module OpenTox

  #PENDING: implement ot error api, move to own file
  class Error
    
    attr_accessor :code, :body, :uri, :payload, :headers
    
    def initialize(code, body, uri, payload, headers)
      self.code = code
      self.body = body.to_s[0..1000]
      self.uri = uri
      self.payload = payload
      self.headers = headers
    end
    
    def self.parse(error_array_string)
      begin
        err = YAML.load(error_array_string)
        if err and err.is_a?(Array) and err.size>0 and err[0].is_a?(Error)
          return err
        else
          return nil
        end
      rescue
        return nil
      end
    end
    
  end
  
  class WrapperResult < String
    attr_accessor :content_type, :code
  end
  
  class RestClientWrapper
    
    # performs a GET REST call
    # raises OpenTox::Error if call fails (rescued in overwrite.rb -> halt 502)
    # per default: waits for Task to finish and returns result URI of Task
    # @param [String] uri destination URI
    # @param [optional,Hash] headers contains params like accept-header
    # @param [optional,OpenTox::Task] waiting_task (can be a OpenTox::Subtask as well), progress is updated accordingly
    # @param [wait,Boolean] wait set to false to NOT wait for task if result is task
    # @return [OpenTox::WrapperResult] a String containing the result-body of the REST call
    def self.get(uri, headers=nil, waiting_task=nil, wait=true )
      execute( "get", uri, headers, nil, waiting_task, wait)
    end
    
    # performs a POST REST call
    # raises OpenTox::Error if call fails (rescued in overwrite.rb -> halt 502)
    # per default: waits for Task to finish and returns result URI of Task
    # @param [String] uri destination URI
    # @param [optional,Hash] headers contains params like accept-header
    # @param [optional,String] payload data posted to the service
    # @param [optional,OpenTox::Task] waiting_task (can be a OpenTox::Subtask as well), progress is updated accordingly
    # @param [wait,Boolean] wait set to false to NOT wait for task if result is task
    # @return [OpenTox::WrapperResult] a String containing the result-body of the REST call
    def self.post(uri, headers, payload=nil, waiting_task=nil, wait=true )
      execute( "post", uri, headers, payload, waiting_task, wait )
    end
    
    # performs a PUT REST call
    # raises OpenTox::Error if call fails (rescued in overwrite.rb -> halt 502)
    # @param [String] uri destination URI
    # @param [optional,Hash] headers contains params like accept-header
    # @param [optional,String] payload data put to the service
    # @return [OpenTox::WrapperResult] a String containing the result-body of the REST call
    def self.put(uri, headers, payload=nil )
      execute( "put", uri, headers, payload )
    end

    # performs a DELETE REST call
    # raises OpenTox::Error if call fails (rescued in overwrite.rb -> halt 502)
    # @param [String] uri destination URI
    # @param [optional,Hash] headers contains params like accept-header
    # @return [OpenTox::WrapperResult] a String containing the result-body of the REST call
    def self.delete(uri, headers=nil )
      execute( "delete", uri, headers, nil)
    end

    # raises an Error message (rescued in overwrite.rb -> halt 502)
    # usage: if the return value of a call is invalid
    # @param [String] error_msg the error message 
    # @param [String] uri destination URI that is responsible for the error
    # @param [optional,Hash] headers sent to the URI
    # @param [optional,String] payload data sent to the URI  
    def self.raise_uri_error(error_msg, uri, headers=nil, payload=nil)
      raise_ot_error( "-", error_msg, uri, headers, payload )         
    end
    
    private
    def self.execute( rest_call, uri, headers, payload=nil, waiting_task=nil, wait=true )
      
      raise_ot_error 400,"uri is null",uri,headers,payload unless uri
      raise_ot_error 400,"not a uri",uri,headers,payload unless uri.to_s.uri?
      raise_ot_error 400,"headers are no hash",uri,headers,payload unless headers==nil or headers.is_a?(Hash)
      raise_ot_error 400,"nil headers for post not allowed, use {}",uri,headers,payload if rest_call=="post" and headers==nil
      headers.each{ |k,v| headers.delete(k) if v==nil } if headers #remove keys with empty values, as this can cause problems
      
