#!/usr/bin/env bash

SCRIPTNAME="$( basename -- "$0" )"

# check : current user is root?
check_root () {
    [[ $EUID -eq 0 ]]
}

# ok if root
ensure_root () {
    if ! check_root; then
	echo "ERROR : This script must be run as root"
	exit 1
    else
	return 0
    fi
}

# ok if non root
ensure_not_root () {
    if check_root; then
	echo "ERROR : This script must not be *run* as root"
	exit 1
    else
	return 0
    fi
}

# ok if running script from current directory
ensure_pwd_is_scriptdir () {
  if [[ $PWD != $ABSDIR ]]; then
    echo "Please cd in the script directory before running it :"
    echo "cd ${ABSDIR}"
    echo "./${SCRIPTNAME}"
    exit 1
  fi
}

# make sure systemd directory exists
ensure_systemd_as_user_dir_exists () {
  [[ -d ${HOME}/.config/systemd/user/ ]] || mkdir -p ${HOME}/.config/systemd/user/
}

# sed or die trying
sed_in_place () {
    grep -q "${1}" "${3}"
    if [ $? -eq 0 ]; then
	sed -i -e "s|${1}|${2}|g" ${3}
    else
	echo "Pattern ${1} not found in file ${3}, exiting."
	exit 1
    fi
}

# check: systemd unit exists
check_systemd_unit_exists () {
  systemctl --user cat -- ${1} &> /dev/null
}

# check if variable is empty
check_variable_is_empty () {
  [[ -z ${!1} ]]
}

# ensure variable is defined
ensure_variable_is_defined () {
  if check_variable_is_empty ${1}; then
    echo "Error : variable ${1} must be defined"
    exit 1
  fi
}

# ensure all variables are defined
ensure_variables_are_defined () {
  for i in ${1}; do
    ensure_variable_is_defined $i
  done
}

# check if IPv4 syntax is valid
check_valid_ipv4() {
    re='^((1?[0-9]{1,2}|2([0-4][0-9]|5[0-5]))\.){3}'
    re+='(1?[0-9]{1,2}|2([0-4][0-9]|5[0-5]))$'

    if [[ ${1} =~ ${re} ]]; then
	return 0
    else
	echo "ERROR : ${1} is not a valid IPv4 address"
	exit 1
    fi
}

# Get default interface IPv4 address
# and return result in variable passed as argument
get_default_iface_ipv4() {
    # Call this function with the name of the variable
    # you want to store the result in :
    # get_default_iface_ipv4 myipv4
    # See https://www.linuxjournal.com/content/return-values-bash-functions
    local __resultvar=${1}
    local __default_iface=$(awk '$2 == 00000000 { print $1 }' /proc/net/route)
    local __default_iface_ipv4=$(ip addr show dev "${__default_iface}" | awk '$1 == "inet" { sub("/.*", "", $2); print $2 }')
    if check_valid_ipv4 ${__default_iface_ipv4}; then
	eval $__resultvar="'${__default_iface_ipv4}'"
	return 0
    else
	exit 1
    fi
}

# ok if systemd unit file {1} exists
ensure_systemd_unit_exists () {
    if ! check_systemd_unit_exists ${1}; then
	echo "ERROR : systemd unit ${1} does not exists!"
	exit 1
    else
	return 0
    fi
}

# ok if systemd unit file {1} does not exists
ensure_systemd_unit_not_exists () {
    if check_systemd_unit_exists ${1}; then
	echo "ERROR : systemd unit ${1} exists!"
	exit 1
    else
	return 0
    fi
}

# check: systemd unit running
check_systemd_unit_running () {
  systemctl --user is-active --quiet service ${1}
}

# ok if systemd unit {1} is running
ensure_systemd_unit_running () {
    if ! check_systemd_unit_running ${1}; then
	echo "ERROR : systemd unit ${1} is not running!"
	exit 1
    else
	return 0
    fi
}

# ok if systemd unit {1} is NOT running
ensure_systemd_unit_not_running () {
    if check_systemd_unit_running ${1}; then
	echo "ERROR : systemd unit ${1} is running!"
	exit 1
    else
	return 0
    fi
}

# check: container $1 exists?
check_container_exists () {
    podman container exists ${1}
}

# ok if container exists
ensure_container_exists () {
    if ! check_container_exists ${1}; then
	echo "ERROR : container ${1} does not exists"
	exit 1
    else
	return 0
    fi
}

