=begin
  * Name: PadReader.rb
  * Description : This is an independent file viewer that uses a Pad and traps keys
  * Author: rkumar (http://github.com/rkumar/rbcurse/)
  * Date: 22.10.11 - 20:35
  * License: Same as Ruby's License (http://www.ruby-lang.org/LICENSE.txt)
  * Last update:  2013-04-01 13:43

  == CHANGES
  == TODO
     make the window configurable so we can move to a textview that is pad based, later even list ?
     Note that cursor does not move, in real life applicatino cursor must move to bottom row
     and only then scrolling should start.
     NOTE: I have continued this in textpad which is a widget that uses pads to scroll.
           This is very rough, i may work on this more later.
=end
require 'rbhex/core'

include Rbhex
module Rbhex
  class PadReader

    # You may pass height, width, row and col for creating a window otherwise a fullscreen window
    # will be created. If you pass a window from caller then that window will be used.
    # Some keys are trapped, jkhl space, pgup, pgdown, end, home, t b
    # This is currently very minimal and was created to get me started to integrating
    # pads into other classes such as textview.
    def initialize config={}, &block

      @config = config
      @rows = FFI::NCurses.LINES-1
      @cols = FFI::NCurses.COLS-1
      @prow = @pcol = 0
      @startrow = 0
      @startcol = 0

      h = config.fetch(:height, 0)
      w = config.fetch(:width, 0)
      t = config.fetch(:row, 0)
      l = config.fetch(:col, 0)
      @rows = h unless h == 0
      @cols = w unless w == 0
      @startrow = t unless t == 0
      @startcol = l unless l == 0
      @suppress_border = config[:suppress_border]
      unless @suppress_border
        @startrow += 1
        @startcol += 1
        @rows -=3  # 3 is since print_border_only reduces one from width, to check whether this is correct
        @cols -=3
      end
      @top = t
      @left = l
      view_file config[:filename]
      @window = config[:window] || VER::Window.new(:height => h, :width => w, :top => t, :left => l)
      # print border reduces on from width for some historical reason
      @window.print_border_only @top, @left, h-1, w, $datacolor
      @ph = @content_rows
      @pw = @content_cols # get max col
      @pad = FFI::NCurses.newpad(@ph, @pw)

      Ncurses::Panel.update_panels
      @content.each_index { |ix|

        FFI::NCurses.mvwaddstr(@pad,ix, 0, @content[ix])
      }
      @window.wrefresh
      padrefresh
      #FFI::NCurses.prefresh(@pad, 0,0, @startrow ,@startcol, @rows,@cols);

      @window.bkgd(Ncurses.COLOR_PAIR(5));
      FFI::NCurses.keypad(@pad, true);
      #@form = Form.new @window
      config[:row] = config[:col] = 0 # ??? XXX
    end

    private
    def view_file(filename)
      @file = filename
      @content = File.open(filename,"r").readlines
      @content_rows = @content.count
      @content_cols = content_cols()
      #run()
    end
    # write pad onto window
    private
    def padrefresh
      FFI::NCurses.prefresh(@pad,@prow,@pcol, @startrow,@startcol, @rows + @startrow,@cols+@startcol);
    end
    # returns button index
    # Call this after instantiating the window
    public
    def run
      #@form.repaint
      #@window.wrefresh
      return handle_keys
    end

    # convenience method
    private
    def key x
      x.getbyte(0)
    end
    def content_cols
      longest = @content.max_by(&:length)
      longest.length
    end

    # returns button index
    private
    def handle_keys
      ht = @window.height.ifzero FFI::NCurses.LINES-1
      buttonindex = catch(:close) do
        @maxrow = @content_rows - @rows
        @maxcol = @content_cols - @cols
        while((ch = @window.getchar()) != FFI::NCurses::KEY_F10 )
          #while((ch = FFI::NCurses.wgetch(@pad)) != FFI::NCurses::KEY_F10 )
          break if ch == ?\C-q.getbyte(0)
          begin
            case ch
            when key(?g), 279 # home as per iterm2
              @prow = 0
            when key(?b), key(?G), 277 # end as per iterm2
              @prow = @maxrow-1
            when key(?j)
              @prow += 1
            when key(?k)
              @prow -= 1
            when 32, 338   # Page Down abd Page Up as per iTerm2
              @prow += 10
            when key(?\C-d)
              @prow += ht
            when key(?\C-b)
              @prow -= ht
            when 339
              @prow -= 10
            when key(?l)
              @pcol += 1
            when key(?$)
              @pcol = @maxcol - 1
            when key(?h)
              @pcol -= 1
            when key(?0)
              @pcol = 0
            when key(?q)
              throw :close
            else
              alert " #{ch} not mapped "
            end
            @prow = 0 if @prow < 0
            @pcol = 0 if @pcol < 0
            if @prow > @maxrow-1
              @prow = @maxrow-1
            end
            if @pcol > @maxcol-1
              @pcol = @maxcol-1
            end
            #@window.wclear
            #FFI::NCurses.prefresh(@pad,@prow,@pcol, @startrow,0, @rows,@cols);
            padrefresh
            Ncurses::Panel.update_panels
            #@form.handle_key(ch)
            #@window.wrefresh
          rescue => err
            $log.debug( err) if err
            $log.debug(err.backtrace.join("\n")) if err

            textdialog ["Error in padreader: #{err} ", *err.backtrace], :title => "Exception"
            $error_message.value = ""
          ensure
          end

        end # while loop
      end # close
      $log.debug "XXX: CALLER GOT #{buttonindex} "
      @window.destroy unless @config[:window]
      FFI::NCurses.delwin(@pad)
      return buttonindex
    end
  end
end
if __FILE__ == $PROGRAM_NAME
  require 'rbhex/core/util/app'
  App.new do
    #status_line :row => FFI::NCurses.LINES-1
    @form.repaint
    #p = PadReader.new :filename => "padreader.rb", :height => 20, :width => 60, :row => 4, :col => 4, :window => @window, :suppress_border => true
    p = PadReader.new :filename => "padreader.rb", :height => FFI::NCurses.LINES-1, :width => 0, :row => 0, :col => 0, :window => @window, :suppress_border => true
    p.run
    throw :close
  end
end