require 'cgi'
require 'uri'
require 'httparty'
require 'hashie'
require 'json'

module CreateSend

  # Represents a CreateSend API error. Contains specific data about the error.
  class CreateSendError < StandardError
    attr_reader :data
    def initialize(data)
      @data = data
      # @data should contain Code, Message and optionally ResultData
      extra = @data.ResultData ? "\nExtra result data: #{@data.ResultData}" : ""
      super "The CreateSend API responded with the following error"\
        " - #{@data.Code}: #{@data.Message}#{extra}"
    end
  end

  # Raised for HTTP response codes of 400...500
  class ClientError < StandardError; end
  # Raised for HTTP response codes of 500...600
  class ServerError < StandardError; end
  # Raised for HTTP response code of 400
  class BadRequest < CreateSendError; end
  # Raised for HTTP response code of 401
  class Unauthorized < CreateSendError; end
  # Raised for HTTP response code of 404
  class NotFound < ClientError; end

  # Raised for HTTP response code of 401, specifically when an OAuth token
  # in invalid (Code: 120, Message: 'Invalid OAuth Token')
  class InvalidOAuthToken < Unauthorized; end
  # Raised for HTTP response code of 401, specifically when an OAuth token
  # has expired (Code: 121, Message: 'Expired OAuth Token')
  class ExpiredOAuthToken < Unauthorized; end
  # Raised for HTTP response code of 401, specifically when an OAuth token
  # has been revoked (Code: 122, Message: 'Revoked OAuth Token')
  class RevokedOAuthToken < Unauthorized; end

  # Provides high level CreateSend functionality/data you'll probably need.
  class CreateSend
    include HTTParty
    attr_reader :auth_details

    # Get the authorization URL for your application, given the application's
    # client_id, redirect_uri, scope, and optional state data.
    def self.authorize_url(client_id, redirect_uri, scope, state=nil)
      qs = "client_id=#{CGI.escape(client_id.to_s)}"
      qs << "&redirect_uri=#{CGI.escape(redirect_uri.to_s)}"
      qs << "&scope=#{CGI.escape(scope.to_s)}"
      qs << "&state=#{CGI.escape(state.to_s)}" if state
      "#{@@oauth_base_uri}?#{qs}"
    end

    # Exchange a provided OAuth code for an OAuth access token, 'expires in'
    # value, and refresh token.
    def self.exchange_token(client_id, client_secret, redirect_uri, code)
      body = "grant_type=authorization_code"
      body << "&client_id=#{CGI.escape(client_id.to_s)}"
      body << "&client_secret=#{CGI.escape(client_secret.to_s)}"
      body << "&redirect_uri=#{CGI.escape(redirect_uri.to_s)}"
      body << "&code=#{CGI.escape(code.to_s)}"
      options = {:body => body}
      response = HTTParty.post(@@oauth_token_uri, options)
      if response.has_key? 'error' and response.has_key? 'error_description'
        err = "Error exchanging code for access token: "
        err << "#{response['error']} - #{response['error_description']}"
        raise err
      end
      r = Hashie::Mash.new(response)
      [r.access_token, r.expires_in, r.refresh_token]
    end

    # Refresh an OAuth access token, given an OAuth refresh token.
    # Returns a new access token, 'expires in' value, and refresh token.
    def self.refresh_access_token(refresh_token)
      options = {
        :body => "grant_type=refresh_token&refresh_token=#{CGI.escape(refresh_token)}" }
      response = HTTParty.post(@@oauth_token_uri, options)
      if response.has_key? 'error' and response.has_key? 'error_description'
        err = "Error refreshing access token: "
        err << "#{response['error']} - #{response['error_description']}"
        raise err
      end
      r = Hashie::Mash.new(response)
      [r.access_token, r.expires_in, r.refresh_token]
    end

    def initialize(*args)
      if args.size > 0
        auth args.first # Expect auth details as first argument
      end
    end

