#!/bin/bash

_error () {
    echo "error: $*" 1>&2
    exit 1
}

command -v gsettings &>/dev/null || _error "no gsettings command found. Is GNOME installed?"
command -v convert &>/dev/null || _error "no convert command found"

uri="$(gsettings get org.gnome.desktop.background picture-uri)"
if [[ $? -ne 0 || -z $uri ]]; then
    _error "failed to query desktop background path"
fi

walldir="${WALLDIR:-$HOME/.gblurlock}"
[[ -d $walldir ]] || mkdir -p $walldir

uri="${uri#\'}"
uri="${uri%\'}"

case "$uri" in
    file://*)
        wallpath="${uri#file://}"
        ;;
    http*|ftp*)
        wallpath="${TMP:-/tmp}/${uri##*/}"
        if command -v wget &>/dev/null; then
            wget $uri -O "$wallpath" || _error "failed to download $uri"
        elif command -v curl &>/dev/null; then
            curl $uri -o "$wallpath" || _error "failed to download $uri"
        else
            _error "no wget or curl command found. Cannot download $uri."
        fi
        mv $wallpath $walldir && wallpath="$walldir/${wallpath##*/}"
        ;;
    *)
        _error "unknown URI type: $uri"
        ;;
esac

fullname="${wallpath##*/}"
name="${fullname%.*}"
ext="${fullname##*.}"

blurpath="$walldir/$name.blur.$ext"

convert "$wallpath" -blur 0x8 "$blurpath" || _error "failed to apply blur to $wallpath"
echo "Saved blurred image to $blurpath"

gsettings set org.gnome.desktop.screensaver picture-uri "file://$blurpath" \
    && echo "Applied blurred image to lock screen" \
    || _error "failed to apply image to lock screen"