#!/usr/bin/env bash

set -e

PICARD_REPO="circleci/picard"

PICARD_CLI_URL="https://circle-downloads.s3.amazonaws.com/releases/build_agent_wrapper/circleci"
PICARD_CLI_FILE="$0"

CIRCLECI_DIR="$HOME/.circleci"
CURRENT_DIGEST_FILE="$CIRCLECI_DIR/current_picard_digest"
LATEST_DIGEST_FILE="$CIRCLECI_DIR/latest_picard_digest"

UNKNOWN_DIGEST=""

CLI_VERSION="0.1.0"

# Both the new CLI install script and the `switch` command are assuming the install path.
# For users who have followed our documented instructions here:
#   https://circleci.com/docs/2.0/local-cli/#installing-the-circleci-local-cli-on-macos-and-linux-distros
CIRCLECI_CLI_URL="https://raw.githubusercontent.com/CircleCI-Public/circleci-cli/master/install.sh"
CIRCLECI_PREFIX="/usr/local/bin/circleci"

# Pull `latest` tag from docker repo and write digest into the file
pull_latest_image() {
  latest_image=$(docker pull $PICARD_REPO | grep -o "sha256.*$")
  echo $latest_image > $LATEST_DIGEST_FILE
}

# Write given digest into the file
update_current_digest() {
  version="$@"
  echo $version > $CURRENT_DIGEST_FILE
}

# Read latest digest from file
get_latest_digest() {
  if [ -e "$LATEST_DIGEST_FILE" ];
  then
    echo $(cat $LATEST_DIGEST_FILE)
  else
    echo $UNKNOWN_DIGEST
  fi
}

# Read current digest from file
get_current_digest() {
  if [ -e "$CURRENT_DIGEST_FILE" ];
  then
    echo $(cat $CURRENT_DIGEST_FILE)
  else
    echo $UNKNOWN_DIGEST
  fi
}

# Compare latest_digest and current_digest
is_update_available() {
  current=$(get_current_digest)
  latest=$(get_latest_digest)

  return $([[ $latest != $UNKNOWN_DIGEST ]] && [[ $current != $latest ]])
}

# Printing version of this script
print_cli_version() {
  echo "circleci version:" $CLI_VERSION
}

update_picard_cli() {
  cmd_prefix=""
  if ! [[ -w $PICARD_CLI_FILE ]]; then
    echo "[WARN] Not enough permissions to write to $PICARD_CLI_FILE, trying sudo..."
    cmd_prefix="sudo "
  fi
  bash -c "$cmd_prefix curl -o $PICARD_CLI_FILE $PICARD_CLI_URL --fail --silent --show-error && $cmd_prefix chmod +x $PICARD_CLI_FILE"
}

upgrade_circleci_cli() {
  cmd_prefix=""
  echo "Upgrading CircleCI to the newest version."
  if ! [[ -w $CIRCLECI_PREFIX ]]; then
    echo "[WARN] Not enough permissions to write to $CIRCLECI_PREFIX, trying sudo..."
    cmd_prefix="sudo "
  fi
  bash -c "$cmd_prefix curl $CIRCLECI_CLI_URL --fail --show-error | $cmd_prefix bash"
  exit 0
}

switch() {
  echo "Thank you for your interest in trying the new CLI!"
  echo ""
  echo "Be sure to read the docs if you get stuck. [https://github.com/CircleCI-Public/circleci-cli#readme]"
  echo ""
  printf "Are you sure you're ready to upgrade? [y/N]: "
  while true;
  do
    read -r reply
    case "$reply" in
      [yY][eE][sS]|[yY])
        upgrade_circleci_cli
        ;;
      *)
        echo "Ok, please let us know when you're ready."
        exit 0
        ;;
    esac
  done
}

#
# Main program
#
if [ ! -e $CIRCLECI_DIR ];
then
  mkdir -p $CIRCLECI_DIR >/dev/null
fi

case $1 in
  # Option for development purpose only
  --image | -i )
    picard_image="$2"
    shift; shift;
    echo "[WARN] Using circleci:" $picard_image
    ;;

  --tag | -t )
    picard_image="$PICARD_REPO:$2"
    shift; shift;
    echo "[WARN] Using circleci:" $picard_image
  ;;

  --version )
    echo $CLI_VERSION
    exit 0
esac

# Do not check for update if --image of --tag is specified (to avoid overriding :latest tag)
if [[ ! $picard_image ]]; then
  current_digest=$(get_current_digest)
  if [[ $current_digest == $UNKNOWN_DIGEST ]]; then
    # Receiving latest image of picard in case of there's no current digest stored
    echo "Receiving latest version of circleci..."
    pull_latest_image >/dev/null
    current_digest=$(get_latest_digest)
    update_current_digest $current_digest
  else
    # Otherwise pulling latest image in background
    pull_latest_image &>/dev/null &disown
    echo
  fi
  picard_image="$PICARD_REPO@$current_digest"
fi

case $1 in
  version )
    print_cli_version
    ;;

  update )
    echo "Updating CircleCI build agent..."
    update_picard_cli
    echo "Done"
    echo "Updating CircleCI version..."
    current_digest=$(get_latest_digest)
    update_current_digest $current_digest
    echo "Done"
    exit 0
    ;;

  switch )
    switch
    ;;

  "" )
    set -- "-h"
esac

echo "INFO: We've built a brand new CLI for CircleCI! Please run 'circleci switch' to upgrade."

docker run -it --rm \
       -e DOCKER_API_VERSION=${DOCKER_API_VERSION:-1.23} \
       -v /var/run/docker.sock:/var/run/docker.sock \
       -v $(pwd):$(pwd) \
       -v ~/.circleci/:/root/.circleci \
       --workdir $(pwd) \
       $picard_image \
       circleci "$@"