dotfiles/config/scripts/.local/scripts/change-wallpaper

#!/usr/bin/env bash

# Description:
#   Change the desktop wallpaper and generate a blurred version.
#
# Requirs:
# - zenity (for file selection dialog)
# - imagemagick (for image processing)
# - swww (wallpaper daemon)
# - notify-send (for notifications)
# - change-colortheme (from scripts/change-colortheme)
# - flock (usually part of util-linux)

# Lock

exec {LOCK_FD}>/tmp/"$(basename "$0")".lock || {
    echo "Failed to open lock file"
    exit 1
}

flock -n "$LOCK_FD" || {
    echo "Another instance is running. Exiting."
    notify-send -a "change-wallpaper" "Error" "Another instance is running. Exiting."
    exit 1
}

# Open a file selection dialog if no argument is provided

if [ -z "$1" ]; then
    image=$(zenity --file-selection --title="Open File" --file-filter="*.jpg *.jpeg *.png *.webp *.bmp *.jfif *.tiff *.avif *.heic *.heif")
else
    image="$1"
fi

[ -z "$image" ] && exit 1
[ ! -f "$image" ] && exit 1

# Obtain screen resolution

screen_width=$2
screen_height=$3

[ -z "$screen_width" ] && {
    if [ "$XDG_CURRENT_DESKTOP" = "Hyprland" ]; then
        screen_width=$(hyprctl -j monitors | jq '.[0].resolution.x')
    elif [ "$XDG_CURRENT_DESKTOP" = "niri" ]; then
        screen_width=$(niri msg focused-output | grep 'Current mode' | awk '{print $3}' | cut -d'x' -f1)
    fi
}

[ -z "$screen_height" ] && {
    if [ "$XDG_CURRENT_DESKTOP" = "Hyprland" ]; then
        screen_height=$(hyprctl -j monitors | jq '.[0].resolution.y')
    elif [ "$XDG_CURRENT_DESKTOP" = "niri" ]; then
        screen_height=$(niri msg focused-output | grep 'Current mode' | awk '{print $3}' | cut -d'x' -f2)
    fi
}

[ -z "$screen_width" ] && screen_width=2560
[ -z "$screen_height" ] && screen_height=1440

# $HOME/.config/wallpaper-chooser/config.json:
# ```json
# "sort": {
#    "type": "date",
#    "reverse": true
# }
# ```
# So in order to let the most recently used wallpapers appear first:
touch "$image"


# Copy image to local wallpaper directory

ext=${image##*.}
random_name=$(tr -dc 'a-zA-Z0-9' </dev/urandom | head -c 16)
current_dir="$HOME/.local/share/wallpaper/current"
image_copied="$current_dir/wallpaper-${random_name}.${ext}"

mkdir -p "$current_dir" || {
    echo "Could not create directory $current_dir"
    exit 1
}

temp_img=$(mktemp --suffix=."$ext") || exit 1
trap 'rm -f "$temp_img"' EXIT
magick convert "$image" -resize "${screen_width}x${screen_height}^" -gravity center -extent "${screen_width}x${screen_height}" "$temp_img" || {
    echo "Could not resize and crop image"
    exit 1
}
cp "$temp_img" "$image_copied" || exit 1
hash=$(md5sum "$image_copied" | awk '{print $1}')

# Clean up old wallpapers

find "$current_dir" -type f -name "wallpaper-*" ! -name "$(basename "$image_copied")" -delete

# Generate blurred wallpaper

blur_dir="$HOME/.local/share/wallpaper/blurred"
blur_cache_dir="$HOME/.local/share/wallpaper/blurred-cache"
mkdir -p "$blur_dir" "$blur_cache_dir" || {
    echo "Could not create cache directory"
    exit 1
}
blurred_image="$blur_dir/blurred-${random_name}.$ext"
blurred_cache_image="$blur_cache_dir/${hash}.$ext"

## Time consuming task (magick -blur) in background
(
    # notify-send -a "change-wallpaper" "Generating Blurred Wallpaper" "This may take a few seconds..."

    ### Check if cached blurred image exists
    if [ -f "$blurred_cache_image" ]; then
        # sleep 1 # Some ugly workaround
        if ! cp -f "$blurred_cache_image" "$blurred_image"; then
            echo "Could not copy cached blurred image"
            # exit 1 # Non-critical error
        else
            find "$blur_dir" -type f -name "blurred-*" ! -name "$(basename "$blurred_image")" -delete
            if [ "$XDG_CURRENT_DESKTOP" = "niri" ]; then
                swww img -n backdrop "$blurred_image" --transition-type fade --transition-duration 2 > /dev/null 2> /dev/null
            fi
            notify-send -a "change-wallpaper" "Blurred Wallpaper From Cache" "$blurred_image" -i "$blurred_image"
            exit 0
        fi
    fi

    sigma=$(magick identify -format "%w %h" "$image_copied" | awk -v f=0.01 '{
        m=($1>$2)?$1:$2;
        s=m*f;
        if(s<2) s=2;
        if(s>200) s=200;
        printf "%.2f", s
    }')

    ### use a temporary file to avoid incomplete file being used
    temp_blurred=$(mktemp --suffix=."$ext") || exit 1
    trap 'rm -f "${temp_blurred}"' EXIT
    magick "$image_copied" -blur 0x"$sigma" "$temp_blurred" || {
        echo "Could not create blurred image"
        exit 1
    }

    mv -f "$temp_blurred" "$blurred_image" || {
        echo "Could not move blurred image to cache directory"
        exit 1
    }

    find "$blur_dir" -type f -name "blurred-*" ! -name "$(basename "$blurred_image")" -delete

    cp -f "$blurred_image" "$blurred_cache_image" || {
        echo "Could not cache blurred image"
        # exit 1 # Non-critical error
    }

    if [ "$XDG_CURRENT_DESKTOP" = "niri" ]; then
        swww img -n backdrop "$blurred_image" --transition-type fade --transition-duration 2 > /dev/null 2> /dev/null
    fi

    notify-send -a "change-wallpaper" "Blurred Wallpaper Generated" "$blurred_image" -i "$blurred_image"
) &

# Apply wallpaper

if [ "$XDG_CURRENT_DESKTOP" = "Hyprland" ]; then
    swww img -n background "$image_copied" --transition-type fade --transition-duration 2 > /dev/null 2> /dev/null

    notify-send -a "change-wallpaper" "Wallpaper Changed" "$image" -i "$image_copied"

    change-colortheme -i "$image_copied" || exit 1
elif [ "$XDG_CURRENT_DESKTOP" = "niri" ]; then
    ### Handled in wallpaper-daemon
    # swww img -n background "$image_copied" --transition-type fade --transition-duration 2 > /dev/null 2> /dev/null

    notify-send -a "change-wallpaper" "Wallpaper Changed" "$image" -i "$image_copied"

    change-colortheme -i "$image_copied" || exit 1
else
    echo "Unsupported desktop environment: $XDG_CURRENT_DESKTOP"
    exit 1
fi