# VMC client
#
# Example:
#
#   require 'vmc'
#   client = VMC::Client.new('api.vcap.me')
#   client.login(:user, :pass)
#   client.create('myapplication', manifest)
#   client.create_service('redis', 'my_redis_service', opts);
#

require 'rubygems'
require 'json/pure'

require File.expand_path('../const', __FILE__)

class VMC::Client

  def self.version
    VMC::VERSION
  end

  attr_reader   :target, :host, :user, :proxy, :auth_token
  attr_accessor :trace

  # Error codes
  VMC_HTTP_ERROR_CODES = [ 400, 403, 404, 500 ]

  # Errors
  class BadTarget <  RuntimeError; end
  class AuthError <  RuntimeError; end
  class TargetError < RuntimeError; end
  class NotFound < RuntimeError; end
  class BadResponse < RuntimeError; end
  class HTTPException <  RuntimeError; end

  # Initialize new client to the target_uri with optional auth_token
  def initialize(target_url=VMC::DEFAULT_TARGET, auth_token=nil)
    target_url = "http://#{target_url}" unless /^https?/ =~ target_url
    target_url = target_url.gsub(/\/+$/, '')
    @target =  target_url
    @auth_token = auth_token
  end

  ######################################################
  # Target info
  ######################################################

  # Retrieves information on the target cloud, and optionally the logged in user
  def info
    # TODO: Should merge for new version IMO, general, services, user_account
    json_get(VMC::INFO_PATH)
  end

  def raw_info
    http_get(VMC::INFO_PATH)
  end

  # Global listing of services that are available on the target system
  def services_info
    check_login_status
    json_get(VMC::GLOBAL_SERVICES_PATH)
  end

  ######################################################
  # Apps
  ######################################################

  def apps
    check_login_status
    json_get(VMC::APPS_PATH)
  end

  def create_app(name, manifest={})
    check_login_status
    app = manifest.dup
    app[:name] = name
    app[:instances] ||= 1
    json_post(VMC::APPS_PATH, app)
  end

  def update_app(name, manifest)
    check_login_status
    json_put("#{VMC::APPS_PATH}/#{name}", manifest)
  end

  def upload_app(name, zipfile, resource_manifest=nil)
    #FIXME, manifest should be allowed to be null, here for compatability with old cc's
    resource_manifest ||= []
    check_login_status
    upload_data = {:_method => 'put'}
    if zipfile
      if zipfile.is_a? File
        file = zipfile
      else
        file = File.new(zipfile, 'rb')
      end
      upload_data[:application] = file
    end
    upload_data[:resources] = resource_manifest.to_json if resource_manifest
    http_post("#{VMC::APPS_PATH}/#{name}/application", upload_data)
  end

  def delete_app(name)
    check_login_status
    http_delete("#{VMC::APPS_PATH}/#{name}")
  end

  def app_info(name)
    check_login_status
    json_get("#{VMC::APPS_PATH}/#{name}")
  end

  def app_stats(name)
    check_login_status
    stats_raw = json_get("#{VMC::APPS_PATH}/#{name}/stats")
    stats = []
    stats_raw.each_pair do |k, entry|
      # Skip entries with no stats
      next unless entry[:stats]
      entry[:instance] = k.to_s.to_i
      entry[:state] = entry[:state].to_sym if entry[:state]
      stats << entry
    end
    stats.sort { |a,b| a[:instance] - b[:instance] }
  end

  def app_instances(name)
    check_login_status
    json_get("#{VMC::APPS_PATH}/#{name}/instances")
  end

  def app_crashes(name)
    check_login_status
    json_get("#{VMC::APPS_PATH}/#{name}/crashes")
  end

  # List the directory or download the actual file indicated by
  # the path.
  def app_files(name, path, instance=0)
    check_login_status
    url = "#{VMC::APPS_PATH}/#{name}/instances/#{instance}/files/#{path}"
    url.gsub!('//', '/')
    _, body, headers = http_get(url)
    body
  end

  ######################################################
  # Services
  ######################################################

  # listing of services that are available in the system
  def services
    check_login_status
    json_get(VMC::SERVICES_PATH)
  end

  def create_service(service, name)
    check_login_status
    services = services_info
    services ||= []
    service_hash = nil

    service = service.to_s

    # FIXME!
    services.each do |service_type, value|
      value.each do |vendor, version|
        version.each do |version_str, service_descr|
          if service == service_descr[:vendor]
            service_hash = {
              :type => service_descr[:type], :tier => 'free',
              :vendor => service, :version => version_str
            }
            break
          end
        end
      end
    end

    raise TargetError, "Service [#{service}] is not a valid service choice" unless service_hash
    service_hash[:name] = name
    json_post(VMC::SERVICES_PATH, service_hash)
  end

  def delete_service(name)
    check_login_status
    svcs = services || []
    names = svcs.collect { |s| s[:name] }
    raise TargetError, "Service [#{name}] not a valid service" unless names.include? name
    http_delete("#{VMC::SERVICES_PATH}/#{name}")
  end

  def bind_service(service, appname)
    check_login_status
    app = app_info(appname)
    services = app[:services] || []
    app[:services] = services << service
    update_app(appname, app)
  end

  def unbind_service(service, appname)
    check_login_status
    app = app_info(appname)
    services = app[:services] || []
    services.delete(service)
    app[:services] = services
    update_app(appname, app)
  end

  ######################################################
  # Resources
  ######################################################

