#!/bin/bash
:<<'#license'
           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
                   Version 2, December 2004

Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>

Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.

            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

  0. You just DO WHAT THE FUCK YOU WANT TO.
#license

:<<'#version'
0.0.1
#version

:<<'#keybind'
Default key bind is vi-like
press h => move up directory
press l(L) => chenge directory or edit file or execute file
press j => move up line
press k => move down line
press e => select next file
press b => select prev file
press : => eval mode
#keybind

#########################################################

declare STATUS=$(basename $(pwd)) # カレントディレクトリの名前
declare -a DIR=()                 # カレントディレクトリのファイルを一つづつ格納
declare -a LINE=()                # DIRの要素を1行づつにくぎった値
declare -i array_length=0         # DIR配列の最大値
declare -i updown=0               # LINEの添字につかう

dir_read()
{
  array_length=0
  local -i i=0
  local -i length=0
  DIR=($(ls -F))
  for DIR in ${DIR[@]};
  do
    if [ $length -ge 40 ]; then
      LINE=("${LINE[@]}" $(expr $i - 1))
      array_length=$(expr $array_length + 1)
      length=0
    fi
    length=$(expr $length + ${#DIR[$i]})
    i=$(expr $i + 1)
  done
  LINE=("${LINE[@]}" $(expr $i - 1))
  array_length=$(expr $array_length + 1)
}
#行のクリアとカーソルのポジションを先頭に移動する
line_erase()
{                               # \x1B[ => 16進数表記のESC文字
  printf "\x1B[2K\x1B[1G"       # 2K => カレント行の削除
}
declare -a word=(0 1)
declare -i x_max=0
body_print()
{
  word=(0 1)
  x_max=0
  local -i i=0
  local -i word_length=0
  if [ $updown -eq 0 ]; then
    while [ $i -lt ${LINE[0]} ];
    do
      printf "%s " ${DIR[$i]}
      word_length=$(expr $word_length + ${#DIR[$i]})
      word=("${word[@]}" $word_length)
      i=$(expr $i + 1)
      x_max=$(expr $x_max + 1)
    done
  else
    i=$(expr ${LINE[$(expr $updown - 1 )]})
    while [ $i -lt ${LINE[$updown]} ];
    do
      printf "%s " ${DIR[$i]}
      word_length=$(expr $word_length + ${#DIR[$i]})
      word=("${word[@]}" $word_length)
      i=$(expr $i + 1)
      x_max=$(expr $x_max + 1)
    done
  fi
}
line_print()
{
  printf "< %-6s > " ${STATUS:0:6}
  printf "\x1B[?25l"
  body_print
  printf "(%3d/%3d)" $(expr $updown + 1) $array_length
  printf "\x1B[?25h"
  printf "\x1B[10G"
}

move_cursor()
{
  if [ $cursor_move_flag -ne 0 ]; then
    if [ $x -gt $x_max ]; then
      x=$(expr $x_max - 1)
    elif [ $x -le 0 ]; then
      x=0
    elif [ $x -eq 0 ]; then
      printf "\x1B[10G"
      printf "\x1B[0C"
    elif [ $x -eq 1 ]; then
      printf "\x1B[10G"
      printf "\x1B[2C"
    else
      printf "\x1B[10G"
      printf "\x1B[%dC" $(expr ${word[$x]} + $x + 1)
    fi
  fi
}

line_down()
{
  updown=$(expr $updown + 1)
  if [ $updown -gt $(expr $array_length - 1) ]; then
    updown=$(expr $updown - 1)
  fi
}
line_up()
{
  updown=$(expr $updown - 1)
  if [ $updown -le -1 ]; then
    updown=0
  fi
}
declare -i cursor_move_flag=0
declare -i x=0
file_select()
{
  local file
  file=$(body_print | awk -v position="${x}" '{printf $position}' | tr '\*' '  ')
  if [ -d "$file" ]; then
    cd "$file" >/dev/null 2>&1
    STATUS=$(basename $(pwd))
    updown=0
    dir_read
    x=0
  elif [ -x "$file" ]; then
    line_erase
    read   -p "Do you want to run $file ? y/n: " anser
    case $anser in
      'y')
        ./"$file"
      ;;

      'n')
      :
      ;;
      *)
      ;;
    esac
  elif [ -f "$file" ]; then
    vim "$file"
  fi
}

dir_read
line_erase
line_print
while :
do

  read -s -n1 c

  case $c in

    'j')
      line_down
      x=0
      line_erase
      line_print
    ;;

    'k')
      line_up
      line_erase
      line_print
      x=0
    ;;

    'q')
      break
    ;;

    'h')
      { #もどるボタン( < )を押したっぽくみせる
        printf "\x1B[1G"
        sleep 0.1
        printf "\x1B[10G"
      }
      #pushdするかどうかの判断
      if [ "$STATUS" != "/" ]; then
        pushd . >/dev/null 2>&1
        cd ..
        STATUS=$(basename $(pwd))
        updown=0
      fi
      dir_read
      x=0
      line_erase
      line_print
    ;;

    "l")
      if [ $cursor_move_flag -eq 0 ]; then
        popd >/dev/null 2>&1
        STATUS=$(basename $(pwd))
        updown=0
        dir_read
        x=0
      else
        file_select
      fi
      line_erase
      line_print
    ;;

    'e')
      x=$(expr $x + 1)
      cursor_move_flag=1
      move_cursor
    ;;
    'b')
      x=$(expr $x - 1)
      move_cursor
    ;;

    ':') #入力した文字列をevalする
    line_erase
    read -e -p ": " command; eval "$command"
    line_erase
    line_print
    ;;

  esac
done
line_erase
printf "\x1B[1Gbye!\n"