require "net/http"
require "enumerator"

module CouchObject
  class View

    # 
    # Takes:
    # * db as CouchObject::Database object or a string containing the database
    #   uri and database name (http://localhost:5984/mydb)
    # * name (string). The name of the view
    # * query (JSON string). The JSON document that should be 
    #   added to the database
    # 
    # Returns:
    # CouchObject::Reponse object instance
    # 
    # Raises:
    # * an exeption if it can't figure out the database
    #     
    def self.create(db, name, query)
      _db = self.get_db(db)
      # %2F => /
      _db.put("_design%2F#{name}", query)
    end

    # 
    # Takes:
    # * db as CouchObject::Database object or a string containing the database
    #   uri and database name (http://localhost:5984/mydb)
    # * name (string). The name of the view
    # 
    # Returns:
    # new CouchObject::View instance
    # 
    # Raises:
    # * an exeption if it can't figure out the database
    # 
    def initialize(db, name)
      @db = self.class.get_db(db)
      @name = name
    end
    attr_accessor :db
    
    def name
      "_view/#{@name.dup}"
    end
    
    #
    # Returns an array of the rows returned by the view
    # 
    # Takes:
    # * [+params+] (hash): a hash of URL query arguments supported
    #   by couchDB. If omitted it defaults to not use a key 
    #   and to update the view.
    # 
    #   Example:
    # 
    #     view.query({:update => false, :key => "bar"}) => Array
    # 
    # Returns:
    # * a array of rows from the view
    # 
    # Raises:
    # * CouchObject::Errors::MissingView if the view doesn't exist
    # 
    def query(params = {})

      response = raw_query(params)
      
      rows_to_return = []
      response["rows"].each do |params_for_object|
          rows_to_return << params_for_object["value"]
      end
      
      rows_to_return
      
    end

    #
    # Returns the response data from CouchDB for a view query without 
    # 
    # Takes:
    # * [+params+] (hash): a hash of URL query arguments supported
    #   by couchDB. If omitted it defaults to not use a key 
    #   and to update the view.
    # 
    #   Example:
    # 
    #     view.raw_query({:update => false, :key => "bar"}) => data
    # 
    # Returns:
    # * the response data for the view
    # 
    # Raises:
    # * CouchObject::Errors::MissingView if the view doesn't exist
    # 
    def raw_query(params = {})

      #Create a querystring with the parameters passed inn
      querystring = "?"
      params.each_pair do |key, value|
        querystring += \
          "#{key}=#{Utils.encode_querystring_parameter(value)}&"
      end
      querystring = querystring[0...-1]

      view_with_parameters = name + querystring

      response = JSON.parse(db.get(view_with_parameters).body)

      raise CouchObject::Errors::MissingView, \
        "The view '#{name}' doesn't exist on the server" \
        if response["error"] == "not_found"

      raise CouchObject::Errors::MapProcessError \
        if response["error"] == "map_process_error"
          
      raise CouchObject::Errors::CouchDBError, \
        "CouchDB returned and error and described the problem as #{response['reason']}" \
        if response["error"]
      
      return response
      
    end
    
    def delete
      @db.delete("/#{db.name}/#{name}")
    end
 
    protected
    def self.get_db(db)
     case db.class.to_s
     when "CouchObject::Database"
       db
     when "String"
       CouchObject::Database.open(db)
     else
       raise "You have to supply a database URI " + \
         "or a CouchObject::Database object"        
     end
   end
    
 end
end