CMakeLists.txt

# ___________________________________________________________________________________
# SPDX-License-Identifier: MIT
# This file is part of H5CPP.
# Copyright (c) 2025-2026 Varga Labs, Toronto, ON, Canada.
# __________________________________________________________________________________

cmake_minimum_required(VERSION 3.22.0)

# Must be set before project() — CMake's Apple toolchain reads this at project() time.
# macOS 14.0 is the minimum deployment target that exposes std::stop_token in Apple's libc++.
if(APPLE)
    set(CMAKE_OSX_DEPLOYMENT_TARGET "14.4" CACHE STRING "Minimum macOS deployment version")
endif()

# Derive package version from the latest git tag before project(), so CPack
# embeds it as PROJECT_VERSION rather than a stale hardcoded number.  Falls
# back to a placeholder when building from a tarball without git history.
find_package(Git QUIET)
set(H5CPP_PROJECT_VERSION "1.12.7")
if(GIT_FOUND AND EXISTS "${CMAKE_SOURCE_DIR}/.git")
    execute_process(
        COMMAND ${GIT_EXECUTABLE} describe --tags --abbrev=0 --match "v[0-9]*"
        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
        OUTPUT_VARIABLE H5CPP_GIT_TAG
        OUTPUT_STRIP_TRAILING_WHITESPACE
        ERROR_QUIET)
    if(H5CPP_GIT_TAG MATCHES "^v([0-9]+(\\.[0-9]+)*)$")
        set(H5CPP_PROJECT_VERSION "${CMAKE_MATCH_1}")
    endif()
endif()

project(libh5cpp-dev VERSION ${H5CPP_PROJECT_VERSION} LANGUAGES CXX C)

# ─── Standard Settings ────────────────────────────────────────────────────────────
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

if(CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
    message(WARNING "In-source builds are discouraged.")
else()
    execute_process(
        COMMAND ${CMAKE_COMMAND} -E create_symlink
            ${CMAKE_BINARY_DIR}/compile_commands.json
            ${CMAKE_SOURCE_DIR}/compile_commands.json
        OUTPUT_QUIET ERROR_QUIET
    )
endif()

# ─── Git Version Injection ────────────────────────────────────────────────────────
execute_process(COMMAND git rev-parse --short HEAD
    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
    OUTPUT_VARIABLE GIT_COMMIT_HASH OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)
execute_process(COMMAND git describe --tags --abbrev=0
    WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
    OUTPUT_VARIABLE GIT_TAG OUTPUT_STRIP_TRAILING_WHITESPACE ERROR_QUIET)

set(H5CPP_BASE_VERSION ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH})
if(GIT_TAG)
    set(H5CPP_VERSION "${GIT_TAG}")
else()
    set(H5CPP_VERSION "${H5CPP_BASE_VERSION}-${GIT_COMMIT_HASH}")
endif()

# ─── Options ──────────────────────────────────────────────────────────────────────
option(H5CPP_BUILD_EXAMPLES "Build examples" OFF)
option(H5CPP_BUILD_TESTS    "Build tests"    OFF)
option(H5CPP_BUILD_BENCH    "Build benches"  OFF)
option(H5CPP_USE_LIBDEFLATE "Use libdeflate for H5CPP deflate/gzip filters when available" ON)
option(H5CPP_REQUIRE_LIBDEFLATE "Fail configuration if H5CPP_USE_LIBDEFLATE is ON and libdeflate is not found" OFF)
option(H5CPP_INSTALL_LIBDEFLATE "Install the resolved libdeflate header and library with H5CPP" OFF)
option(H5CPP_USE_LZ4  "Use LZ4 compression filter when available" ON)
option(H5CPP_USE_ZSTD "Use Zstd compression filter when available" ON)
option(H5CPP_USE_SZIP "Use vendored SZIP (Rice) compression filter when available" ON)

# ─── System Dependencies ──────────────────────────────────────────────────────────
include(GNUInstallDirs)

find_package(Threads REQUIRED QUIET)
find_package(Python3 COMPONENTS Interpreter QUIET)