# ok if container does not exists
ensure_container_not_exists () {
    if check_container_exists ${1}; then
	echo "ERROR : container ${1} exists"
	exit 1
    else
	return 0
    fi
}

# check: container ${1} is running?
check_container_running () {
  [[ `podman container inspect -f '{{.State.Status}}' ${1}` == "running" ]]
}

# ok if container is running
ensure_container_running () {
    if ! check_container_running ${1}; then
	echo "ERROR : container ${1} is not running"
	exit 1
    else
	return 0
    fi
}

# ok if container is not running
ensure_container_not_running () {
    if check_container_running ${1}; then
	echo "ERROR : container ${1} is running"
	exit 1
    else
	return 0
    fi
}

# check: pod $1 exists?
check_pod_exists () {
    podman pod exists ${1}
}

# ok if pod exists
ensure_pod_exists () {
    if ! check_pod_exists ${1}; then
	echo "ERROR : pod ${1} does not exists"
	exit 1
    else
	return 0
    fi
}

# ok if pod does not exists
ensure_pod_not_exists () {
    if check_pod_exists ${1}; then
	echo "ERROR : pod ${1} exists"
	exit 1
    else
	return 0
    fi
}

# check: pod ${1} is running?
check_pod_running () {
  [[ `podman pod inspect -f '{{.State}}' ${1}` == "Running" ]]
}

# ok if pod is running
ensure_pod_running () {
    if ! check_pod_running ${1}; then
	echo "ERROR : pod ${1} is not running"
	exit 1
    else
	return 0
    fi
}

# ok if pod is not running
ensure_pod_not_running () {
    if check_pod_running ${1}; then
	echo "ERROR : pod ${1} is running"
	exit 1
    else
	return 0
    fi
}

# Get podman volume path
# WARNING : this function assumes the volume exists
get_podman_volume_path () {
    podman volume inspect --format '{{ .Mountpoint }}' ${1}
}

# Execute elf binary from stdin
elfexec () {
    opts=$(echo "$@")
    if [[ $(uname -i) == 'aarch64' ]]; then
	memfd_create='279'
    else
	# defaults to amd64
	memfd_create='319'
    fi

    python3 -c "
import ctypes, os;
from sys import stdin;
l = ctypes.CDLL(None);
s = l.syscall;
e = stdin.buffer.read();
f = s(${memfd_create}, '', 1);
os.write(f, e);
p = '/proc/self/fd/%d' % f;
myargs='${opts}';
os.execve(p, ['binary'] + myargs.split(), {'PATH': '${PATH}'})"
}

# Execute buildctl directly from the web
my_buildctl () {
    buildkitversion='v0.10.5'
    if [[ $(uname -i) == 'aarch64' ]]; then
	buildkitarch='arm64'
        buildctlchecksum='4b194eeb1d1079c7842e40ed0894221405dddf09ce8f0892072afa6c0581e3b5750efbcb93924c2f6739dcab7c1c8a63e99d0084233280bc6f5adb1471bc7c12'
    else
	# defaults to amd64
	buildkitarch='amd64'
        buildctlchecksum='b9e56aebf4dec0cc2f0abfec27c0a89bb1a747ef6fd85233b6358cd83b394ecf879dd963e6e5bfaad08db1c3c46b9a754bbef5d421e74f89781e1849b7c40187'
    fi
    curl -sSLf https://github.com/moby/buildkit/releases/download/${buildkitversion}/buildkit-${buildkitversion}.linux-${buildkitarch}.tar.gz |
	tar xOz bin/buildctl | python3 -c "
import os, hashlib, sys
from sys import stdin
e = stdin.buffer.read();
if hashlib.sha512(e).hexdigest() == '${buildctlchecksum}':
  sys.stdout.buffer.write(e)
  sys.exit(0)
else:
  sys.stderr.write('Invalid hash\n')
  sys.exit(-1)" | elfexec "${@}"
}

oci_push_to_registry () {
    if ! skopeo inspect --format "Image ${1} found on remote container registry." docker://${1}; then
        if podman image exists ${1}; then
            ensure_variables_are_defined "CONTAINER_REPO_USER CONTAINER_REPO_PASSWORD"
            podman push --creds=${CONTAINER_REPO_USER}:${CONTAINER_REPO_PASSWORD} ${1} &&
            podman image rm ${1} &&
            podman pull ${1}
        else
            echo "Error : image ${1} does not exists"
            exit 1
        fi
    fi
}