#!/bin/bash
# Copyright 2019 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.

#### CATEGORY=Source tree
### runs source linters on modified files

## Usage: fx lint
##           [--dry-run] [--verbose] [--fix]
##           [--all]
##           [--files=FILES,[FILES ...]]
##           [--target=GN_TARGET]
##           [--git] [-- PATTERN]
##
##   --fix     If supported by the linter tool for the target language,
##             attempt to apply recommended fixes
##   --dry-run Print the linter commands but don't run them
##   --verbose Print the linter commands before running them
##   --all     Lints all code in the git repo under the current working
##             directory.
##   --files   Allows the user to specify files separated by commas or (with
##             quotes) whitespace. Basic globs are supported, for example:
##                 fx lint --files=foo/*
##             Or for more advanced filename pattern matching, you can use
##             double quotes with command substitution:
##                 fx lint --files="$(find some/path -name '*.cc')"
##   --target  Allows the user to specify a gn target.
##   --git     The default; it uses `git diff` against the newest parent
##             commit in the upstream branch (or against HEAD if no such
##             commit is found).  Files that are locally modified, staged
##             or touched by any commits introduced on the local branch are
##             linted.
##    -- [PATTERN...] -additional -args -for -linter
##             For --all or --git, passes along PATTERNs to `git ls-files`
##             to filter what files are affected. The first argument starting
##             with a dash, and all arguments thereafter, are passed to the
##             linter command (positioned before the filename). Used in
##             combination, the pattern can constrain which linter is selected,
##             so linter options are only applied to the expected linter
##             program.
##
## Examples:
##     fx lint -- "*.fidl" --include-check no-trailing-comment
##     fx lint --files=sdk/fidl/fuchsia.sys/service_provider.fidl \
##             -- --exclude-check string-bounds-not-specified
##     fx lint --verbose --files="$(echo sdk/**/*.cc sdk/**/*.fidl)"

set -e

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/../lib/vars.sh || exit $?

function usage() {
  fx-command-help
}

function zap-commas() {
  printf %s "$1" | tr ',' '\n'
}

function get-diff-base() {
  local upstream=$(git rev-parse --abbrev-ref --symbolic-full-name "@{u}" 2>/dev/null)
  if [[ -z "${upstream}" ]]; then
    upstream="origin/master"
  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
}

DRY_RUN=
VERBOSE=
FIX_OPTION=
TARGET=

fx-config-read

GET_FILES=get_git_files
while [ $# -gt 0 ]; do
  ARG="$1"
  case "$1" in
    --verbose) VERBOSE="1" ;;
    --dry-run) DRY_RUN="1" ;;
    --fix) FIX_OPTION="-fix" ;;
    --all) GET_FILES=get_all_files ;;
    --git) GET_FILES=get_git_files ;;
    --files=*)
      GET_FILES=:
      FILES=$(canonicalize "${PWD}" $(zap-commas "${ARG#--files=}"))
      ;;
    --target=*)
      GET_FILES=:
      >&2 echo "Looking up files for target ${ARG#--target=}..."
      declare -i status=0
      GN_OUTPUT=(
         $(fx-gn desc "${FUCHSIA_BUILD_DIR}" "${ARG#--target=}" sources)
      ) || status=$?
      # Hacky, but we need to be able to continue when the target is an action,
      # because Rust and Go targets don't list their files.
      if [[ ${status} != 0 && "${GN_OUTPUT}" == *"action"* ]]; then
        >&2 echo "${GN_OUTPUT[@]}"
        exit ${status}
      fi
      FILES=$(canonicalize "${FUCHSIA_DIR}" "${GN_OUTPUT[@]}")
      TARGET="${ARG#--target=}"
      ;;
    --)
      shift
      break
      ;;
    --help) usage && exit 0 ;;
    *) usage && fx-error "Unknown flag '${ARG}'\n" && exit 1 ;;
  esac
  shift
done

GIT_FILTER=()
while [ $# -gt 0 ]; do
  if [[ $1 == -* ]]; then
    break
  fi
  if [[ ${#GIT_FILTER[@]} == 0 ]]; then
    GIT_FILTER=(--)
  fi
  GIT_FILTER+=($1)
  shift
done

