#!/usr/bin/env bash
  SCRIPT=$(basename "${0}")
 VERSION='2016-07-25'
  AUTHOR='ffmprovisr'
     RED='\033[1;31m'
   BLUE='\033[1;34m'
      NC='\033[0m'

_output_prompt() {
    cat <<END_OF_MSG
Usage: ${SCRIPT} [-h | <av_file> <md5_file>]
END_OF_MSG
}

_output_help() {
    cat <<END_OF_MSG
Syntax:
  ${SCRIPT}
    Prompts a short help message.
  ${SCRIPT} -h
    This help.
  ${SCRIPT} <av_file> <md5_file>
    Pass to the script the audio-visual file and the corresponding MD5
    file to check.
Dependency:
  ffmpeg
About:
  Version: ${VERSION}
  Website: https://github.com/amiaopensource/ffmprovisr/blob/gh-pages/check_framemd5.sh
END_OF_MSG
}

if [[ $OSTYPE == "cygwin" ]] || [ ! $(which diff) ] ; then
    echo -e "${RED}ERROR:${NC} diff is not installed by default. Please install diffutils from Cygwin."
    exit 1
fi

if [ "${#}" -eq 0 ]; then
    _output_prompt
    exit 0
elif [ "${#}" -eq 1 ]; then
    if [ "${1}" == '-h' ]; then
        _output_help
        exit 0
    else
        echo -e "${RED}ERROR:${NC} '$1' is an invalid argument."
        _output_prompt
        exit 1
    fi
elif [ "${#}" -eq 2 ]; then
    if ! [ -f "${1}" ]; then
        echo -e "${RED}ERROR:${NC} There is no file '$(basename ${1})'."
        _output_prompt
        exit 1
    elif ! [ -f "${2}" ]; then
        echo -e "${RED}ERROR:${NC} There is no file '$(basename ${2})'."
        _output_prompt
        exit 1
    else
        unset md5_tmp
        if [[ $OSTYPE == "cygwin" ]]; then
            md5_tmp=""${USERPROFILE}/$(basename ${2}).tmp""
        else 
            md5_tmp="${HOME}/$(basename ${2}).tmp"
        fi
        echo "Please wait..."
        $(ffmpeg -y -i ${1} -loglevel 0 -f framemd5 -an ${md5_tmp})
        old_file=$(grep -v '^#' ${2})
        tmp_file=$(grep -v '^#' ${md5_tmp})
        if [ "${old_file}" = "${tmp_file}" ]; then
            echo -e "${BLUE}OK${NC} '$(basename ${1})' matches '$(basename ${2})'."
            exit 0
        else
            echo -e "${RED}ERROR:${NC} The following differences were detected between '$(basename ${1})' and '$(basename ${2})':"
            diff "${2}" "${md5_tmp}"
            exit 1
        fi
        rm "${md5_tmp}"
    fi
else
    echo -e "${RED}ERROR:${NC} Too many arguments."
    _output_prompt
    exit 1
fi