vevent_dump

#! /bin/sh

# Create somewhat readable output from ICS (or similar) files.

# Copyright (C) 2017-2023 Erik Auerswald <auerswal@unix-ag.uni-kl.de>

# Copying and distribution of this file, with or without modification,
# are permitted in any medium without royalty provided the copyright
# notice and this notice are preserved.  This file is offered as-is,
# without any warranty.

# Version 2023-06-04-01

process_event_data() {
  test $# -eq 0 && FILE='-' NAME='standard input' || FILE=$1 NAME=$1
  printf -- '========[ %s ]========\n' "$NAME"
  sed -n '/BEGIN:VEVENT/,/END:VEVENT/p' "$FILE" \
  | sed -e '/BEGIN:VALARM/,/END:VALARM/d' \
        -e '/^[[:space:]]*X-MS-OLK/d' \
        -e 's/\r$//' \
  | sed ':RN;$!N;s/\n[[:space:]]//;tRN;P;D' \
  | sed -nE \
        -e '/ORGANIZER/s/^.*CN="?([^":;]+)"?.*:[Mm][Aa][Ii][Ll][Tt][Oo]:([^[:space:]]+).*$/Organizer: \1 <\2>/p' \
        -e '/ATTENDEE/s/^.*CN="?([^":;]+)"?.*:[Mm][Aa][Ii][Ll][Tt][Oo]:([^[:space:]]+).*$/Attendee: \1 <\2>/p' \
        -e '/SUMMARY/s/^[^:]*:(.*)$/Summary: \1/p' \
        -e '/DTSTART;TZID=/s/^.*TZID=([^:]+):([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2}).*$/Start: \4.\3.\2 at \5:\6:\7 (\1)/p' \
        -e '/DTSTART/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2})([A-Z]{1,4}).*$/Start: \3.\2.\1 at \4:\5:\6 (\7)/p' \
        -e '/DTSTART/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2}).*$/Start: \3.\2.\1 at \4:\5:\6/p' \
        -e '/DTSTART;VALUE=DATE:/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})/Start: \3.\2.\1/p' \
        -e '/DTEND;TZID=/s/^.*TZID=([^:]+):([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2}).*$/End: \4.\3.\2 at \5:\6:\7 (\1)/p' \
        -e '/DTEND/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2})([A-Z]{1,4}).*$/End:   \3.\2.\1 at \4:\5:\6 (\7)/p' \
        -e '/DTEND/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})T([[:digit:]]{2})([[:digit:]]{2})([[:digit:]]{2}).*$/End:   \3.\2.\1 at \4:\5:\6/p' \
        -e '/DTEND;VALUE=DATE:/s/^.*:([[:digit:]]{4})([[:digit:]]{2})([[:digit:]]{2})/End:   \3.\2.\1/p' \
        -e '/DESCRIPTION/s/^[^:]*:(.*)$/----=[ start description ]=----\n\1\n-----=[ end description ]=-----/p' \
        -e '/LOCATION/s/^[^:]*:(.*)$/Location: \1/p' \
  | sed 's/\\,/,/g;s/\\n/\n/g'
}

if test $# -eq 0; then
  process_event_data
else
  for F in "$@"; do
    process_event_data "$F"
  done
fi