#!/bin/bash
CONFIG_DIR="$HOME/.config/chwp"
CONFIG_FILE="$CONFIG_DIR/chwp.conf"
WALLPAPERS_LIST="$CONFIG_DIR/wplist"

# Make config directory if not exist
mkdir -p $CONFIG_DIR

# If config file not exist create one with defaults
if [ ! -f $CONFIG_FILE ]; then
cat <<EOF > ${CONFIG_FILE}
# Directory with wallpapers
wallpaper_dir=/usr/share/backgrounds/
# Rotate time in seconds
interval=10
# Wallpaper setter program: nitrogen or feh
setter=nitrogen
EOF
fi

# read config variables from file
source <(grep = $CONFIG_FILE)

# decide which setter and command use to set wallpaper
case "$setter" in
    nitrogen) command="nitrogen --set-zoom-fill";;
    feh) command="feh --bg-fill" ;;
    *) echo "Unknown wallpaper setter. Please check your config file $CONFIG_FILE";exit 1;;
esac

while true
do
    # If list does not exist or is empty
    if [[ ! -f $WALLPAPERS_LIST || $(wc -l <$WALLPAPERS_LIST) -lt 1 ]]; then
    # Prepare list with wallpapers (only PNG and JPG)
    ls -1 "$wallpaper_dir"/*{.jpg,.png} > "$WALLPAPERS_LIST"
    fi
    
    # if wallpapers list have more than 0 lines
    while [ $(wc -l <$WALLPAPERS_LIST) -gt 0 ]
    do
        # get random line
        line=$(shuf -n 1 $WALLPAPERS_LIST)
        #delete it from list
        grep -v "$line" "$WALLPAPERS_LIST" > "$CONFIG_DIR/tmpfile"; mv "$CONFIG_DIR/tmpfile" "$WALLPAPERS_LIST"
        #run command to set wallpaper
        ${command} ${line}
        sleep ${interval}
    done
done