#!/bin/bash
#
# The filename should be changed from "pcvs.txt" to "pcvs".
#
# pcvs is a tool to "commit" files to a CVS repository
# before you are ready to overwrite the file. It creates
# a new file ("filename".pcv) that is committed, and 
# deletes this file when you are ready to release.
#
# IMPORTANT: CVS has branches, which can be used to allow 
#       concurrent separate development paths on the same file.  
#       This script is for illustratory purposes and branches
#       are the standard way to accomplish the same thing.
#
# Bryan Smith - bryanesmith [at] gmail.com
# Created - Thurs Sept 10 2010
# Last Updated - Fri Sept 11 2010
#
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
error() {
    if [ "$#" -eq "2" ]; then
        echo
        echo "ERROR: $2"
    fi

    usage

    exit $1
}

COMMIT_MSG='"Some commit message..."'

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

usage() {
    cat <<MYUSAGE
USAGE
  pcvs [pcvs_command] [pcvs_args...]

DESCRIPTION
  If you have files under CVS that you want to save but
  don't wish to overwrite the files yet in the repository,
  this tool can help.

  First, you ADD files, which creates a special file called
  {filename}.pcvs, which is committed to CVS repository
  instead of {filename}. When you COMMIT {filename} through
  this tool, {filename}.pcvs is actually committed.

  When you are ready, you can RELEASE the file (or all
  files), which removes {filename}.pcvs and commits the
  changes to the original file.

IMPORTANT: 
  CVS has branches, which can be used to allow concurrent
  separate development paths on the same file. This script 
  is for illustratory purposes and branches are the 
  standard way to accomplish the same thing.

NOTES
  * Edit the original file -- not the pcvs file! This
    utility will copy from original to pcvs file when
    needed.

  * When releasing, this utility releases what is in the
    original file -- not whatever was last saved in the
    pcvs file.

COMMANDS
  add       Add a file to pcvs. This creates a special
            file that ends with .pcvs 

            \$ pcvs add /path/to/file

  commit    Commit changes to file (using the pcvs file)

            \$ pcvs commit /path/to/file $COMMIT_MSG
            \$ pcvs commit all $COMMIT_MSG

  release   Clobbers the original file with the .pcvs
            file and commits it to CVS. (I.e., no 
            hiding the file.)

            \$ pcvs release /path/to/file $COMMIT_MSG
                  Releases specified file

            \$ pcvs release all $COMMIT_MSG
                  Releases all files recursively in
                  working directory

  list      Show all .pcvs files recursively for directory.

            \$ pcvs list
                  Defaults to working directory

MYUSAGE
}

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

tracer() {
    #echo "DEBUG: $1"
    return 0
}

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

if [ "$#" -eq "0" ]; then
  error 1
fi

Task=$1

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

if [ "$Task" == 'add' ]; then
  
    if [ "$#" -ne "2" ]; then
        error 3 "Expecting two arguments: add /path/to/file"
    fi

    Src=$2
    Dest=${Src}.pcvs

    tracer "Adding $Src with message: $Message"

    if [ ! -e $Src ]; then
        error 4 "File $Src does not exist."
    fi

    if [ -e $Dest ]; then
        error 5 "File $Src has already been added (or file with name $Dest already exists)"
    fi

    tracer "cp $Src $Dest"
    cp $Src $Dest

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

elif [ "$Task" == 'release' ]; then
  
    if [ "$#" -ne "3" ]; then
        error 3 "Expecting three arguments: release /path/to/file (or all) $COMMIT_MSG"
    fi

    Src=$2
    Message=$3

    if [ "$Src" == 'all' ]; then
        tracer "Releasing everything with message: $Message"

        ToCommit=''
        for Dest in `find . -name "*.pcvs" -print`; do
            
            # Remove .pcvs extension
            Src=`echo "$Dest" | awk '{sub(/\.pcvs$/,"");print}'`
         
            tracer "cvs remove $Dest"
            cvs remove $Dest

            ToCommit="$ToCommit $Src $Dest"
        done
        
        tracer "cvs commit -m $Message $ToCommit"
        cvs commit -m "$Message" $ToCommit
    else 
        Dest="${Src}.pcvs"
        tracer "Releasing $Src with message: $Message"

        if [ ! -e $Dest ]; then
            error 6 "File $Src was not added and hence cannot be released (or file at $Dest was removed)"
        fi

        tracer "cvs remove $Dest"
        cvs remove $Dest

        tracer "cvs commit -m $Message $Src $Dest"
        cvs commit -m "$Message" $Src $Dest
    fi

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

elif [ "$Task" == 'commit' ]; then

   if [ "$#" -ne "3" ]; then
        error 3 "Expecting three arguments: commit /path/to/file (or all) $COMMIT_MSG"
    fi

    Src=$2
    Message=$3

    if [ "$Src" == 'all' ]; then
        tracer "Committing everything with message: $Message"

        ToCommit=''
        for Dest in `find . -name "*.pcvs" -print`; do
            
            # Remove .pcvs extension
            Src=`echo "$Dest" | awk '{sub(/\.pcvs$/,"");print}'`
         
            tracer "cp -f $Src $Dest"
            cp -f $Src $Dest

            ToCommit="$ToCommit $Dest"
        done
        
        tracer "cvs commit -m $Message $ToCommit"
        cvs commit -m "$Message" $ToCommit
    else 
        Dest="${Src}.pcvs"
        tracer "Releasing $Src with message: $Message"

        if [ ! -e $Dest ]; then
            error 6 "File $Src was not added and hence cannot be committed (or file at $Dest was removed)"
        fi

        tracer "cp -f $Src $Dest"
        cp -f $Src $Dest

        tracer "cvs commit -m $Message $Src"
        cvs commit -m "$Message" $Src
    fi

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

elif [ "$Task" == 'list' ]; then
    
    if [ "$#" -ne "1" ]; then
        error 3 "Expecting two argument: list"
    fi

    for File in `find . -name "*.pcvs" -print`; do

        # Remove .pcvs extension
        File=`echo "$File" | awk '{sub(/\.pcvs$/,"");print}'`

        # Remove preceding ./
        File=`echo "$File" | awk '{sub(/^\.\//,"");print}'`

        echo "$File"
    done

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

else
  error 2 "Unrecognized option \"${Task}\""
fi