# Copyright 2019-2026 Gentoo Authors
# Distributed under the terms of the GNU General Public License v2

EAPI=8

# https://codeberg.org/ziglang/zig/src/tag/${PV}#building-from-source
LLVM_COMPAT=( 21 )
LLVM_OPTIONAL=1

ZIG_SLOT="$(ver_cut 1-2)"
ZIG_OPTIONAL=1

inherit check-reqs cmake flag-o-matic edo llvm-r2 toolchain-funcs zig

DESCRIPTION="A robust, optimal, and maintainable programming language"
HOMEPAGE="https://ziglang.org/ https://codeberg.org/ziglang/zig/"
if [[ ${PV} == 9999 ]]; then
	EGIT_REPO_URI="https://codeberg.org/ziglang/zig.git"
	inherit git-r3
else
	VERIFY_SIG_METHOD=minisig
	VERIFY_SIG_OPENPGP_KEY_PATH=/usr/share/minisig-keys/zig-software-foundation.pub
	inherit verify-sig

	SRC_URI="
		https://ziglang.org/download/${PV}/${P}.tar.xz
		verify-sig? ( https://ziglang.org/download/${PV}/${P}.tar.xz.minisig )
	"
	KEYWORDS="~amd64 ~arm ~arm64"

	BDEPEND="verify-sig? ( sec-keys/minisig-keys-zig-software-foundation )"
fi

# project itself: MIT
# There are bunch of projects under "lib/" folder that are needed for cross-compilation.
# Files that are unnecessary for cross-compilation are removed by upstream
# and therefore their licenses (if any special) are not included.
# lib/libunwind: Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )
# lib/libcxxabi: Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )
# lib/libcxx: Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT )
# lib/libc/wasi: || ( Apache-2.0-with-LLVM-exceptions Apache-2.0 MIT BSD-2 ) public-domain
# lib/libc/musl: MIT BSD-2
# lib/libc/mingw: ZPL public-domain BSD-2 ISC HPND
# lib/libc/glibc: BSD HPND ISC inner-net LGPL-2.1+
LICENSE="MIT Apache-2.0-with-LLVM-exceptions || ( UoI-NCSA MIT ) || ( Apache-2.0-with-LLVM-exceptions Apache-2.0 MIT BSD-2 ) public-domain BSD-2 ZPL ISC HPND BSD inner-net LGPL-2.1+"
SLOT="${ZIG_SLOT}"
IUSE="debug doc +llvm"
REQUIRED_USE="
	!llvm? ( !doc )
	llvm? ( ${LLVM_REQUIRED_USE} )
"
RESTRICT="!llvm? ( test )"

# Used by both "cmake" and "zig" eclasses.
BUILD_DIR="${WORKDIR}/${P}_build"

# Zig requires zstd and zlib compression support in LLVM, if using LLVM backend.
# (non-LLVM backends don't require these)
# They are not required "on their own", so please don't add them here.
# You can check https://codeberg.org/ziglang/zig-bootstrap in future, to see
# options that are passed to LLVM CMake building (excluding "static" ofc).
LLVM_DEPEND="$(llvm_gen_dep '
	llvm-core/clang:${LLVM_SLOT}
	llvm-core/lld:${LLVM_SLOT}[zstd]
	llvm-core/llvm:${LLVM_SLOT}[zstd]
')"

BDEPEND+=" llvm? ( ${LLVM_DEPEND} )"
DEPEND="llvm? ( ${LLVM_DEPEND} )"
RDEPEND="${DEPEND}"
IDEPEND="app-eselect/eselect-zig"

DOCS=( "README.md" "doc/build.zig.zon.md" )

# zig.eclass does not set this for us since we use ZIG_OPTIONAL=1
QA_FLAGS_IGNORED="usr/.*/zig/${PV}/bin/zig"

# https://codeberg.org/ziglang/zig/src/tag/0.16.0/build.zig#L775-L778
CHECKREQS_MEMORY="8G"

pkg_setup() {
	# Skip detecting zig executable.
	declare -r -g ZIG_VER="${PV}"
	ZIG_EXE="not-applicable" zig_pkg_setup

	declare -r -g ZIG_SYS_INSTALL_DEST="/usr/$(get_libdir)/zig/${PV}"

	if use llvm; then
		[[ ${MERGE_TYPE} != binary ]] && llvm_cbuild_setup
	fi

	# Requires running stage3 which is built for cross-target.
	if use doc && tc-is-cross-compiler; then
		die "USE=doc is not yet supported when cross-compiling"
	fi

