#!/bin/bash
# This script is used to change the background of the desktop
# 2025, Raoul Branten

# Function to show a spinning cursor
spinner() {
    local pid=$1
    local delay=0.1
    local spinstr='|/-\'
    while [ "$(ps a | awk '{print $1}' | grep $pid)" ]; do
        local temp=${spinstr#?}
        printf " [%c]  " "$spinstr"
        local spinstr=$temp${spinstr%"$temp"}
        echo -en "\b\b\b\b\b\b"
        sleep $delay
    done
    printf "    \b\b\b\b"
}

echo "[1/4] Getting screen resolution..."
# get screen resolution using xdpyinfo to get info from X server
SCREENWIDTH=$(xdpyinfo | awk '/dimensions/{print $2}' | grep -oE ^[[:digit:]]\+)
SCREENHEIGHT=$(xdpyinfo | awk '/dimensions/{print $2}' | grep -oE [[:digit:]]\+$)
SIZE="${SCREENWIDTH}x${SCREENHEIGHT}"
echo "    Screen resolution: $SIZE"

echo "[2/4] Checking for xstarfish..."
# check if xstarfish is installed
if [ -f /usr/bin/xstarfish ]; then
    echo "[3/4] Generating background image..."
    # Generate a background image using xstarfish
    /usr/bin/xstarfish -g $SIZE -o /tmp/background.jpg &
    spinner $!
else
    echo "ERROR: xstarfish not found"
    exit 1
fi

echo "[4/4] Setting background on all displays..."
# get all possible displays
# use xfconf-query to generate a list of all possible displays
# then use grep to cut out the correct path
# sort is used for unique results
BACKDROP=$(xfconf-query --channel xfce4-desktop --list | grep -E -o '/backdrop/screen0/monitor[a-zA-Z0-1-]+/workspace0/last-image' | sort -u) 

# foreach display set the background image to the generated image
while IFS= read -r line; do 
    # set the background image
    xfconf-query -c xfce4-desktop -p $line -s /tmp/background.jpg
    echo "    Set background for display: $line"
done <<< "$BACKDROP"

echo "✓ Background change completed successfully!"