require 'usps_flags'
require 'usps_flags/grades/config'
require 'usps_flags/grades/errors'

# Main class for generating grade and other insignia.
class USPSFlags::Grades
  require 'usps_flags/grades/grade'
  require 'usps_flags/grades/membership'
  require 'usps_flags/grades/edpro'
  require 'usps_flags/grades/merit_marks'

  ALL_CONFIGS ||= [
    [:s, false, nil], [:p, false, nil], [:ap, false, nil], [:ap, true, nil],
    [:jn, false, nil], [:jn, true, nil], [:n, false, nil], [:n, true, nil],
    [:sn, false, nil], [nil, false, :senior], [nil, false, :life]
  ].freeze

  # Constructor for generating grade insignia.
  #
  # @example Generate JN with EdPro and Senior Member
  #  insignia = USPSFlags::Grades.new do |b|
  #    b.grade = :jn
  #    b.edpro = :edpro
  #    b.membership = :senior
  #    b.outfile = "/path/to/svg/output.svg"
  #  end
  #
  #  insignia.svg #=> Generates SVG file at "/path/to/svg/output.svg"
  def initialize(options = {})
    @grade = options[:grade] || nil
    @edpro = options[:edpro] || false
    @membership = options[:membership] || nil
    @merit_marks = options[:merit_marks] || 0
    @outfile = options[:outfile] || nil
    @generated_at = Time.now.strftime("%Y%m%d.%H%S%z")
    yield self if block_given?
  end

  attr_accessor :grade
  attr_accessor :edpro
  attr_accessor :membership
  attr_accessor :merit_marks
  attr_accessor :outfile

  # Generates the constructed file as SVG.
  #
  # @return [String] Returns the SVG file output path, or the svg data if no path was specified.
  def svg
    validate
    @svg = <<~SVG
      #{USPSFlags::Core.headers(title: title).gsub('0 0 3072 2048', '0 0 1024 682')}
      <g transform="translate(0, 50)">
        #{USPSFlags::Grades::Grade.get(@grade)}
        #{USPSFlags::Grades::EdPro.get(@grade) if @edpro && USPSFlags::Grades::EdPro.for_grade(@grade)}
        #{USPSFlags::Grades::Membership.get(@membership) unless @membership.nil?}
      </g>
      <g transform="translate(0, 450)">
         #{USPSFlags::Grades::MeritMarks.get(@merit_marks)}
      </g>
      #{USPSFlags::Core.footer}
    SVG

    USPSFlags::Helpers.output(@svg, outfile: @outfile)
  end

  # Generates the descriptive title for the SVG.
  #
  # @return [String] Returns the descriptive title.
  def title
    grade = @grade.to_s.upcase
    edpro = " - EdPro" if @edpro && @grade != :sn
    membership = case @membership
    when :senior
      " - Senior Member"
    when :life
      " - Life Member"
    end

    "#{grade}#{edpro}#{membership}"
  end

  def self.all(dir = nil)
    dir ||= USPSFlags.configuration.flags_dir

    ALL_CONFIGS.each do |grade, edpro, membership|
      path = "#{dir}/#{grade}"
      path += '_edpro' if edpro

      insignia = USPSFlags::Grades.new(
        grade: grade, edpro: edpro, membership: membership,
        outfile: "#{path}.svg"
      )

      USPSFlags::Generate.png(insignia.svg, outfile: "#{path}.png", trim: true)
    end
  end

  private

  def validate
    validate_grade
    validate_edpro
    validate_membership
  end

  def validate_grade
    return if @grade.nil? || USPSFlags::Grades::Grade.valid_grades.include?(@grade)

    raise USPSFlags::Errors::InvalidInsignia, "Unknown grade: #{@grade}"
  end

  def validate_edpro
    return if [true, false].include?(@edpro)

    raise USPSFlags::Errors::InvalidInsignia, "EdPro must be boolean"
  end

  def validate_membership
    return if [nil, :senior, :life].include?(@membership)

    raise USPSFlags::Errors::InvalidInsignia, "Unknown membership level: #{@membership}"
  end
end