# match hdf5 versioning x.x.x.h5cpp-version
set(H5CPP_VERSION ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}.${PROJECT_VERSION_PATCH})
if(WIN32)
    if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
        set(CMAKE_INSTALL_PREFIX "C:/h5cpp" CACHE PATH "default install path" FORCE)
    endif()
elseif(UNIX)
    # Pick up custom HDF Group installs at /usr/local/HDF_Group/HDF5/<version>/
    # before falling back to system paths.  Versioned directories are sorted
    # in descending order so the newest custom install wins over older ones
    # and over /usr/local. Honour a pre-set HDF5_ROOT (via -D or $ENV{...},
    # e.g. CI source-build at /home/runner/work/_temp/hdf5-X.Y.Z-install)
    # without overwriting it.
    if(NOT DEFINED HDF5_ROOT AND DEFINED ENV{HDF5_ROOT})
        set(HDF5_ROOT "$ENV{HDF5_ROOT}")
    endif()
    if(NOT DEFINED HDF5_ROOT)
        file(GLOB _hdf5_custom_roots LIST_DIRECTORIES true "/usr/local/HDF_Group/HDF5/[0-9]*")
        list(SORT _hdf5_custom_roots ORDER DESCENDING)
        set(HDF5_ROOT ${_hdf5_custom_roots} "/usr/local" "/usr")
    endif()
    find_package(PkgConfig REQUIRED QUIET)
endif()
if(APPLE)
    message(STATUS "H5CPP macOS support: CI runs on macos-13 with Homebrew HDF5 and LLVM clang-17/18")
endif()
if(ANDROID)
    message(STATUS "***WARNING: h5cpp is not fully tested on android ***")
endif()
find_package(Threads REQUIRED QUIET)

# ─── HDF5 ─────────────────────────────────────────────────────────────────────────
find_package(HDF5 REQUIRED COMPONENTS C)

# HDF5 floor is decoupled from h5cpp package version.  Previously the check
# compared HDF5_VERSION against PROJECT_VERSION, which coupled package
# versioning to HDF5 minimums by coincidence.  After #247 made
# PROJECT_VERSION track the git tag, the comparison stopped being meaningful.
# Pin the floor explicitly.
#
# 1.10.4 matches the prior implicit floor (the stale project(VERSION 1.10.4.6)
# line that #247 removed).  The CI matrix runs Ubuntu 22.04 with system
# HDF5 1.10.7 (floor coverage restored by #235); raising the floor above
# 1.10.4 would break that matrix entry.  When dropping 1.10.x coverage in
# a future cohort, bump this constant deliberately and remove the 22.04
# matrix entry in the same commit.
set(H5CPP_HDF5_FLOOR "1.10.4")
if(HDF5_VERSION VERSION_LESS ${H5CPP_HDF5_FLOOR})
    message(FATAL_ERROR
        "-- !!! H5CPP requires HDF5 v${H5CPP_HDF5_FLOOR} or greater (found ${HDF5_VERSION}) !!!"
    )
else()
    message(STATUS
        "H5CPP ${PROJECT_VERSION} matches with minimum required HDF5 v${HDF5_VERSION}"
    )
endif()

# ─── ROS3 VFD detection ───────────────────────────────────────────────────────────
foreach(_hdf5_inc IN LISTS HDF5_INCLUDE_DIRS)
    foreach(_pubconf IN ITEMS "H5pubconf.h" "H5pubconf-64.h")
        if(EXISTS "${_hdf5_inc}/${_pubconf}")
            file(STRINGS "${_hdf5_inc}/${_pubconf}" _ros3_line REGEX "H5_HAVE_ROS3_VFD")
            if(_ros3_line MATCHES "#define H5_HAVE_ROS3_VFD")
                set(H5CPP_HAVE_ROS3_VFD TRUE)
                break()
            endif()
        endif()
    endforeach()
    if(H5CPP_HAVE_ROS3_VFD)
        break()
    endif()
endforeach()
if(H5CPP_HAVE_ROS3_VFD)
    message(STATUS "H5CPP: ROS3 VFD detected — S3 read-only support enabled")
else()
    message(STATUS "H5CPP: ROS3 VFD not found — S3 support disabled")
endif()

option(H5CPP_NETWORK_TESTS "Enable network-dependent tests (requires outbound S3 access)" OFF)

