#!/usr/bin/env bash

# Copyright 2021 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.

# This script checks the coding style for the Go language files using
# golangci-lint. Which checks are enabled depends on command line flags. The
# default is a minimal set of checks that all existing code passes without
# issues.

usage () {
  cat <<EOF >&2
Usage: $0 [-r <revision>|-a] [-s] [-c none|<config>] [-- <golangci-lint run flags>] [packages]"
   -r <revision>: only report issues in code added since that revision
   -a: automatically select the common base of origin/master and HEAD
       as revision
   -s: select a strict configuration for new code
   -n: in addition to strict checking, also enable hints (aka nits) that may are may not
       be useful
   -g <github action file>: also write results with --out-format=github-actions
       to a separate file
   -c <config|"none">: use the specified configuration or none instead of the default hack/golangci.yaml
   [packages]: check specific packages or directories instead of everything
EOF
  exit 1
}

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

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

# Ensure that we find the binaries we build before anything else.
export GOBIN="${KUBE_OUTPUT_BINPATH}"
PATH="${GOBIN}:${PATH}"

invocation=(./hack/verify-golangci-lint.sh "$@")

# Disable warnings about the logcheck plugin using the old API
# (https://github.com/golangci/golangci-lint/issues/4001).
# Can be removed once logcheck gets updated to a newer release
# which uses the new plugin API
export GOLANGCI_LINT_HIDE_WARNING_ABOUT_PLUGIN_API_DEPRECATION=1

# The logcheck plugin currently has to be configured via env variables
# (https://github.com/golangci/golangci-lint/issues/1512).
#
# Remember to clean the golangci-lint cache when changing
# the configuration and running this script multiple times,
# otherwise golangci-lint will report stale results:
# _output/local/bin/golangci-lint cache clean
golangci=(env LOGCHECK_CONFIG="${KUBE_ROOT}/hack/logcheck.conf" "${GOBIN}/golangci-lint" run)
golangci_config="${KUBE_ROOT}/hack/golangci.yaml"
base=
strict=
hints=
githubactions=
while getopts "ar:sng:c:" o; do
  case "${o}" in
    a)
      base="$(git merge-base origin/master HEAD)"
      ;;
    r)
      base="${OPTARG}"
      if [ ! "$base" ]; then
        echo "ERROR: -c needs a non-empty parameter" >&2
        echo >&2
        usage
      fi
      ;;
    s)
      golangci_config="${KUBE_ROOT}/hack/golangci-strict.yaml"
      strict=1
      ;;
    n)
      golangci_config="${KUBE_ROOT}/hack/golangci-hints.yaml"
      hints=1
      ;;
    g)
      githubactions="${OPTARG}"
      ;;
    c)
      if [ "${OPTARG}" = "none" ]; then
        golangci_config=""
      else
        golangci_config="${OPTARG}"
      fi
      ;;
   *)
     usage
     ;;
  esac
done

# Below the output of golangci-lint is going to be piped into sed to add
# a prefix to each output line. This helps make the output more visible
# in the Prow log viewer ("error" is a key word there) and ensures that
# only those lines get included as failure message in a JUnit file
# by "make verify".
#
# The downside is that the automatic detection whether to colorize output
# doesn't work anymore, so here we force it ourselves when connected to
# a tty.
if tty -s; then
    golangci+=(--color=always)
fi

if [ "$base" ]; then
    # Must be a something that git can resolve to a commit.
    # "git rev-parse --verify" checks that and prints a detailed
    # error.
    base="$(git rev-parse --verify "$base")"
    golangci+=(--new --new-from-rev="$base")
fi

kube::golang::verify_go_version

# Filter out arguments that start with "-" and move them to the run flags.
shift $((OPTIND-1))
targets=()
for arg; do
  if [[ "${arg}" == -* ]]; then
    golangci+=("${arg}")
  else
    targets+=("${arg}")
  fi
done

