again

#!/usr/bin/env bash

#Copyright (C) 2013 Niklas Thorne.
#
#This file is part of again.
#
#again is free software: you can redistribute it and/or modify
#it under the terms of the GNU General Public License as published by
#the Free Software Foundation, either version 3 of the License, or
#(at your option) any later version.
#
#again is distributed in the hope that it will be useful,
#but WITHOUT ANY WARRANTY; without even the implied warranty of
#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#GNU General Public License for more details.
#
#You should have received a copy of the GNU General Public License
#along with again.  If not, see <http://www.gnu.org/licenses/>.

source `dirname $(realpath $0 || echo $0)`/againHelpers.sh

readonly SED_DATE_RE="[0-9]\{4\}-[0-9]\{2\}-[0-9]\{2\}"
readonly BASH_DATE_RE="[0-9]{4}-[0-9]{2}-[0-9]{2}"
readonly AGAIN_TAG="${TODO_AGAIN_TAG:-again}"

function usage()
{
  echo "    again N"
  echo "      Mark N as complete and recreate with any due date set as today."
  echo "    again N ADJUST"
  echo "      Mark N as complete and recreate with any due date and deferral date"
  echo "      set as ADJUST from _today_."
  echo "    again N +ADJUST"
  echo "      Mark N as complete and recreate with any due date and deferral date"
  echo "      set as ADJUST from _their original values_."
  echo ""
  exit
}

function parse_options()
{
  local action=$1
  shift

  [ "$action" = "usage" ] && usage

  # Retrieve the item number from the arguments
  ITEM=$1
  if [[ ! "$ITEM" =~ ^[0-9]+$ ]]
  then
    error "$ITEM: invalid item number"
  exit
  fi

  shift
  ADJUST=$1
}

# Retrieve line number $ITEM from the file $TODO_FILE
function get_line()
{
  [ -f "$TODO_FILE" ] || error "$TODO_FILE: no such file"
  # Get the line from the todo file
  LINE=$(sed "$ITEM!d" "$TODO_FILE")
  [ -z "$LINE" ] && error "$ITEM: no such line"
}

# Find $ADJUST in the task
function get_days_from_line()
{
  if [[ $LINE == *" $AGAIN_TAG:"* ]]
  then
    ADJUST=`sed "s/.* $AGAIN_TAG:\([^ ]*\).*/\1/" <<< "$LINE"`
  fi
}

# Replace any creation date of the item in $LINE to $TODAY
function replace_creation_date()
{
  if [[ "$LINE" =~ ^(\([A-Z]\) )*$BASH_DATE_RE.* ]]
  then
    LINE=$(echo "$LINE" | sed "s/^\(([A-Z]) \)*\($SED_DATE_RE \)*\(.*\)/\1$TODAY \3/")
  fi
}


# Remove any creation date of the item in $LINE
function remove_creation_date()
{
  LINE=$(echo "$LINE" | sed "s/^\(([A-Z]) \)*$SED_DATE_RE /\1/g")
}


# Replace any date with $TAG in $LINE by $ADJUST
function replace_tagged_date()
{
  if [[ "$LINE" =~ .*$TAG:$BASH_DATE_RE.* ]]
  then
    if [[ -z $ADJUST ]]
    then
      # ADJUST not detailed; adjust to today.
      NEW_DATE=$TODAY
    else
      if [[ "$ADJUST" =~ ^\+[0-9]+ ]]
      then
        # Adjust to ADJUST from original values.
        ORIGINAL=$(echo "$LINE" | sed "s/.*$TAG:\($SED_DATE_RE\).*/\1/")
      else
        # Adjust to ADJUST from today.
        ORIGINAL=$TODAY
      fi
      adjust_date
    fi
    LINE=$(echo "$LINE" | sed "s/\(.*$TAG:\)\($SED_DATE_RE\)\(.*\)/\1$NEW_DATE\3/")
  fi
}

# Replace any due date (due:DATE) of the item in $LINE by $ADJUST
function replace_due_date()
{
  TAG=due
  replace_tagged_date
}

# Replace any deferral date (t:DATE) of the task in $LINE by $ADJUST
function replace_deferral_date()
{
  TAG=t
  replace_tagged_date
}

parse_options "$@"
determine_date_version
today
get_line
[ "$ADJUST" == "" ] && get_days_from_line
if [[ "$TODOTXT_DATE_ON_ADD" != 1 ]]
then
  replace_creation_date
else
  remove_creation_date
fi
replace_due_date
replace_deferral_date

if [[ "$LINE" != "" ]]
then
  "$TODO_FULL_SH" command do "$ITEM"

  if [[ -z "$TODO_NO_AGAIN_IF_NOT_TAGGED" || "$LINE" =~ .*" $AGAIN_TAG:" ]]
  then
    "$TODO_FULL_SH" command add "$LINE"
  fi
fi