# ─── MPI (optional) ───────────────────────────────────────────────────────────────
find_package(MPI QUIET COMPONENTS C CXX)
if(MPI_FOUND AND HDF5_IS_PARALLEL)
    message(STATUS "MPI and PHDF5 found: Parallel H5CPP enabled")
endif()

# ─── Include Directories & Libraries ──────────────────────────────────────────────
find_package(ZLIB REQUIRED)
list(APPEND H5CPP_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR} ${HDF5_INCLUDE_DIRS})
list(APPEND H5CPP_LIBS Threads::Threads ${HDF5_LIBRARIES} ZLIB::ZLIB)

# ─── Thirdparty ───────────────────────────────────────────────────────────────────
add_subdirectory(thirdparty EXCLUDE_FROM_ALL)
if(H5CPP_LIBDEFLATE_FOUND)
    message(STATUS "H5CPP libdeflate support: vendored ${H5CPP_LIBDEFLATE_INCLUDE_DIR}")
elseif(H5CPP_USE_LIBDEFLATE)
    message(STATUS "H5CPP libdeflate support: not found; zlib fallback will be used")
endif()

if(H5CPP_INSTALL_LIBDEFLATE AND NOT H5CPP_LIBDEFLATE_FOUND)
    message(FATAL_ERROR "H5CPP_INSTALL_LIBDEFLATE is ON, but libdeflate was not found")
endif()

# ─── LZ4 (optional) ───────────────────────────────────────────────────────────────
if(H5CPP_USE_LZ4)
    find_library(H5CPP_LZ4_LIBRARY NAMES lz4)
    find_path(H5CPP_LZ4_INCLUDE_DIR NAMES lz4.h)
    if(H5CPP_LZ4_LIBRARY AND H5CPP_LZ4_INCLUDE_DIR)
        message(STATUS "H5CPP LZ4 support: ${H5CPP_LZ4_LIBRARY}")
    else()
        message(STATUS "H5CPP LZ4 support: not found")
    endif()
endif()

# ─── Zstd (optional) ──────────────────────────────────────────────────────────────
if(H5CPP_USE_ZSTD)
    if(H5CPP_ZSTD_FOUND)
        message(STATUS "H5CPP Zstd support: vendored ${H5CPP_ZSTD_INCLUDE_DIR}")
    else()
        message(STATUS "H5CPP Zstd support: not found")
    endif()
endif()

# ─── SZIP (optional) ──────────────────────────────────────────────────────────────
if(H5CPP_USE_SZIP)
    if(H5CPP_SZIP_FOUND)
        message(STATUS "H5CPP SZIP support: vendored ${H5CPP_SZIP_INCLUDE_DIR}")
    else()
        message(STATUS "H5CPP SZIP support: not found")
    endif()
endif()

# ─── Header-only Library Target ───────────────────────────────────────────────────
add_library(h5cpp INTERFACE)
add_library(h5cpp::h5cpp ALIAS h5cpp)
target_include_directories(h5cpp INTERFACE  $<BUILD_INTERFACE:${H5CPP_INCLUDE_DIRS}> $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)

target_link_libraries(h5cpp INTERFACE ${H5CPP_LIBS})
target_compile_features(h5cpp INTERFACE cxx_std_20)

# MSVC does not update __cplusplus to reflect the actual standard without this flag;
# without it the #error guard in H5Qall.hpp always fires even under /std:c++20.
if(MSVC)
    target_compile_options(h5cpp INTERFACE /Zc:__cplusplus)
endif()

