#!/usr/bin/env bash
# build-aux/lint-src - Lint checks for source files
#
# Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
# SPDX-License-Identifier: AGPL-3.0-or-later

RED=$(tput setaf 1)
RESET=$(tput sgr0)

err() {
	printf "${RED}%s${RESET}: %s\n" "$1" "$2" >&2
	r=1
}

get-dscname() {
	if [[ $1 == */Documentation/* ]] && [[ "$(sed 1q -- "$1")" == 'NAME' ]]; then
		sed -n '
			2{
				s,[/.],_,g;
				s,^\s*_,Documentation/,;
				s,$,.txt,;

				p;
				q;
			}
			' -- "$1"
	else
		sed -n '
			1,3{
				/^\#!/d;
				/^<!--$/d;
				/-\*- .* -\*-/d;
				s,[/*\# ]*,,;
				s/ - .*//;

				p;
				q;
			}
			' -- "$1"
	fi
}

{
	filetype=$1
	filenames=("${@:2}")

	r=0
	for filename in "${filenames[@]}"; do
		# File header ##########################################################

		shebang="$(sed -n '1{/^#!/p;}' "$filename")"
		if [[ -x $filename && (-z $shebang || $shebang == '#!/hint/'*) ]]; then
			err "$filename" 'is executable but does not have a shebang'
		elif [[ (-n $shebang && $shebang != '#!/hint/'*) && ! -x $filename ]]; then
			err "$filename" 'has a shebang but is not executable'
		fi
		case "$shebang" in
			'') : ;;
			'#!/bin/sh') : ;;
			'#!/usr/bin/env bash') : ;;
			'#!/usr/bin/env python3') : ;;
			*) err "$filename" 'has an unrecognized shebang' ;;
		esac
		if [[ -n $shebang && $shebang != */"$filetype" && $shebang != *' '"$filetype" ]]; then
			err "$filename" "wrong shebang for $filetype"
		fi

		if ! grep -E -q 'Copyright \(C\) 202[4-9]((-|, )202[5-9])*  Luke T. Shumaker' "$filename"; then
			err "$filename" 'is missing a copyright statement'
		fi
		if test -e .git && ! git diff --quiet milestone/2025-01-01 HEAD -- "$filename"; then
			if ! grep -E -q 'Copyright \(C\) .*2025  Luke T. Shumaker' "$filename"; then
				err "$filename" 'has an outdated copyright statement'
			fi
		fi
		if ! grep -q '\sSPDX-License-Identifier[:] ' "$filename"; then
			err "$filename" 'is missing an SPDX-License-Identifier'
		fi

		dscname_act=$(get-dscname "$filename")
		dscname_exp=$(echo "$filename" | sed \
			-e 's,.*/config/,,' \
			-e 's,.*/config\.h$,config.h,' \
			-e 's,.*include/,,' \
			-e 's,.*static/,,' \
			-e 's/\.wip$//')
		if [ "$dscname_act" != "$dscname_exp" ] && [ "cmd/$dscname_act" != "$dscname_exp" ]; then
			err "$filename" "self-identifies as $dscname_act (expected $dscname_exp)"
		fi

		# File body ############################################################

		if grep -n --color=auto "$(printf '\\S\t')" "$filename"; then
			err "$filename" 'uses tabs for alignment'
		fi
	done
	case "$filetype" in
		unknown)
			for filename in "${filenames[@]}"; do
				err "$filename" 'cannot lint unknown file type'
			done
			;;
		c)
			for filename in "${filenames[@]}"; do
				if [[ $filename == *.h ]]; then
					dscname=$(get-dscname "$filename")
					guard=${dscname//'/'/'_'}
					guard=${guard//'.'/'_'}
					guard="_${guard^^}_"
					if ! { grep -Fxq "#ifndef ${guard}" "$filename" &&
						grep -Fxq "#define ${guard}" "$filename" &&
						grep -Fxq "#endif /* ${guard} */" "$filename"; }; then
						err "$filename" "does not have ${guard} guard"
					fi
				fi
			done
			;;
		sh | bash)
			shellcheck "${filenames[@]}" || exit $?
			shfmt --diff --case-indent --simplify "${filenames[@]}" || exit $?
			;;
		python3)
			./build-aux/venv/bin/mypy --strict --scripts-are-modules "${filenames[@]}" || exit $?
			./build-aux/venv/bin/black --check "${filenames[@]}" || exit $?
			./build-aux/venv/bin/isort --check "${filenames[@]}" || exit $?
			./build-aux/venv/bin/pylint "${filenames[@]}" || exit $?
			if grep -nh 'SPECIAL$$' -- lib9p/core.gen lib9p/core_gen/*.py; then exit 1; fi
			testfiles=()
			for filename in "${filenames[@]}"; do
				if [[ ${filename##*/} == test_*.py ]]; then
					testfiles+=("$filename")
				fi
			done
			./build-aux/venv/bin/pytest "${testfiles[@]}" || exit $?
			;;
		make | cmake | gitignore | ini | 9p-idl | 9p-log | markdown | pip | man-cat)
			# TODO: Write/adopt linters for these file types
			:
			;;
		*)
			err "$0" "unknown filetype: ${filetype}"
			;;
	esac
	exit $r
}