#!/bin/bash

# Copyright (c) 2015 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# This aptly-named script verifies and fixes time ordering
# problems with Makefile.{am,in} aclocal.m4 configure* files.

set -eu
#set -vx

touch=""
commit=""
comma_v=""
aclocal=""
optimize=""

# The old autowank scheme used "touch <foo> ; sleep 1"
# to ensure differentiable, ordered timestamps. Worked, but
# took N seconds given N files to fix. We have an example
# which wastes multiple minutes given the old scheme.
#
# This version generates a sequence of timestamps 
# starting an hour ago. That gives us
# lots to play with, in case some obnoxious program feels the need
# to complain about timestamps in the future.

# If we're in UTC+N land, generate UTC+(N+1) 
# If we're in UTC-N land, generate UTC-(N-1)

my_tz=`date +%z`
sign=`echo $my_tz | sed -n -e 's/^\(.\{1\}\).*$/\1/p'`
t=`echo $my_tz | sed -n -e 's/^\(.\{1\}\)//p'`
tz_hour=`echo $t | sed -n -e 's/^\(.\{2\}\).*$/\1/p'`
tz_hour=`echo $tz_hour | sed 's/^0//'`

if [ $sign = "-" ] ; then
    sign="+"
    let tz_hour=$tz_hour+1
    if [[ $tz_hour -ge "24" ]] ; then
        tz_hour=0
    fi
else
    sign="-"
    let tz_hour=$tz_hour-1 || true
    if [[ $tz_hour -lt "0" ]] ; then
        tz_hour=23
    fi
fi

# Timestamp, an hour ago:
ts_begin=`TZ=UTC${sign}${tz_hour} date +%Y%m%d%H%M.%S`

# break into constituent parts
year=`echo $ts_begin | sed -n -e 's/^\(.\{4\}\).*$/\1/p'`
t=`echo $ts_begin | sed -n -e 's/^\(.\{4\}\)//p'`
month=`echo $t | sed -n -e 's/^\(.\{2\}\).*$/\1/p'`
t=`echo $t | sed -n -e 's/^\(.\{2\}\)//p'`
day=`echo $t | sed -n -e 's/^\(.\{2\}\).*$/\1/p'`
t=`echo $t | sed -n -e 's/^\(.\{2\}\)//p'`
hour=`echo $t | sed -n -e 's/^\(.\{2\}\).*$/\1/p'`
t=`echo $t | sed -n -e 's/^\(.\{2\}\)//p'`
min=`echo $t | sed -n -e 's/^\(.\{2\}\).*$/\1/p'`
t=`echo $t | sed -n -e 's/^\(.\{2\}\)//p'`
sec=`echo $t | sed -n -e 's/\.//p'`

# How many days in the current month?
# Good until someone changes the calendar rules
days_in_current_month() {
    if [[ $month -eq 9 || $month -eq 4 \
        || $month -eq 6 || $month -eq 11 ]] ; then
	return 30;
    fi
    if [[ $month -eq 2 ]] ; then
	let t=($year/400)*400
	if [[ $t -eq $year ]] ; then
	    return 29;
	fi
	let t=($year/100)*100
	if [[ $t -eq $year ]] ; then
	    return 28;
	fi
	let t=($year/4)*4
	if [[ $t -eq $year ]] ; then
	    return 29;
	fi
	return 28;
    fi
    return 31;
}

# The next timestamp to issue via touch
# A real hemorrhoid because bash isnt easily convinced
# that 08 is a decimal number
next_ts() {
    sec=`echo $sec | sed 's/^0//'`
    let sec=$sec+1
    if [[ "$sec" -lt "60" ]] ; then
        if [[ "$sec" -lt "10" ]] ; then
            sec=0$sec
        fi
	return 0;
    fi
    sec="00"
    min=`echo $min | sed 's/^0//'`
    let min=$min+1
    if [[ "$min" -lt "60" ]] ; then
        if [[ "$min" -lt "10" ]] ; then
            min=0$min
        fi
	return 0;
    fi
    min="00"
    hour=`echo $hour | sed 's/^0//'`
    let hour=$hour+1
    if [[ "$hour" -lt "24" ]] ; then
        if [[ "$hour" -lt "10" ]] ; then
            hour=0$hour
        fi
	return 0;
    fi
    hour="00"
    days_in_current_month
    days_in_month=$?
    if [[ "$day" -lt "$days_in_month" ]] ; then
        day=`echo $day | sed 's/^0//'`
	let day=$day+1
        if [[ "$day" -lt "10" ]] ; then
            day=0$day
        fi
	return 0;
    fi
    day="01"
    month=`echo $month | sed 's/^0//'`
    let month=$month+1
    if [[ "$month" -lt "13" ]] ; then
        if [[ "$month" -lt "10" ]] ; then
            month=0$month
        fi
	return 0;
    fi
    month="01"
    let year=$year+1
    return 0;
}

while [ $# != 0 ] ; do
  case "$1" in
    (--commav) comma_v=",v" ;;
    (--touch) touch=yes ;;
    (--aclocal) aclocal=yes ;;
    (--nooptimize) optimize="" ;;
    (--commit=*) commit="$1" ;;
    (*) echo "$0: usage [--touch|--commit|]" > /dev/stderr
        exit 17 ;;
  esac
  shift
done

if [ "${aclocal}" != "" ] ; then
    if [ -f aclocal.m4 ] ; then
        echo touching aclocal.m4
        sleep 1
        touch aclocal.m4
    else
        echo aclocal.m4 not found
    fi
fi

if [ "${comma_v}" != "" -a "${commit}" != "" ] ; then
  echo "No, you may NOT molest ,v files directly.  Go away." > /dev/stderr
  exit 1
fi

function touchme ()
{
  local victim="${1}"
  shift
  local touchmebaby=""
  local sein="is"
  local newer="no"
  local older="no"

  if [ ! -r "$victim" ] ; then
    return
  fi

  while [ $# != 0 ] ; do
    if [ "${1}" -nt "${victim}" ] ; then
        newer="yes"
    fi
    if [ "${1}" -ot "${victim}" ] ; then
        older="yes"
    fi
    if [ "${newer}" = "no" -a "${older}" = "no" ] ; then
        newer="yes"
    fi

    if [ "${newer}" = "yes" ] ; then
      if [ "${touchmebaby}" = "" ] ; then
        touchmebaby="${1}"
      else
        sein="are"
        touchmebaby="${touchmebaby} ${1}"
      fi
    fi
    shift
  done
  if [ -n "${touchmebaby}" ] ; then
    echo "*** ${touchmebaby} ${sein} newer than ${victim}  "
    if [ -n "${touch}" ] ; then
      # 
      # This is the old version, in case something backfires...
      if [ "${optimize}" != "yes" ] ;<style>
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