#!/bin/sh
set -e

skip_unusable_snapd() {
    if [ -e "/run/snapd.socket" ]; then
        # Snapd is present, run the upgrade
        return 1
    fi

    if [ ! -e "/var/lib/lxd/server.crt" ]; then
        # LXD was never used, safe to skip
        return 0
    fi

    for path in containers images networks storage-pools; do
        if [ ! -e "/var/lib/lxd/${path}" ]; then
            # Path doesn't exist, continue to next one
            continue
        fi

        if [ -n "$(ls -A "/var/lib/lxd/${path}")" ]; then
            # Detected some data, unsafe to skip automatically
            return 1
        fi
    done

    return 0
}

case "$1" in
    install|upgrade)
        . /usr/share/debconf/confmodule

        # Early check for systems that were already switched
        if ([ ! -e "/var/lib/lxd/server.crt" ] || [ ! -e "/var/lib/lxd" ]) && [ -e "/var/snap/lxd" ]; then
            exit 0
        fi

        echo "=> Installing the LXD snap"

        # Warn about downtime
        if [ -e "/var/lib/lxd/server.crt" ]; then
            db_input high lxd/snap-upgrade-warning || true
            db_go
        fi

        # Check store connectivity
        echo "==> Checking connectivity with the snap store"
        COUNT=0
        SKIP=false
        while :; do
            if skip_unusable_snapd; then
                echo "===> System doesn't have a working snapd and LXD was never used, skipping"
                SKIP=true
                break
            fi

            snap info lxd >/dev/null 2>&1 && break

            db_fset lxd/snap-no-connectivity seen false
            if ! db_input critical lxd/snap-no-connectivity; then
                db_go

                if [ "${COUNT}" = "0" ]; then
                    echo "===> Unable to contact the store, trying every minute for the next 30 minutes"
                elif [ "${COUNT}" = "10" ]; then
                    echo "===> Still unable to contact the store, trying for another 20 minutes"
                elif [ "${COUNT}" = "20" ]; then
                    echo "===> Still unable to contact the store, trying for another 10 minutes"
                elif [ "${COUNT}" = "30" ]; then
                    echo "===> Still unable to contact the store, aborting"
                    exit 1
                fi

                sleep 1m
            else
                db_go
                db_get lxd/snap-no-connectivity
                if [ "${RET}" = "Abort" ]; then
                    echo "===> Aborting at user request"
                    exit 1
                elif [ "${RET}" = "Skip" ]; then
                    if ! [ -e "/var/lib/lxd/server.crt" ]; then
                        echo "===> Skipping at user request"
                        SKIP=true
                        break
                    else
                        db_fset lxd/snap-install-cant-be-skipped seen false
                        db_input critical lxd/snap-install-cant-be-skipped || true
                        db_go
                    fi
                fi

                if [ "${COUNT}" = "0" ]; then
                    echo "===> Unable to contact the store"
                fi
            fi

            COUNT=$((COUNT+1))
        done

        if ! ${SKIP}; then
            # Set the default track
            db_get lxd/snap-track
            if [ -z "${RET}" ]; then
                if [ -e "/etc/os-release" ] && grep -q " LTS " /etc/os-release; then
                    db_set lxd/snap-track "4.0"
                fi

                db_fset lxd/snap-track seen false
            fi

            # Prompt about track
            db_input high lxd/snap-track || true
            db_go

            # Get the track
            db_get lxd/snap-track
            track=${RET}

            # Workaround for broken systems
            mkdir -p /lib/modules

            # Extract the OS release
            RELEASE="19.04"
            if [ -e "/etc/os-release" ]; then
                RELEASE=$(. /etc/os-release && echo "${VERSION_ID}")
            fi

            # Install the snap
            echo "==> Installing the LXD snap from the ${track} track for ubuntu-${RELEASE}"
            if [ "${track}" = "latest" ]; then
                snap install lxd --channel="stable/ubuntu-${RELEASE}"
            else
                snap install lxd --channel="${track}/stable/ubuntu-${RELEASE}"
            fi

            if [ -e "/var/lib/lxd/server.crt" ]; then
                echo "==> Waiting for LXD to be online (10min timeout)"
                /snap/bin/lxd waitready --timeout=600

                echo "==> Running migration from Deb to Snap"
                export LXD_PREINST=1
                /snap/bin/lxd.migrate --yes
            fi

            echo "=> Snap installation complete"
        fi

        echo "==> Cleaning up leftovers"
        deb-systemd-invoke stop lxd.socket lxd.service lxd-containers.service || true
        deb-systemd-invoke disable lxd.socket lxd.service lxd-containers.service || true
        update-rc.d lxd remove || true
        rm -rf --one-file-system /etc/dnsmasq.d-available/lxd
        rm -rf --one-file-system /etc/init.d/lxd
        rm -rf --one-file-system /etc/logrotate.d/lxd
        rm -rf --one-file-system /etc/sysctl.d/10-lxd-inotify.conf
        rm -rf --one-file-system /var/lib/lxd
        rm -rf --one-file-system /var/log/lxd

    ;;

    abort-upgrade|abort-remove|abort-deconfigure)
    ;;

    *)
        echo "postinst called with unknown argument \`$1'" >&2
        exit 1
    ;;
esac



exit 0