#! /usr/bin/ksh
#
#	Author: Mike Fleming mike@tauzero.co.uk
#
#	Allows a list of files to be selected for viewing using more or
#	fileview
#
#	The special literal "today" or "today-n" where n is a number can be
#	used to indicate file names containing today's date or a date n days
#	in the past. By default the form ccyymmdd will be used - the -y option
#	specifies that the short yymmdd form is to be used. The -s parameter
#	can be used to specify a date separator character.
#
#	As well as a number, N for next, P for previous, and Q to quit, if
#	! is input, a shell command can be executed - it can either be supplied
#	after ! (eg. !ls -l) or, if it is not supplied there, it will be
#	requested.
#
#	Usage:
#	morefrom [ -a ] [ -c ] [ -s separator ] [ -v ] [ -y ] filelist
#	Options
#
#	-a	Show all files in filelist, including zero-length files
#	-c	Case sensitive searches in more
#	-s	Specify a date separator character
#	-v	Use fileview to view file
#	-y	Use short date (yymmdd) for "today-n" date form

PGLEN=25
CASE=-i
CHK=""
YR=Y
DS=Y
YRFLAG=""
DSFLAG=""
VIEWER=more
VCASE=-i

USAGE="morefrom [ -a ] [ -c ] [ -s separator ] [ -v ] [ -y ] filelist\n\n
\t-a\tShow all files in filelist, including zero-length files\n
\t-c\tSearches in 'more' command are case sensitive\n
\t-s\tSpecify a date separator character (default is no separator)\n
\t-v\tUse fileview to view file\n
\t-y\tUse short date (yymmdd) for 'today-n' date form\n"

while getopts :acs:vy opt
do
	case $opt in
	a)	CHK="A";;
	c)	CASE=""
		VCASE="";;
	s)	DS=$OPTARG
		DSFLAG="-s $OPTARG";;
	v)	VIEWER=fv
		VCASE="";;
	y)	YR=y
		YRFLAG=-y;;
	?)	echo "Unknown option $OPTARG"
		echo $USAGE
		return 1;;
	:)	echo "Missing value for option $OPTARG"
		echo $USAGE
		return 1;;
	*)	echo $USAGE
		return;;
	esac
done

shift $((OPTIND - 1))

typeset -i ptr=0

if [[ "$1" == "" && "$CHK" != "A" ]]
then
	echo $USAGE
	return
fi

while [[ -n "$1" ]]
do
	if [[ "$(echo $1 | cut -c1-5)" == "today" ]]
	then
		if [[ "$1" == "today" ]]
		then
			l=$(LC_COLLATE=C ls *$(date +%$YR$DS%m$DS%d)* 2>/dev/null)
		else
			dd=$(echo $1 | cut -c7-)
			l=$(LC_COLLATE=C ls *$(prev_date $DSFLAG $YRFLAG $dd)* 2>/dev/null)
		fi
	elif [[ "$1" == "yesterday" ]]
	then
		l=$(LC_COLLATE=C ls *$(prev_date $DSFLAG $YRFLAG 1)* 2>/dev/null)
	else
		l=$(LC_COLLATE=C ls $1) 2>/dev/null
	fi
	for a in $l
	do
		if [[ -s "$a" || ( -f "$a" && "$CHK" == "A" ) ]]
		then
			if [[ ! -d "$a" ]]
			then
				fnames[$ptr]=$a
				ptr=$(($ptr + 1))
			fi
		fi
	done
	shift
done

if [[ -z "${fnames[0]}" ]]
then
	echo "No matching files found"
	return
fi

#	page = current page (starts at 0)
#	index = screen array pointer for display (starts at 0)
#	line = display line number (starts at 1)
#	ptr = pointer to file to display

typeset -i page=0
typeset -i index
typeset -i line

while [[ "$REPLY" != "Q" && "$REPLY" != "q" ]]
do

	line=1
	lastline=$((PGLEN - 1))
	index=$((page * lastline))

	while [[ -n "${fnames[$index]}" && $line -le $lastline ]]
	do
		if (( $line < 10 ))
		then
			lno=" "$line
		else
			lno=$line
		fi
		echo "$lno" ${fnames[$index]}
		index=$((index + 1))
		line=$((line + 1))
	done

	FURTHER=""

	if [[ -n "${fnames[$index]}" ]]
	then
		FURTHER=$FURTHER" [N]ext page,"
	fi

	if (( $page > 0 ))
	then
		FURTHER=$FURTHER" [P]revious,"
	fi

	read REPLY?"No. of file to view,$FURTHER [Q]uit, ! - shell cmd: "

	if [[ "$REPLY" == "" ]]
	then
		REPLY="X"
	fi

	if (( $(echo $REPLY | grep -c "^[0-9]*$") > 0 ))
	then
		if (( REPLY > 0 && REPLY <= lastline ))
		then
			ptr=$(((page * lastline) + (REPLY - 1)))
			if [[ -n "${fnames[$ptr]}" ]]
			then
				fn=${fnames[$ptr]}
				suffix=$(expr "$fn" : '.*\.\([^./]*\)$')
				if [[ "$suffix" == "Z" ]]
				then
					uncompress -c $fn | $VIEWER $VCASE
				else
					$VIEWER $VCASE $fn
				fi
			fi
		fi
	elif (( $(echo $REPLY | grep -c "^!") > 0 ))
	then
		CMD=$(echo $REPLY | cut -c 2-)
		if [[ "$CMD" == "" ]]
		then
			read CMD?"Command to execute: "
		fi
		if [[ "$CMD" != "" ]]
		then
			eval $CMD
		fi
	else
		case $REPLY in
		P | p)  if (( page > 0 ))
			then
				page=$((page - 1))
			fi;;
		N | n)  if [[ -n "${fnames[$index]}" ]]
			then
				page=$((page + 1))
			fi;;
		esac
	fi

done