#!/usr/bin/env bash
# Copyright 2015 The Kubernetes Authors.
#
# 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.

# Update the LICENSES directory.
# Generates a table of Go dependencies and their licenses.
#
# Usage:
#    $0 [--create-missing] [/path/to/licenses]
#
#    --create-missing will write the files that only exist upstream, locally.
#    This option is mostly used for testing as we cannot check-in any of the
#    additionally created files into the vendor auto-generated tree.
#
#    Run every time a license file is added/modified within /vendor to
#    update /LICENSES

set -o errexit
set -o nounset
set -o pipefail

KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
source "${KUBE_ROOT}/hack/lib/init.sh"

export LANG=C
export LC_ALL=C

###############################################################################
# Process package content
#
# @param package  The incoming package name
# @param type     The type of content (LICENSE, COPYRIGHT or COPYING)
#
process_content () {
  local package=$1
  local type=$2

  local package_root
  local ensure_pattern
  local dir_root
  local find_maxdepth
  local find_names
  local -a local_files=()

  # Necessary to expand {}
  case ${type} in
      LICENSE) find_names=(-iname 'licen[sc]e*')
               find_maxdepth=1
               # Sadly inconsistent in the wild, but mostly license files
               # containing copyrights, but no readme/notice files containing
               # licenses (except to "see license file")
               ensure_pattern="license|copyright"
               ;;
    # We search READMEs for copyrights and this includes notice files as well
    # Look in as many places as we find files matching
    COPYRIGHT) find_names=(-iname 'notice*' -o -iname 'readme*')
               find_maxdepth=3
               ensure_pattern="copyright"
               ;;
      COPYING) find_names=(-iname 'copying*')
               find_maxdepth=1
               ensure_pattern="license|copyright"
               ;;
  esac

  # Start search at package root
  case ${package} in
    github.com/*|golang.org/*|bitbucket.org/*|gonum.org/*)
     package_root=$(echo "${package}" |awk -F/ '{ print $1"/"$2"/"$3 }')
     ;;
    go4.org/*)
     package_root=$(echo "${package}" |awk -F/ '{ print $1 }')
     ;;
    gopkg.in/*)
     # Root of gopkg.in package always ends with '.v(number)' and my contain
     # more than two path elements. For example:
     # - gopkg.in/yaml.v2
     # - gopkg.in/inf.v0
     # - gopkg.in/square/go-jose.v2
     package_root=$(echo "${package}" |grep -oh '.*\.v[0-9]')
     ;;
    */*)
     package_root=$(echo "${package}" |awk -F/ '{ print $1"/"$2 }')
     ;;
    *)
     package_root="${package}"
     ;;
  esac

  # Find files - only root and package level
  local_files=()
  IFS=" " read -r -a local_files <<< "$(
    for dir_root in ${package} ${package_root}; do
      [[ -d ${DEPS_DIR}/${dir_root} ]] || continue

      # One (set) of these is fine
      find "${DEPS_DIR}/${dir_root}" \
          -xdev -follow -maxdepth ${find_maxdepth} \
          -type f "${find_names[@]}"
    done | sort -u)"

  local index
  local f
  index="${package}-${type}"
  if [[ -z "${CONTENT[${index}]-}" ]]; then
    for f in "${local_files[@]-}"; do
      if [[ -z "$f" ]]; then
        # Set the default value and then check it to prevent
        # accessing potentially empty array
        continue
      fi
      # Find some copyright info in any file and break
      if grep -E -i -wq "${ensure_pattern}" "${f}"; then
        CONTENT[${index}]="${f}"
        break
      fi
    done
  fi
}


#############################################################################
# MAIN
#############################################################################

# use modules, and use module info rather than the vendor dir for computing dependencies
export GO111MODULE=on
export GOFLAGS=-mod=mod

# Check bash version
if (( BASH_VERSINFO[0] < 4 )); then
  echo
  echo "ERROR: Bash v4+ required."
  # Extra help for OSX
  if [[ "$(uname -s)" == "Darwin" ]]; then
    echo
    echo "Ensure you are up to date on the following packages:"
    echo "$ brew install md5sha1sum bash jq"
  fi
  echo
  exit 9
fi

# This variable can be injected, as in the verify script.
LICENSE_ROOT="${LICENSE_ROOT:-${KUBE_ROOT}}"
cd "${LICENSE_ROOT}"

kube::util::ensure-temp-dir

# Save the genreated LICENSE file for each package temporarily
TMP_LICENSE_FILE="${KUBE_TEMP}/LICENSES.$$"

# The directory to save all the LICENSE files
LICENSES_DIR="${LICENSES_DIR:-${LICENSE_ROOT}/LICENSES}"
mkdir -p "${LICENSES_DIR}"

