set_wallpaper_by_geo

#!/bin/bash

# This script is expected to be executed on each startup
# In the end it would probably be nice to set a user symlink to the wallpaper
# any dynamic changing in /usr would not work on immutable systems anyway

# Get the current timezone offset using the date command
current_offset=$(date +%z)

wallpaper_dir="file:///usr/share/wallpapers/geo-wallpapers"
if [ -d ".git" ]; then
	scriptdir=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd );
	wallpaper_dir="file://$scriptdir/png"
fi

# Declare an associative array with timezone as keys and wallpaper paths as values
declare -A timezones_wallpapers=(
    ["Indian/Mauritius"]="$wallpaper_dir/lemorne.png"
    ["Asia/Taipei"]="$wallpaper_dir/taipei.png"
    # Add more timezones with their respective wallpaper paths
)

function get_utc_offset() {
    local timezone=$1
    echo $(TZ=$timezone date +%z)
}

closest_timezone=""
closest_wallpaper=""
min_offset_diff=99999  # A large initial value

# Convert offset to an integer value for comparison
current_offset_hours=$(echo $current_offset | sed 's/^+//;s/^0*//')

for timezone in "${!timezones_wallpapers[@]}"; do
    place_offset=$(get_utc_offset "$timezone")
    place_offset_hours=$(echo $place_offset | sed 's/^+//;s/^0*//')

    # The absolute difference between current and place offset
    offset_diff=$(( current_offset_hours - place_offset_hours ))
    offset_diff=${offset_diff#-}  # Absolute value

    # Check if this is the smallest difference
    if (( offset_diff < min_offset_diff )); then
        min_offset_diff=$offset_diff
        closest_timezone=$timezone
        closest_wallpaper=${timezones_wallpapers[$timezone]}
    fi
done

# Best would be to choose day/night for dark/light scheme ... not sure if we'll have enough time to do all variants :-)
#echo "The closest timezone to the current timezone offset ($current_offset) is: $closest_timezone"
echo "The corresponding wallpaper file is: $closest_wallpaper"
gsettings set org.gnome.desktop.background picture-uri $closest_wallpaper
gsettings set org.gnome.desktop.background picture-uri-dark $closest_wallpaper