require_relative '../dencli'

class DenCli::Interactive
	attr_reader :cl, :prompt, :cur, :histfile

	def initialize cl, prompt, histfile: nil
		require 'readline'
		@cl, self.prompt = cl, prompt
		@cur = cl.subs
		cur.instance_variable_set :@name, ''

		@histfile =
			case histfile
			when nil then nil
			when Pathname then histfile
			else Pathname.new histfile.to_s
			end
		read_history  if @histfile

		Readline.vi_editing_mode  rescue NotImplementedError
		Readline.completion_append_character = " "
		Readline.completion_proc = method :complete

		prepare_sub cl.subs
		cl.cmd :exit, "exit", min: 2 do
			exit 0
		end
		cl.subs.aliases['?'] = cl.subs.subs['help']
		cl.subs.subs.delete 'cli'

		stty_save = %x`stty -g`.chomp
		trap "INT" do
			system "stty", stty_save
			Readline.refresh_line
		end
	end

	def history_file file = nil
		file =
			case file
			when Pathname then file
			when nil then @histfile
			else Pathname.new file.to_s
			end
	end

	def read_history file = nil
		file = history_file file
		return  unless file and file.exist?
		file.each_line do |line|
			Readline::HISTORY.push line.chomp
		end
	end

	def write_history file = nil
		file = history_file file
		return  unless file
		file.open 'w+' do |f|
			Readline::HISTORY.each do |line|
				f.puts line
			end
		end
	end

	def prompt= s
		@prompt = s.to_s
	end

	def complete s
		ws = words Readline.line_buffer
		@cur.complete *ws[0...-1], s
	end

	def sub *args, cur: nil
		args.inject( cur || @cur) do |r, a|
			return nil  unless r.is_a? DenCli::Sub
			r[a]
		end
	end
	private :sub

	def words line = nil
		r = line.split " "
		r.push ''  if ' ' == line[-1]
		r
	end
	private :words

	def prepare_sub c
		c.subs.values.each do |n|
			case n
			when DenCli::Sub
				n.cmd :exit, "<- #{n.parent.full_cmd.join ' '} - #{n.parent.desc[3..-1]}", min: 2 do
					@cur = n.parent
				end
				n.cmd '', "", min: 2, aliases: [nil] do
					@cur = n
				end
				n.subs.delete ''
				n.aliases['?'] = n.subs['help']
				prepare_sub n
			when DenCli::CMD
			else raise "Unsupported sub-type: #{x}"
			end
		end
	end

	def read
		line = Readline.readline( "#{prompt}#{cur.full_cmd.join ' '}> ", true)
		return nil  if line.nil?
		Readline::HISTORY.pop  if /^\s*$/ =~ line
		if 0 < Readline::HISTORY.length-2 and Readline::HISTORY[Readline::HISTORY.length-2] == line
			Readline::HISTORY.pop
		end
		line.split " "
	end

	def step
		line = read
		return nil  if line.nil?
		begin
			cur.call *line
		rescue ::UsageError
			STDERR.puts "! #$!"
		end
		true
	end

	def run
		while step
		end
	end
end