      begin
        #LOGGER.debug "RestCall: "+rest_call.to_s+" "+uri.to_s+" "+headers.inspect
        resource = RestClient::Resource.new(uri,{:timeout => 60}) 
        if payload
          result = resource.send(rest_call, payload, headers)
        elsif headers
          result = resource.send(rest_call, headers)
        else
          result = resource.send(rest_call)
        end
        
        # result is a string, with the additional fields content_type and code
        res = WrapperResult.new(result.body)
        res.content_type = result.headers[:content_type]
        raise "content-type not set" unless res.content_type
        res.code = result.code
        
        # TODO: Ambit returns task representation with 200 instead of result URI
        return res if res.code==200 || !wait
        
        while (res.code==201 || res.code==202)
          res = wait_for_task(res, uri, waiting_task)
        end
        raise "illegal status code: '"+res.code.to_s+"'" unless res.code==200
        return res
        
      rescue RestClient::RequestTimeout => ex
        raise_ot_error 408,ex.message,uri,headers,payload
      rescue => ex
        #raise ex
        #raise "'"+ex.message+"' uri: "+uri.to_s
        begin
          code = ex.http_code
          msg = ex.http_body
        rescue
          code = 500
          msg = ex.to_s
        end
        raise_ot_error code,msg,uri,headers,payload
      end
    end
    
    def self.wait_for_task( res, base_uri, waiting_task=nil )
                          
      task = nil
      case res.content_type
      when /application\/rdf\+xml/
        task = OpenTox::Task.from_rdfxml(res)
      when /yaml/
        task = OpenTox::Task.from_yaml(res)
      when /text\//
        raise "uri list has more than one entry, should be a task" if res.content_type=~/text\/uri-list/ and res.split("\n").size > 1 #if uri list contains more then one uri, its not a task
        task = OpenTox::Task.find(res.to_s.chomp) if res.to_s.uri?
      else
        raise "unknown content-type for task: '"+res.content_type.to_s+"'" #+"' content: "+res[0..200].to_s
      end
      
      LOGGER.debug "result is a task '"+task.uri.to_s+"', wait for completion"
      task.wait_for_completion waiting_task
      raise task.description unless task.completed? # maybe task was cancelled / error
      
      res = WrapperResult.new task.result_uri
      res.code = task.http_code
      res.content_type = "text/uri-list"
      return res
    end
    
    def self.raise_ot_error( code, body, uri, headers, payload=nil )
      
      #build error
      causing_errors = Error.parse(body)
      if causing_errors
        error = causing_errors + [Error.new(code, "subsequent error", uri, payload, headers)]
      else
        error = [Error.new(code, body, uri, payload, headers)]
      end

      #debug utility: write error to file       
      error_dir = "/tmp/ot_errors"
      FileUtils.mkdir(error_dir) unless File.exist?(error_dir)
      raise "could not create error dir" unless File.exist?(error_dir) and File.directory?(error_dir)
      file_name = "error"
      time=Time.now.strftime("%m.%d.%Y-%H:%M:%S")
      count = 1
      count+=1 while File.exist?(File.join(error_dir,file_name+"_"+time+"_"+count.to_s))
      File.new(File.join(error_dir,file_name+"_"+time+"_"+count.to_s),"w").puts(body)
      
      # handle error
      # PENDING: always return yaml for now
      
      # raising OpenTox::Error
      # to handle the error yourself, put rest-call in begin, rescue block
      # if the error is not caught: 
      #   if we are in a task, the error is caught, logged, and task state is set to error in Task.as_task 
      #   if we are in a default call, the error is handled in overwrite.rb to return 502 (according to OT API)
      raise error.to_yaml
    end
  end
end