#!/usr/bin/env bash

# originally got the idea from this script:
# src:https://github.com/veltall/custom-i3lock

# get random image to use
# https://stackoverflow.com/questions/61290199/how-do-i-select-a-random-file-from-a-directory
random_image=$(ls -1 /home/${USER}/.local/share/img/*.png | shuf | head -1)
random_image_filname="$(basename -- $random_image)"

# get random gravity to use for the overlay image, take the number of displays into account
numberOfDisplays=$(xrandr --query | grep -o " connected " | wc -l)
gravity=("center") # "center" "northwest" "northeast" "southwest" "southeast"
if [[ numberOfDisplays == 1 ]] || [[ numberOfDisplays == 3 ]] ; then
    gravity=("center" "northwest" "northeast" "southwest" "southeast")
elif [[ numberOfDisplays == 2 ]] || [[ numberOfDisplays == 4 ]] ; then
    gravity=("northeast" "southeast")
else
    gravity=("northeast" "southeast")
fi
random_gravity=${gravity[ $RANDOM % ${#gravity[@]} ]}

# take a screenshot of the entire screen, blur it, and adjust white balance
scrot --overwrite /tmp/currentworkspace.png
magick /tmp/currentworkspace.png -blur 0x9 /tmp/currentworkspaceblur.png
mogrify -brightness-contrast 50 /tmp/currentworkspaceblur.png

# send a notification to the user after the screenshot is taken, to avoid including the notification
notify-send "LOCKING SCREEN" "The system is about to be locked.\nPress any key to stop this from happening.\n\n${random_image_filname} @ ${random_gravity}"

# https://linuxsimply.com/bash-scripting-tutorial/input-output/input/wait-for-input/
read -t 15 -n 1 key  # read a single character within a X-seconds period
if [ $? = 0 ]; then

    notify-send "'${key}' is pressed ➔ the screen will not be locked"
    exit

else

    # find height of background image, and set the overlay to be 1/3 of this
    workspaceHeight=$(magick /tmp/currentworkspaceblur.png -print "%h" /dev/null)
    overlayHeight=$((${workspaceHeight} / 3))

    # resize the overlay image
    cp ${random_image} /tmp/overlayimage.png
    mogrify -resize x${overlayHeight} /tmp/overlayimage.png

    # create the final image to be used as the lock screen, and lock the system
    composite -gravity ${random_gravity} /tmp/overlayimage.png /tmp/currentworkspaceblur.png /tmp/lockbackground.png
    i3lock --tiling -i /tmp/lockbackground.png

fi