# Defines the Dropbox::API module.

require 'json'
require 'net/http/post/multipart'

module Dropbox

  # Extensions to the Dropbox::Session class that add core Dropbox API
  # functionality to this class. You must have authenticated your
  # Dropbox::Session instance before you can call any of these methods. (See the
  # Dropbox::Session class documentation for instructions.)
  #
  # API methods generally return +Struct+ objects containing their results,
  # unless otherwise noted. See the Dropbox API documentation at
  # http://developers.dropbox.com for specific information on the schema of each
  # result.
  #
  # You can opt-in to memoization of API method results. See the
  # Dropbox::Memoization class documentation to learn more.
  #
  # == Modes
  #
  # The Dropbox API works in three modes: sandbox, Dropbox (root), and
  # metadata-only.
  #
  # * In sandbox mode (the default), all operations are rooted from your
  #   application's sandbox folder; other files elsewhere on the user's Dropbox
  #   are inaccessible.
  # * In Dropbox mode, the root is the user's Dropbox folder, and all files are
  #   accessible. This mode is typically only available to certain API users.
  # * In metadata-only mode, the root is the Dropbox folder, but write access
  #   is not available. Operations that modify the user's files will
  #   fail.
  #
  # You should configure the Dropbox::Session instance to use whichever mode
  # you chose when you set up your application:
  #
  #  session.mode = :metadata_only
  #
  # Valid values are listed in Dropbox::API::MODES, and this step is not
  # necessary for sandboxed applications, as the sandbox mode is the default.
  #
  # You can also temporarily change the mode for many method calls using their
  # options hash:
  #
  #  session.move 'my_file', 'new/path', :mode => :dropbox

  module API
    include Dropbox::Memoization

    # Valid API modes for the #mode= method.
    MODES = [ :sandbox, :dropbox, :metadata_only ]

    # Returns a Dropbox::Entry instance that can be used to work with files or
    # directories in an object-oriented manner.

    def entry(path)
      Dropbox::Entry.new(self, path)
    end
    alias :file :entry
    alias :directory :entry
    alias :dir :entry

    # Returns a +Struct+ with information about the user's account. See
    # https://www.dropbox.com/developers/docs#account-info for more information
    # on the data returned.

    def account
      get('account', 'info', :ssl => @ssl).to_struct_recursively
    end
    memoize :account

    # Downloads the file at the given path relative to the configured mode's
    # root.
    #
    # Returns the contents of the downloaded file as a +String+. Support for
    # streaming downloads and range queries is available server-side, but not
    # available in this API client due to limitations of the OAuth gem.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.

    def download(path, options={})
      path = path.sub(/^\//, '')
      rest = Dropbox.check_path(path).split('/')
      rest << { :ssl => @ssl }
      api_body :get, 'files', root(options), *rest
      #TODO streaming, range queries
    end
    
    # Downloads a minimized thumbnail for a file. Pass the path to the file,
    # optionally the size of the thumbnail you want, and any additional options.
    # See https://www.dropbox.com/developers/docs#thumbnails for a list of valid
    # size specifiers.
    #
    # Returns the content of the thumbnail image as a +String+. The thumbnail
    # data is in JPEG format. Returns +nil+ if the file does not have a
    # thumbnail. You can check if a file has a thumbnail using the metadata
    # method.
    #
    # Because of the way this API method works, if you pass in the name of a
    # file that does not exist, you will not receive a 404, but instead just get
    # +nil+.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # Examples:
    #
    # Get the thumbnail for an image (default thunmbnail size):
    #
    #  session.thumbnail('my/image.jpg')
    #
    # Get the thumbnail for an image in the +medium+ size:
    #
    #  session.thumbnail('my/image.jpg', 'medium')
    
    def thumbnail(*args)
      options = args.extract_options!
      path = args.shift
      size = args.shift
      raise ArgumentError, "thumbnail takes a path, an optional size, and optional options" unless path.kind_of?(String) and (size.kind_of?(String) or size.nil?) and args.empty?
      
      path = path.sub(/^\//, '')
      rest = Dropbox.check_path(path).split('/')
      rest << { :ssl => @ssl }
      rest.last[:size] = size if size
      
      begin
        api_body :get, 'thumbnails', root(options), *rest
      rescue Dropbox::UnsuccessfulResponseError => e
        raise unless e.response.code.to_i == 404
        return nil
      end
    end

