# frozen_string_literal: true

require 'cas'
require 'rule'
require 'rw_rules'
require 'simp_rules'

# sucks
class Solver
  def initialize(solve_for: :x, given: [])
    @solve_for = solve_for
    @visited = MySet.new([given])
  end

  def winner
    found = @visited.find { |g| g.lhs == @solve_for || g.rhs == @solve_for && g.lhs != g.rhs }
    return unless found

    simp(if found.lhs == @solve_for
      found.rhs
    else
      found.lhs
    end)
  end

  def elaborate!
    @visited.each do |t|
      (SIMP_RULES + RW_RULES).each do |rule|
        @visited.add(rule.apply(t))
      end
    end

    simp!
  end

  def simp!
    @visited.map! { |g| g.simp }

    self
  end
end

class MySet < Set
  def add(item)
    super.add(item) unless any? { |i| item == i }

    self
  end
end