#!/usr/bin/env bash
# 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.
#
# Wrapper for thrift that attempts to use the system thrift if it's of the expected version,
# otherwise it bootstraps a new one.
set -e -u

if [[ $# -lt 1 ]]; then
  cat <<EOF
Usage: thriftw EXPECTED_THRIFT_VERSION THRIFT_ARGS...

Run the thrift compiler at EXPECTED_THRIFT_VERSION with THRIFT_ARGS, bootstrapping if necessary.
EOF
fi
expected_version=$1
shift

HERE=$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)

function check_thrift_version() {
  local readonly thrift="$1"

  [[ $("${thrift}" --version) = "Thrift version ${expected_version}" ]]
}

function check_thrift_gen_lang() {
  local readonly thrift="$1"
  local readonly gen_identifier="$2"

  "${thrift}" -help 2>&1 | grep -q "${gen_identifier}:"
}

function compatible_thrift() {
  local readonly thrift="$1"

  [[ -x "${thrift}" ]] && \
  check_thrift_version "${thrift}" && \
  check_thrift_gen_lang "${thrift}" "java (Java)" && \
  check_thrift_gen_lang "${thrift}" "js (Javascript)" && \
  check_thrift_gen_lang "${thrift}" "html (HTML)" && \
  check_thrift_gen_lang "${thrift}" "py (Python)"
}

function compatible_system_thrift() {
  if compatible_thrift "${HERE}/thrift"; then
    echo "${HERE}/thrift"
  else
    which -a thrift 2> /dev/null | while read thrift; do
      if compatible_thrift "${thrift}"; then
         echo "${thrift}"
         return
      fi
    done
  fi
}

function run_pants() {
  pushd "${HERE}/../.." &> /dev/null
  ./pants --no-colors --no-lock "$@"
  popd &> /dev/null
}

function get_pants_option() {
  local readonly scope="$1"
  local readonly name="$2"

  run_pants options --output-format=json --scope=${scope} --name=${name} | python <(cat << EOF
from __future__ import print_function

import json
import sys


object = json.load(sys.stdin)
key = "${name}" if "${scope}" == "GLOBAL" else "${scope}.${name}"
value = object[key]["value"]
print(value)
EOF
)
}

thrift="$(compatible_system_thrift)"
if [[ -z "${thrift}" ]]; then
  readonly pants_thrift_version="$(get_pants_option thrift version)"
  if [[ "${expected_version}" != "${pants_thrift_version}" ]]; then
    echo "Pants thrift version ${pants_thrift_version} does not match expected version ${expected_version}!"
    exit 1
  fi

  # Bootstrap thrift compiler with pants
  run_pants --quiet gen --cache-ignore api/src/main/thrift/org/apache/aurora/gen::

  # Without reverse engineering pants custom os-specific path names,
  # find a suitable thrift compiler
  readonly pants_cache_dir="$(get_pants_option GLOBAL pants_bootstrapdir)"
  readonly thrift_bin_dir="$(get_pants_option thrift-binary supportdir)"
  for candidate in "${pants_cache_dir}/${thrift_bin_dir}"/*/*/"${expected_version}"/thrift; do
    if compatible_thrift "${candidate}"; then
      thrift="${candidate}"
      break
    fi
  done

  if ! compatible_thrift "${thrift}"; then
    echo "Failed to find or build a thrift binary compatible with Aurora requirements!"
    exit 1
  fi

  ln -f -s "${thrift}" "${HERE}/thrift"
fi

exec "${thrift}" "$@"