#!/bin/bash
usage(){
    cat << HEREDOC
    $0 [-h] [MAXFILE] [TAG]
    This script loads and merges images based on random words 
    -h          this help
    MAXFILE     Limit number of images to compose 
    TAG         Don't pick tag randomly
HEREDOC
    exit 1
}
panic(){ echo $@; exit 2; }
[[ $1 == "-h" ]] || [[ $1 == --help ]] && usage 

cd $( dirname $0 )
MAXFILE=${1:-20}
TAG=${2}
TMPFILE=$(mktemp)

# Search images
for i in {1..99}; do
    RAND=$( echo | awk ' { srand(); print int(rand() * 234937 ) } ')
    WORD=$(awk "NR==$RAND" /usr/share/dict/words); 
    [ -n "$TAG" ] && WORD=$TAG
    URL="https://api.flickr.com/services/feeds/photos_public.gne?tags=$WORD&tagmode=any"; 
    IMGLIST=($(curl -s "$URL" | grep '"enclosure"'|  sed -r 's_^.*href="(.*jpg)".*$_\1_' | grep "^http"))
    [ $i -eq 2 ] && [ -n "$TAG" ] && panic "Failed to load tag" ]
    [ 2 -gt ${#IMGLIST[@]} ] && continue
    break;
done

# Download images 
mkdir -p images
for i in $( seq 0 $(( ${#IMGLIST[@]} -1 )) ); do 
    IMGURL="${IMGLIST[$i]}"
    [[ ${IMGLIST[$i]} =~ ^http ]] || continue
    wget -q "$IMGURL" -P images
    [[ O -eq $? ]] && FILELIST+=(images/$(basename ${IMGLIST[$i]} ) ) 
    [ $i -gt $(( $MAXFILE -2 )) ] && break
done

# Create synthetic image
mkdir -p synthesis
SYNTH_NAME="synthesis/$(date +%s)-$WORD.jpg"
SRC=${FILELIST[0]}
#copy the first image
cp $SRC $SYNTH_NAME
for i in $( seq 1 $(( ${#FILELIST[@]} -1 )) ); do
    composite ${FILELIST[$i]} $SYNTH_NAME -gravity center -compose difference "$SYNTH_NAME"
done 

mkdir logs
echo "File generated with word $WORD and ${#FILELIST[@]} images: file://$PWD/$SYNTH_NAME" | tee "logs/$(basename $SYNTH_NAME)"
echo "${FILELIST[@]}" | tee -a "logs/$(basename $SYNTH_NAME)"