	check-reqs_pkg_setup
}

src_unpack() {
	if [[ ${PV} == 9999 ]]; then
		git-r3_src_unpack
	else
		if use verify-sig; then
			verify-sig_verify_detached "${DISTDIR}"/${P}.tar.xz{,.minisig}
		fi
	fi
	zig_src_unpack
}

src_prepare() {
	if use llvm; then
		cmake_src_prepare
	else
		# Sync with zig_src_prepare
		default_src_prepare
		mkdir -p "${BUILD_DIR}" || die
		einfo "BUILD_DIR: \"${BUILD_DIR}\""
		# "--system" mode is not used during bootstrap.
	fi

	sed -i '/exe\.allow_so_scripts = true;/d' build.zig || die
}

src_configure() {
	# Has no effect on final binary and only causes failures during bootstrapping.
	filter-lto

	# Used during bootstrapping. stage1/stage2 have limited functionality
	# and can't resolve native target, so we pass target in exact form.
	declare -r -g ZIG_HOST_AS_TARGET="$(zig-utils_c_env_to_zig_target "${CBUILD:-${CHOST}}" "${CFLAGS}"})"

	# Note that if we are building with CMake, "my_zbs_args"
	# are used only after compiling zig2.
	local my_zbs_args=(
		--zig-lib-dir "${S}/lib/"

		--prefix "${EPREFIX}/${ZIG_SYS_INSTALL_DEST}/"
		--prefix-lib-dir lib/

		# These are built separately
		-Dno-langref=true
		-Dstd-docs=false

		# More commands and options if "debug" is enabled.
		-Ddebug-extensions=$(usex debug true false)
		# More asserts and so on by default if "debug" is enabled.
		--release=$(usex debug safe fast)
	)

	# Scenarios of compilation:

	# With LLVM, native:
	# CMake:
	#   * generate "config.h" for LLVM libraries and build "zigcpp"
	#   * build "zig2" using common "config.h" and "zigcpp"
	# build.zig:
	#   * build "stage3" using common "config.h" and "zigcpp"

	# With LLVM, cross-compiled:
	# CMake:
	#   * generate cross-target "config.h" for LLVM libraries from ESYSROOT
	#     and build cross-target "zigcpp", and stash them away
	#   * generate native "config.h" for LLVM libraries from BROOT and
	#     build native "zigcpp"
	#   * build native "zig2" using native "config.h" and "zigcpp"
	# build.zig:
	#   * build cross-target "stage3" using stashed "config.h" and "zigcpp"

	# Without LLVM:
	# bootstrap.c:
	#   * build native "zig2"
	# build.zig:
	#   * build (cross-)target "stage3"

	if use llvm; then
		my_zbs_args+=(
			-Denable-llvm=true
			-Dstatic-llvm=false
			-Dconfig_h="${BUILD_DIR}/config.h"
		)
	else
		my_zbs_args+=(
			-Denable-llvm=false
		)
	fi
	zig_src_configure

	if use llvm; then
		local mycmakeargs=(
			-DZIG_SHARED_LLVM=ON
			-DZIG_USE_LLVM_CONFIG=ON
			-DZIG_HOST_TARGET_TRIPLE="${ZIG_HOST_AS_TARGET}"
			# Don't set ZIG_TARGET_TRIPLE, ZIG_TARGET_MCPU and
			# CMAKE_INSTALL_PREFIX because we build up to zig2 max,
			# after that "zig build" is used to compile stage3.

			# Don't set CMAKE_PREFIX_PATH because "llvm_chost_setup"
			# and "llvm_cbuild_setup" already set PATH in such way
			# that suitable llvm-config is found and used in
			# "cmake/Findllvm.cmake", and "cmake.eclass" help with
			# cross-compilation pathes for "Findclang" and "Findlld".

			# CMP0144, Zig has own packages with these names, so ignore
			# LLVM_ROOT, Clang_ROOT, LLD_ROOT from "llvm_chost_setup".
			-DCMAKE_FIND_USE_PACKAGE_ROOT_PATH=OFF
		)
		if tc-is-cross-compiler; then
			# Enable cross-compilation for CMake when filling "config.h"
			# and building "zigcpp". They would be used for stage3 build.
			# Here we are using LLVM from ESYSROOT/DEPEND.
			# Uses script llvm-config.

			# Isolate PATH changes in subshell so that it would not
			# affect next `cmake_src_configure` with BROOT/BDEPEND.
			(
				llvm_chost_setup
				cmake_src_configure
				cmake_build zigcpp
			)

			mv "${BUILD_DIR}/config.h" "${T}/target_config.h" || die
			mv "${BUILD_DIR}/zigcpp/" "${T}/target_zigcpp/" || die
			rm -rf "${BUILD_DIR}" || die
		fi

		# Force disable cross-compilation for CMake when building "zig2".
		# Here we are using LLVM from BROOT/BDEPEND.
		# Uses native llvm-config.

