#!/bin/bash
#
# This script must be run in the location of the script!
#
# This script generates Android.bp files for this and all subdirs of this
#
DIR="${ANDROID_BUILD_TOP}/device/google/cuttlefish_vmm"

function remove_trailing_slash {
  if [[ $1 == "/" ]]; then
    echo $i
  else
    echo ${1%/}
  fi
}

set -o errexit

function check_location() {
  local my_loc="$(realpath ${DIR})"
  my_loc=$(remove_trailing_slash ${my_loc})

  local my_pwd="$(realpath $PWD)"
  my_pwd="$(remove_trailing_slash ${my_pwd})"
  if [[ "${my_loc}" != "${my_pwd}" ]]; then
    echo ${my_loc}
    echo ${my_pwd}
    >&2 echo "the script location must be run where the script is located"
    exit 10
  fi
}

my_name=`basename $0`
seccomp_archs=("x86_64" "aarch64")
# under get_arch_dir() in cuttlefish_vmm, where is seccomp?
subdir="etc/seccomp"

# define arch dir pattern: e.g. ${ARCH}-linux-gnu
function get_arch_dir() {
  local suffix="-linux-gnu"
  local arch=$1
  echo ${arch}${suffix}
}

# take arch, return the path of the output Android.bp file
function get_output_file() {
  local blueprint_dir=$1
  blueprint_dir="$(remove_trailing_slash ${blueprint_dir})"
  echo "${blueprint_dir}/Android.bp"
}

# utility function to enumerate policy files
#
# 1: seccomp dir to scan
function scan_policy_name() {
  local seccomp_dir=$1
  (
    # pushd but no output to stdout/stderr
    # the output is taken and used by the caller
    pushd $seccomp_dir > /dev/null 2>&1
    ls -1
    popd > /dev/null 2>&1
  )
}

# starting from old Android.bp
function gen_license() {
  local year=${1:-"2019"}
cat <<EOF
// Autogenerated via ${my_name}
//
// Copyright (C) ${year} The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

EOF
}

#
# first two args are module type (e.g. prebuilt_usr_share_host)
# and the whitespaces for indentation
#
# the rest must be in this form:
#  --name=value
#
# then, it simply generates this line repeatedly:
# <indent>name: value,
#
# e.g. --name="\"foo\"" will generate
#   name: "foo",
#
function gen_module() {
  local mod_name=$1  # e.g. prebuilt_usr_share_host
  local indent="$2"
  shift 2
  local long_options=()
  local long_opt=""
  local OPTIND=1
  while getopts ":-:" op; do
    # a long opt like --srcs="some" is actually:
    # - + - + "srcs=some"
    # that's a short option '-' just like h, and
    # the OPTARGS of the option '-' is srcs=some 
    if [[ "$op" != "-" ]]; then
      >&2 echo "gen_module does take long options with = only"
      exit 8
    fi
    long_op="${OPTARG%%=*}"
    OPTARG="${OPTARG#$long_op}"
    OPTARG="${OPTARG#=}"
    long_options+=( "$long_op" )
    declare local ${long_op}="${OPTARG}"
  done

  echo "$mod_name {"
  for field in "${long_options[@]}"; do
    eval local value=\$$field
    echo "${indent}${field}: ${value},"
  done
  echo "}"
}

function gen_android_bp4seccomp() {
  local arch="$1"
  local arch_dir="$(get_arch_dir ${arch})"
  local seccomp_dir="${arch_dir}/${subdir}"
  local where_in_etc_on_user_machine="cuttlefish/${arch_dir}/seccomp"
  gen_license 2019
  for i in $(scan_policy_name $seccomp_dir); do
    # first two are: e.g. prebuilt_usr_share_host and whitespace for intentation
    local base_name="$(basename $i)"
    gen_module "prebuilt_usr_share_host" '  ' \
      --name="\"${base_name}_at_${arch}\"" \
      --src="\"${subdir}/${base_name}\"" \
      --filename="\"${base_name}\"" \
      --sub_dir="\"${where_in_etc_on_user_machine}\""
  done
}

function gen_main_android_bp() {
  gen_license 2019

  gen_module "cc_prebuilt_binary" '  ' \
    --name="\"common_crosvm\"" \
    --stem="\"crosvm"\" \
    --srcs="[\"scripts/crosvm\"]" \
    --defaults="[\"cuttlefish_host_only\"]"

  cat <<EOF
// NOTE: Using cc_prebuilt_binary because cc_prebuilt_library can't handle stem on pie

EOF

for i in */bin/*; do
  if [[ ! -L "$i" ]]; then
    name="${i//\//_}"
    name="${name//-/_}"
    name="${name/_bin_/_}"
    path="$(dirname $(dirname "$i"))"
    stem="$(basename "$i")"

    if [[ "crosvm" != "${stem}" ]]; then
      name="${name}_for_crosvm"
    fi

    gen_module "cc_prebuilt_binary" '  ' \
    --name="\"${name}\"" \
    --srcs="[\"$i\"]" \
    --stem="\"$stem"\" \
    --relative_install_path="\"${path}\"" \
    --defaults="[\"cuttlefish_host_only\"]"
  fi
done
}

# main
check_location
gen_main_android_bp > $(get_output_file ${DIR})
for arch in ${seccomp_archs[@]}; do
  arch_dir=$(get_arch_dir ${arch})
  outfile="$(get_output_file ${arch_dir})"
  gen_android_bp4seccomp $arch > $outfile
done