#!/bin/bash

# Copyright 2013  Norman Carver  <carver@cs.siu.edu>
#
# cp viewer -- Bash shell script to use pv (pipe viewer) to copy files,
# so see progress and rate info, but accepts cp's argument syntax.
#
# Syntax: cpv [OPTION] SOURCE DESTINATION
#         cpv [OPTION] SOURCE... DIRECTORY
#         cpv [OPTION] -t DIRECTORY SOURCE...
# Options:
#   -i for interactive (overrides previous -n)"
#   -n for no clobber (overrides previous -i)"
#
# Copies only regular files (so does not behave exactly like cp)!
#
# Requires: pv (pipe viewer)
#
# Version history:
#   1.0  (07/28/2013) Initial public release
#   1.1  (03/08/2014) Minor cleanup/improvements

# Copyright 2013-2014  Norman Carver  <carver@cs.siu.edu>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or (at
# your option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


# Change default options used by pv if desired:
# E.g., to show only progress bar: pvoptions="-p"
# See "man pv" for options, default is like -pterb.
pvoptions=


# Make certain pv program is installed:
if ! which pv &> /dev/null; then
    echo "Program pv (pipe viewer) required, please install first!"
    exit 1
fi


function print_usage()
{
    echo "Usage: cpv [OPTION] SOURCE DESTINATION"
    echo "       cpv [OPTION] SOURCE... DIRECTORY"
    echo "       cpv [OPTION] -t DIRECTORY SOURCE... "
    echo " Options:"
    echo "   -i for interactive (overrides previous -n)"
    echo "   -n for no clobber (overrides previous -i)"
}

# Function to determine if copy action should be done:
# Takes two arguments, (1) source path, (2) target/copy path.
function do_copy()
{
    source=$1
    target=$2

    # Check that source is a regular file:
    if [[ ! -f "${source}" ]]; then
        type=$(stat --format="%F" "${source}")
        echo  "$0: omitting ${type} \`${source}'"
        return 1
    fi

    # Check whether will overwrite file:
    if ( $interactive || $noclobber ) && [[ -e "${target}" ]]; then
        if $interactive; then
            echo -n "$0: overwrite \`$target'?"
            if read && [[ ! "$REPLY" =~ ^[yY].*$ ]]; then
                return 1
            fi
        else
            return 1
        fi
    fi
 
    return 0
}


# Check that number of arguments was valid:
if [[ $# -lt 2 ]]; then
    print_usage
    exit 1
fi

# Decode options:
reverse=false
interactive=false
noclobber=false
while getopts ":int" opt; do
    case $opt in
        i)
            interactive=true 
            noclobber=false ;;
        n)
            noclobber=true
            interactive=false ;;
        t)
            reverse=true ;;
        \?)
            print_usage
            exit 1 ;;
    esac
done
shift $((OPTIND-1))

# Check that number of file arguments is valid:
if [[ $# -lt 2 ]]; then
    print_usage
    exit 1
fi

# Determine which syntax case we have and do copying:
lastarg=${!#}
if $reverse || [[ -d "${lastarg}" ]]; then
    # File(s) are to be copied to a directory, so
    # first determine the directory:
    if $reverse; then
        directory="${1}"
        first=2
        last=$#
    else
        directory=$lastarg
        first=1
        last=$(($# - 1))
    fi
    for (( i=$first ; i <= $last ; i++ )); do
        source=${!i}
        target=${directory}/$(basename  "${source}")
        if do_copy "${source}" "${target}"; then
            if [[ $last -gt $first ]]; then echo "${source}:"; fi
            pv  $pvoptions "${source}" > "${target}"
        fi
    done

else
    # A single file is to be copied:
    if [[ $# != 2 ]]; then
        print_usage
        exit 1
    fi

    source=$1
    target=$2
    if do_copy "${source}" "${target}"; then
        pv  $pvoptions "${source}" > "${target}"
    fi
fi

# Normal completion:
exit

# EOF