kube::golang::verify_go_version

# Explicitly opt into go modules, even though we're inside a GOPATH directory
export GO111MODULE=on

# Install golangci-lint
echo "installing golangci-lint and logcheck plugin from hack/tools into ${GOBIN}"
pushd "${KUBE_ROOT}/hack/tools" >/dev/null
  go install github.com/golangci/golangci-lint/cmd/golangci-lint
  if [ "${golangci_config}" ]; then
    # This cannot be used without a config.
    go build -o "${GOBIN}/logcheck.so" -buildmode=plugin sigs.k8s.io/logtools/logcheck/plugin
  fi
popd >/dev/null

if [ "${golangci_config}" ]; then
  # The relative path to _output/local/bin only works if that actually is the
  # GOBIN. If not, then we have to make a temporary copy of the config and
  # replace the path with an absolute one. This could be done also
  # unconditionally, but the invocation that is printed below is nicer if we
  # don't to do it when not required.
  if grep -q 'path: ../_output/local/bin/' "${golangci_config}" &&
     [ "${GOBIN}" != "${KUBE_ROOT}/_output/local/bin" ]; then
    kube::util::ensure-temp-dir
    patched_golangci_config="${KUBE_TEMP}/$(basename "${golangci_config}")"
    sed -e "s;path: ../_output/local/bin/;path: ${GOBIN}/;" "${golangci_config}" >"${patched_golangci_config}"
    golangci_config="${patched_golangci_config}"
  fi
  golangci+=(--config="${golangci_config}")
fi

cd "${KUBE_ROOT}"

res=0
run () {
  if [[ "${#targets[@]}" -gt 0 ]]; then
    echo "running ${golangci[*]} ${targets[*]}" >&2
    "${golangci[@]}" "${targets[@]}" 2>&1 | sed -e 's;^;ERROR: ;' >&2 || res=$?
  else
    echo "running ${golangci[*]} ./..." >&2
    "${golangci[@]}" ./... 2>&1 | sed -e 's;^;ERROR: ;' >&2 || res=$?
    for d in staging/src/k8s.io/*; do
      MODPATH="staging/src/k8s.io/$(basename "${d}")"
      echo "running ( cd ${KUBE_ROOT}/${MODPATH}; ${golangci[*]} --path-prefix ${MODPATH} ./... )"
      pushd "${KUBE_ROOT}/${MODPATH}" >/dev/null
        "${golangci[@]}" --path-prefix "${MODPATH}" ./... 2>&1 | sed -e 's;^;ERROR: ;' >&2 || res=$?
      popd >/dev/null
    done
  fi
}
# First run with normal output.
run "${targets[@]}"

# Then optionally do it again with github-actions as format.
# Because golangci-lint caches results, this is faster than the
# initial invocation.
if [ "$githubactions" ]; then
  golangci+=(--out-format=github-actions)
  run "$${targets[@]}" >"$githubactions" 2>&1
fi

# print a message based on the result
if [ "$res" -eq 0 ]; then
  echo 'Congratulations! All files are passing lint :-)'
else
  {
    echo
    echo "Please review the above warnings. You can test via \"${invocation[*]}\""
    echo 'If the above warnings do not make sense, you can exempt this warning with a comment'
    echo ' (if your reviewer is okay with it).'
    if [ "$strict" ]; then
        echo 'The more strict golangci-strict.yaml was used.'
    elif [ "$hints" ]; then
        echo 'The golangci-hints.yaml was used. Some of the reported issues may have to be fixed'
        echo 'while others can be ignored, depending on the circumstances and/or personal'
        echo 'preferences. To determine which issues have to be fixed, check the report that'
        echo 'uses golangci-strict.yaml.'
    fi
    if [ "$strict" ] || [ "$hints" ]; then
        echo 'If you feel that this warns about issues that should be ignored by default,'
        echo 'then please discuss with your reviewer and propose'
        echo 'a change for hack/golangci.yaml.in as part of your PR.'
    fi
    echo 'In general please prefer to fix the error, we have already disabled specific lints'
    echo ' that the project chooses to ignore.'
    echo 'See: https://golangci-lint.run/usage/false-positives/'
    echo
  } >&2
  exit 1
fi

# preserve the result
exit "$res"