    # Uploads a file to a path relative to the configured mode's root. The
    # +remote_path+ parameter is taken to be the path portion _only_; the name
    # of the remote file will be identical to that of the local file. You can
    # provide any of the following for the first parameter:
    #
    # * a +File+ object, in which case the name of the local file is used, or
    # * a path to a file, in which case that file's name is used.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # Examples:
    #
    #  session.upload 'music.pdf', '/' # upload a file by path to the root directory
    #  session.upload 'music.pdf, 'music/' # upload a file by path to the music folder
    #  session.upload File.new('music.pdf'), '/' # same as the first example

    def upload(local_file, remote_path, options={})
      if local_file.kind_of?(File) or local_file.kind_of?(Tempfile) then
        file = local_file
        name = local_file.respond_to?(:original_filename) ? local_file.original_filename : File.basename(local_file.path)
        local_path = local_file.path
      elsif local_file.kind_of?(String) then
        file = File.new(local_file)
        name = File.basename(local_file)
        local_path = local_file
      else
        raise ArgumentError, "local_file must be a File or file path"
      end

      remote_path = remote_path.sub(/^\//, '')
      remote_path = Dropbox.check_path(remote_path).split('/')

      remote_path << { :ssl => @ssl }
      url = Dropbox.api_url('files', root(options), *remote_path)
      uri = URI.parse(url)

      oauth_request = Net::HTTP::Post.new(uri.path)
      oauth_request.set_form_data 'file' => name

      alternate_host_session = clone_with_host(@ssl ? Dropbox::ALTERNATE_SSL_HOSTS['files'] : Dropbox::ALTERNATE_HOSTS['files'])
      alternate_host_session.instance_variable_get(:@consumer).sign!(oauth_request, @access_token)
      oauth_signature = oauth_request.to_hash['authorization']

      request = Net::HTTP::Post::Multipart.new(uri.path,
                                               'file' => UploadIO.convert!(
                                                       file,
                                                       'application/octet-stream',
                                                       name,
                                                       local_path))
      request['authorization'] = oauth_signature.join(', ')
      
      response = Net::HTTP.start(uri.host, uri.port) { |http| http.request(request) }
      if response.kind_of?(Net::HTTPSuccess) then
        begin
          return JSON.parse(response.body).symbolize_keys_recursively.to_struct_recursively
        rescue JSON::ParserError
          raise ParseError.new(uri.to_s, response)
        end
      else
        raise UnsuccessfulResponseError.new(uri.to_s, response)
      end
    end

    # Copies the +source+ file to the path at +target+. If +target+ ends with a
    # slash, the new file will share the same name as the old file. Returns a
    # +Struct+ with metadata for the new file. (See the metadata method.)
    #
    # Both paths are assumed to be relative to the configured mode's root.
    #
    # Raises FileNotFoundError if +source+ does not exist. Raises
    # FileExistsError if +target+ already exists.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # TODO The API documentation says this method returns 404/403 if the source or target is invalid, but it actually returns 5xx.

    def copy(source, target, options={})
      source = source.sub(/^\//, '')
      target = target.sub(/^\//, '')
      target << File.basename(source) if target.ends_with?('/')
      begin
        parse_metadata(post('fileops', 'copy', :from_path => Dropbox.check_path(source), :to_path => Dropbox.check_path(target), :root => root(options), :ssl => @ssl)).to_struct_recursively
      rescue UnsuccessfulResponseError => error
        raise FileNotFoundError.new(source) if error.response.kind_of?(Net::HTTPNotFound)
        raise FileExistsError.new(target) if error.response.kind_of?(Net::HTTPForbidden)
        raise error
      end
    end
    alias :cp :copy

    # Creates a folder at the given path. The path is assumed to be relative to
    # the configured mode's root. Returns a +Struct+ with metadata about the new
    # folder. (See the metadata method.)
    #
    # Raises FileExistsError if there is already a file or folder at +path+.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # TODO The API documentation says this method returns 403 if the path already exists, but it actually appends " (1)" to the end of the name and returns 200.

    def create_folder(path, options={})
      path = path.sub(/^\//, '')
      path.sub! /\/$/, ''
      begin
        parse_metadata(post('fileops', 'create_folder', :path => Dropbox.check_path(path), :root => root(options), :ssl => @ssl)).to_struct_recursively
      rescue UnsuccessfulResponseError => error
        raise FileExistsError.new(path) if error.response.kind_of?(Net::HTTPForbidden)
        raise error
      end
    end
    alias :mkdir :create_folder

    # Deletes a file or folder at the given path. The path is assumed to be
    # relative to the configured mode's root.
    #
    # Raises FileNotFoundError if the file or folder does not exist at +path+.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # TODO The API documentation says this method returns 404 if the path does not exist, but it actually returns 5xx.
    
