#!/bin/bash

#
# Default variables
#
UPGRADE_PACKAGES=false
SCRIPT_NAME="$(basename -- "$0")"
SCRIPT_DIR="$(
    cd -- "$(dirname "$0")" >/dev/null 2>&1 || exit 1
    pwd -P
)"

function _acpib() {
    acpi -b | grep -Fv ' 0%'
}

function is_laptop() {
    [[ $(_acpib | wc -l) -gt 0 ]] && return 0 || return 1
}

function usage() {
    echo "Usage: $SCRIPT_NAME [OPTIONS]"
    echo
    echo "Options:"
    echo "  -h      Display help."
    echo "  -u      Upgrade existing packages."
    exit 0
}

while getopts ":uh" arg; do
    case $arg in
    h) usage ;;
    u) UPGRADE_PACKAGES=true ;;
    :)
        echo "$0: Must supply an argument to -$OPTARG." >&2
        exit 1
        ;;
    ?)
        echo "Invalid option: -${OPTARG}."
        echo
        usage
        exit 2
        ;;
    esac
done

# Returns a comma-separated list of packages for one or more targets.
# The packages file may contain multiple rows with the same target name.
function get_packages() {
    local packages pkg_file="$SCRIPT_DIR/.installer/packages"

    for target in "$@"; do
        while read -r row; do
            for package in ${row//,/ }; do
                echo "$package"
            done
        done <<<"$(grep "^${target:?}:" "$pkg_file" | cut -d':' -f2)"
    done
}

function configure_sddm() {
    local sddm_config_dir="/etc/sddm.conf.d"
    local theme_dir="/usr/share/sddm/themes/aerial"

    echo "Setting up '$sddm_config_dir'."

    if ! [ -d "$sddm_config_dir" ]; then
        sudo mkdir "$sddm_config_dir"
        sudo chown root:root -R "$sddm_config_dir"
    fi

    {
        echo "[Theme]"
        echo "Current=aerial"
    } | sudo tee "$sddm_config_dir/theme" >/dev/null

    {
        echo "[X11]"
        echo "DisplayCommand=/usr/share/sddm/scripts/Xsetup"
    } | sudo tee "$sddm_config_dir/xsetup" >/dev/null

    echo "Setting up '$theme_dir'."
    sudo mv "$theme_dir/theme.conf.user" "$theme_dir/theme.conf.user.disabled"
}

function prepare_arch() {
    which pamac >/dev/null && return 0
    sudo pacman -S pamac --noconfirm || return 1
}

function setup_arch_with_pamac() {
    local targets=("pacman-any") packages
    is_laptop && targets+=("pacman-laptop")

    packages="$(get_packages "${targets[@]}")"
    # shellcheck disable=SC2086
    sudo pamac install $packages --no-confirm || return 1
}

function setup_arch_with_yay() {
    local targets=("aur-any") packages
    is_laptop && targets+=("aur-laptop")

    for package in $(get_packages "${targets[@]}"); do
        if pacman -Qs "^$package$" >/dev/null; then
            if $UPGRADE_PACKAGES; then
                echo "Package '$package' will be upgraded."
            else
                echo "Package '$package' already exists."
                continue
            fi
        else
            echo "Package '$package' will be installed."
        fi

        sudo pamac build "$package" --no-confirm || return 1
    done
}

function setup_arch() {
    prepare_arch || return 1
    setup_arch_with_pamac || return 2
    setup_arch_with_yay || return 3
    configure_sddm || return 4
}

ID_LIKE="$(grep ID_LIKE= </etc/os-release | cut -d= -f2)"

echo "Setting up ${ID_LIKE^:?}-like OS."

if [[ "$ID_LIKE" == "arch" ]]; then
    setup_arch
else
    echo "ERROR: Unsupported system: ID_LIKE=$ID_LIKE"
    exit 2
fi

echo "Setup finished."