#!/usr/bin/env bash
# clang-format gate. Whole repo has format debt (139/141 first-party files fail),
# so default mode checks only lines CHANGED vs base. --all checks whole files.
# Usage: tools/lint.sh [base-commit] | tools/lint.sh --all
set -euo pipefail
cd "$(dirname "$0")/.."

CF="${CLANG_FORMAT:-$(command -v clang-format || true)}"
if [ -z "$CF" ]; then
	echo "lint: clang-format not found (pip install clang-format)" >&2
	exit 2
fi

PATHSPEC=(
	'*.cpp' '*.hpp' '*.h'
	':(exclude)ext/*' ':(exclude)java/*' ':(exclude)rustybits/*'
	':(exclude)windows/*' ':(exclude)attic/*'
)

fail=0

check() { # $1=file, rest=--lines args; empty args = whole file
	local f=$1
	shift
	if ! "$CF" --dry-run --Werror "$@" "$f"; then
		fail=1
	fi
}

if [ "${1:-}" = "--all" ]; then
	while IFS= read -r f; do check "$f"; done < <(git ls-files "${PATHSPEC[@]}")
else
	base=${1:-}
	if [ -z "$base" ]; then
		base=$(git merge-base HEAD '@{upstream}' 2>/dev/null || echo HEAD~1)
	fi
	# tracked changed files: only changed line ranges (MR = modified/renamed content)
	while IFS= read -r f; do
		args=()
		while IFS= read -r hunk; do
			# new-side header is "+start,count" (git diff format), not "+start,end"
			[[ $hunk =~ \+([0-9]+)(,([0-9]+))? ]] || continue
			start=${BASH_REMATCH[1]}
			count=${BASH_REMATCH[3]:-1}
			end=$((start + count - 1))
			if [ "$count" -eq 0 ]; then  # deletion-only: nearest surviving line
				start=$((start > 1 ? start - 1 : 1))
				end=$start
			fi
			args+=(--lines="$start:$end")
		done < <(git diff -U0 --no-color "$base" --diff-filter=ACMR -- "$f" | grep '^@@' || true)
		[ ${#args[@]} -eq 0 ] && continue
		check "$f" "${args[@]}"
	done < <(git diff --name-only --diff-filter=ACMR "$base" -- "${PATHSPEC[@]}")
	# untracked new files: whole file (no debt possible yet)
	while IFS= read -r f; do check "$f"; done < <(git ls-files --others --exclude-standard "${PATHSPEC[@]}")
fi

exit $fail