    def delete(path, options={})
      path = path.sub(/^\//, '')
      path.sub! /\/$/, ''
      begin
        api_response(:post, 'fileops', 'delete', :path => Dropbox.check_path(path), :root => root(options), :ssl => @ssl)
      rescue UnsuccessfulResponseError => error
        raise FileNotFoundError.new(path) if error.response.kind_of?(Net::HTTPNotFound)
        raise error
      end
      return true
    end
    alias :rm :delete

    # Moves the +source+ file to the path at +target+. If +target+ ends with a
    # slash, the file name will remain unchanged. If +source+ and +target+ share
    # the same path but have differing file names, the file will be renamed (see
    # also the rename method). Returns a +Struct+ with metadata for the new
    # file. (See the metadata method.)
    #
    # Both paths are assumed to be relative to the configured mode's root.
    #
    # Raises FileNotFoundError if +source+ does not exist. Raises
    # FileExistsError if +target+ already exists.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # TODO The API documentation says this method returns 404/403 if the source or target is invalid, but it actually returns 5xx.

    def move(source, target, options={})
      source = source.sub(/^\//, '')
      target = target.sub(/^\//, '')
      target << File.basename(source) if target.ends_with?('/')
      begin
        parse_metadata(post('fileops', 'move', :from_path => Dropbox.check_path(source), :to_path => Dropbox.check_path(target), :root => root(options), :ssl => @ssl)).to_struct_recursively
      rescue UnsuccessfulResponseError => error
        raise FileNotFoundError.new(source) if error.response.kind_of?(Net::HTTPNotFound)
        raise FileExistsError.new(target) if error.response.kind_of?(Net::HTTPForbidden)
        raise error
      end
    end
    alias :mv :move

    # Renames a file. Takes the same options and raises the same exceptions as
    # the move method.
    #
    # Calling
    #
    #  session.rename 'path/to/file', 'new_name'
    #
    # is equivalent to calling
    #
    #  session.move 'path/to/file', 'path/to/new_name'

    def rename(path, new_name, options={})
      raise ArgumentError, "Names cannot have slashes in them" if new_name.include?('/')
      path = path.sub(/\/$/, '')
      destination = path.split('/')
      destination[destination.size - 1] = new_name
      destination = destination.join('/')
      move path, destination, options
    end

    # Returns a cookie-protected URL that the authorized user can use to view
    # the file at the given path. This URL requires an authorized user.
    #
    # The path is assumed to be relative to the configured mode's root.
    #
    # Options:
    #
    # +mode+:: Temporarily changes the API mode. See the MODES array.

    def link(path, options={})
      path = path.sub(/^\//, '')
      begin
        rest = Dropbox.check_path(path).split('/')
        rest << { :ssl => @ssl }
        api_response(:get, 'links', root(options), *rest)
      rescue UnsuccessfulResponseError => error
        return error.response['Location'] if error.response.kind_of?(Net::HTTPFound)
        #TODO shouldn't be using rescue blocks for normal program flow
        raise error
      end
    end
    memoize :link

    # Returns a +Struct+ containing metadata on a given file or folder. The path
    # is assumed to be relative to the configured mode's root.
    #
    # If you pass a directory for +path+, the metadata will also contain a
    # listing of the directory contents (unless the +suppress_list+ option is
    # true).
    #
    # For information on the schema of the return struct, see the Dropbox API
    # at https://www.dropbox.com/developers/docs#metadata
    #
    # The +modified+ key will be converted into a +Time+ instance. The +is_dir+
    # key will also be available as <tt>directory?</tt>.
    #
    # Options:
    #
    # +suppress_list+:: Set this to true to remove the directory list from
    #                   the result (only applicable if +path+ is a directory).
    # +limit+:: Set this value to limit the number of entries returned when
    #           listing a directory. If the result has more than this number of
    #           entries, a TooManyEntriesError will be raised.
    # +mode+:: Temporarily changes the API mode. See the MODES array.
    #
    # TODO hash option seems to return HTTPBadRequest for now

    def metadata(path, options={})
      path = path.sub(/^\//, '')
      args = [
              'metadata',
              root(options)
              ]
      args += Dropbox.check_path(path).split('/')
      args << Hash.new
      args.last[:file_limit] = options[:limit] if options[:limit]
      #args.last[:hash] = options[:hash] if options[:hash]
      args.last[:list] = !(options[:suppress_list].to_bool)
      args.last[:ssl] = @ssl
      
      begin
        parse_metadata(get(*args)).to_struct_recursively
      rescue UnsuccessfulResponseError => error
        raise TooManyEntriesError.new(path) if error.response.kind_of?(Net::HTTPNotAcceptable)
        raise FileNotFoundError.new(path) if error.response.kind_of?(Net::HTTPNotFound)
        #return :not_modified if error.kind_of?(Net::HTTPNotModified)
        raise error
      end
    end
    memoize :metadata
    alias :info :metadata

