#!/bin/bash
# set -x

# mosaic available at: http://montage.ipac.caltech.edu/
# js9helper available at: https://js9.si.edu

# clean up on exit or error
cleanup() {
  if [ -s $CLEANLST ]; then
    vlog "cleaning up"
    for F in `cat $CLEANLST`; do
      rm -f "$F"
    done
    rm -f $CLEANLST
  fi
}

# error handler: send to stderr
error() {
  echo "ERROR: $*" >&2
  cleanup
  exit 1
}

# vlog output, if necessary
vlog() {
  if [ x"$VERBOSE" = xtrue ]; then
    echo "$*"
  fi
}

usage(){
  echo "$0 [switches] image1 image2 ... imagen ofile"
  echo "switches:"
  echo "  -dim [dim]     # shrink using mShrinkHdr or js9helper before reprojecting"
  echo "  -nopp          # use mProject instead of mProjectPP"
  echo "  -nojs9         # always use mShrinkHdr, don't use js9helper"
  echo "  -save          # save logs, tables, and headers"
  echo "  -v             # verbose output"
  echo ""
  exit 0
}

# init varibles
DOFAST=true
BASEDIR=.
ROOT=_mosaic
STATUS=${ROOT}_status_$$.log
INLST=${ROOT}_in_$$.lst
OUTLST=${ROOT}_out_$$.lst
INTBL=${ROOT}_in_$$.tbl
OUTTBL=${ROOT}_out_$$.tbl
INHDR=${ROOT}_$$.hdr
OUTHDR=${ROOT}_out_$$.hdr
LINE1='|                                                    fname|'
LINE2='|                                                     char|'
CLEANLST=${ROOT}_clean_$$.lst
USEJS9=true

# sanity check that we have system programs in the path
hash mImgtbl mMakeHdr mProjectPP mAdd 1>/dev/null 2>&1
if [ $? != 0 ]; then
    error "can't find Montage programs. Check the PATH or install Montage (http://montage.ipac.caltech.edu)"
fi

# process command line arguments
while [ x"$1" != x ]; do
    case $1 in
	-dim*) shift
	    DIM=$1
	    shift
	    continue;;
	-nopp) shift
	    DOFAST=false
	    continue;;
	-nojs9) shift
	    USEJS9=false
	    continue;;
	-save) shift
	    DOSAVE=true
	    continue;;
	-v) shift
	    VERBOSE=true
	    continue;;
	*)  break;;
    esac
done

# we don't necesssarily use js9helper, but check it we have it
if [ x"$USEJS9" = xtrue ]; then
  hash js9helper 1>/dev/null 2>&1
  if [ $? = 0 ]; then
    JS9HELPER=true
  fi
fi

# required args: FITS file(s) for mosaic and output file
if [ $# -lt 2 ]; then
  usage
fi
# output file is last argument
OFILE=${@:$#}
# input file are all but the last argument
set -- ${@:1:$(($# - 1))}

# cleanup these files
if [ x${DOSAVE} = x ]; then
  echo ${OUTHDR} >> ${CLEANLST}
  echo ${STATUS} >> ${CLEANLST}
fi

# choose shrink/bin method:
# if we have more exactly 1 input file, use js9helper if available
# if we have more than 1 input file, use shrink instead of js9helper
if [ x"$DIM" != x ]; then
  # if we have exactly 1 input file, use js9helper instead of shrink
  if [ $# = 1 ]; then
    if [ x"$JS9HELPER" = xtrue ]; then
      vlog "use js9helper instead of shrink for a single file"
      DOJS9=true
      DOSHRINK=false
    else
      vlog "use shrink (js9helper not available) for a single file"
      DOSHRINK=true
      DOJS9=false
    fi
  else
    vlog "use shrink instead of js9helper for multiple files"
    DOSHRINK=true
    DOJS9=false
  fi
fi

# generate input list from command line arguments
echo "$LINE1" >> $INLST
echo "$LINE2" >> $INLST
if [ x${DOSAVE} = x ]; then
  echo ${INLST} >> ${CLEANLST}
fi
while [ x"$1" != x ]; do
  FILE="$1"
  if [ ! -r "$FILE" ]; then
    error "$FILE not found"
  fi
  if [[ "$FILE" =~ \.fz$ ]]; then 
    LINK=`echo $FILE | sed 's/\.fz//'`
    LINK=`basename $LINK`
    if [ ! -r $LINK ]; then
      vlog "linking $LINK to $FILE"
      ln -s $FILE $LINK
      echo ${LINK} >> ${CLEANLST}
    fi
    FILE=$LINK
  fi
  echo $FILE >> $INLST
  shift
done

