#!/usr/bin/env ruby
require 'curses'
require 'optparse'
$LOAD_PATH.unshift File.expand_path('../../lib', __FILE__)

def parse_options
  options = {}
  parser = OptionParser.new do |opts|
    opts.banner = <<BANNER
[Ru]by [Co]mmandline editor

Shortcuts:
 Ctrl+w/q   Exit
 Ctrl+s     Save

Usage:
    ruco FILE

Options:
BANNER
    opts.on("--debug-cache","Show caching in action") { options[:debug_cache] = true }
    opts.on("--debug-keys", "Show pressed keys") { options[:debug_keys] = true }
    opts.on("-h", "--help","Show this.") { puts opts; exit }
  end
  parser.parse!

  if ARGV.empty?
    puts parser
    exit
  end

  options
end

def write(line,row,text)
  Curses.setpos(line,row)
  Curses.addstr(text);
end

def init_screen
  Curses.init_screen
  Curses.noecho # do not show typed chars
  Curses.nonl # turn off newline translation
  Curses.stdscr.keypad(true) # enable arrow keys
  Curses.raw # give us all other keys

  begin
    yield
  ensure
    Curses.close_screen
  end
end

def display(lines, offset, color)
  @screen ||= [] # current screen is used as cache
  Curses.attrset color

  lines.each_with_index do |content, line|
    line += offset
    clearer = Curses.stdscr.maxx - content.size
    clearer = " " * clearer
    content += clearer

    next if @screen[line] == content
    @screen[line] = content

    write(line, 0, content)
    write(line, 0, (rand(899)+100).to_s) if @options[:debug_cache]
  end
end

def show_app(app)
  lines = app.view.naive_split("\n")

  # TODO move this logic into application
  display([lines.first], 0, Curses::A_REVERSE)
  display(lines[1..-2], 1, Curses::A_NORMAL)
  display([lines.last], Curses.stdscr.maxy - 1, Curses::A_REVERSE)

  Curses.setpos(app.cursor.line, app.cursor.column)
end

def debug_key(key)
  @key_line ||= -1
  @key_line = (@key_line + 1) % Curses.stdscr.maxy
  write(@key_line, 0, "#{key}---")
end

@options = parse_options

require 'ruco'
require 'ruco/keyboard' # needs curses <-> not loaded for specs

app = Ruco::Application.new(ARGV[0], :lines => Curses.stdscr.maxy, :columns => Curses.stdscr.maxx)

init_screen do
  show_app app

  Keyboard.listen do |key|
    debug_key(key) if @options[:debug_keys]
    result = app.key key
    break if result == :quit
    show_app app
  end
end