COMMAND_ARGS=("$@")

get_git_files() {
  FILES=$(canonicalize $(git rev-parse --show-toplevel) \
    $(git diff --name-only $(get-diff-base) "${GIT_FILTER[@]}"))
}

get_all_files() {
  FILES=$(canonicalize "${PWD}" $(git ls-files "${GIT_FILTER[@]}"))
}

$GET_FILES

# Specify both the clang-tidy and the clang-apply-replacements binaries to be
# the ones in //prebuilt, so that they'll work properly on the tree.
declare CLANG_TIDY="${PREBUILT_CLANG_DIR}/bin/clang-tidy"
declare CLANG_APPLY_REPLACEMENTS="${PREBUILT_CLANG_DIR}/bin/clang-apply-replacements"
declare RUN_CLANG_TIDY="${PREBUILT_CLANG_DIR}/share/clang/run-clang-tidy.py"

# Suppress the "name-repeats-*" checks for now. These produce a high number of
# linter warnings, many of which are questionable. The algorithm will be refined.
declare FIDL_LINT_TARGET="$( fx-command-run list-build-artifacts --expect-one --name fidl-lint tools )"
declare FIDL_LINT="${FUCHSIA_BUILD_DIR}/${FIDL_LINT_TARGET}"

declare CLANG_TIDY_CMD=(
  "${RUN_CLANG_TIDY}"
  -clang-tidy-binary "${CLANG_TIDY}"
  -clang-apply-replacements-binary "${CLANG_APPLY_REPLACEMENTS}"
)
if [[ -n "${FIX_OPTION}" ]]; then
  CLANG_TIDY_CMD+=( ${FIX_OPTION} )
fi

declare FIDL_LINT_CMD=( "${FIDL_LINT}" )
# TODO(fxbug.dev/27283): add command and args for Dart linter
declare DART_LINT_CMD=() # "${FUCHSIA_DIR}/prebuilt/third_party/dart/${HOST_PLATFORM}/bin/dart<cmd?> <options?>"
# TODO(fxbug.dev/27269): add command and args for Go linter
declare GO_LINT_CMD=() # "${PREBUILT_GO_DIR}/bin/go<cmd?> <options?>"
# TODO(fxbug.dev/27270): add command and args for JSON linter
declare JSON_LINT_CMD=() # "${FUCHSIA_DIR}"/scripts/style/json-<cmd?> <options?>"

declare RUST_LINT_CMD=( "${FUCHSIA_DIR}/tools/devshell/contrib/lib/rust/run-clippy.py" )
if [[ -n "${VERBOSE}" ]]; then
  RUST_LINT_CMD+=( "-v" )
fi

declare CLANG_TIDY_FILES=()
declare DART_LINT_FILES=()
declare FIDL_LINT_FILES=()
declare GO_LINT_FILES=()
declare JSON_LINT_FILES=()
declare RUST_LINT_FILES=()

function add_file_to_linter() {
  local file="$1"
  # Git reports deleted files, which we don't want to try to lint
  if [ -f "${file}" ]; then
    case "${file}" in
      *.c) CLANG_TIDY_FILES+=(${file}) ;;
      *.cc) CLANG_TIDY_FILES+=(${file}) ;;
      *.cmx) JSON_LINT_FILES+=(${file}) ;;
      *.cpp) CLANG_TIDY_FILES+=(${file}) ;;
      *.dart) DART_LINT_FILES+=(${file}) ;;
      *.fidl) FIDL_LINT_FILES+=(${file}) ;;
      *.go) GO_LINT_FILES+=(${file}) ;;
      *.h) CLANG_TIDY_FILES+=(${file}) ;;
      *.hh) CLANG_TIDY_FILES+=(${file}) ;;
      *.hpp) CLANG_TIDY_FILES+=(${file}) ;;
      *.rs) RUST_LINT_FILES+=(${file}) ;;
    esac

