#!/usr/bin/env bash
# SPDX-FileCopyrightText: 2020 Citadel and contributors
#
# SPDX-License-Identifier: GPL-3.0-or-later

CITADEL_ROOT="$(readlink -f $(dirname "${BASH_SOURCE[0]}")/..)"

# Fail if not running as root
if [[ $EUID -ne 0 ]]; then
  echo "This script must be run as root" 1>&2
  exit 1
fi

# Get the memory usage of a docker container by name
function get_memory_usage() {
  docker stats --no-stream --format "{{.MemPerc}}" "$1" | sed "s/%//"
}

# Convert a memory usage in MiB to the percentage of the total memory
# With two decimal places
function mem_usage_to_percent() {
  local mem_usage="$1"
  local total_mem="$(free -m | awk 'NR==2 {print $2}')"
  echo "$(awk "BEGIN {printf \"%.1f\", $mem_usage / $total_mem * 100}")"
}

get_total_used_mem_raw() {
  free -m | awk 'NR==2 {print $3}'
}

get_total_used_mem() {
  echo "$(mem_usage_to_percent "$(get_total_used_mem_raw)")"
}

# To get the containers of the app, list every container whose name starts with the name of the app
get_app_containers () {
  local app_name="$1"
  "${CITADEL_ROOT}/scripts/app" compose "${app_name}" ps | awk '{print $1}' | grep -v 'Name\|-----'
}

# Get the memory usage of the whole system, excluding docker containers
get_system_memory_usage() {
  local docker_usage_all="$(docker stats --no-stream --format "{{.MemUsage}}" | awk '{sum+=$1} END {print sum}')"
  # Now, subtract that from get_total_used_mem_raw, and convert the output to a percentage
  local total_usage="$(get_total_used_mem_raw)"
  local system_usage="$(awk "BEGIN {printf \"%.1f\", $total_usage - $docker_usage_all}")"
  echo "$(mem_usage_to_percent "$system_usage")"
}

main() {
  echo "total: $(get_total_used_mem)%"&
  for service in bitcoin lnd electrs tor; do
    echo "${service}: $(get_memory_usage "$service")%" &
  done
  for app in $("${CITADEL_ROOT}/scripts/app" ls-installed); do
    # For every container of the app, get the mem usage, save it, and at the end, print the total mem usage of the app
    local mem_usage=0
    for container in $(get_app_containers "$app"); do
      # Use awk to add, it supports floating point numbers
      mem_usage=$(awk "BEGIN {printf \"%.2f\", $mem_usage + $(get_memory_usage "$container")}")
    done
    wait
    echo "${app}: $mem_usage%"
  done
  echo "system: $(get_system_memory_usage)%"
  wait
}

main | sort --key 2 --numeric-sort --reverse