#!/bin/bash

# Script to setup hibernation in Linux Mint 22
# Author: Random Person
# Data: 2024-08-12
# Based on: https://ubuntuhandbook.org/index.php/2021/08/enable-hibernate-ubuntu-21-10

# Print text inside a boxed border.
box_title() {
    local len=$((${#1}+2))

    printf "\n╔"
    printf -- "═%.0s" $(seq 1 $len)
    printf "╗\n║ $1 ║\n╚"
    printf -- "═%.0s" $(seq 1 $len)
    printf "╝\n\n"
}

# Setup swap file
setup_swap() {
    echo
    echo "Setting up the swap file."
    echo "Please wait..."
    echo

    swapoff -a
    rm -f /swapfile
    dd if=/dev/zero of=/swapfile bs=1M count=$needed
    chmod 0600 /swapfile
    mkswap /swapfile
    sed -i '/swap/{s/^/#/}' /etc/fstab
    tee -a /etc/fstab <<< "/swapfile  none  swap  sw 0  0"
    swapon -a
}

# Setup Hibernate
setup_hibernate() {
    local resume_params="resume=UUID=$(findmnt / -o UUID -n) resume_offset=$(filefrag -v /swapfile|awk 'NR==4{gsub(/\./,"");print $4;}') "

    echo
    echo "Setting up hibernation."
    echo "Please wait..."
    echo

    # Adds kernel parameter in grub boot configuration file
    if grep resume /etc/default/grub>/dev/null; then
        sed -i "s/GRUB_CMDLINE_LINUX_DEFAULT=\".*resume_offset=[0-9]* /GRUB_CMDLINE_LINUX_DEFAULT=\"$resume_params/" /etc/default/grub
    else
        sed -i "s/GRUB_CMDLINE_LINUX_DEFAULT=\"/GRUB_CMDLINE_LINUX_DEFAULT=\"$resume_params/" /etc/default/grub
    fi
    update-grub

    # Adds device major:minor numbers in resume configuration
    echo $(findmnt / -o MAJ:MIN -n) > /sys/power/resume
    echo "#    Path                   Mode UID  GID  Age Argument" > /etc/tmpfiles.d/hibernation_resume.conf
    echo "w    /sys/power/resume       -    -    -    -   $(findmnt / -o MAJ:MIN -n)" >> /etc/tmpfiles.d/hibernation_resume.conf

    # Adds hibernation option in power-off menu
    apt install -y -qq polkitd-pkla

    mkdir -p /etc/polkit-1/localauthority/50-local.d
    tee /etc/polkit-1/localauthority/50-local.d/com.ubuntu.enable-hibernate.pkla << 'EOB' >/dev/null
[Re-enable hibernate by default in upower]
Identity=unix-user:*
Action=org.freedesktop.upower.hibernate
ResultActive=yes

[Re-enable hibernate by default in logind]
Identity=unix-user:*
Action=org.freedesktop.login1.hibernate;org.freedesktop.login1.handle-hibernate-key;org.freedesktop.login1;org.freedesktop.login1.hibernate-multiple-sessions;org.freedesktop.login1.hibernate-ignore-inhibit
ResultActive=yes
EOB

    mkdir -p /etc/polkit-1/localauthority/90-mandatory.d
    tee /etc/polkit-1/localauthority/90-mandatory.d/enable-hibernate.pkla << 'EOB' >/dev/null
[Enable hibernate]
Identity=unix-user:*
Action=org.freedesktop.login1.hibernate;org.freedesktop.login1.handle-hibernate-key;org.freedesktop.login1;org.freedesktop.login1.hibernate-multiple-sessions
ResultActive=yes
EOB

    mkdir -p /etc/polkit-1/rules.d
    tee /etc/polkit-1/rules.d/10-enable-hibernate.rules << 'EOB' >/dev/null
polkit.addRule(function(action, subject) {
    if (action.id == \"org.freedesktop.login1.hibernate\" ||
        action.id == \"org.freedesktop.login1.hibernate-multiple-sessions\" ||
        action.id == \"org.freedesktop.upower.hibernate\" ||
        action.id == \"org.freedesktop.login1.handle-hibernate-key\" ||
        action.id == \"org.freedesktop.login1.hibernate-ignore-inhibit\")
    {
        return polkit.Result.YES;
    }
});
EOB

    echo
    echo "Hibernation setup completed."
    echo "Please reboot your system for all changes to take effect."
    echo
}

main() {
    local available=$(df -m / | tail -n1 | awk '{print $4}')
    local swap=$(free -m | tail -n1 | awk '{print $2}')
    local needed=$(($1 * 1024))

    box_title "Setup Hibernate"

    if [[ ! `id -u` -eq "0" ]] || [[ "$#" != "1" ]] || ! [[ $1 =~ ^[0-9]+$ ]]; then
        echo
        echo "Use: sudo bash setup-hibernate.sh [SIZE]"
        echo "[SIZE] => Swap size in GB."
        echo
    else
        # Check required swap file size
        available=$(($available + $swap))
        if [ "$available" -gt "$needed" ]; then
            setup_swap
            setup_hibernate
        else
            echo
            echo "Hibernate setup aborted."
            echo "Available swap space: $available"
            echo "Needed swap space: $needed"
            echo
        fi
    fi
}

main "$@"