    # Note: clang-tidy can produce errors on header files (*.h, *.hh, *.hpp)
    # clang-tidy uses a compilation database that only contains implementation
    # files, and so it makes a best-effort guess at what the relevant
    # implementation file is based on the name. However, if you have a header
    # with no implementation file or with a different name than the
    # implementation file (e.g. "functions.h" and "function_a.cpp" that
    # implements it), clang-tidy will return an error.
  fi
}

fidl_lint_is_outdated() {
  local yes=0
  local no=1
  if [[ ! -x "${FIDL_LINT}" ]]; then
    # "fx build zircon/tools" does not build the "${FIDL_LINT}" hard link
    # if that is the only missing hard link to the architecture-specific
    # executable. Touching these files in this order will ensure the
    # executable is rebuilt and relinked.
    touch "${FIDL_LINT}"
    touch "${FUCHSIA_DIR}/tools/fidl/fidlc/linter/main.cc"
    return $yes
  fi
  local files_out_of_date=$(
    find "${FUCHSIA_DIR}/tools/fidl/fidlc" -newer "${FIDL_LINT}" | wc -l
  )
  if (( ${files_out_of_date} > 0 )); then
    return $yes
  fi
  return $no
}

ensure_fidl_lint() {
  if [[ -t 0 ]]; then  # only if interactive
    # If there is a FIDL file to check, and we don't have an up-to-date
    # copy of fidl-lint, generate one.
    for file in ${FILES}; do
      if [[ ${file} =~ .*\.fidl ]]; then
        if fidl_lint_is_outdated; then
          # echo directly to /dev/tty in case stdout and/or stderr are redirected
          fx-warn "fidl-lint is out of date or missing..." >/dev/tty
          echo -n "OK to run 'fx build host_x64/fidl-lint' to rebuild it? [Y/n] " >/dev/tty
          read
          if [[ $REPLY == "" || $REPLY =~ Y|y ]]; then
            fx-command-run build "${FIDL_LINT_TARGET}" >/dev/tty 2>&1 || return $?
          fi
        fi
        break
      fi
    done
  fi
  return 0
}

execute() {
  if [[ -n "${VERBOSE}" || -n "${DRY_RUN}" ]]; then
    echo "$@"
    echo
  fi

  if [[ ! -n "${DRY_RUN}" ]]; then
    "$@" || return $?
  fi
}

call_linters() {
  if (( "${#CLANG_TIDY_CMD[@]}" > 0 && "${#CLANG_TIDY_FILES[@]}" > 0 )); then
    execute "${CLANG_TIDY_CMD[@]}" "${COMMAND_ARGS[@]}" "${CLANG_TIDY_FILES[@]}" || return $?
  fi
  if (( "${#DART_LINT_CMD[@]}" > 0 && "${#DART_LINT_FILES[@]}" > 0 )); then
    execute "${DART_LINT_CMD[@]}" "${COMMAND_ARGS[@]}" "${DART_LINT_FILES[@]}" || return $?
  fi
  if (( "${#FIDL_LINT_CMD[@]}" > 0 && "${#FIDL_LINT_FILES[@]}" > 0 )); then
    execute ensure_fidl_lint || return $?
    execute "${FIDL_LINT_CMD[@]}" "${COMMAND_ARGS[@]}" "${FIDL_LINT_FILES[@]}" || return $?
  fi
  if (( "${#GO_LINT_CMD[@]}" > 0 && "${#GO_LINT_FILES[@]}" > 0 )); then
    execute "${GO_LINT_CMD[@]}" "${COMMAND_ARGS[@]}" "${GO_LINT_FILES[@]}" || return $?
  fi
  if (( "${#JSON_LINT_CMD[@]}" > 0 && "${#JSON_LINT_FILES[@]}" > 0 )); then
    execute "${JSON_LINT_CMD[@]}" "${COMMAND_ARGS[@]}" "${JSON_LINT_FILES[@]}" || return $?
  fi
  if [[ "${#RUST_LINT_CMD[@]}" > 0 && (( "${#RUST_LINT_FILES[@]}" > 0 || -n "${TARGET}" )) ]]; then
    local args=()
    if [[ -n "${TARGET}" ]]; then
      args+=( "--target=${TARGET}" )
    fi
    for file in ${RUST_LINT_FILES}; do
      args+=( "--file=${file}" )
    done
    execute "${RUST_LINT_CMD[@]}" "${COMMAND_ARGS[@]}" "${args}" || return $?
  fi
}

for file in ${FILES}; do
  add_file_to_linter ${file}
done

call_linters || exit $?