# frozen_string_litera: true

module Strings
  # A class responsible for parsing padding value
  #
  # Used internally by {Strings::Pad}
  #
  # @api private
  class Padder
    ParseError = Class.new(ArgumentError)

    # Parse padding options
    #
    # Turn possible values into 4 element array
    #
    # @example
    #   padder = TTY::Table::Padder.parse(5)
    #   padder.padding # => [5, 5, 5, 5]
    #
    # @param [Object] value
    #
    # @return [TTY::Padder]
    #   the new padder with padding values
    #
    # @api public
    def self.parse(value = nil)
      return value if value.is_a?(self)

      new(convert_to_ary(value))
    end

    # Convert value to 4 element array
    #
    # @return [Array[Integer]]
    #   the 4 element padding array
    #
    # @api private
    def self.convert_to_ary(value)
      if value.class <= Numeric
        [value, value, value, value]
      elsif value.nil?
        []
      elsif value.size == 2
        [value[0], value[1], value[0], value[1]]
      elsif value.size == 4
        value
      else
        raise ParseError, 'Wrong :padding parameter, must be an array'
      end
    end

    # Padding
    #
    # @return [Array[Integer]]
    attr_reader :padding

    # Initialize a Padder
    #
    # @api public
    def initialize(padding)
      @padding = padding
    end

    # Top padding
    #
    # @return [Integer]
    #
    # @api public
    def top
      @padding[0].to_i
    end

    # Set top padding
    #
    # @param [Integer] value
    #
    # @return [nil]
    #
    # @api public
    def top=(value)
      @padding[0] = value
    end

    # Right padding
    #
    # @return [Integer]
    #
    # @api public
    def right
      @padding[1].to_i
    end

    # Set right padding
    #
    # @param [Integer] value
    #
    # @api public
    def right=(value)
      @padding[1] = value
    end

    # Bottom padding
    #
    # @return [Integer]
    #
    # @api public
    def bottom
      @padding[2].to_i
    end

    # Set bottom padding
    #
    # @param [Integer] value
    #
    # @return [nil]
    #
    # @api public
    def bottom=(value)
      @padding[2] = value
    end

    # Left padding
    #
    # @return [Integer]
    #
    # @api public
    def left
      @padding[3].to_i
    end

    # Set left padding
    #
    # @param [Integer] value
    #
    # @return [nil]
    #
    # @api public
    def left=(value)
      @padding[3] = value
    end

    # Check if padding is set
    #
    # @return [Boolean]
    #
    # @api public
    def empty?
      padding.empty?
    end

    # String represenation of this padder with padding values
    #
    # @return [String]
    #
    # @api public
    def to_s
      inspect
    end
  end # Padder
end