		# Isolate environment changes in subshell so that it would not
		# affect next phases.
		(
			export BUILD_CFLAGS="${CFLAGS}"
			export BUILD_CXXFLAGS="${CXXFLAGS}"
			export BUILD_CPPFLAGS="${CPPFLAGS}"
			export BUILD_LDFLAGS="${LDFLAGS}"
			tc-env_build

			unset SYSROOT
			export CHOST="${CBUILD:-${CHOST}}"
			strip-unsupported-flags
			cmake_src_configure
		)
	fi
}

src_compile() {
	if use llvm; then
		cmake_build zig2

		if tc-is-cross-compiler; then
			rm -rf "${BUILD_DIR}/zigcpp/" || die
			rm -f "${BUILD_DIR}/config.h" || die

			mv "${T}/target_zigcpp/" "${BUILD_DIR}/zigcpp/" || die
			mv "${T}/target_config.h" "${BUILD_DIR}/config.h" || die
		fi
	else
		cd "${BUILD_DIR}" || die
		ln -s "${S}/stage1/" . || die
		ln -s "${S}/src/" . || die
		ln -s "${S}/lib/" . || die

		local native_cc="$(tc-getBUILD_CC)"
		"${native_cc}" -o bootstrap "${S}/bootstrap.c" || die "Zig's bootstrap.c compilation failed"
		ZIG_HOST_TARGET_TRIPLE="${ZIG_HOST_AS_TARGET}" CC="${native_cc}" edo ./bootstrap
	fi

	cd "${BUILD_DIR}" || die
	ZIG_EXE="./zig2" zig_src_compile --prefix stage3/

	# Requires running stage3 which is built for cross-target.
	if ! tc-is-cross-compiler; then
		./stage3/bin/zig env || die "Zig compilation failed"

		if use doc; then
			ZIG_EXE="./stage3/bin/zig" zig_src_compile langref --prefix docgen/
		fi
	fi
}

src_test() {
	if has_version -b app-emulation/qemu; then
		ewarn "QEMU executable was found on your building system."
		ewarn "If you have qemu-binfmt (binfmt_misc) hooks enabled for"
		ewarn "foreign architectures, Zig tests might fail."
		ewarn "In this case, please disable qemu-binfmt and try again."
	fi

	cd "${BUILD_DIR}" || die

	# XXX: When we pass a libc installation to Zig, it will fail to find
	#      the bundled libraries for targets like aarch64-macos and
	#      *-linux-musl. Zig doesn't run binaries for these targets when
	#      -Dskip-non-native is passed, but they are still compiled, so
	#      the test will fail. There's no way to disable --libc once passed,
	#      so we need to strip it from ZBS_ARGS.
	#      See: https://github.com/ziglang/zig/issues/22383

	# XXX: Also strip --release=* flags to run tests with Debug mode,
	# like upstream runs in CI. Full test suite with other modes is
	# in a sad state right now...
	(
		local -a filtered_args=()
		local i=0

		local arg
		while (( i < ${#ZBS_ARGS[@]} )); do
			arg="${ZBS_ARGS[i]}"
			case "$arg" in
				--libc)
					(( i += 2 ))
					;;
				--release=*)
					(( i += 1 ))
					;;
				*)
					filtered_args+=("$arg")
					(( i += 1 ))
					;;
			esac
		done

		ZBS_ARGS=("${filtered_args[@]}")

		ZIG_EXE="./stage3/bin/zig" zig_src_test -Dskip-non-native
	)
}

src_install() {
	use doc && local HTML_DOCS=( "${BUILD_DIR}/docgen/doc/langref.html" )

	ZIG_EXE="./zig2" zig_src_install

	cd "${ED}/${ZIG_SYS_INSTALL_DEST}" || die
	mv lib/zig/ lib2/ || die
	rm -rf lib/ || die
	mv lib2/ lib/ || die
	dosym -r "${ZIG_SYS_INSTALL_DEST}/bin/zig" /usr/bin/zig-${PV}
}

pkg_postinst() {
	eselect zig update ifunset || die

	if ! use llvm; then
		elog "Currently, Zig built without LLVM support lacks some"
		elog "features such as optimizations, linker features, etc."
		elog "They are listed under \"Building from Source without LLVM\""
		elog "section of the README file from \"/usr/share/doc/${PF}\" ."
	fi
}

pkg_postrm() {
	eselect zig update ifunset
}