# The h5cpp-compiler reflection annotations ([[h5::doc]], [[h5::chunk]],
# [[h5::compress]], [[h5::name]], [[h5::ignore]], ...) live in the `h5::`
# attribute namespace. A plain compiler — i.e. one not running the h5cpp-compiler
# preprocessing pass — does not know that namespace, ignores the attributes, and
# emits -Wattributes for every annotated struct. Declare the namespace
# intentional so consumers that annotate their own types build cleanly. Scoped
# to `h5::` where the compiler supports it (GCC 11+); Clang/older GCC fall back
# to the broader unknown-attribute switch; MSVC silences C5030.  Guarded by
# check_cxx_compiler_flag so unsupported toolchains are left untouched. (#291)
if(MSVC)
    target_compile_options(h5cpp INTERFACE /wd5030)
else()
    include(CheckCXXCompilerFlag)
    check_cxx_compiler_flag("-Wno-attributes=h5::" H5CPP_HAS_WNO_ATTRIBUTES_NS)
    if(H5CPP_HAS_WNO_ATTRIBUTES_NS)
        target_compile_options(h5cpp INTERFACE -Wno-attributes=h5::)
    else()
        check_cxx_compiler_flag("-Wno-unknown-attributes" H5CPP_HAS_WNO_UNKNOWN_ATTRIBUTES)
        if(H5CPP_HAS_WNO_UNKNOWN_ATTRIBUTES)
            target_compile_options(h5cpp INTERFACE -Wno-unknown-attributes)
        endif()
    endif()
endif()

if(H5CPP_HAVE_ROS3_VFD)
    target_compile_definitions(h5cpp INTERFACE H5CPP_HAVE_ROS3_VFD=1)
endif()

if(H5CPP_LIBDEFLATE_FOUND)
    target_link_libraries(h5cpp INTERFACE ${H5CPP_LIBDEFLATE_TARGET})
    target_compile_definitions(h5cpp INTERFACE H5CPP_HAS_LIBDEFLATE=1)
else()
    target_compile_definitions(h5cpp INTERFACE H5CPP_DISABLE_LIBDEFLATE=1)
endif()

if(H5CPP_USE_LZ4 AND H5CPP_LZ4_LIBRARY AND H5CPP_LZ4_INCLUDE_DIR)
    target_compile_definitions(h5cpp INTERFACE H5CPP_HAS_LZ4=1)
    target_include_directories(h5cpp INTERFACE $<BUILD_INTERFACE:${H5CPP_LZ4_INCLUDE_DIR}>)
    target_link_libraries(h5cpp INTERFACE ${H5CPP_LZ4_LIBRARY})
endif()

if(H5CPP_USE_ZSTD AND H5CPP_ZSTD_FOUND)
    target_link_libraries(h5cpp INTERFACE ${H5CPP_ZSTD_TARGET})
endif()

if(H5CPP_USE_SZIP AND H5CPP_SZIP_FOUND)
    target_link_libraries(h5cpp INTERFACE ${H5CPP_SZIP_TARGET})
endif()

# ─── Subdirectories ───────────────────────────────────────────────────────────────
if(H5CPP_BUILD_EXAMPLES)
    add_subdirectory(examples)
endif()

include(CTest)
if(H5CPP_BUILD_TESTS AND BUILD_TESTING AND EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/test/CMakeLists.txt)
    add_subdirectory(test)
endif()

if(H5CPP_BUILD_BENCH AND EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/bench/CMakeLists.txt)
    add_subdirectory(bench)
endif()

# ─── Install Rules ────────────────────────────────────────────────────────────────
#
# Install destinations are RELATIVE to CMAKE_INSTALL_PREFIX (or, when packaging,
# to CPACK_PACKAGING_INSTALL_PREFIX). This is what CPack's productbuild driver
# expects on macOS — absolute destinations bypass CPack's staging entirely and
# the .pkg build fails trying to write to /usr/local/include literally
# (see https://gitlab.kitware.com/cmake/cmake/-/issues/14642). DEB/RPM on Linux
# use DESTDIR-style staging, so they tolerate either form, but keeping a single
# relative scheme across all generators is cleaner.
#
# productbuild on macOS always builds per-component sub-packages, and NSIS
# on Windows derives an internal variable name from the component name
# (rejecting '-' chars). Set a single short, alpha-only component name
# ("h5cpp") for every install() rule. CPACK_COMPONENTS_ALL below tells
# productbuild to actually pack it; DEB/RPM/NSIS treat the component name
# as cosmetic and produce the same monolithic output. The user-visible
# package name (CPACK_PACKAGE_NAME = "h5cpp-dev") and DEB/RPM/Brew names
# are unchanged.
set(CMAKE_INSTALL_DEFAULT_COMPONENT_NAME "h5cpp")
if(WIN32)
    set(INSTALL_DIR_CMAKE    "share/h5cpp/cmake")
    set(INSTALL_DIR_INCLUDE  "include")
    set(INSTALL_DIR_EXAMPLES "examples")
elseif(UNIX)
    set(INSTALL_DIR_CMAKE    "${CMAKE_INSTALL_LIBDIR}/cmake/h5cpp")
    set(INSTALL_DIR_INCLUDE  "${CMAKE_INSTALL_INCLUDEDIR}")
    set(INSTALL_DIR_EXAMPLES "${CMAKE_INSTALL_DATADIR}/h5cpp")
endif()

