require_relative '../dencli'

class DenCli::Sub
	attr_reader :parent, :name, :description, :subs, :aliases, :defined_in

	def initialize parent, name, description, noshortaliases: nil, defined_in: nil
		#DenCli::assert_type self, __method__, :name, name, Symbol
		#DenCli::assert_type self, __method__, :parent, parent, DenCli, DenCli::Sub
		#DenCli::assert_type self, __method__, :description, description, String
		@parent, @name, @description, @subs, @aliases = parent, name, "-> #{description}", {}, {}
		@noshortaliases, @defined_in = ! ! noshortaliases, defined_in || Kernel.caller
	end

	def _full_cmd( post) parent._full_cmd [@name]+post end
	def full_cmd() _full_cmd [] end
	def []( name) @aliases[name&.to_s] end
	def has?( name) @aliases.has_key? name&.to_s end


	def usage output: nil
		output ||= ''
		_usage output
		output
	end

	def _usage output
		output << full_cmd.join( ' ')
		if @aliases.has_key? nil
			output << " [<command> ...]"
		else
			output << " <command> [...]"
		end
	end

	def help n = nil, *a, output: nil
		output ||= ''
		_help output, n, *a
		output
	end

	def _help output, n = nil, *a
		if n.nil?
			output << "#{full_cmd.join ' '}: #{description}\n\n"
			self.class._help_commands output, @subs
		elsif has? n
			self[n]._help output, *a
		else
			raise DenCli::UnknownCommand, "unknown command: #{_full_cmd( [n])[1..-1].join ' '}, available for #{full_cmd[1..-1].join' '}: #{@subs.keys.join ' '}"
		end
	end

	def commands &exe
		yield name, self
		@subs.each {|k, c| c.commands &exe }
	end

	def help_commands output: nil
		output ||= ''
		self.class._help_commands output, subs.map {|_,c| c}
		output
	end

	class <<self
		def _help_commands output, subs
			m = subs.map {|_name,c| x = c.usage.length; 25 < x ? 0 : x }.max
			subs.each do |_name, c|
				if 25 < c.usage.length
					output << "% -#{m}s\n#{' ' * m} " % [c.usage]
				else
					output << "% -#{m}s " % [c.usage]
				end
				n = m+2
				prefix = nil
				c.description.split( /\n/).each do |l|
					c = 0
					l.split( %r< >).each do |w|
						if prefix
							output << prefix
							prefix = nil
						end
						wl = w.length
						if 75 < c+wl
							output << "\n#{' ' * n}#{w}"
							c = n+2+wl
						else
							output << " #{w}"
							c += 1 + wl
						end
					end
					prefix = "\n#{' ' * n}"
				end
				output << "\n"
			end
			output
		end
	end

	def goto *a
		return self  if a.empty?
		n, *a = *a
		if has? n
			self[n].goto *a
		else
			raise DenCli::UnknownCommand, "unknown command: #{_full_cmd( [n])[1..-1].join ' '}, available for #{full_cmd[1..-1].join' '}: #{@subs.keys.join ' '}"
		end
	end

	def call *a
		n, *a = *a
		if has? n
			self[n].call *a
		else
			raise DenCli::UnknownCommand, "unknown command: #{_full_cmd( [n])[1..-1].join ' '}, available for #{full_cmd[1..-1].join' '}: #{@subs.keys.join ' '}"
		end
	end

	def _add name, min, obj, aliases
		#DenCli::assert_type self, __method__, :name, name, Symbol, String
		#DenCli::assert_type self, __method__, :min, min, Integer, NilClass
		#DenCli::assert_type self, __method__, :obj, obj, DenCli::Sub, DenCli::CMD
		#DenCli::assert_type self, __method__, :aliases, aliases, Array, NilClass
		name = name.to_s
		@subs[name] = obj
		if @noshortaliases
			warn "Command/Alias for #{obj.full_cmd} defined in #{obj.defined_in} already exists: #{full_cmd.join ' '} #{name}.  Used by #{@aliases[name].full_cmd} defined in #{@aliases[name].defined_in}"  if @aliases.has_key? name
			@aliases[name] = obj
		else
			DenCli.gen_aliases name, min do |a|
				warn "Command/Alias for #{obj.full_cmd} defined in #{obj.defined_in} already exists: #{full_cmd.join ' '} #{a}.  Used by #{@aliases[a].full_cmd} defined in #{@aliases[a].defined_in}" if @aliases.has_key? a
				@aliases[a] ||= obj
			end
		end
		if aliases
			[*aliases].each do |a|
				a = a&.to_s
				raise ArgumentError, "Alias for #{obj.full_cmd} defined in #{obj.defined_in} already exists: #{full_cmd.join ' '} #{a}.  Used by #{@aliases[a].full_cmd} defined in #{@aliases[a].defined_in}"  if @aliases.has_key? a
				@aliases[a] = obj
			end
		end
		obj
	end
	private :_add

	# Define a new sub-menu:
	#
	#   DenCli.new {|c|
	#     c.sub( 'sub-command') {|s|
	#       s.cmd( :hello, 'Greetings', &lambda {|| puts 'hello world' })
	#     }
	#   }
	#
	#   # ./prog sub-command hello
	#
	# name should be a string/symbol.  It will be converted to string.
	# If provided, aliases must be a list of different aliases.  It will be converted to string.
	def sub name, description, min: nil, aliases: nil, noshortaliases: nil, defined_in: nil, &exe
		r = _add name.to_s, min, DenCli::Sub.new( self, name, description, noshortaliases: noshortaliases, defined_in: defined_in || Kernel.caller.first), aliases
		block_given? ? yield( r) : r
	end

	# Define a new command:
	#
	#   DenCli.new {|c|
	#     c.cmd( :hello, 'Greetings', &lambda {|| puts 'hello world' })
	#   }
	#
	#   # ./prog hello
	#   hello world
	#
	# name should be a string/symbol.  It will be converted to string.
	# If provided, aliases must be a list of different aliases.  Except of nil, any alias will be converted to string.
	# nil is an alias for a default command for sub-commands, but interactive shells.
	#
	#   DenCli.new {|c|
	#     c.sub( :greetings, 'Hello, Welcome, ...') do |s|
	#       s.cmd( :hello, 'A simple Hello', aliases: %w[hello-world hello_world], &lambda {|| puts 'Hello World' })
	#       s.cmd( :welcome, 'More gracefull', aliases: [nil, 'welcome-world', :hello_world], &lambda {|| puts 'Welcome World' })
	#     }
	#   }
	#
	#   # ./prog greetings
	#   Welcome World
	#   # ./prog greetings welcome
	#   Welcome World
	#   # ./prog greetings hello
	#   Hello World
	def cmd name, description, min: nil, aliases: nil, defined_in: nil, &exe
		_add name, min, DenCli::CMD.new( self, name, description, exe, defined_in || Kernel.caller.first), aliases
	end

	def complete *pre, str
		if pre.empty?
			@subs.keys.grep /\A#{Regexp.escape str}/
		elsif sub = @subs[pre[0]]
			sub.complete *pre[1..-1], str
		else
			$stdout.print "\a"
		end
	end

	def inspect
		"#<%s:0x%x %s @name=%p @description=%p @subs={%s} @aliases={%s} @parent=<%s:0x%x %s>>" % [
			self.class.name, self.object_id, self.full_cmd,
			@name, @description, @subs.keys.join(', '), @aliases.keys.join(', '), @parent.class.name, @parent.class.object_id, @parent.full_cmd
		]
	end
end