#!/bin/bash

# Copyright 2026 The OpenXLA Authors. 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.
# ============================================================================
set -xe

# Get targets from git diff if not specified on the command nline.
get_targets_from_diff() {
  if ! git rev-parse --is-inside-work-tree > /dev/null 2>&1; then
    set +x
    echo "Error: This script must be run inside a Git repository." >&2
    exit 1
  fi
  REMOTE=${REMOTE:-$(git remote -v | awk '/openxla\/xla/ { print $1; exit }')}
  if [ -z "$REMOTE" ]; then
    set +x
    echo "Could not find a git remote pointing to openxla/xla. Please add it as a remote." >&2
    echo "Example: git remote add upstream https://github.com/openxla/xla.git" >&2
    exit 1
  fi
  TARGET_REF=${TARGET_REF:-${REMOTE}/main}
  MERGE_BASE=$(git merge-base "$TARGET_REF" HEAD || true)
  if [ -z "$MERGE_BASE" ]; then
    set +x
    echo "Could not find a common ancestor with $TARGET_REF. Please rebase on $REMOTE main." >&2
    echo "Example: git pull --rebase $REMOTE main" >&2
    exit 1
  fi
  CHANGED_FILES=$(git diff --name-only --diff-filter=d "$MERGE_BASE" |
    grep -E '\.(cc|h)$' || true)
  if [ -z "$CHANGED_FILES" ]; then
    set +x
    echo "No C++ files changed."
    exit 0
  fi
  PACKAGES=$(echo "$CHANGED_FILES" | while read -r file; do
      echo "//$(dirname "$file"):all"
  done | sort -u | tr '\n' ' ')
  BASE_QUERY="kind('cc_(library|binary|test)', rdeps(set($PACKAGES), set($CHANGED_FILES), 1))"
  if [ -n "$TAGS_TO_IGNORE" ]; then
    QUERY="(${BASE_QUERY} except attr('tags', '${TAGS_TO_IGNORE}', (${BASE_QUERY})))"
  else
    QUERY="${BASE_QUERY}"
  fi
  
  # Populate global TARGETS variable
  # We use readarray to handle multi-line output from bazel cquery
  readarray -t TARGETS < <($BAZEL_CMD cquery --output=starlark --starlark:expr="target.label" --config="$CONFIG" "$QUERY")
  
  if [ ${#TARGETS[@]} -eq 0 ]; then
    set +x
    echo "No relevant targets found for changed files."
    exit 0
  fi
}

BUILD_WORKSPACE_DIRECTORY=${BUILD_WORKSPACE_DIRECTORY:-$(pwd)}
cd "$BUILD_WORKSPACE_DIRECTORY"
BAZEL_CMD=${BAZEL_CMD:-bazelisk}
CONFIG="clang-tidy-noerrors"

FIX=false
# Explicitly specify targets to run clang-tidy on.
# TODO(sohaibiftikhar): Move the bash orchestration to python.
TARGETS=()
while [[ $# -gt 0 ]]; do
  case $1 in
    --fix)
      FIX=true
      shift
      ;;
    --target)
      TARGETS+=("$2")
      shift 2
      ;;
    *)
      echo "Unknown option: $1"
      echo "Usage: $0 [--fix] [--target <target> ...]"
      exit 1
      ;;
  esac
done

if [ ${#TARGETS[@]} -eq 0 ]; then
  USE_DIFF=true
  get_targets_from_diff
else
  USE_DIFF=false
fi

# Create temporary files for the patch and BEP
PATCH_FILE=$(mktemp)
BEP_FILE=$(mktemp)
# Ensure cleanup on exit
trap 'rm -f "$PATCH_FILE" "$BEP_FILE"' EXIT


$BAZEL_CMD build --config="$CONFIG" --build_event_json_file="$BEP_FILE" --keep_going \
  "${TARGETS[@]}"
EXTRA_ARGS=()
if [ "$FIX" = true ]; then
  EXTRA_ARGS+=("--fix")
fi
if [ "$USE_DIFF" = true ]; then
  # Generate the patch file for changed lines
  git diff "$MERGE_BASE" > "$PATCH_FILE"
  EXTRA_ARGS+=("--patch" "$PATCH_FILE")
fi

$BAZEL_CMD run //build_tools/ci:clang_tidy_diff -- \
  --repo-root "$BUILD_WORKSPACE_DIRECTORY" \
  --bep-file "$BEP_FILE" \
  "${EXTRA_ARGS[@]}"