module Thor::Util

def self.constant_from_thor_path(str)
  make_constant(to_constant(str))
rescue NameError => e
  raise e unless e.message =~ /^uninitialized constant (.*)$/
  raise Error, "There was no available namespace `#{str}'."
end

def self.constant_to_thor_path(str, remove_default = true)
  str = str.to_s.gsub(/^Thor::Tasks::/, "")
  str = snake_case(str).squeeze(":")
  str.gsub!(/^default/, '') if remove_default
  str
end

def self.constants_in_contents(str, file = __FILE__)
  klasses = ObjectSpace.classes.dup
  Module.new.class_eval(str, file)
  klasses = ObjectSpace.classes - klasses
  klasses = klasses.select {|k| k < Thor }
  klasses.map! {|k| k.to_s.gsub(/#<Module:\w+>::/, '')}
end

def self.full_const_get(obj, name)
  list = name.split("::")
  list.shift if list.first.empty?
  list.each do |x| 
    # This is required because const_get tries to look for constants in the 
    # ancestor chain, but we only want constants that are HERE
    obj = obj.const_defined?(x) ? obj.const_get(x) : obj.const_missing(x)
  end
  obj
end

def self.make_constant(str, base = [Thor::Tasks, Object])
  which = base.find do |obj|
    full_const_get(obj, str) rescue nil
  end
  return full_const_get(which, str) if which
  raise NameError, "uninitialized constant #{str}"
end

def self.snake_case(str)
  return str.downcase if str =~ /^[A-Z_]+$/
  str.gsub(/\B[A-Z]/, '_\&').squeeze('_') =~ /_*(.*)/
  return $+.downcase
end  

def self.to_constant(str)
  str = 'default' if str.empty?
  str.gsub(/:(.?)/) { "::#{$1.upcase}" }.gsub(/(?:^|_)(.)/) { $1.upcase }
end