gs.rb

#!/usr/bin/env ruby

require 'io/console'

GIT_LIST_PATH = "#{ENV['HOME']}/tmp/git-demo.lst"

RED = "\e[31m"
YELLOW = "\e[33m"
BLACK = "\e[30m"
FIN = "\e[0m"

UP = "\e[A"
DOWN = "\e[B"
RETURN = "\r"


def show_log_item(item, current)
  if current
    print "#{RED}#{item[0]} #{BLACK}#{item[1]}#{FIN}#{RETURN}"
  else
    print "#{YELLOW}#{item[0]} #{BLACK}#{item[1]}#{FIN}#{RETURN}"
  end
end

def show_git_log(log, current_index)
  log.each_with_index do |item, ix|
    show_log_item(item, ix == current_index)
    puts
  end
end

def get_current_hash
  IO.read("|git log --pretty=format:'%h' -1")
end

def find_current_hash(log, current_hash)
  log.find_index {|item| item[0] == current_hash}
end

def wait_key
  key = STDIN.getch
  if key == "\e" && STDIN.getch == "["
    case STDIN.getch
    when "A" then "↑"
    when "B" then "↓"
    else ""
    end
  else
    key
  end
end

def cursor_up
  print UP
  STDOUT.flush
end

def cursor_down
  print DOWN
  STDOUT.flush
end

def set_cursor(log, current_index)
  (log.size - current_index).times { cursor_up }
end

def reset_cursor(log, current_index)
 (log.size - current_index).times { cursor_down }
end

def move_current_postion(log, index, delta)
  show_log_item(log[index], false)

  if delta > 0
    if index < log.size - 1
      cursor_down
      index += 1
    end
  else
    if index > 0
      cursor_up
      index -= 1
    end
  end

  show_log_item(log[index], true)
  index
end

def get_git_log
  IO.readlines(GIT_LIST_PATH).map {|s| s.scan(/^(\w+) (.*)\n?/)[0]}
end

def put_git_log
  system "git log --pretty=format:'%h %s' > #{GIT_LIST_PATH}"
end

def git_reset_hard(log, index)
  system "git reset --hard #{log[index][0]}"
end

def main
  log = get_git_log
  current_index = find_current_hash(log, get_current_hash)
  show_git_log(log, current_index)
  set_cursor(log, current_index)
  do_reset = false

  while true
    case wait_key
    when 'n'
      current_index = move_current_postion(log, current_index,  - 1)
      do_reset = true
      break
    when 'p'
      current_index = move_current_postion(log, current_index,  + 1)
      do_reset = true
      break
    when "\r", "\n"
      do_reset = true
      break
    when "\C-c", "q"
      break
    when "↑"
      current_index = move_current_postion(log, current_index,  - 1)
    when "↓"
      current_index = move_current_postion(log, current_index,  + 1)
    end
  end
  reset_cursor(log, current_index)
  git_reset_hard(log, current_index)  if do_reset

end

if ARGV.size > 0
  if ARGV[0] == "-c"
    put_git_log
    puts "#{GIT_LIST_PATH} created."
  else
    puts "#{$0} -c"
    puts "     or  "
    puts "#{$0} "
    puts "  n: git reset --hard Next commit"
    puts "  p: git reset --hard Pervious commit"
    puts "  ↑ ↓: seek commit"
    puts "  RETURN: git reset --hard Current commit"
    puts "  q: quit"
  end
else
  main
end