vlog "making input table for $FILE"
if [ x${DOSAVE} = x ]; then
  echo ${INTBL} >> ${CLEANLST}
fi
mImgtbl -t ${INLST} -s ${STATUS} ${BASEDIR} ${INTBL}
if [ $? != 0 ]; then
  cat $STATUS
  exit
fi
# make sure input table has FITS files
if [ ! -s ${INTBL} ]; then
  error "no FITS files were added to input table"
fi

vlog "making input header"
if [ x${DOSAVE} = x ]; then
  echo ${INHDR} >> ${CLEANLST}
fi
mMakeHdr -s ${STATUS} ${INTBL} ${INHDR}
if [ $? != 0 ]; then
  cat $STATUS
  exit
fi

# auto binning
if [ x"$DOJS9" = xtrue ]; then
  BIN=`awk -v dim=$DIM '
    /^NAXIS1/{ naxis1 = $3}
    /^NAXIS2/{ naxis2 = $3}
    END{
      if( naxis1 > naxis2 ){
        naxis = naxis1
      } else {
        naxis = naxis2
      }
      bin = int((naxis / dim) + 0.5)
      print bin
    }
  ' < ${INHDR}`
  if [ $BIN -le 2 ]; then
      vlog "small bin ($BIN) warrants use of shrink instead of js9helper"
      DOSHRINK=true
      DOJS9=false
  else
      vlog "bin factor: $BIN"
  fi
fi

# shrink header, if necessary
if [ x$DOSHRINK = xtrue ]; then
    # use shrink input header for reprojection
    vlog "shrink input header using mShrinkHdr $DIM"
    mShrinkHdr -s ${DIM} ${INHDR} ${OUTHDR}  2>&1 1>/dev/null
    if [ $? != 0 ]; then
      error "mShrinkHdr failed: $F"
    fi
else
    # use original input header for reprojection
    cp -p ${INHDR} ${OUTHDR}
fi

# header for output list
echo "$LINE1" >> $OUTLST
echo "$LINE2" >> $OUTLST
if [ x${DOSAVE} = x ]; then
  echo ${OUTLST} >> ${CLEANLST}
fi
vlog "processing input table"
awk < ${INTBL} '/^[^|\\]/{EXT=NF-1; print $NF, $EXT}' | while read F E
do
  if [ x$DOJS9 = xtrue ]; then
    # bin each input image extension into a smaller file before reprojecting
    vlog "  bin $F[$E] using js9helper $DIM [$BIN]"
    S=bin_${E}_`basename ${F}`
    js9helper -i ${F}'['${E}']' imsection \!${S} '0@0,0@0,'"$BIN" 2>&1 1>/dev/null
    if [ $? != 0 ]; then
      error "js9helper failed: $F"
    fi
    echo ${S} >> ${CLEANLST}
  else
    # reproject each extension of the input image
    S=${F}
    ARGS="-h ${E}"
  fi
  # reproject the (possibly binned or shrunk) image
  R=reproj_${E}_`basename ${F}`
  if [ x"$DOFAST" = xtrue ]; then
    vlog "  mProjectPP ${S} ${ARGS}"
    mProjectPP $ARGS -s ${STATUS} ${S} ${R} ${OUTHDR}
  else
    vlog "  mProject ${S} ${ARGS}"
    mProject $ARGS -s ${STATUS} ${S} ${R} ${OUTHDR}
  fi
  if [ $? != 0 ]; then
    cat $STATUS
    exit
  fi
  # add reprojected file to output list
  echo ${R} >> ${OUTLST}
  R1=`echo ${R} | sed 's/\[[^]]*\]//'`
  echo ${R1} >> ${CLEANLST}
  R2=`echo ${R1} | sed 's/\.fits/_area\.fits/'`
  echo ${R2} >> ${CLEANLST}
done

vlog "making output table"
if [ x${DOSAVE} = x ]; then
  echo ${OUTTBL} >> ${CLEANLST}
fi
mImgtbl -t ${OUTLST} -s ${STATUS} ${BASEDIR} ${OUTTBL}
if [ $? != 0 ]; then
  cat $STATUS
  exit
fi
# make sure output table has FITS files
if [ ! -s ${OUTTBL} ]; then
  error "no FITS files were added to output table"
  exit
fi

vlog "making mosaic: ${OFILE}"
mAdd -s ${STATUS} ${OUTTBL} ${OUTHDR} ${OFILE}
if [ $? != 0 ]; then
  cat $STATUS
  exit
fi
echo ${OFILE} | sed 's/\.fits/_area\.fits/' >> ${CLEANLST}

# clean up on exit
trap cleanup EXIT