_key
delete oa.oauth_consumer_secret
delete oa.oauth_private_key

var token_secret = oa.oauth_token_secret
delete oa.oauth_token_secret

var realm = oa.oauth_realm
delete oa.oauth_realm
delete oa.oauth_transport_method

var baseurl = uri.protocol + '//' + uri.host + uri.pathname
var params = qsLib.parse([].concat(query, form, qsLib.stringify(oa)).join('&'))

oa.oauth_signature = oauth.sign(
  oa.oauth_signature_method,
  method,
  baseurl,
  params,
  consumer_secret_or_private_key,
  token_secret)

if (realm) {
  oa.realm = realm
}

return oa

}

OAuth.prototype.buildBodyHash = function(_oauth, body) {

if (['HMAC-SHA1', 'RSA-SHA1'].indexOf(_oauth.signature_method || 'HMAC-SHA1') < 0) {
  this.request.emit('error', new Error('oauth: ' + _oauth.signature_method +
    ' signature_method not supported with body_hash signing.'))
}

var shasum = crypto.createHash('sha1')
shasum.update(body || '')
var sha1 = shasum.digest('hex')

return new Buffer(sha1).toString('base64')

}

OAuth.prototype.concatParams = function (oa, sep, wrap) {

wrap = wrap || ''

var params = Object.keys(oa).filter(function (i) {
  return i !== 'realm' && i !== 'oauth_signature'
}).sort()

if (oa.realm) {
  params.splice(0, 0, 'realm')
}
params.push('oauth_signature')

return params.map(function (i) {
  return i + '=' + wrap + oauth.rfc3986(oa[i]) + wrap
}).join(sep)

}

OAuth.prototype.onRequest = function (_oauth) {

var self = this
self.params = _oauth

var uri = self.request.uri || {}
  , method = self.request.method || ''
  , headers = caseless(self.request.headers)
  , body = self.request.body || ''
  , qsLib = self.request.qsLib || qs

var form
  , query
  , contentType = headers.get('content-type') || ''
  , formContentType = 'application/x-www-form-urlencoded'
  , transport = _oauth.transport_method || 'header'

if (contentType.slice(0, formContentType.length) === formContentType) {
  contentType = formContentType
  form = body
}
if (uri.query) {
  query = uri.query
}
if (transport === 'body' && (method !== 'POST' || contentType !== formContentType)) {
  self.request.emit('error', new Error('oauth: transport_method of body requires POST ' +
    'and content-type ' + formContentType))
}

if (!form && typeof _oauth.body_hash === 'boolean') {
  _oauth.body_hash = self.buildBodyHash(_oauth, self.request.body.toString())
}

var oa = self.buildParams(_oauth, uri, method, query, form, qsLib)

switch (transport) {
  case 'header':
    self.request.setHeader('Authorization', 'OAuth ' + self.concatParams(oa, ',', '"'))
    break

  case 'query':
    var href = self.request.uri.href += (query ? '&' : '?') + self.concatParams(oa, '&')
    self.request.uri = url.parse(href)
    self.request.path = self.request.uri.path
    break

  case 'body':
    self.request.body = (form ? form + '&' : '') + self.concatParams(oa, '&')
    break

  default:
    self.request.emit('error', new Error('oauth: transport_method invalid'))
}

}

exports.OAuth = OAuth