LND_VERSION_DIR_AARCH64=lnd-linux-arm64-v0.17.4-beta
LND_URL_AARCH64=https://github.com/lightningnetwork/lnd/releases/download/v0.17.4-beta/lnd-linux-arm64-v0.17.4-beta.tar.gz
LND_SHA256_AARCH64=3c3472f3f1c93fef5b4e8989278c7538602c9d7c36c35092251c8bad0abf3cef

# binaries and config root; data is elsewhere, in /ssd/lnd as per lnd conf.
LND_HOME=/home/lnd
# no root slash since it's combined with other path prefixes.
LND_SVDIR=etc/sv/lnd

lnd_bin_install() {
    cd $LND_HOME
    local lnd_targz=$LND_VERSION_DIR_AARCH64.tar.gz
    test -f $LND_VERSION_DIR_AARCH64/lnd && return 0;
    curl -sSL -o $lnd_targz "$LND_URL_AARCH64"
    if [ $? -ne 0 ]; then
        printf "ERROR: unable to download $LND_URL_AARCH64\n" 1>&2
        return 1
    fi
    printf "$LND_SHA256_AARCH64 $lnd_targz" | sha256sum --check
    [ $? -ne 0 ] && return 1
    tar -C $LND_HOME --no-same-owner -xf $lnd_targz
    rm -f $lnd_targz
    return $?
}

lnd_svc_install() {
    # service directories
    mkdir -p /$LND_SVDIR
    mkdir -p /$LND_SVDIR/log

    # logging facility
    if [ ! -f /$LND_SVDIR/log/run ]; then
        cp $SYSUPDATES_ROOTDIR/files/$LND_SVDIR/log/run /$LND_SVDIR/log/
        chmod +x /$LND_SVDIR/log/run
    fi

    # the actual lnd service
    cat <<EOF > /$LND_SVDIR/run.new
#!/bin/sh
[ -r conf ] && . ./conf
exec 2>&1
# wait for OS to acquire a clock sync.
# random date in the past: Oct 22 06:40:00 PM UTC 2023
while [ "\$(date +%s)" -lt 1698000000 ]
do
    echo "service start suspended until clock sync"
    sleep 5
done
exec chpst -u lnd $LND_HOME/$LND_VERSION_DIR_AARCH64/lnd -C /home/lnd/lnd.mainnet.conf 2>&1
EOF
    chmod +x /$LND_SVDIR/run.new
    test -f /$LND_SVDIR/run && diff /$LND_SVDIR/run /$LND_SVDIR/run.new
    if [ $? -ne 0 ]; then
        sv -w 600 stop lnd || printf "ERROR: sv stop lnd failed\n" 1>&2
        mv /$LND_SVDIR/run.new /$LND_SVDIR/run
        sv start lnd || printf "ERROR: sv start lnd failed\n" 1>&2
    fi
    rm -f /$LND_SVDIR/run.new
    # whatever happened above, try to ensure the service is up
    chmod +x /$LND_SVDIR/run
    [ ! -f /$LND_SVDIR/down ] && sv start lnd
}

lnd_cli_install() {
    mkdir -p /opt/bin
    cat <<EOF > /opt/bin/lncli.sh
#!/bin/sh
set -e
cli=$LND_HOME/$LND_VERSION_DIR_AARCH64/lncli
exec doas -u lnd \$cli --macaroonpath /ssd/lnd/data/chain/bitcoin/mainnet/admin.macaroon "\$@"
EOF
    chmod +x /opt/bin/lncli.sh
}

lnd_apply() {
    lnd_bin_install || return 1
    lnd_svc_install || return 1
    lnd_cli_install || return 1
}