# The tmp directory to save all the LICENSE files, will move to LICENSES_DIR
TMP_LICENSES_DIR="${KUBE_TEMP}/LICENSES.DIR.$$"
mkdir -p "${TMP_LICENSES_DIR}"

DEPS_DIR="vendor"
declare -Ag CONTENT

# Put the K8S LICENSE on top
if [ -f "${LICENSE_ROOT}/LICENSE" ]; then
  (
    echo "================================================================================"
    echo "= Kubernetes licensed under: ="
    echo
    cat "${LICENSE_ROOT}/LICENSE"
    echo
    echo "= LICENSE $(kube::util::md5 "${LICENSE_ROOT}/LICENSE")"
    echo "================================================================================"
  ) > "${TMP_LICENSE_FILE}"
  mv "${TMP_LICENSE_FILE}" "${TMP_LICENSES_DIR}/LICENSE"
fi

# Loop through every vendored package
for PACKAGE in $(go list -m -json all | jq -r .Path | sort -f); do
  if [[ -e "staging/src/${PACKAGE}" ]]; then
    echo "${PACKAGE} is a staging package, skipping" >&2
    continue
  fi
  if [[ ! -e "${DEPS_DIR}/${PACKAGE}" ]]; then
    echo "${PACKAGE} doesn't exist in ${DEPS_DIR}, skipping" >&2
    continue
  fi
  # Skip a directory if 1) it has no files and 2) all the subdirectories contain a go.mod file.
  misses_go_mod=false
  DEPS_SUBDIR="${DEPS_DIR}/${PACKAGE}"
  search_for_mods () {
    if [[ -z "$(find "${DEPS_SUBDIR}/" -mindepth 1 -maxdepth 1 -type f)" ]]; then
      while read -d "" -r SUBDIR; do
          if [[ ! -e "${SUBDIR}/go.mod" ]]; then
              DEPS_SUBDIR=${SUBDIR}
              search_for_mods
          fi
      done < <(find "${DEPS_SUBDIR}/" -mindepth 1 -maxdepth 1 -type d -print0)
    else
      misses_go_mod=true
    fi
  }
  search_for_mods
  if [[ $misses_go_mod = false ]]; then
      echo "${PACKAGE} has no files, skipping" >&2
      continue
  fi
  echo "${PACKAGE}"

  process_content "${PACKAGE}" LICENSE
  process_content "${PACKAGE}" COPYRIGHT
  process_content "${PACKAGE}" COPYING

  # copy content and throw error message
  {
    echo "= ${DEPS_DIR}/${PACKAGE} licensed under: ="
    echo

    file=""
    if [[ -n "${CONTENT[${PACKAGE}-LICENSE]-}" ]]; then
      file="${CONTENT[${PACKAGE}-LICENSE]-}"
    elif [[ -n "${CONTENT[${PACKAGE}-COPYRIGHT]-}" ]]; then
      file="${CONTENT[${PACKAGE}-COPYRIGHT]-}"
    elif [[ -n "${CONTENT[${PACKAGE}-COPYING]-}" ]]; then
      file="${CONTENT[${PACKAGE}-COPYING]-}"
    fi
    if [[ -z "${file}" ]]; then
      cat >&2 << __EOF__
No license could be found for ${PACKAGE} - aborting.

Options:
1. Check if the upstream repository has a newer version with LICENSE, COPYRIGHT and/or
   COPYING files.
2. Contact the author of the package to ensure there is a LICENSE, COPYRIGHT and/or
   COPYING file present.
3. Do not use this package in Kubernetes.
__EOF__
      exit 9
    fi

    cat "${file}"
    echo
    echo "= ${file} $(kube::util::md5 "${file}")"
  } >> "${TMP_LICENSE_FILE}"

  dest_dir="${TMP_LICENSES_DIR}/vendor/${PACKAGE}"
  mkdir -p "${dest_dir}"
  mv "${TMP_LICENSE_FILE}" "${dest_dir}/LICENSE"
done

# copy licenses for forked code from vendor and third_party directories
(cd "${KUBE_ROOT}" && \
  find vendor third_party -iname 'licen[sc]e*' -o -iname 'notice*' -o -iname 'copying*' | \
  grep -E 'third_party|forked' | \
  xargs tar -czf - | tar -C "${TMP_LICENSES_DIR}" -xzf -)

# Leave things like OWNERS alone.
rm -f "${LICENSES_DIR}/LICENSE"
rm -rf "${LICENSES_DIR}/vendor"
rm -rf "${LICENSES_DIR}/third_party"
mv "${TMP_LICENSES_DIR}"/* "${LICENSES_DIR}"
