#!/bin/sh
#    crossmatch
#	Keep two CVS trees (stored in different repositories) in sync with
#	each other.  Changes can be made in either or both repositories,
#	and this script aims to cross-copy those changes across to the other
#	tree.

ghc=/usr/malcolm/local/haskell/compilers/ghc/cvs-rw/libraries/core
nhc=/usr/malcolm/local/haskell/compilers/nhccvs/src/libraries
safecopy=/usr/malcolm/local/haskell/libraries/safety

# Deal with commandline arguments
case $# in
  1) if [ "$1" = "-c" ]
     then echo "`basename $0`: -c option requires argument nhc or ghc"
     else echo "Usage:  `basename $0` [ -c (nhc|ghc) ]"
     fi
     exit 1 ;;
  2) if [ "$1" = "-c" ]
     then commit () { true; }
     else echo "Usage:  `basename $0` [ -c (nhc|ghc) ]"
          exit 1
     fi
     case $2 in
       ghc) toGhc () { true; } ;;
       nhc) toGhc () { false; } ;;
       *)  echo "Usage:  `basename $0` [ -c (nhc|ghc) ]"
           exit 1 ;;
     esac ;;
  *) commit () { false; }
     toGhc () { false; } ;;
esac

listDirectories () {
    root=$1
    for dir in $root/*
    do
      if [ -d "$dir" ]
      then
        if [ `basename $dir` != "CVS" ]
        then echo $dir
             listDirectories $dir
        fi
      fi
    done
}

listHaskellFilesInDirectory () {
    dir=$1
    cd $nhc/$dir
    for file in `echo *.hs *.lhs`
    do
      if [ -f "$ghc/$dir/$file" ]
      then
        echo $dir/$file
      fi
    done
}

listAllFilesOfInterest () {
    cd $nhc
    for dir in `listDirectories .`
    do
      listHaskellFilesInDirectory $dir
    done
}

# main program
for file in `listAllFilesOfInterest`
do
    if [ ! -f $safecopy/$file ]
    then echo "U       $file"
         if [ ! -d `dirname $safecopy/$file` ]
         then mkdir -p `dirname $safecopy/$file`
         fi
         cp $ghc/$file $safecopy/$file
    fi
    if diff -q $ghc/$file $safecopy/$file >/dev/null
    then
      if diff -q $nhc/$file $safecopy/$file >/dev/null
      then
        echo "        $file"	# neither ghc nor nhc differ from safecopy
      else
        echo "M [nhc] $file"	# only nhc copy has changed
        commit && toGhc && cp $nhc/$file $ghc/$file
        commit && toGhc && cp $nhc/$file $safecopy/$file
      fi
    else
      if diff -q $nhc/$file $safecopy/$file >/dev/null
      then
        echo "M [ghc] $file"	# only ghc copy has changed
        commit && { toGhc || cp $ghc/$file $nhc/$file; }
        commit && { toGhc || cp $ghc/$file $safecopy/$file; }
      else
        if diff -q $nhc/$file $ghc/$file >/dev/null
        then
          echo "O [g/n] $file"	# both differ from safecopy in the same way
          commit && cp $ghc/$file $safecopy/$file
        else			# both differ but in different ways
          if diff3 -m -E $nhc/$file $safecopy/$file $ghc/$file \
             >/tmp/`basename $file`
          then
            echo "M g->n  $file"
            commit && { toGhc || cp /tmp/`basename $file` $nhc/$file; }
          else
            echo "C g->n  $file"	# there were conflicts in the merge
            commit && { toGhc || cp /tmp/`basename $file` $nhc/$file; }
          fi
          if diff3 -m -E $ghc/$file $safecopy/$file $nhc/$file \
             >/tmp/`basename $file`
          then
            echo "M n->g  $file"
            commit && toGhc && cp /tmp/`basename $file` $ghc/$file
          else
            echo "C n->g  $file"	# there were conflicts in the merge
            commit && toGhc && cp /tmp/`basename $file` $ghc/$file
          fi
        fi
      fi
    fi
done