#!/usr/bin/env bash
  SCRIPT=$(basename "${0}")
 VERSION='2016-12-31'
  AUTHOR='ffmprovisr'
     RED='\033[1;31m'
    BLUE='\033[1;34m'
      NC='\033[0m'

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

_output_prompt(){
    cat <<EOF
Usage: ${SCRIPT} [-h] | [ -i <av_file> -m <md5_file> ]
EOF
    exit 1
}

_output_help(){
    cat <<EOF
Syntax:
  ${SCRIPT}
    Prompts a short help message.
  ${SCRIPT} -h
    This help.
  ${SCRIPT} -i <av_file> -m <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
EOF
    exit 0
}

unset input_file
unset input_hash

while getopts ":hi:m:" opt; do
    case "${opt}" in
        h) _output_help ;;
        i) input_file=$OPTARG ;;
        m) input_hash=$OPTARG ;;
        :) echo -e "${RED}Error: option -${OPTARG} requires an argument${NC}" ; _output_prompt ;;
        *) echo -e "${RED}Error: bad option -${OPTARG}${NC}" ; _output_prompt ;;
    esac
done

[[ -z "${#}" || ! ${input_file} || ! ${input_hash} ]] && _output_prompt
echo -e "${BLUE}Please wait...${NC}"
unset md5_tmp
if [[ $OSTYPE = "cygwin" ]]; then
    md5_tmp=""${USERPROFILE}/$(basename ${input_hash}).tmp""
else
    md5_tmp="${HOME}/$(basename ${input_hash}).tmp"
fi
$(ffmpeg -i ${input_file} -loglevel 0 -f framemd5 -an ${md5_tmp})
[[ ! -f ${md5_tmp} ]] && { echo -e "${RED}Error: '${input_file}' is not a valid audio-visual file.${NC}" ; _output_prompt ; }
unset old_file
unset tmp_file
old_file=$(grep -v '^#' ${input_hash})
tmp_file=$(grep -v '^#' ${md5_tmp})
if [[ "${old_file}" = "${tmp_file}" ]]; then
    echo -e "${BLUE}'$(basename ${input_file})' matches '$(basename ${input_hash})'${NC}"
    rm "${md5_tmp}"
else
    echo -e "${RED}The following differences were detected between '$(basename ${input_file})' and '$(basename ${input_hash})':${NC}"
    diff "${input_hash}" "${md5_tmp}"
    rm "${md5_tmp}"
fi