#!/bin/bash

# Copyright 2017 Google
# 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.

# Usage:
# ./scripts/style.sh [branch-name | filenames]
#
# With no arguments, formats all eligible files in the repo
# Pass a branch name to format all eligible files changed since that branch
# Pass a specific file or directory name to format just files found there
#
# Commonly
# ./scripts/style.sh master

# Strip the clang-format version output down to the major version. Examples:
#   clang-format version 7.0.0 (tags/google/stable/2018-01-11)
#   clang-format version google3-trunk (trunk r333779)
version=$(clang-format --version)

# Remove leading "clang-format version"
version="${version/*version /}"
# Remove trailing parenthetical version details
version="${version/ (*)/}"
# Remove everything after the first dot (note this is a glob, not a regex)
version="${version/.*/}"

case "$version" in
  6 | 7)
    # Allow an older clang-format to accommodate Travis version skew.
    ;;
  google3-trunk)
    echo "Please use a publicly released clang-format; a recent LLVM release"
    echo "from http://releases.llvm.org/download.html will work."
    echo "Prepend to PATH when running style.sh."
    exit 1
    ;;
  *)
    echo "Please upgrade to clang-format version 7."
    echo "If it's installed via homebrew you can run: brew upgrade clang-format"
    exit 1
    ;;
esac

system=$(uname -s)
if [[ "$system" == "Darwin" ]]; then
  version=$(swiftformat --version)
  version="${version/*version /}"
  # Allow an older swiftformat because travis isn't running High Sierra yet
  # and the formula hasn't been updated in a while on Sierra :-/.
  if [[ "$version" != "0.32.0" && "$version" != "0.33"* ]]; then
    echo "Please upgrade to swiftformat 0.33.3"
    echo "If it's installed via homebrew you can run: brew upgrade swiftformat"
    exit 1
  fi
fi

# Joins the given arguments with the separator given as the first argument.
function join() {
  local IFS="$1"
  shift
  echo "$*"
}

clang_options=(-style=file)

# Rules to disable in swiftformat:
swift_disable=(
  # sortedImports is broken, sorting into the middle of the copyright notice.
  sortedImports

  # Too many of our swift files have simplistic examples. While technically
  # it's correct to remove the unused argument labels, it makes our examples
  # look wrong.
  unusedArguments
)

swift_options=(
  # Mimic Objective-C style.
  --indent 2

  --disable $(join , "${swift_disable[@]}")
)

if [[ $# -gt 0 && "$1" == "test-only" ]]; then
  test_only=true
  clang_options+=(-output-replacements-xml)
  swift_options+=(--dryrun)
  shift
else
  test_only=false
  clang_options+=(-i)
fi

files=$(
(
  if [[ $# -gt 0 ]]; then
    if git rev-parse "$1" -- >& /dev/null; then
      # Argument was a branch name show files changed since that branch
      git diff --name-only --relative --diff-filter=ACMR "$1"
    else
      # Otherwise assume the passed things are files or directories
      find "$@" -type f
    fi
  else
    # Do everything by default
    find . -type f
  fi
) | sed -E -n '
# find . includes a leading "./" that git does not include
s%^./%%

# Build outputs
\%/Pods/% d
\%^build/% d
\%^Debug/% d
\%^Release/% d

# Sources controlled outside this tree
\%/third_party/% d
\%/Firestore/Port/% d

# Generated source
\%/Firestore/core/src/firebase/firestore/util/config.h% d

# Sources pulled in by travis bundler
\%/vendor/bundle/% d

# Sources within the tree that are not subject to formatting
\%^(Example|Firebase)/(Auth|AuthSamples|Database|Messaging)/% d

# Checked-in generated code
\%\.pb(objc|rpc)\.% d
\%\.pb\.% d
\%\.nanopb\.% d

# Format C-ish sources only
\%\.(h|m|mm|cc|swift)$% p
'
)

needs_formatting=false
for f in $files; do
  if [[ "${f: -6}" == '.swift' ]]; then
    if [[ "$system" == 'Darwin' ]]; then
      swiftformat "${swift_options[@]}" "$f" 2> /dev/null | grep 'would have updated' > /dev/null
    else
      false
    fi
  else
    clang-format "${clang_options[@]}" "$f" | grep "<replacement " > /dev/null
  fi

  if [[ "$test_only" == true && $? -ne 1 ]]; then
    echo "$f needs formatting."
    needs_formatting=true
  fi
done

if [[ "$needs_formatting" == true ]]; then
  echo "Proposed commit is not style compliant."
  echo "Run scripts/style.sh and git add the result."
  exit 1
fi