#!/bin/bash
#
# Copyright 2016-present Google Inc. 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.

old_commit=""
new_commit=""
verbose=0

usage() {
  echo "Usage: $0 -o [old commit] -n [new commit]]"
  echo
  echo "Example usage: $0 -o v2.0.0 -n develop"
}

while getopts "h?vo:n:" opt; do
  case "$opt" in
  h|\?)
      usage
      exit 0
      ;;
  v)  verbose=1
      ;;
  o)  old_commit=$(git rev-parse $OPTARG)
      ;;
  n)  new_commit=$(git rev-parse $OPTARG)
      ;;
  esac
done

if [[ -z "$old_commit" || -z "$new_commit" ]]; then
  usage
  exit 0
fi

validate_commit() {
  git cat-file -t $1 >> /dev/null 2> /dev/null || { echo "$1 is not a valid commit."; exit 1; }
}

validate_commit $old_commit
validate_commit $new_commit

# Compute directories relative to the script's known location in scripts/
SCRIPTS_PATH="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
REPO_ROOT_PATH="$( cd "$( dirname $SCRIPTS_PATH )" && pwd )"

# Where to fetch the objc-diff repo from
OBJC_DIFF_REPO_URL="https://github.com/mattstevens/objc-diff.git"

# Where to install the objc-diff repo
OBJC_DIFF_REPO_PATH="$SCRIPTS_PATH/external/objc-diff"
OBJC_DIFF_BINARY_RELATIVE_PATH="build/Release/objc-diff"
OBJC_DIFF_BINARY_PATH=$OBJC_DIFF_REPO_PATH/$OBJC_DIFF_BINARY_RELATIVE_PATH

SYSROOT="$(xcode-select --print-path)/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk"

echo "Fetching objc-diff..."

# Runs git commands in the objc-diff repository directory.
git_objc_diff() {
  pushd $OBJC_DIFF_REPO_PATH >> /dev/null
  git "$@"
  popd >> /dev/null
}

# Clone/update the objc-diff repo
if [ ! -d "$OBJC_DIFF_REPO_PATH" ]; then
  git clone "$OBJC_DIFF_REPO_URL" "$OBJC_DIFF_REPO_PATH" || { echo "Failed to clone."; exit 1; }
else
  git_objc_diff fetch || { echo "Failed to update objc-diff."; exit 1; }
fi

# Build objc-diff binary
xcodebuild build -project $OBJC_DIFF_REPO_PATH/OCDiff.xcodeproj -target OCDiff -configuration Release

# Verify objc-diff binary existence
if [ ! -f "$OBJC_DIFF_BINARY_PATH" ]; then
  echo "Unable to find objc-diff at $OBJC_DIFF_BINARY_PATH"
  exit 1
fi

objc_diff() {
  "$OBJC_DIFF_BINARY_PATH" "$@"
}

TMP_PATH=$(mktemp -d)

OLD_ROOT_PATH="$TMP_PATH/old"
NEW_ROOT_PATH="$TMP_PATH/new"

# prep_repo <path> <commit>
prep_repo() {
  if [ ! -d "$1" ]; then
    git clone "$REPO_ROOT_PATH" "$1" || { echo "Failed to clone."; exit 1; }
  fi
  pushd $1 >> /dev/null
  git remote add github git@github.com:google/material-components-ios.git
  git fetch || { echo "Failed to update repo."; exit 1; }
  git checkout "$2" --quiet
  popd >> /dev/null
}

prep_repo $OLD_ROOT_PATH $old_commit
prep_repo $NEW_ROOT_PATH $new_commit

old_header_search_paths=""
new_header_search_paths=""
for d in $NEW_ROOT_PATH/components/*/src; do
  folder=$(dirname $d)
  component=$(basename $folder)
  old_header_search_paths="$old_header_search_paths --oldargs -I$OLD_ROOT_PATH/components/$component/src/ "
  new_header_search_paths="$new_header_search_paths --newargs -I$NEW_ROOT_PATH/components/$component/src/ "
done

for d in $NEW_ROOT_PATH/components/*/src; do
  folder=$(dirname $d)
  component=$(basename $folder)

  echo
  echo "### $component"
  echo

  if [ ! -d "$OLD_ROOT_PATH/components/$component/src" ]; then
    echo "**New component.**"
    continue
  fi

  objc_diff \
    --xml \
    --sdk iphonesimulator \
    --old "$OLD_ROOT_PATH/components/$component/src" \
    --new "$NEW_ROOT_PATH/components/$component/src" \
    $old_header_search_paths \
    $new_header_search_paths | $SCRIPTS_PATH/objc_diff_xml_to_md $old_commit $new_commit components/$component/src
done

if [ ! -z "$TMP_PATH" ]; then
  echo "Cleaning up..."
  rm -rf $TMP_PATH
fi