space_game_server/lib/game/command_parser.rb

# Parser for client commands.
# Translates incoming JSON requests into game actions.


# Handles the parsing of incoming JSON commands from clients.
class CommandParser
  def initialize
  end

  # Parses a command based on its type.

  # @param client [TCPSocket] The client socket.

  # @param command [Hash] The command hash.

  # @return [Hash] The response hash.
  def parse(client, command)
    response = {'request_id' => command['request_id']}
    case command['type']
    when 'hello'
      parse_hello(client, command)
    when 'query'
      parse_query(command)
    when 'command'
      parse_command(command)
    else
      raise CommandParserError, "Unable to parse unknown type of '#{commad['type']}'"
    end
    return response
  end

  # Parses a "hello" type command.

  # @param client [TCPSocket] The client socket.

  # @param command [Hash] The command hash.

  # @return [Hash] The response hash.
  def parse_hello(client, command)
    response = {'type' => command['type']}
    id = command['player_id']
    case command['domain']
    when 'player'
      hello_player(client, id, command['payload'])
    else
      raise CommandParserError, "Unable to parse the hello type, domain '#{command['domain']}'"
    end
    return response
  end

  # Parses a "query" type command.

  # @param command [Hash] The command hash.

  # @return [Hash] The response hash.
  def parse_query(command)
    response = {'type' => command['type']}
    id = command['player_id']
    case command['domain']
    when 'game'
      query_game(id, command['payload'])
    when 'player'
      query_player(id, command['payload'])
    else
      raise CommandParserError, "Unable to parse the query type, domain '#{command['domain']}'"
    end
    return response
  end

  # Parses a "command" type command.

  # @param command [Hash] The command hash.

  # @return [Hash] The response hash.
  def parse_command(command)
    response = {'type' => command['type']}
    id = command['player_id']
    case command['domain']
    when 'game'
      command_game(id, command['payload'])
    when 'player'
      command_player(id, command['payload'])
    else
      raise CommandParserError, "Unable to parse the command type, domain '#{command['domain']}'"
    end
    return response
  end

  # Perform the actions for the type of hello and domain of player.
  def hello_player(client, id, payload)
    response = {}
    payload.keys.each do |key, value|
      case key
      when 'build'
      when 'connect'
        game.connect_player(client, id, value)
      when 'faction'
        game.set_player_faction(id, value)
      else
        raise CommandParserError, "Unable to parse the type hello, domain player, key '#{key}'"
      end
    end
    return response
  end

  # Perform the actions for the type of query and the domain of game
  def query_game(id, payload)
    response = {}
    payload.keys.each do |key, value|
      case key
      when 'build'
      when 'time'
        game.send_time(id, value)
      when 'size'
        game.send_size(id, value)
      else
        raise CommandParserError, "Unable to parse the type query, domain game, key '#{key}'"
      end
    end
    return response
  end

  # Perform the actions for the type of query and the domain of player
  def query_player(id, payload)
    response = {}
    payload.keys.each do |key, value|
      case key
      when 'build'
      when 'resources'
        game.get_player_resources(id, value)
      when 'planets'
        game.get_player_planets(id, value)
      when 'buildings'
        game.get_player_buildings(id, value)
      when 'ships'
        game.get_player_ships(id, value)
      when 'construction'
        game.get_player_construction(id, value)
      else
        raise CommandParserError, "Unable to parse the type query, domain player, key '#{key}'"
      end
    end
    return response
  end

  # Perform the actions for the type command and the domain of game
  def command_game(id, payload)
    response = {}
    payload.keys.each do |key, value|
      case key
      when 'build'
      else
        raise CommandParserError, "Unable to parse the type command, domain game, key '#{key}'"
      end
    end
    return response
  end

  # Perform the actions for the type command and the domain of player
  def command_player(id, payload)
    response = {}
    payload.keys.each do |key, value|
      case key
      when 'build'
      else
        raise CommandParserError, "Unable to parse the type command, domain player, key '#{key}'"
      end
    end
    return response
  end
end

# Handles the parsing of incoming JSON commands from clients.
# Exception raised when a command cannot be parsed.
class CommandParserError < StandardError
end