#!/bin/bash
#
# Copyright 2015 The Bazel Authors. All rights reserved.
#
# 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.

# Scripts to configure the service that will poll git repositories for
# in sync check.

# Format of each entry is:
#   origin destination local-name bidirectional branch1 ... branchN
REPOSITORIES=(
    "https://bazel.googlesource.com/bazel git@github.com:bazelbuild/bazel.git bazel false master"
    "https://bazel.googlesource.com/tulsi git@github.com:bazelbuild/tulsi.git tulsi false master"
    "https://bazel.googlesource.com/continuous-integration git@github.com:bazelbuild/continuous-integration.git continuous-integration true master"
    "https://bazel.googlesource.com/eclipse git@github.com:bazelbuild/eclipse.git eclipse true master"
    "https://bazel.googlesource.com/bazel-toolchains git@github.com:bazelbuild/bazel-toolchains.git bazel-toolchains true master"
)

set -euxo pipefail

# Download & decrypt gitcookies.
gsutil cat "gs://bazel-encrypted-secrets/gitsync-cookies.enc" | \
    gcloud kms decrypt --location "global" --keyring "buildkite" --key "gitsync-cookies-key" --plaintext-file "-" --ciphertext-file "-" \
    > /home/gitsync/.gitcookies
chmod 0600 /home/gitsync/.gitcookies

# Download & decrypt GitHub SSH key.
gsutil cat "gs://bazel-encrypted-secrets/gitsync-ssh.enc" | \
    gcloud kms decrypt --location "global" --keyring "buildkite" --key "gitsync-ssh-key" --plaintext-file "-" --ciphertext-file "-" \
    > /home/gitsync/.ssh/id_rsa
chmod 0600 /home/gitsync/.ssh/id_rsa

function clone() {
  git clone "$1" "$3"
  pushd "$3"
  git remote add destination "$2"
  popd
}

function sync_branch() {
  echo "sync_branch $*"
  local branch="$1"
  local bidirectional="$2"
  git checkout "origin/${branch}" -B "${branch}" || {
    echo "Failed to checkout ${branch}, aborting sync..."
    return 1
  }

  echo "Origin branch is $(git rev-parse origin/master), destination is $(git rev-parse destination/master)"
  if $bidirectional; then
    git rebase "destination/${branch}" || {
      echo "Failed to rebase ${branch} from destination, aborting sync..."
      git rebase --abort &>/dev/null || true
      return 1
    }
    git push -f origin "${branch}" || {
      echo "Failed to force pushed to origin, aborting sync..."
      return 1
    }
  fi

  echo "New head for destination is $(git rev-parse HEAD)"
  git push destination "${branch}" || {
    echo "Failed to push to destination..."
    return 1
  }
}

function sync() {
  echo "sync $*"
  local bidirectional="$4"
  pushd "$3"
  shift 4
  git fetch origin
  git fetch destination
  for branch in "$@"; do
    sync_branch "${branch}" "${bidirectional}" || true
  done
  popd
}

# Get a local clone
for i in "${REPOSITORIES[@]}"; do
  clone $i
done

# Sync loop
while true; do
  for i in "${REPOSITORIES[@]}"; do
    sync $i
  done
  # Sleep 30 seconds between each sync
  sleep 30
done