#!/bin/bash

#
# Copyright 2022 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

set -e

REPO_ROOT="$(git rev-parse --show-toplevel)"
readonly REPO_ROOT

# Returns true if colors are supported.
function is-stderr-tty {
  [[ -t 2 ]]
}
# echo-info prints a line to stderr with a green INFO: prefix.
function echo-info {
  if is-stderr-tty; then
    echo -e >&2 "\033[1;32mINFO:\033[0m $*"
  else
    echo -e >&2 "INFO: $*"
  fi
}
# echo-warning prints a line to stderr with a yellow WARNING: prefix.
function echo-warning {
  if is-stderr-tty; then
    echo -e >&2 "\033[1;33mWARNING:\033[0m $*"
  else
    echo -e >&2 "WARNING: $*"
  fi
}
# echo-error prints a line to stderr with a red ERROR: prefix.
function echo-error {
  if is-stderr-tty; then
    echo -e >&2 "\033[1;31mERROR:\033[0m $*"
  else
    echo -e >&2 "ERROR: $*"
  fi
}

function get-diff-base() {
  local upstream=$(git rev-parse --abbrev-ref --symbolic-full-name "@{u}" 2>/dev/null)
  if [[ -z "${upstream}" ]]; then
    upstream="origin/main"
  fi
  local local_commit=$(git rev-list HEAD ^${upstream} --  2>/dev/null | tail -1)
  if [[ -z "${local_commit}" ]]; then
    printf "HEAD"
  else
    git rev-parse "${local_commit}"^
  fi
}

# Removes leading //, resolves to absolute path, and resolves globs.  The first
# argument is a path prefix, and the remaining arguments are relative to that
# path prefix.
function canonicalize() {
  local root_dir="$1"
  shift
  for fileglob in "${@}"; do
    # // means it comes from gn, [^/]* means it is relative
    if [[ "${fileglob}" = //* || "${fileglob}" = [^/]* ]]; then
      local dir="${root_dir}"/
    else
      local dir=""
    fi
    for file in "${dir}"${fileglob#"//"}; do
      echo "${file}"
    done
  done
}

# Format the given file.
function format-file() {
  # If the user requested formatting of a single specific file, we want to
  # loudly alert them to the fact that we can't actually format that file, since
  # silently exiting would suggest that we *do* know how to format the file and
  # that it was already properly formatted.
  must_format=false
  if $FILES_SPECIFIED && [[ ${#FILES[@]} == 1 ]]; then
    must_format=true
  fi
  filename="$(basename "$1")"
  case "${filename}" in
    *.c | *.cc | *.cpp | *.h | *.hh | *.hpp | *.proto | *.ts) format_cc "$1" ;;
    *.bazel| *.bzl| BUILD| WORKSPACE) format_bazel "$1" ;;
    *.cml) format_cml "$1";;
    *.fidl) format_fidl "$1" ;;
    *.*)
      if $must_format; then
        echo-error "Unsupported extension for file $1"
        exit 1
      fi
      ;;
    *)
      if $must_format; then
        echo-error "Unable to determine language for file $1"
        exit 1
      fi
      ;;
  esac
}

function run_tool {
  tool_type="$1"
  tool_name="$2"
  shift 2
  bazel_project="$(basename "$REPO_ROOT")"
  bazel_dir="${REPO_ROOT}/bazel-${bazel_project}"
  if [[ $tool_type == "clang" ]]; then
    str="Clang"
    build_args=( "--config=fuchsia_x64" "@fuchsia_clang//:toolchain" )
    tool_path="${bazel_dir}/external/fuchsia_clang/bin"
  else
    str="Fuchsia SDK"
    build_args=( "@fuchsia_sdk//:fuchsia_toolchain_sdk" )
    tool_path="${bazel_dir}/external/fuchsia_sdk/tools/x64"
  fi
  if [[ ! -d "${bazel_dir}" ]]; then
    if [[ ! -x "${REPO_ROOT}/tools/bazel" && -x "${REPO_ROOT}/scripts/bootstrap.sh" ]]; then
      echo >&2 "INFO: Cannot find Bazel, attempting to fetch it..."
      "${REPO_ROOT}/scripts/bootstrap.sh"
    fi
    if [[ ! -x "${REPO_ROOT}/tools/bazel" ]]; then
      echo >&2 "ERROR: cannot fetch bazel. Ensure scripts/boostrap.sh is able to fetch tools/bazel."
      return 1
    fi
    echo >&2 "INFO: Cannot find the ${str} toolchain, attempting to fetch it..."
    "${REPO_ROOT}/tools/bazel" build "${build_args[@]}"
  fi
  "${tool_path}/${tool_name}" "$@"
}

function format_cc() {
  run_tool clang clang-format -style=file -fallback-style=Google -sort-includes -i "$1"
}

function format_bazel() {
  if ! command -v buildifier &> /dev/null; then
    echo-warning "Cannot find buildifier in path. Please install it to format Bazel BUILD files."
    echo-warning "Skipping these files for now: $bazel_source_files"
  else
    buildifier -lint=warn "$1"
  fi
}

function format_cml() {
  run_tool sdk cmc format --cml --in-place "$1"
}

function format_fidl() {
  run_tool sdk fidl-format -i "$1"
}

# if this tool is named (or symlinked as) 'pre-commit', it is assumed to be a git commit hook and
# it will behave slightly differently:
#
# - it will run 'git add' at the end

if [[ "$( basename "${BASH_SOURCE[0]}" )" == "pre-commit" ]]; then
  IN_GIT_HOOK=true
  echo-info "Formatting files"
else
  IN_GIT_HOOK=false
fi


# with no arguments, this command will format files in the current git diff
# If arguments are given, they are assumed to be file names, which will be
# formatted based on their type regardless of their git status.

FILES_SPECIFIED=false

GIT_FILTER=(
  ":(top,exclude)third_party"
)

if [[ $# -gt 0 ]]; then
  FILES=( "$@" )
  FILES_SPECIFIED=true
else
  FILES=( \
    $(canonicalize $(git rev-parse --show-toplevel) \
      $(git diff --name-only $(get-diff-base) "${GIT_FILTER[@]}")) \
  )
fi

EXISTING_FILES=()
# Format files.
for file in "${FILES[@]}"; do
  # Git reports deleted files, which we don't want to try to format
  if [[ ! -f "${file}" ]]; then
    if $FILES_SPECIFIED; then
      echo-warning "Cannot find file, ignoring: $file"
    fi
    continue
  fi
  # Format the file
  format-file "${file}"
  EXISTING_FILES+=( "$file" )
done

if $IN_GIT_HOOK && [[ ${#EXISTING_FILES[@]} -gt 0 ]]; then
  git add "${EXISTING_FILES[@]}"
fi