#!/usr/bin/env bash

set -uo pipefail

REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
BUILD_DIR="$REPO_ROOT/build/release"
WARNINGS_LOG="/tmp/warnings.log"
failures=0

fail() {
	printf 'ERROR: %s\n' "$1" >&2
	failures=$((failures + 1))
}

info() {
	printf '%s\n' "$1"
}

check_stale_files() {
	info 'Checking for stale backup files...'

	local stale_files
	stale_files="$({
		find "$REPO_ROOT" \
			\( -path "$REPO_ROOT/.git" -o -path "$REPO_ROOT/build" \) -prune -o \
			-type f \
			\( -name '*.bak' -o -name '*.orig' -o -name '*.tmp' -o -name '*.swp' -o -name '*~' \) \
			-print
	} | sed "s#^$REPO_ROOT/##" | sort)"

	if [[ -n "$stale_files" ]]; then
		printf 'Stale backup files found:\n%s\n' "$stale_files" >&2
		fail 'Remove stale backup files before committing.'
		return
	fi

	info 'No stale backup files found.'
}

check_build_warnings() {
	info 'Checking for compiler warnings with strict warnings enabled...'
	local project_warning_lines

	if ! command -v meson >/dev/null 2>&1; then
		fail 'meson is not installed.'
		return
	fi

	if ! command -v ninja >/dev/null 2>&1; then
		fail 'ninja is not installed.'
		return
	fi

	if [[ ! -f "$BUILD_DIR/build.ninja" ]]; then
		fail "Meson build directory not configured: $BUILD_DIR"
		return
	fi

	if ! meson configure "$BUILD_DIR" -Dstrict_warnings=enabled; then
		fail 'Failed to enable strict warnings in the Meson build directory.'
		return
	fi

	rm -f "$WARNINGS_LOG"

	if ! ninja -C "$BUILD_DIR" clean; then
		fail 'Failed to clean the release build directory.'
		return
	fi

	if ! ninja -C "$BUILD_DIR" 2>&1 | tee "$WARNINGS_LOG"; then
		fail 'Build failed while checking strict compiler warnings.'
		return
	fi

	project_warning_lines="$(grep -E '(^|[^[:alpha:]])warning:' "$WARNINGS_LOG" |
		grep -E '^(\.\./\.\./)?(src|include|tests)/' || true)"
	if [[ -n "$project_warning_lines" ]]; then
		printf 'Compiler warnings were found in %s\n%s\n' "$WARNINGS_LOG" "$project_warning_lines" >&2
		fail 'Strict warning build produced compiler warnings in project sources.'
		return
	fi

	info 'Strict warning build completed with zero warnings.'
}

check_clang_tidy() {
	info 'Running clang-tidy on src/*.cpp files...'

	if ! command -v clang-tidy >/dev/null 2>&1; then
		fail 'clang-tidy is not installed.'
		return
	fi

	if [[ ! -f "$BUILD_DIR/compile_commands.json" ]]; then
		fail "compile_commands.json not found in $BUILD_DIR"
		return
	fi

	local file
	local tidy_failures=0
	while IFS= read -r file; do
		[[ -n "$file" ]] || continue
		if ! clang-tidy -p "$BUILD_DIR" "$file"; then
			tidy_failures=$((tidy_failures + 1))
		fi
	done < <(find "$REPO_ROOT/src" -type f -name '*.cpp' | sort)

	if [[ "$tidy_failures" -gt 0 ]]; then
		fail "clang-tidy reported issues in $tidy_failures file(s)."
		return
	fi

	info 'clang-tidy passed.'
}

cd "$REPO_ROOT" || exit 2

check_stale_files
check_build_warnings
check_clang_tidy

if [[ "$failures" -gt 0 ]]; then
	printf 'Hygiene checks failed (%d issue(s)).\n' "$failures" >&2
	exit 1
fi

printf 'Hygiene checks passed.\n'