#!/bin/bash
set -euo pipefail

curl -sL https://raw.githubusercontent.com/Luzifer/github-publish/master/SHA256SUMS |
  grep "golang.sh" | sha256sum -c || exit 2

(which zip 2>&1 1>/dev/null) || {
  (which apk 2>&1 1>/dev/null) && apk add --update gawk zip
  (which apt-get 2>&1 1>/dev/null) && apt-get update && apt-get install -y zip
}

function log() {
  echo "${@}" >&2
}

function step() {
  log "===> $@..."
}

function substep() {
  log "======> $@..."
}

VERSION=$(git describe --tags --always || echo "dev")
PWD=$(pwd)
godir=${PWD/${GOPATH}\/src\//}
REPO=${REPO:-$(echo ${godir} | cut -d '/' -f 3)}
GHUSER=${GHUSER:-$(echo ${godir} | cut -d '/' -f 2)}
ARCHS=(${ARCHS:-linux/amd64 linux/arm darwin/amd64 windows/amd64})
DEPLOYMENT_TAG=${DEPLOYMENT_TAG:-${VERSION}}
PACKAGES=(${PACKAGES:-$(echo ${godir} | cut -d '/' -f 1-3)})
BUILD_DIR=${BUILD_DIR:-.build}
DRAFT=${DRAFT:-true}
FORCE_SKIP_UPLOAD=${FORCE_SKIP_UPLOAD:-false}
MOD_MODE=${MOD_MODE:-readonly}
NO_TESTS=${NO_TESTS:-false}

go_params=(
  "-mod=${MOD_MODE}"
  -modcacherw
  -trimpath
)

step "Check go environment"
go version

step "Retrieve dependencies"
tool_gopath=$(mktemp -d)
trap "rm -rf ${tool_gopath}" EXIT

substep "Install github-release"
GOPATH=${tool_gopath} go install \
  "${go_params}" \
  github.com/Luzifer/github-release@master

if [[ $NO_TESTS == false ]]; then
  step "Test code"
  go vet "${go_params[@]}" ${PACKAGES}
  go test "${go_params[@]}" ${PACKAGES}
fi

step "Extract changelog"
changelog=$([ -f "${PWD}/History.md" ] && awk '/^#/ && ++c==2{exit}; /^#/f' "${PWD}/History.md" | tail -n +2 || echo "")

step "Cleanup build directory if present"
rm -rf ${BUILD_DIR}

step "Compile program"
mkdir ${BUILD_DIR}

build_params=(
  -ldflags="-X main.version=${VERSION}"
)

for package in "${PACKAGES[@]}"; do
  for osarch in "${ARCHS[@]}"; do
    export GOOS=${osarch%%/*}
    export GOARCH=${osarch##*/}

    [[ ${GOOS} == "windows" ]] && suffix=".exe" || suffix=""
    outfile="${BUILD_DIR}/${package##*/}_${GOOS}_${GOARCH}${suffix}"

    substep "Build for ${osarch} into ${outfile}"

    go build \
      -o "${outfile}" \
      "${go_params[@]}" \
      "${build_params[@]}" \
      "${package}"
  done
done

step "Generate binary SHASUMs"
cd ${BUILD_DIR}
sha256sum * >SHA256SUMS

step "Pack archives"
for file in *; do
  if [ "${file}" = "SHA256SUMS" ]; then
    continue
  fi

  if [[ ${file} == *linux* ]]; then
    tar -czf "${file%%.*}.tar.gz" "${file}"
  else
    zip "${file%%.*}.zip" "${file}"
  fi

  rm "${file}"
done

step "Generate archive SHASUMs"
sha256sum * >>SHA256SUMS
grep -v 'SHA256SUMS' SHA256SUMS >SHA256SUMS.tmp
mv SHA256SUMS.tmp SHA256SUMS

log -e "\n\n=== Recorded checksums ==="
cat SHA256SUMS

if [[ ${FORCE_SKIP_UPLOAD} == "true" ]]; then
  log "Upload is skipped, stopping build now."
  exit 0
fi

step "Publish builds to Github"

if ! git describe --tags --exact-match; then
  log "No tag present, stopping build now."
  exit 0
fi

if [ -z "${GITHUB_TOKEN}" ]; then
  log 'Please set $GITHUB_TOKEN environment variable'
  exit 1
fi

if [[ ${DRAFT} == "true" ]]; then
  step "Create a drafted release"
  echo "${changelog}" | ${tool_gopath}/bin/github-release release --user ${GHUSER} --repo ${REPO} --tag ${DEPLOYMENT_TAG} --name ${DEPLOYMENT_TAG} --description - --draft || true
else
  step "Create a published release"
  echo "${changelog}" | ${tool_gopath}/bin/github-release release --user ${GHUSER} --repo ${REPO} --tag ${DEPLOYMENT_TAG} --name ${DEPLOYMENT_TAG} --description - || true
fi

step "Upload build assets"
for file in *; do
  substep ${file}
  ${tool_gopath}/bin/github-release upload --user ${GHUSER} --repo ${REPO} --tag ${DEPLOYMENT_TAG} --name ${file} --file ${file}
done

cd -