require 'oauth'
require 'json'

module Logworm
  class ForbiddenAccessException < Exception ; end
  class DatabaseException < Exception ; end
  class InvalidQueryException < Exception ; end
  
  class DB
    
    DB_HOST            = "http://db.logworm.com"
  
    def initialize(keys = nil)
      if keys.is_a? Array and keys.size == 4
        @consumer_key, @consumer_secret, @token, @token_secret = keys
      elsif keys.is_a? Array and keys.size == 2
        @consumer_key    = ENV["#{ENV['APP_ID']}_APPS_KEY"]
        @consumer_secret = ENV["#{ENV['APP_ID']}_APPS_SECRET"]
        @token, @token_secret = keys
      else
        config = Logworm::Config.instance
        if config.file_found?
          @consumer_key, @consumer_secret, @token, @token_secret = config.keys
        else
          raise "Could not find .logworm file in current directory." if keys.is_a? FalseClass
          @consumer_key, @consumer_secret = [ENV['LW_CONSUMER_KEY'], ENV['LW_CONSUMER_SECRET']]
          @token, @token_secret           = [ENV['LW_PROJECT_KEY'], ENV['LW_PROJECT_SECRET']]
        end
      end
      raise ForbiddenAccessException.new("Missing keys") if @consumer_key.nil? or @consumer_secret.nil? 
      raise ForbiddenAccessException.new("Missing keys") if @token.nil? or @token_secret.nil?
      @connection = OAuth::AccessToken.new(OAuth::Consumer.new(@consumer_key, @consumer_secret), @token, @token_secret)
    end
  
    def tables()
      res = db_call(:get, "#{DB_HOST}/")
    end
  
    def query(table, cond)
      res = db_call(:post, "#{DB_HOST}/queries", {:table => table, :query => cond})
    end
  
    def results(uri)
      res = db_call(:get, uri)
      raise InvalidQueryException.new("#{res['error']}") if res['error']
      res["results"] = JSON.parse(res["results"])
      res
    end
    
    def batch_log(entries)
      db_call(:post, "#{DB_HOST}/log", {:entries => $lr_queue.to_json})
    end

  private
    def db_call(method, uri, params = {})
      begin
        res = @connection.send(method, uri, params)
      rescue SocketError
        raise DatabaseException
      end
      raise DatabaseException if res.code.to_i == 404
      raise DatabaseException.new("Server returned: #{res.body}") if res.code.to_i == 500
      raise ForbiddenAccessException if res.code.to_i == 403
      raise InvalidQueryException.new("#{res.body}") if res.code.to_i == 400
      begin
        JSON.parse(res.body)
      rescue Exception => e
        raise DatabaseException.new("Database reponse cannot be parsed: #{e}")
      end
    end
  end

end