#!/bin/bash

#==========================================================================
#
#   Copyright NumFOCUS
#
#   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
#
#          https://www.apache.org/licenses/LICENSE-2.0.txt
#
#   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.
#
#==========================================================================*/


# This script, given a path to another script, applies this to the source
# code of the remote modules in the ITK source tree whose CI status shows
# a successful build.
#
# The script clones the successful remote modules to the ITK source tree,
# creates a feature branch on each module, applies the provided script to the
# source code of each module, adds the modified files to the git stage area,
# commits them using the provided commit message, and pushes the commit to the
# remote module repository.
#
# Please, review the commit message directives at:
# https://github.com/InsightSoftwareConsortium/ITK/blob/master/CONTRIBUTING.md


# Utility functions
usage() {
cat << EOF
Usage: $0 <script_filename> <feature_branch> <commit_message>

Use this script to apply another script to the source code of the remote
remote modules in the ITK source tree whose CI status shows a successful
build.

The script clones the successful remote modules to the ITK source tree,
creates a feature branch on each module, applies the provided script to the
source code of each module, adds the modified files to the git stage area,
commits them using the provided commit message, and pushes the commit to the
remote module repository.

Please, review the commit message directives at:
https://github.com/InsightSoftwareConsortium/ITK/blob/master/CONTRIBUTING.md
EOF
}

die() {
  echo "$@" 1>&2; exit 1
}

# Parse arguments
help=false
script=""
feature_branch=""
commit_message=""
while test $# -gt 0;
do
  opt="$1";
  case "$opt" in
    "-h"|"--help")
      shift;
      help=true
      break;;
    *)
      break;;
  esac
done

script="$1"
feature_branch="$2"
commit_message="$3"

if test "${script}" = "" || test "${feature_branch}" = "" || test "${commit_message}" = "" || $help; then
  usage
  exit 1
fi

# Make sure we are inside the repository
cd "${BASH_SOURCE%/*}" &&

remote_modules_path='../../Modules/Remote'

# Ask for GitHub username and password once
echo "Please provide your GitHub (https://github.com)"
read -p "username: " username

remotes=()

function list_candidate_remotes() {
  if [ $# -ge 1 ] && [ $1 = "-ongreen" ]; then
    ongreen=1
    failing=()
  else
    ongreen=0
  fi

  # Loop over the remote modules' CMake files
  for filename in ${remote_modules_path}/*.cmake; do
    echo -n "."

    # Get the current module name
    module_name=$(grep -v "\s*#" $filename | grep -m 1 -o "itk_fetch_module(\(\w\|\.\|\-\|_\)*")
    module_name=${module_name/*itk_fetch_module(/}

    # Get the current commit hash
    curr_commit=$(grep -v "\s*#" $filename | grep -m 1 -o "GIT_TAG \(\w\|\.\|\-\|_\)*")
    curr_commit=${curr_commit/*GIT_TAG /}

    # Read the git repository information
    repository=$(grep -v "\s*#" $filename | grep -m 1 -o "GIT_REPOSITORY \https://github.com/\(\w\|\-\|_\|/\)*")
    repository=${repository/*GIT_REPOSITORY \${git_protocol\}:\/\/github.com\//}

    # Get the latest git commit hash of the remote module.
    # Remotes will usually not be tagged.
    latest_commit=$(git ls-remote https://github.com/$repository refs/heads/master)
    latest_commit=${latest_commit/[[:space:]]refs\/heads\/master/}

    # Skip remotes whose current commit in ITK differs from the latest
    if [ $curr_commit != $latest_commit ]; then
      continue
    fi

    # Get the remotes' build status
    if [ $ongreen -eq 1 ]; then
      # Get the repository status
      # Be careful of rate limiting (https://developer.github.com/v3/#rate-limiting)
      # alternatively using Azure: https://docs.microsoft.com/en-us/azure/data-factory/monitor-programmatically#rest-api
      status=$(curl -s https://api.github.com/repos/$repository/commits/$latest_commit/status | grep -m 1 -o "\"state\": \"\w*\"")
      if [ "$status" != "\"state\": \"success\"" ]; then
        continue
      fi
    fi

    remotes+=($module_name)

  done
}

function configure_itk_remotes() {
  mkdir ../../../ITK-build
  cd ../../../ITK-build

  cmake_remote_flags=()

  # Switch on all remotes that have a success build status
  for remote in ${remotes[@]}; do
    cmake_remote_flags+=(-D'Module_'$remote':BOOL=ON' )
  done

  cmake ${cmake_remote_flags[@]} ../ITK
}

function apply_script_and_push_remotes() {
  cd ../ITK/Modules/Remote

  # Loop over remotes and apply the changes
  for remote in ${remotes[@]}; do
    echo -e $remote

    cd $remote

    repository_basename=$(basename -s .git `git config --get remote.origin.url`)

    git checkout main || git checkout master
    git checkout -b $feature_branch origin/main || git checkout -b $feature_branch origin/master || git checkout $feature_branch
    $script

    # Add the files, adding filters if necessary, and redirecting stdout and
    # stderr to /dev/null in order to avoid a too verbose output and
    # displaying error messages if files with some given extensions are not
    # found.
    git add -u *.txt > /dev/null 2>&1
    git add -u *.cmake > /dev/null 2>&1
    git add -u *.rst > /dev/null 2>&1
    git add -u *.py > /dev/null 2>&1
    git add -u *.yml > /dev/null 2>&1
    git add -u *.c > /dev/null 2>&1
    git add -u *.cxx > /dev/null 2>&1
    git add -u *.h > /dev/null 2>&1
    git add -u *.hxx > /dev/null 2>&1
    git add -u *.wrap > /dev/null 2>&1

    # Commit and push to the feature branch
    git commit -m "$commit_message"

    read -ep "Push $feature_branch changes to git@github.com:$username/$repository_basename.git? [y/n]" dopush
    if [ $dopush = 'y' ]; then
      git push --quiet git@github.com:$username/$repository_basename.git $feature_branch
    fi

    cd ..
  done
}

echo -e "\nChecking remote modules build status..."
list_candidate_remotes
echo -e "\nDone checking remote modules build status."

echo -e "Configuring ITK with succeeding remote modules..."
configure_itk_remotes
echo -e "Done configuring ITK with succeeding remote modules."

echo -e "Applying script to remotes..."
apply_script_and_push_remotes
echo -e "Done applying script to remotes."

rm -Rf ../../../ITK-build

echo -e "Visit the remote repositories and open the corresponding pull requests."