message(STATUS "Install directory: ${CMAKE_INSTALL_PREFIX}/${INSTALL_DIR_INCLUDE}")

# Generate single-header amalgamation during build
set(H5CPP_AMALGAMATED_HEADER ${CMAKE_BINARY_DIR}/h5cpp.hpp)
add_custom_command(
    OUTPUT ${H5CPP_AMALGAMATED_HEADER}
    COMMAND ${Python3_EXECUTABLE} ${CMAKE_SOURCE_DIR}/scripts/amalgamate.py ${CMAKE_SOURCE_DIR}/h5cpp ${H5CPP_AMALGAMATED_HEADER}
    DEPENDS ${CMAKE_SOURCE_DIR}/scripts/amalgamate.py ${CMAKE_SOURCE_DIR}/h5cpp/core ${CMAKE_SOURCE_DIR}/h5cpp/io
    COMMENT "Amalgamating h5cpp headers into h5cpp.hpp"
)
add_custom_target(h5cpp-amalgamate ALL DEPENDS ${H5CPP_AMALGAMATED_HEADER})

# Install header-only library (directory + single-header)
install(DIRECTORY h5cpp DESTINATION ${INSTALL_DIR_INCLUDE})
install(FILES ${H5CPP_AMALGAMATED_HEADER} DESTINATION ${INSTALL_DIR_INCLUDE})
install(TARGETS h5cpp EXPORT h5cpp-targets)

if(H5CPP_LIBDEFLATE_FOUND)
    install(FILES "${H5CPP_LIBDEFLATE_INCLUDE_DIR}/libdeflate.h" DESTINATION "${INSTALL_DIR_INCLUDE}")
    install(TARGETS libh5cpp-libdeflate libh5cpp-libdeflate-static EXPORT h5cpp-targets ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}")
endif()

if(H5CPP_ZSTD_FOUND)
    install(TARGETS libh5cpp-zstd libh5cpp-zstd-static EXPORT h5cpp-targets ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}")
endif()
if(H5CPP_SZIP_FOUND)
    install(TARGETS libh5cpp-szip libh5cpp-szip-static  EXPORT h5cpp-targets ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}")
endif()

# Install examples
install(DIRECTORY examples/attributes   DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/basics       DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY thirdparty/           DESTINATION "${INSTALL_DIR_EXAMPLES}/thirdparty"
    # blitz/v*/config/ and m4/ hold autotools-era symlinks (compile,
    # config.guess, ltmain.sh, libtool.m4 …) pointing into /usr/share/
    # automake-1.16/.  On Windows git checks them out as broken symlinks
    # which CPack -G NSIS aborts on ("File: failed opening file …
    # blitz/v1.0.2/config/compile"). h5cpp examples are CMake-only so
    # these autotools artifacts are dead weight everywhere — drop them
    # from the install entirely.
    REGEX "blitz/v[0-9.]+/(config|m4)/" EXCLUDE)
install(DIRECTORY examples/compound     DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/csv          DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/datasets     DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/datatypes    DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/half-float   DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/multi-tu     DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/optimized    DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/packet-table DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/raw_memory   DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/stl          DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/string       DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/transform    DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(DIRECTORY examples/utf          DESTINATION "${INSTALL_DIR_EXAMPLES}")
install(FILES     examples/CMakeLists.txt DESTINATION "${INSTALL_DIR_EXAMPLES}")