  # Send in a resources manifest array to the system to have
  # it check what is needed to actually send. Returns array
  # indicating what is needed. This returned manifest should be
  # sent in with the upload if resources were removed.
  # E.g. [{:sha1 => xxx, :size => xxx, :fn => filename}]
  def check_resources(resources)
    check_login_status
    status, body, headers = json_post(VMC::RESOURCES_PATH, resources)
    json_parse(body)
  end

  ######################################################
  # Validation Helpers
  ######################################################

  # Checks that the target is valid
  def target_valid?
    return false unless descr = info
    return false unless descr[:name]
    return false unless descr[:build]
    return false unless descr[:version]
    return false unless descr[:support]
    true
  rescue
    false
  end

  # Checks that the auth_token is valid
  def logged_in?
    descr = info
    if descr
      return false unless descr[:user]
      return false unless descr[:usage]
      @user = descr[:user]
      true
    end
  end

  ######################################################
  # User login/password
  ######################################################

  # login and return an auth_token
  # Auth token can be retained and used in creating
  # new clients, avoiding login.
  def login(user, password)
    status, body, headers = json_post("#{VMC::USERS_PATH}/#{user}/tokens", {:password => password})
    response_info = json_parse(body)
    if response_info
      @user = user
      @auth_token = response_info[:token]
    end
  end

  # sets the password for the current logged user
  def change_password(new_password)
    check_login_status
    user_info = json_get("#{VMC::USERS_PATH}/#{@user}")
    if user_info
      user_info[:password] = new_password
      json_put("#{VMC::USERS_PATH}/#{@user}", user_info)
    end
  end

  ######################################################
  # System administration
  ######################################################

  def proxy=(proxy)
    @proxy = proxy
  end

  def proxy_for(proxy)
    @proxy = proxy
  end

  def add_user(user_email, password)
    json_post(VMC::USERS_PATH, { :email => user_email, :password => password })
  end

  def delete_user(user_email)
    http_delete("#{VMC::USERS_PATH}/#{user_email}")
  end

  ######################################################

  private

  def json_get(url)
    status, body, headers = http_get(url, 'application/json')
    json_parse(body)
  rescue JSON::ParserError
    raise BadResponse, "Can't parse response into JSON", body
  end

  def json_post(url, payload)
    http_post(url, payload.to_json, 'application/json')
  end

  def json_put(url, payload)
    http_put(url, payload.to_json, 'application/json')
  end

  def json_parse(str)
    if str
      JSON.parse(str, :symbolize_names => true)
    end
  end

  require 'rest_client'

  # HTTP helpers

  def http_get(path, content_type=nil)
    request(:get, path, content_type)
  end

  def http_post(path, body, content_type=nil)
    request(:post, path, content_type, body)
  end

  def http_put(path, body, content_type=nil)
    request(:put, path, content_type, body)
  end

  def http_delete(path)
    request(:delete, path)
  end

  def request(method, path, content_type = nil, payload = nil, headers = {})
    headers = headers.dup
    headers['AUTHORIZATION'] = @auth_token if @auth_token
    headers['PROXY-USER'] = @proxy if @proxy
    headers['Content-Type'] = content_type if content_type

    req = {
      :method => method, :url => "#{@target}#{path}",
      :payload => payload, :headers => headers
    }
    status, body, response_headers = perform_http_request(req)

    if VMC_HTTP_ERROR_CODES.include?(status)
      # FIXME, old cc returned 400 on not found for file access
      err = (status == 404 || status == 400) ? NotFound : TargetError
      raise err, parse_error_message(status, body)
    else
      return status, body, response_headers
    end
  rescue URI::Error, SocketError, Errno::ECONNREFUSED => e
    raise BadTarget, "Cannot access target (%s)" % [ e.message ]
  end

  def perform_http_request(req)
    RestClient.proxy = ENV['https_proxy'] || ENV['http_proxy']

    result = nil
    RestClient::Request.execute(req) do |response, request|
      result = [ response.code, response.body, response.headers ]
      if trace
        puts '>>>'
        puts "PROXY: #{RestClient.proxy}" if RestClient.proxy
        puts "REQUEST: #{req[:method]} #{req[:url]}"
        puts "REQUEST_BODY: #{req[:payload]}" if req[:payload]
        puts "RESPONSE: [#{response.code}] #{response.body}"
        puts '<<<'
      end
    end
    result
  rescue Net::HTTPBadResponse => e
    raise BadTarget "Received bad HTTP response from target: #{e}"
  rescue SystemCallError, RestClient::Exception => e
    raise HTTPException, "HTTP exception: #{e.class}:#{e}"
  end

  def truncate(str, limit = 30)
    etc = '...'
    stripped = str.strip[0..limit]
    if stripped.length > limit
      stripped + etc
    else
      stripped
    end
  end

  def parse_error_message(status, body)
    parsed_body = json_parse(body.to_s)
    if parsed_body && parsed_body[:code] && parsed_body[:description]
      desc = parsed_body[:description].gsub("\"","'")
      "Error #{parsed_body[:code]}: #{desc}"
    else
      "Error (HTTP #{status}): #{body}"
    end
  rescue JSON::ParserError
    if body.nil? || body.empty?
      "Error (#{status}): No Response Received"
    else
      "Error (JSON #{status}): #{truncate(body)}"
    end
  end

  def check_login_status
    raise AuthError unless @user || logged_in?
  end

end