#!/bin/bash

# flac2opus

# Usage examples

# Simple:
# ...........................................
# flac2opus *.flac
# parallel --gnu flac2opus {} ::: *.flac

# With find:
# ...........................................
# If the symlinks are in question (cp -rs flacs /destination/), you could call this script:
# find . -lname "*.flac" -exec flac2opus {} \+
# or with parallel
# find . -lname "*.flac" | parallel --gnu flac2opus {}

# Or if the files are to be found
# find . -type f -iname "*.flac" -exec flac2opus {} \+
# or with parallel
# find . -type f -iname "*.flac" | parallel --gnu flac2opus {}

# note: Using parallel (apt-get install parallel) will give enormous encoding speed boost. 


command -v opusenc >/dev/null 2>&1 || { echo >&2 "I require opusenc but it's not installed, exiting."; exit 1; }
command -v mediainfo >/dev/null 2>&1 || { echo "I need mediainfo installed." ; exit 1; }

encode() { # put your opusenc settings here
   opusenc "$expanded" "$dir/$base.opus"
}

while [ $# -gt 0 ]; do

  
    expanded=$(readlink -f "$1")
    echo ".............................."
    echo "$expanded"
    
    base=$(basename "${1}")     # basename, like                file.flac
    base="${base%.*}"           # basename without extension    file
    dir=$(dirname "${1}")       # directory
    

        # Do some checks first
        if [ -f "$dir/$base.opus" ]
        then # opus file in existance, do some duration checking
            echo "the file exists, checking if flac and opus durations match"
        
                if diff <(mediainfo "$expanded" | grep -m 1 Duration) <(mediainfo "$dir/$base.opus" | grep -m 1 Duration)
                then
                    echo "yes, durations match, skipping"
                else
                    echo "no, durations does not match, reencoding" 
                    encode 
                   
                fi
            
            
        else # the opus file does not exist yet
            encode
        fi
   
    shift
done