#!/usr/bin/env bash
# Copyright 2015 The Vanadium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# bootstrap_jiri initializes a root directory for jiri.  The following
# directories and files will be created:
#   <root_dir>                         - root directory (picked by user)
#   <root_dir>/.jiri_root              - root metadata directory
#   <root_dir>/.jiri_root/bin/jiri     - jiri binary
#
# The jiri sources are downloaded and built into a temp directory, which is
# always deleted when this script finishes.  The <root_dir> is deleted on any
# failure.

set -euf -o pipefail

# Jiri repo, from which we will download the jiri script wrapper.
readonly JIRI_REPO_URL="https://fuchsia.googlesource.com/jiri"

# Google Storage bucket that contains prebuilt versions of jiri.
readonly GS_BUCKET_URL="https://fuchsia-build.storage.googleapis.com/jiri"

# fatal prints an error message, followed by the usage string, and then exits.
fatal() {
  usage='

Usage:
   bootstrap_jiri <root_dir>

A typical bootstrap workflow looks like this:

$ curl -s https://raw.githubusercontent.com/fuchsia-mirror/jiri/master/scripts/bootstrap_jiri | bash -s myroot
$ export PATH=myroot/.jiri_root/bin:$PATH
$ cd myroot
$ jiri import manifest https://example.com/manifest
$ jiri update'
  echo "ERROR: $@${usage}" 1>&2
  exit 1
}

# toabs converts the possibly relative argument into an absolute path.  Run in a
# subshell to avoid changing the caller's working directory.
toabs() (
  cd $(dirname $1)
  echo ${PWD}/$(basename $1)
)

# Check the <root_dir> argument is supplied.
if [[ $# -ne 1 ]]; then
  fatal "need <root_dir> argument"
fi

# Ensure <root_dir> doesn't already exist: this is important since we trap this script and
# rm -rf <root_dir> if anything fails.
mkdir -p "$(dirname $1)"
readonly ROOT_DIR="$(toabs $1)"
if [[ -e "${ROOT_DIR}" ]]; then
  if ! [[ -z "$(ls -A "$ROOT_DIR")" ]]; then
    fatal "${ROOT_DIR} is not empty"
  fi
fi

# Remove the root_dir if this script fails so as to not leave the environment in a strange half-state.
trap "rm -rf ${ROOT_DIR}" INT TERM EXIT

# Make the output directories.
readonly BIN_DIR="${ROOT_DIR}/.jiri_root/bin"
mkdir -p "${BIN_DIR}"

# Determine and validate the version of jiri.
readonly HOST_OS=$(uname | tr '[:upper:]' '[:lower:]')
readonly TARGET="${HOST_OS}-amd64"
readonly COMMIT_URL="${JIRI_REPO_URL}/+refs/heads/master?format=JSON"
readonly LOG_URL="${JIRI_REPO_URL}/+log/refs/heads/master?format=JSON"
readonly VERSION=$(curl -sSf "${COMMIT_URL}" | sed -n 's/.*"value": "\([0-9a-f]\{40\}\)"/\1/p')
readonly VERSIONS=$(curl -sSf "${LOG_URL}" | sed -n 's/.*"commit": "\([0-9a-f]\{40\}\)".*/\1/p')

JIRI_URL=""
for version in ${VERSIONS}; do
  url="${GS_BUCKET_URL}/${TARGET}/${version}"
  if curl --output /dev/null --silent --head --fail "${url}"; then
    JIRI_URL="${url}"
	break
  fi
done

if [[ -z "${JIRI_URL}" ]]; then
  echo "Cannot find prebuilt Jiri binary." 1>&2
  exit 1
fi

if ! curl -sf -o "${BIN_DIR}/jiri" "${JIRI_URL}"; then
  echo "Failed downloading prebuilt Jiri binary." 1>&2
  exit 1
fi
chmod 755 "${BIN_DIR}/jiri"
echo "Please add ${BIN_DIR} to your PATH"

trap - EXIT