#!/bin/sh

# Copyright 2023 - 2024 Paul Hänsch
# 
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
# 
# THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
# IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

. $_EXEC/cgilite/cgilite.sh
. $_EXEC/cgilite/storage.sh
. $_EXEC/datetime.sh

_(){ printf %s\\n "$*"; }
[ "${LANGUAGE}" -a -r "${_EXEC}/l10n/${LANGUAGE}.sh" ] && . "${_EXEC}/l10n/${LANGUAGE}.sh"

start_date= start_time= end_date= end_time=
rec_freq= rec_int= error_msg= rec_end=
title=
start= end= nstart= nend=

while [ $# -gt 0 ]; do case $1 in
  --from|from|--start|start)
    if   isdate "$2" && istime "$3" ; then
      start_date="$(isdate "$2" )" start_time="$(istime "$3")"
      shift 3
    elif isdate "${2%% *}" && istime "${2#* }" ; then
      start_date="$(isdate "${2%% *}" )" start_time="$(istime "${2#* }")"
      shift 2
    elif isdate "$2" ; then
      start_date="$(isdate "$2")" start_time="00:00"
      shift 2
    else
      error_msg="Event start should be \"YYYY-MM-DD\" or \"YYYY-MM-DD hh:mm\""
      shift 1
    fi >/dev/null
    ;;
  --to|to|--end|end)
    if   isdate "$2" && istime "$3"; then
      end_date="$(isdate "$2")" end_time="$(istime "$3")"
      shift 3
    elif isdate "${2%% *}" && istime "${2#* }"; then
      end_date="$(isdate "${2%% *}")" end_time="$(istime "${2#* }")"
      shift 2
    elif isdate "$2"; then
      end_date="$(isdate "$2")" end_time="23:59"
      shift 2
    elif istime "$2"; then
      end_time="$(istime "$2")"
      shift 2
    else
      error_msg="Event end should be \"YYYY-MM-DD\" or \"YYYY-MM-DD hh:mm\" or \"hh:mm\""
      shift 1
    fi >/dev/null
    ;;
  --repeat|--recur|--recurrence|--every|every)
    if expr "$2" : '^[0-9]\+$' &&
       expr "$3" : '^\(days\|nights\|weeks\|months\|years\|weekday\)$'; then
      rec_freq="$2" rec_int="$3"
      shift 3
    elif expr "$2" : '^[0-9]\+ \+\(days\|nights\|weeks\|months\|years\|weekday\)$'; then
      rec_freq="${2%% *}" rec_int="${2##* }"
      shift 2
    elif expr "$2" : '^\(day\|daily\|night\|nightly\|week\|weekly\|month\|monthly\|year\|yearly\|annually\)$'; then
      rec_freq="1" rec_int="$2"
      shift 2
    elif expr "$2" : '^last weekday$'; then
      rec_freq="-1" rec_int="weekday"
      shift 2
    elif expr "$2 $3" : '^last weekday$'; then
      rec_freq="-1" rec_int="weekday"
      shift 3
    elif expr "$2" : '^\(biweekly\|bimonthly\)$'; then
      rec_freq="2" rec_int="$2"
      shift 2
    else
      error_msg="Recurrence should be \"N days|weeks|months|years\" or \"N|last weekday\""
      shift 1
    fi >/dev/null
    ;;
  --until|until)
    if isdate $2; then
      rec_end="$(isdate "$2")"
      shift 2
    else
      error_msg="Recurrence end should be \"YYYY-MM-DD\""
      shift 1
    fi >/dev/null
    ;;
  --title)
    title="$2"
    shift 2
    ;;
  *) shift 1;;
esac; done

if [ ! "$end_time" ]; then
  end_time="23:59"
fi

shh=${start_time%:*} shh="${shh#0}"
smm=${start_time#*:} smm="${smm#0}"
ehh=${end_time%:*}   ehh="${ehh#0}"
emm=${end_time#*:}   emm="${emm#0}"

if [ ! "$end_date" -a "$end_time" -a "$start_time" ]; then
  if [ "$((ehh * 60 + emm))" -gt "$((shh * 60 + smm))" ]; then
    end_date="$start_date"
  else
    end_date="$(date -ud "@$(($(date -ud "$start_date" +%s) + 86400))" +%F)"
  fi
fi

if [ ! "$start_date" ]; then
  error_msg="Event needs start date, e.g. --start \"YYYY-MM-DD\""
fi

if [ ! "$title" ]; then
  error_msg="Event needs title, e.g. --title \"Event Name\""
fi

if [ "$error_msg" ]; then
  _ "$error_msg"
  exit 1
fi

case $rec_int in
  day|daily|days|night|nightly|nights)
    rec_int="day";;
  week|weeks|weekly|biweekly)
    rec_int="week";;
  month|monthly|months|bimonthly)
    rec_int="month";;
  year|yearly|years|annually)
    rec_int="year";;
esac

[ "$rec_end" ] && rec_end="$(date -ud "$rec_end" +%s)" \

if LOCK './#events'; then
  sed -i "/^${_DATE}	/!d" './#events'
  evid="$(wc -l <'./#events' || printf 0)"
  printf '%i	%i	%i	%i	%s	%i	%s	%s\n' \
    "$_DATE" "$(date -ud "$start_date $start_time" +%s)" "$(date -ud "$end_date $end_time" +%s)" \
    "${rec_freq:-0}" "${rec_int:-\\}" "${rec_end:--1}" "$(STRING "${title}")" "$(STRING "${PATH_INFO}#event${evid}")" \
    >>'./#events'
  RELEASE './#events'
fi

printf '<div class="macro event" id="#event%s"></div>' "${evid}"

# uid="$(timeid)"
# tzid="$(cat /etc/timezone || printf 'UTC')"
# 
# cat >>"#events.ics" <<-EOF
# BEGIN:VCALENDAR
# VERSION:2.0
# PRODID:ShellWiki Event Macro
# BEGIN:VEVENT
# UID:$uid@$(HEADER Host)
# DTSTAMP:TZID=${tzid}:$(date -u +%Y%m%dT%H%M%S)
# DTSTART:TZID=${tzid}:$(date -u +%Y%m%dT%H%M%S -d "$start_date $start_time")
# DURATION:
# RRULE:FREQ=$ec_freq;INTERVAL=$rec_int;UNTIL=$(date -u +%Y%m%dT000000Z -d "$rec_end")
# SUMMARY:
# COMMENT:
# END:VEVENT
# END:VCARD
# EOF