#!/bin/sh

############################################################################
#
# MODULE:       v.group for GRASS 6
# AUTHOR(S):    Cedric Shock
# PURPOSE:      To group vector data collapsing it to fewer classes
# COPYRIGHT:    (C) 2006 by the GRASS Development Team
#
#               This program is free software under the GNU General Public
#               License (>=v2). Read the file COPYING that comes with GRASS
#               for details.
#
#############################################################################

# Todos:
#   Wishes:
#     This functionality should be more generalized and worked into v.reclass
#     Rework indentation without using tabs
#     More g.parser prompts would be awesome (column / layer selection, etc.)
#     Ultimately this sort of functionality belongs in the categorization in d.vect
#      Along with this we need a vector legend display.
#   Bugs
#     doesn't select type like reclass does
#     doesn't work with database connections

# Usage example
# v.group input=ownership output=groupedownership columns=LAND_OWN,LAND_MGR

#%Module
#%  description: Groups and reclassifies vector data
#%End
#%option
#% key: input
#% type: string
#% gisprompt: old,vector,vector
#% description: Name of input vector
#% required : yes
#%end
#%option
#% key: output
#% type: string
#% gisprompt: new,dig,vector
#% description: Name of output vector
#% required : yes
#%end
#%option
#% key: columns
#% type: string
#% description: Columns to group on
#% required : yes
#% multiple: yes
#%end
##%option
##% key: type
##% type: string
##% description: Select type
##% options: point,line,boundary,centroid
##% answer: point,line,boundary,centroid
##% multiple: yes
##% required : no
##%end
#%option
#% key: layer
#% type: integer
#% description: Layer number
#% answer: 1
#% required : no
#%end



if  [ -z $GISBASE ] ; then
    echo "You must be in GRASS GIS to run this program." 1>&2
 exit 1
fi

if [ "$1" != "@ARGS_PARSED@" ] ; then
  exec g.parser "$0" "$@"
fi

#### setup temporary file
TMP="`g.tempfile pid=$$`"
if [ $? -ne 0 ] || [ -z "$TMP" ] ; then
    echo "ERROR: unable to create temporary files" 1>&2
    exit 1
fi


#### trap ctrl-c so that we can clean up tmp
trap 'rm -f ${TMP}*' 2 3 15

#eval `g.gisenv`
#: ${GISBASE?} ${GISDBASE?} ${LOCATION_NAME?} ${MAPSET?}
#LOCATION=$GISDBASE/$LOCATION_NAME/$MAPSET

echo "Checking for columns:" 1>&2
COL=0
IFS=,
for opt in $GIS_OPT_columns ; do
	((COL++))
        echo -n " $opt :" 1>&2
	FOUND="`db.columns table=$GIS_OPT_input | fgrep $opt`"
	if [ $opt != $FOUND ] ; then
		echo " not found" 1>&2
		echo "ERROR: table $GIS_OPT_input has no column $opt." 1>&2
		exit 1
	else
		echo " X" 1>&2
	fi
	columns[$COL]=$opt
	columnlength[$COL]=2
done

echo "Extracting Categories:" 1>&2
echo " select $GIS_OPT_columns from $GIS_OPT_input" 1>&2
DATA="`echo "select $GIS_OPT_columns from $GIS_OPT_input" | db.select -c | sort -u`"


echo "Generating Rules:" 1>&2

RULESFILE=$TMP-rules
SQLFILE=$TMP-sql
echo "# Rules file generated by v.group" > $RULESFILE
touch $SQLFILE

CAT=0
IFS="
"
for line in $DATA; do
	((CAT++))
	echo "cat $CAT" >> $RULESFILE
	echo -n "insert into $GIS_OPT_output values ( $CAT " >> $SQLFILE
	COL=0
	IFS="|"
	for field in $line; do
		((COL++))
		if [ $COL = 1 ] ; then
			delimiter="where"
		else
			delimiter=" and"
		fi
		column=${columns[$COL]}
		length=${#field}
		if [ $length -gt ${columnlength[$COL]} ] ; then
			columnlength[$COL]=$length
		fi
		echo -n "$delimiter $column = '$field'" >> $RULESFILE
		echo -n ", '$field' " >> $SQLFILE
	done
	echo >> $RULESFILE
	echo ")" >> $SQLFILE
done

echo "Finishing SQL commands:" 1>&2

echo -n "create table $GIS_OPT_output (cat integer" > $TMP-sqlcopy
COL=0
IFS=,
for opt in $GIS_OPT_columns ; do
	((COL++))
	length=${columnlength[$COL]}
	((length = length * 2))
	echo -n ", $opt varchar($length)" >> $TMP-sqlcopy
done
echo ")" >> $TMP-sqlcopy
cat $SQLFILE >> $TMP-sqlcopy
mv $TMP-sqlcopy $SQLFILE

#cat $RULESFILE
#cat $SQLFILE

echo "Reclassifying Map:" 1>&2

#echo "v.reclass input=$GIS_OPT_input output=$GIS_OPT_output type=$GIS_OPT_type layer=$GIS_OPT_layer rules=$RULESFILE"
# We don't do type; it doesn't work for some reason
# type=$GIS_OPT_type
v.reclass input=$GIS_OPT_input output=$GIS_OPT_output layer=$GIS_OPT_layer rules=$RULESFILE

echo "Creating Table:" 1>&2
IFS="
"
SQLCOMMANDS="`cat $SQLFILE`"
for cmd in $SQLCOMMANDS; do
	echo $cmd | db.execute
done

echo "Connecting Vector to table:" 1>&2
v.db.connect map=$GIS_OPT_output table=$GIS_OPT_output layer=$GIS_OPT_layer

echo "Cleaning Up:" 1>&2

## Clean up tmp
rm -f ${TMP}*

echo "Done." 1>&2