#!/bin/sh
# $MawkId: hical,v 1.4 2009/08/21 00:36:34 tom Exp $

# @(#) hical - displays previous, current & next months - today highlighted
# @(#) an "internationalizationable" version of a 3-month 'cal' display, it
# @(#) may be edited for week to start with Sun or Mon & for local language

prog=${TMPDIR-/tmp}/hical.$$ ; trap 'rm -f $prog ; trap 0 ; exit' 0 1 2 3 15

: ${so:=`tput smso`} ${se:=`tput rmso`}

# USER EDITS MAY BE REQUIRED for the arguments to the 'date' command
# the script presumes 'date' recognizes these arguments in these ways:
#   w - Day of the week - Sunday = 0
#   m - Month of year - 01 to 12
#   d - Day of month - 01 to 31
#   T - Time as HH:MM:SS
#   Y - Year (including century), as decimal numbers
DATE_ARGS='%w %m %d %T %Y'

# the 'awk' program file is written to a temporary file to avoid any
# "arg list too long" error messages, yet have all the code in one file.
cat >$prog <<'EOF'
{
# USER EDITS MAY BE REQUIRED (for FMT, day & month names, and the time stuff)
# FMT = 0  # for weekdays ordered "Mo Tu We Th Fr Sa Su"
  FMT = 1  # for weekdays ordered "Su Mo Tu We Th Fr Sa"
  Header[0] = "Mo Tu We Th Fr Sa Su"
  Header[1] = "Su Mo Tu We Th Fr Sa"
  months    = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec"
  time_is   = "The time is:" ; time_fmt = "%s   %s  %s %s\n"
# NO MORE USER EDITS REQUIRED (I think!)
  split(months,M_Name) ; split("31 28 31 30 31 30 31 31 30 31 30 31",M_Len)
  daynum  = $1 + FMT
  Mon[2]  = $2 + 0
  today   = $3 + 0
  time    = $4
  Year[1] = Year[2] = Year[3] = $NF
  if ( Mon[2] ==  1 ) { Year[1] = Year[1] - 1 ; Mon[1] = 12 }
    else              { Mon[1]  = Mon[2]  - 1 }
  if ( Mon[2] == 12 ) { Year[3] = Year[3] + 1 ; Mon[3] =  1 }
    else              { Mon[3]  = Mon[2]  + 1 }
  if ( Year[2] % 4   == 0 &&
       Year[2] % 100 != 0 ||
       Year[2] % 400 == 0 ) M_Len[2] = 29
  Start[2] = 7 - ( ( today - daynum ) % 7 )
  Start[1] = 7 - ( ( M_Len[Mon[1]] - Start[2] ) % 7 )
  Start[3] =       ( M_Len[Mon[2]] + Start[2] ) % 7
  for (i=1;i<=3;i++) { while ( Start[i] >= 7 ) Start[i] -= 7 }
  for (mm=1;mm<=3;mm++) {
    if ( Year[mm] != Year[mm-1] )
      printf( "%s            %s          %s\n", so, Year[mm], se )
    if ( mm == 1 ) printf( "%s    %s  %s\n", so, Header[FMT], se )
    j = k = 1
    while ( j <= M_Len[Mon[mm]] ) {
      line = ""
      for (i=1;i<=7;i++) {
        if ( Start[mm] > 0 || j > M_Len[Mon[mm]] ) { date = "" ; Start[mm]-- }
          else date = j++
        if ( mm == 2 && date == today ) { So = so ; Se = se }
          else { So = Se = "" }
        line = sprintf( "%s%s%2s%s ", line, So, date, Se )
      }
      m1 = substr(M_Name[Mon[mm]],k++,1)
      printf( "%s %1s %s %s%s %s\n", so, m1, se, line, so, se )
    }
  }
  printf( time_fmt, so, time_is, time, se )
}
EOF

date +"$DATE_ARGS" | ${AWK:=mawk} -f $prog so=$so se=$se

exit 0

# EOF 'hical'  - Tue Dec 19 19:19:19 EST 1994
# Bob Stockler - bob@trebor.iglou.com - CIS: 72726,452