    # Returns an array of <tt>Struct</tt>s with information on each file within
    # the given directory. Calling
    #
    #  session.list 'my/folder'
    #
    # is equivalent to calling
    #
    #  session.metadata('my/folder').contents
    #
    # Returns nil if the path is not a directory. Raises the same exceptions as
    # the metadata method. Takes the same options as the metadata method, except
    # the +suppress_list+ option is implied to be false.


    def list(path, options={})
      metadata(path, options.merge(:suppress_list => false)).contents
    end
    alias :ls :list
    
    def event_metadata(target_events, options={}) # :nodoc:
      get 'event_metadata', :ssl => @ssl, :root => root(options), :target_events => target_events
    end

    def event_content(entry, options={}) # :nodoc:
      request = Dropbox.api_url('event_content', :target_event => entry, :ssl => @ssl, :root => root(options))
      response = api_internal(:get, request)
      begin
        return response.body, JSON.parse(response.header['X-Dropbox-Metadata'])
      rescue JSON::ParserError
        raise ParseError.new(request, response)
      end
    end

    # Returns the configured API mode.

    def mode
      @api_mode ||= :sandbox
    end

    # Sets the API mode. See the MODES array.

    def mode=(newmode)
      raise ArgumentError, "Unknown API mode #{newmode.inspect}" unless MODES.include?(newmode)
      @api_mode = newmode
    end

    private

    def parse_metadata(hsh)
      hsh[:modified] = Time.parse(hsh[:modified]) if hsh[:modified]
      hsh[:directory?] = hsh[:is_dir]
      hsh.each { |_,v| parse_metadata(v) if v.kind_of?(Hash) }
      hsh.each { |_,v| v.each { |h| parse_metadata(h) if h.kind_of?(Hash) } if v.kind_of?(Array) }
      hsh
    end

    def root(options={})
      api_mode = options[:mode] || mode
      raise ArgumentError, "Unknown API mode #{api_mode.inspect}" unless MODES.include?(api_mode)
      return api_mode == :sandbox ? 'sandbox' : 'dropbox'
    end

    def get(*params)
      api_json :get, *params
    end

    def post(*params)
      api_json :post, *params
    end

    def api_internal(method, request)
      raise UnauthorizedError, "Must authorize before you can use API method" unless @access_token
      response = @access_token.send(method, request)
      raise UnsuccessfulResponseError.new(request, response) unless response.kind_of?(Net::HTTPSuccess)
      return response
    end

    def api_json(method, *params)
      request = Dropbox.api_url(*params)
      response = api_internal(method, request)
      begin
        return JSON.parse(response.body).symbolize_keys_recursively
      rescue JSON::ParserError
        raise ParseError.new(request, response)
      end
    end

    def api_body(method, *params)
      api_response(method, *params).body
    end

    def api_response(method, *params)
      api_internal(method, Dropbox.api_url(*params))
    end
  end

  # Superclass for exceptions raised when the server reports an error.

  class APIError < StandardError
    # The request URL.
    attr_reader :request
    # The Net::HTTPResponse returned by the server.
    attr_reader :response

    def initialize(request, response) # :nodoc:
      @request = request
      @response = response
    end

    def to_s # :nodoc:
      "API error: #{request}"
    end
  end

  # Raised when the Dropbox API returns a response that was not understood.

  class ParseError < APIError
    def to_s # :nodoc:
      "Invalid response received: #{request}"
    end
  end

  # Raised when something other than 200 OK is returned by an API method.

  class UnsuccessfulResponseError < APIError
    def to_s # :nodoc:
      "HTTP status #{@response.class.to_s} received: #{request}"
    end
  end

  # Superclass of errors relating to Dropbox files.

  class FileError < StandardError
    # The path of the offending file.
    attr_reader :path

    def initialize(path) # :nodoc:
      @path = path
    end

    def to_s # :nodoc:
      "#{self.class.to_s}: #{@path}"
    end
  end

  # Raised when a Dropbox file doesn't exist.

  class FileNotFoundError < FileError; end

  # Raised when a Dropbox file is in the way.

  class FileExistsError < FileError; end

  # Raised when the number of files within a directory exceeds a specified
  # limit.

  class TooManyEntriesError < FileError; end
  
  # Raised when the event_metadata method returns an error.
  
  class PingbackError < StandardError
    # The HTTP error code returned by the event_metadata method.
    attr_reader :code
    
    def initialize(code) # :nodoc
      @code = code
    end
    
    def to_s # :nodoc:
      "#{self.class.to_s} code #{@code}"
    end
  end
end