    @@base_uri = "https://api.createsend.com/api/v3"
    @@oauth_base_uri = "https://api.createsend.com/oauth"
    @@oauth_token_uri = "#{@@oauth_base_uri}/token"
    headers({
      'User-Agent' => "createsend-ruby-#{VERSION}",
      'Content-Type' => 'application/json; charset=utf-8',
      'Accept-Encoding' => 'gzip, deflate' })
    base_uri @@base_uri

    # Authenticate using either OAuth or an API key.
    def auth(auth_details)
      @auth_details = auth_details
    end

    # Refresh the current OAuth token using the current refresh token.
    def refresh_token
      if not @auth_details or
        not @auth_details.has_key? :refresh_token or
        not @auth_details[:refresh_token]
        raise '@auth_details[:refresh_token] does not contain a refresh token.'
      end

      access_token, expires_in, refresh_token =
        self.class.refresh_access_token @auth_details[:refresh_token]
      auth({
        :access_token => access_token,
        :refresh_token => refresh_token})
      [access_token, expires_in, refresh_token]
    end

    # Gets your CreateSend API key, given your site url, username and password.
    def apikey(site_url, username, password)
      site_url = CGI.escape(site_url)
      options = {:basic_auth => {:username => username, :password => password}}
      response = get("/apikey.json?SiteUrl=#{site_url}", options)
      result = Hashie::Mash.new(response)
      auth({:api_key => result.ApiKey}) if not @auth_details
      result
    end

    # Gets your clients.
    def clients
      response = get('/clients.json')
      response.map{|item| Hashie::Mash.new(item)}
    end

    # Get your billing details.
    def billing_details
      response = get('/billingdetails.json')
      Hashie::Mash.new(response)
    end

    # Gets valid countries.
    def countries
      response = get('/countries.json')
      response.parsed_response
    end

    # Gets the current date in your account's timezone.
    def systemdate
      response = get('/systemdate.json')
      Hashie::Mash.new(response)
    end

    # Gets valid timezones.
    def timezones
      response = get('/timezones.json')
      response.parsed_response
    end

    # Gets the administrators for the account.
    def administrators
      response = get('/admins.json')
      response.map{|item| Hashie::Mash.new(item)}
    end

    # Gets the primary contact for the account.
    def get_primary_contact
      response = get('/primarycontact.json')
      Hashie::Mash.new(response)
    end

    # Set the primary contect for the account.
    def set_primary_contact(email)
      options = { :query => { :email => email } }
      response = put("/primarycontact.json", options)
      Hashie::Mash.new(response)
    end

    def get(*args)
      args = add_auth_details_to_options(args)
      handle_response CreateSend.get(*args)
    end
    alias_method :cs_get, :get

    def post(*args)
      args = add_auth_details_to_options(args)
      handle_response CreateSend.post(*args)
    end
    alias_method :cs_post, :post

    def put(*args)
      args = add_auth_details_to_options(args)
      handle_response CreateSend.put(*args)
    end
    alias_method :cs_put, :put

    def delete(*args)
      args = add_auth_details_to_options(args)
      handle_response CreateSend.delete(*args)
    end
    alias_method :cs_delete, :delete

    def add_auth_details_to_options(args)
      if @auth_details
        options = {}
        if args.size > 1
          options = args[1]
        end
        if @auth_details.has_key? :access_token
          options[:headers] = {
            "Authorization" => "Bearer #{@auth_details[:access_token]}" }
        elsif @auth_details.has_key? :api_key
          if not options.has_key? :basic_auth
            options[:basic_auth] = {
              :username => @auth_details[:api_key], :password => 'x' }
          end
        end
        args[1] = options
      end
      args
    end

    def handle_response(response) # :nodoc:
      case response.code
      when 400
        raise BadRequest.new(Hashie::Mash.new response)
      when 401
        data = Hashie::Mash.new(response)
        case data.Code
        when 120
          raise InvalidOAuthToken.new data
        when 121
          raise ExpiredOAuthToken.new data
        when 122
          raise RevokedOAuthToken.new data
        else
          raise Unauthorized.new data
        end
      when 404
        raise NotFound.new
      when 400...500
        raise ClientError.new
      when 500...600
        raise ServerError.new
      else
        response
      end
    end
  end
end