#!/bin/sh

# Copyright 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/acl.sh"
. "$_EXEC/tools.sh"
. "$_EXEC/datetime.sh"

tags='' ntags='' dir='' depth='' glob_system_pages=false
label='' labeltype='' altlabel='' cnt=0

set -- "$@" --
while [ $# -gt 0 ]; do case $1 in
  --system) glob_system_pages=true; shift 1;;
  --depth)  depth="$2" shift 2;;
  \#*) tags="${tags}${tags:+ }${1###}"; shift 1;;
  \!*) ntags="${ntags}${ntags:+ }${1##!}"; shift 1;;
  --h1|--h2|--h3|--h4|--h5|--h6|--label)
    labeltype="${1#--}" label="$2"; shift 2;;
  --alt-label)
    altlabel="$2"; shift 2;;
  --) shift 1; break;;
  *) if [ ! "$dir" ]; then
      dir="$1"
      set -- "$@" "$1"; shift 1;
    elif [ ! "$depth" ]; then
      depth="$1"; shift 1;
    else
      set -- "$@" "$1"; shift 1;
    fi;;
esac; done

[ "$*" ] || set -- "*"
[ "$depth" -ge 0 -o "$depth" -le 0 ] 2>&- || depth=0

read DY DM DD <<-EOF
	$(date +"%Y %m %d")
	EOF

dstart="$(date -d "${DY}-${DM}-01" +%s)"
[ "$DM" -lt 12 ] \
&& dend="$(date -d "${DY}-$(( ${DM#0} + 1))-01" +%s)" \
|| dend="$(date -d "$(( ${DY#0} + 1))-01-01" +%s)"

expand() {
  local start="$1" end="$2" rrfreq="$3" rrint="$4" rrend="$5" evtitle="$6" evlink="$7"
  local dstart dend
  local nstart nend

  [ "$rrend" -eq -1 ] && rrend=9999999999

  case $rrint in
    day)
      nend=$(( rrfreq * 86400 - (dstart - end) % (rrfreq * 86400) + dstart ))
      nstart=$(( start - end + nend))
      debug "[ $nend -lt $dend -a $nstart -lt $rrend ]"
      while [ "$nend" -lt "$dend" -a "$nstart" -lt "$rrend" ]; do
        printf '%i	%i	%s	%s\n' "$nstart" "$nend" "$evtitle" "$evlink"
        # printf '%i	%i	%s\n' "$nstart" "$nend" "$evlink"
        nstart="$((nstart + rrfreq * 86400))"
          nend="$((nstart - start + end))"
      done
      ;;
    week)
      nend=$(( rrfreq * 604800 - (dstart - end) % (rrfreq * 604800) + dstart ))
      nstart=$(( start - end + nend))
      while [ "$nend" -lt "$dend" -a "$nstart" -lt "$rrend" ]; do
        printf '%i	%i	%s	%s\n' "$nstart" "$nend" "$evtitle" "$evlink"
        nstart="$((nstart + rrfreq * 7 * 86400))"
          nend="$((nstart - start + end))"
      done
      ;;
    month)
      { read _y _m _d; read y m d; } <<-EOF
	$(date -d @$dstart +"%Y %_m %_d"
	  date -d @$start  +"%Y %_m %_d"
	)
	EOF
      _m=$((_y * 12 + _m)) m=$((y * 12 + m))
      while :; do
        m=$(( rrfreq - ((_m - m - 1) % rrfreq + 1) + _m ))
        nstart="$(printf '%04i-%02i-%02i' "$(( (m - 1) / 12 ))" "$(( (m - 1) % 12 + 1 ))" "$d")"
        if isdate "$nstart" && [ "$(date -d "$nstart" +%s)" -ge "$dstart" ]; then
          break
        fi >/dev/null
        _m="$((_m + rrfreq))"
      done
      nstart="$(date -d "$nstart $start_time" +%s)"
        nend="$((end - start + nstart))"
      while [ "$nend" -lt "$dend" -a "$nstart" -lt "$rrend" ]; do
        printf '%i	%i	%s	%s\n' "$nstart" "$nend" "$evtitle" "$evlink"
        m="$((m + rrfreq))"
        nstart="$(printf '%04i-%02i-%02i' "$(( (m - 1) / 12 ))" "$(( (m - 1) % 12 + 1 ))" "$d")"
        nstart="$(date -d "$nstart $start_time" +%s)"
          nend="$((nstart - start + end))"
      done
      ;;
    year)
      { read _y _m _d; read y m d; } <<-EOF
	$(date -d @$dstart +"%Y %_m %_d"
	  date -d @$start  +"%Y %_m %_d"
	)
	EOF
      while :; do
        y=$(( rrfreq - ((_y - y - 1) % rrfreq + 1) + _y ))
        nstart="$(printf '%04i-%02i-%02i' "$y" "$m" "$d")"
        if isdate "$nstart" && [ "$(date -d "$nstart" +%s)" -ge "$dstart" ]; then
          break
        fi >/dev/null
        _y="$((_y + rrfreq))"
      done
      nstart="$(date -d "$nstart $start_time" +%s)"
        nend="$((end - start + nstart))"
      while [ "$nend" -lt "$dend" -a "$nstart" -lt "$rrend" ]; do
        printf '%i	%i	%s	%s\n' "$nstart" "$nend" "$evtitle" "$evlink"
        y="$((y + rrfreq))"
        nstart="$(printf '%04i-%02i-%02i' "$y" "$m" "$d")"
        nstart="$(date -d "$nstart $start_time" +%s)"
          nend="$((nstart - start + end))"
      done
      ;;
    *):
      printf '%i	%i	%s	%s\n' "$start" "$end" "$evtitle" "$evlink"
      ;;
  esac
}

events="$(
  for dir in "$@"; do
    page_glob "$dir" "$depth"
  done \
  | sort -u \
  | while read -r page; do
    pagedir="$(page_abs "$page")"
    if [ -f "$_DATA/pages/${pagedir}/#events" ] \
       && acl_read "$pagedir" \
       && has_tags "$pagedir" $tags \
       && ! has_tag "$pagedir" $ntags
    then
      cat "$_DATA/pages/${pagedir}/#events"
    fi
  done \
  | while read -r junk1 tstart tend rrfreq rrint rrend evtitle evlink junk2; do
    if [ "$tend" -gt "$dstart" -a "$tstart" -lt "$dend" ] \
       || [ "$rrend" -gt "$dstart" -o "$rrend" -eq -1 ]; then
      expand "$tstart" "$tend" "$rrfreq" "$rrint" "$rrend" "$evtitle" "$evlink"
    fi
  done \
  | debug \
  | sort -n
)"

lday=''

printf '<ul class="macro calendar">\n'
printf '%s\n' "${events}" \
| while read start end name link; do
  day="$((start / 86400))"
  if [ "$day" != "$lday" ]; then
    [ "$lday" ] && printf '</ul></li>'
    date -d "@$start" +'<li><label>%A, %F</label><ul class="day">'
    lday="$day"
  fi
  printf '<li>%s: <a href="%s">%s</a></li>' \
         "$(date -d "@$start" +"%T")" "$(URL "${link%%#*}")#$(URL "${link#*#}")" "$(HTML "${name}")"
done
printf '</ul></li></ul>'