#!/usr/bin/env bash
set -o errexit #abort if any command fails
me=$(basename "$0")
help_message="\
Usage: $me [-c FILE] [<options>]
Deploy generated files to a git branch.

Options:

   -h, --help               Show this help information.
   -v, --verbose            Increase verbosity. Useful for debugging.
   -e, --allow-empty        Allow deployment of an empty directory.
   -m, --message MESSAGE    Specify the message used when committing on the
                            deploy branch.
   -n, --no-hash            Don't append the source commit's hash to the deploy
                            commit's message.
   -c, --config-file PATH   Override default & environment variables' values
                            with those in set in the file at 'PATH'. Must be the
                            first option specified.

Variables:

   GIT_DEPLOY_DIR      Folder path containing the files to deploy.
   GIT_DEPLOY_BRANCH   Commit deployable files to this branch.
   GIT_DEPLOY_REPO     Push the deploy branch to this repository.

These variables have default values defined in the script. The defaults can be
overridden by environment variables. Any environment variables are overridden
by values set in a '.env' file (if it exists), and in turn by those set in a
file specified by the '--config-file' option."

npm run build

parse_args() {
   # Set args from a local environment file.
   if [ -e ".env" ]; then
      source .env
      fi
   # Set args from file specified on the command-line.
   if [[ $1 = "-c" || $1 = "--config-file" ]]; then
      source "$2"
      shift 2
      fi
   # Parse arg flags
   # If something is exposed as an environment variable, set/overwrite it
   # here. Otherwise, set/overwrite the internal variable instead.
   while : ; do
      if [[ $1 = "-h" || $1 = "--help" ]]; then
         echo "$help_message"
         return 0
      elif [[ $1 = "-v" || $1 = "--verbose" ]]; then
         verbose=true
         shift
      elif [[ $1 = "-e" || $1 = "--allow-empty" ]]; then
         allow_empty=true
         shift
      elif [[ ( $1 = "-m" || $1 = "--message" ) && -n $2 ]]; then
         commit_message=$2
         shift 2
      elif [[ $1 = "-n" || $1 = "--no-hash" ]]; then
         GIT_DEPLOY_APPEND_HASH=false
         shift
      else
         break
      fi
      done
   # Set internal option vars from the environment and arg flags. All internal
   # vars should be declared here, with sane defaults if applicable.
   # Source directory & target branch.
   deploy_directory=build/3-rev
   deploy_branch=gh-pages
   #if no user identity is already set in the current git environment, use this:
   default_username=${GIT_DEPLOY_USERNAME:-deploy.sh}
   default_email=${GIT_DEPLOY_EMAIL:-}
   repo=origin  #repository to deploy to. must be readable and writable.
   append_hash=${GIT_DEPLOY_APPEND_HASH:-true}  #append commit hash to the end of message by default
   }

main() {
   parse_args "$@"
   enable_expanded_output
   if ! git diff --exit-code --quiet --cached; then
      echo Aborting due to uncommitted changes in the index >&2
      return 1
      fi
   commit_title=`git log -n 1 --format="%s" HEAD`
   commit_hash=` git log -n 1 --format="%H" HEAD`
   # Default commit message uses last title if a custom one is not supplied
   if [[ -z $commit_message ]]; then
      commit_message="publish: $commit_title"
   fi
   # Append hash to commit message unless no hash flag was found
   if [ $append_hash = true ]; then
      commit_message="$commit_message"$'\n\n'"generated from commit $commit_hash"
      fi
   previous_branch=`git rev-parse --abbrev-ref HEAD`
   if [ ! -d "$deploy_directory" ]; then
      echo "Deploy directory '$deploy_directory' does not exist. Aborting." >&2
      return 1
      fi
   # Must use short form of flag in ls for compatibility with OS X and BSD
   if [[ -z `ls -A "$deploy_directory" 2> /dev/null` && -z $allow_empty ]]; then
      echo "Deploy directory '$deploy_directory' is empty. Aborting. If you're sure you want to deploy an empty tree, use the --allow-empty / -e flag." >&2
      return 1
      fi
   if git ls-remote --exit-code $repo "refs/heads/$deploy_branch" ; then
      # deploy_branch exists in $repo; make sure we have the latest version
      disable_expanded_output
      git fetch --force $repo $deploy_branch:$deploy_branch
      enable_expanded_output
      fi
   # check if deploy_branch exists locally
   if git show-ref --verify --quiet "refs/heads/$deploy_branch"
      then incremental_deploy
      else initial_deploy
      fi
   restore_head
   }

initial_deploy() {
   git --work-tree "$deploy_directory" checkout --orphan $deploy_branch
   git --work-tree "$deploy_directory" add --all
   commit+push
   }

incremental_deploy() {
   # Make deploy_branch the current branch
   git symbolic-ref HEAD refs/heads/$deploy_branch
   # Put the previously committed contents of deploy_branch into the index
   git --work-tree "$deploy_directory" reset --mixed --quiet
   git --work-tree "$deploy_directory" add --all
   set +o errexit
   diff=$(git --work-tree "$deploy_directory" diff --exit-code --quiet HEAD --)$?
   set -o errexit
   case $diff in
      0) echo No changes to files in $deploy_directory. Skipping commit.;;
      1) commit+push;;
      *)
         echo git diff exited with code $diff. Aborting. Staying on branch $deploy_branch so you can debug. To switch back to main, use: git symbolic-ref HEAD refs/heads/main && git reset --mixed >&2
         return $diff
         ;;
   esac
   }

commit+push() {
   set_user_id
   git --work-tree "$deploy_directory" commit -m "$commit_message"
   disable_expanded_output
   #--quiet is important here to avoid outputting the repo URL, which may contain a secret token
   git push --quiet $repo $deploy_branch
   enable_expanded_output
   }

enable_expanded_output() {
   # Echo expanded commands as they are executed (for debugging)
   if [ $verbose ]; then
      set -o xtrace
      set +o verbose
      fi
   }

disable_expanded_output() {
   # Avoid outputting the repo URL, which may contain a secret token
   if [ $verbose ]; then
      set +o xtrace
      set -o verbose
      fi
   }

set_user_id() {
   if [[ -z `git config user.name` ]]; then
      git config user.name "$default_username"
      fi
   if [[ -z `git config user.email` ]]; then
      git config user.email "$default_email"
      fi
   }

restore_head() {
   if [[ $previous_branch = "HEAD" ]]; then
      # We weren't on any branch before, so just set HEAD back to the commit it was on
         git update-ref --no-deref HEAD $commit_hash $deploy_branch
      else
         git symbolic-ref HEAD refs/heads/$previous_branch
      fi
   git reset --mixed
   }

filter() {
   sed -e "s|$repo|\$repo|g"
   }

sanitize() {
   "$@" 2> >(filter 1>&2) | filter
   }

[[ $1 = --source-only ]] || main "$@"