# Package config
include(CMakePackageConfigHelpers)

configure_package_config_file(
    ${CMAKE_SOURCE_DIR}/cmake/config.cmake.in
    ${CMAKE_BINARY_DIR}/h5cpp-config.cmake
    INSTALL_DESTINATION ${INSTALL_DIR_CMAKE}
)

write_basic_package_version_file(
    ${CMAKE_BINARY_DIR}/h5cpp-config-version.cmake
    VERSION ${PROJECT_VERSION}
    COMPATIBILITY AnyNewerVersion
)

export(PACKAGE h5cpp)
export(EXPORT h5cpp-targets)

install(EXPORT h5cpp-targets DESTINATION ${INSTALL_DIR_CMAKE})
install(FILES
    ${CMAKE_BINARY_DIR}/h5cpp-config.cmake
    ${CMAKE_BINARY_DIR}/h5cpp-config-version.cmake
    DESTINATION ${INSTALL_DIR_CMAKE}
)

# ─── pkg-config ───────────────────────────────────────────────────────────────
configure_file(cmake/h5cpp.pc.in h5cpp.pc @ONLY)
install(FILES ${CMAKE_BINARY_DIR}/h5cpp.pc
    DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)

# ─── CPack ────────────────────────────────────────────────────────────────────
set(CPACK_PACKAGE_NAME                "h5cpp-dev")
set(CPACK_PACKAGE_VENDOR              "Varga Labs")
set(CPACK_PACKAGE_CONTACT             "steven.varga@gmail.com")
set(CPACK_PACKAGE_DESCRIPTION_SUMMARY "C++ template library for HDF5 I/O")
set(CPACK_PACKAGE_HOMEPAGE_URL        "https://h5cpp.org")
set(CPACK_PACKAGE_VERSION             "${H5CPP_VERSION}")
set(CPACK_PACKAGE_VERSION_MAJOR       "${PROJECT_VERSION_MAJOR}")
set(CPACK_PACKAGE_VERSION_MINOR       "${PROJECT_VERSION_MINOR}")
set(CPACK_PACKAGE_VERSION_PATCH       "${PROJECT_VERSION_PATCH}")
# productbuild on macOS rejects license files without a .rtf/.rtfd/.html/.txt
# extension. The canonical LICENSE in the source tree is extensionless, so
# stage a LICENSE.txt copy in the build dir and point CPack at it. Other
# generators (DEB/RPM/NSIS) accept .txt fine.
configure_file(
    "${CMAKE_CURRENT_SOURCE_DIR}/LICENSE"
    "${CMAKE_CURRENT_BINARY_DIR}/LICENSE.txt"
    COPYONLY)
set(CPACK_RESOURCE_FILE_LICENSE       "${CMAKE_CURRENT_BINARY_DIR}/LICENSE.txt")
set(CPACK_STRIP_FILES                 OFF)

# productbuild iterates CPACK_COMPONENTS_ALL to decide which component
# sub-packages to build and pack. Without this set explicitly, the install
# step shows up as `Install project: libh5cpp-dev []` (empty components
# list) and the resulting .pkg is metadata-only at ~2.3 KB. Listing the
# one component our install rules use (via CMAKE_INSTALL_DEFAULT_COMPONENT_NAME
# above) is enough — CPack will pack that component's files.
# DEB/RPM/NSIS ignore CPACK_COMPONENTS_ALL when no per-component packaging
# is configured, so this is a no-op for them.
set(CPACK_COMPONENTS_ALL              "h5cpp")

# Headers land at <prefix>/include/h5cpp/ — ambient, no -I flag needed by
# consumers. The prefix differs per platform convention:
#   * Linux DEB/RPM      → /usr        (already what apt/yum users expect)
#   * macOS productbuild → /usr/local  (Homebrew / Apple convention)
#   * Windows NSIS does not honour CPACK_PACKAGING_INSTALL_PREFIX; the
#     installer lets the user pick a target dir (defaulting to Program Files).
if(APPLE)
    set(CPACK_PACKAGING_INSTALL_PREFIX "/usr/local")
else()
    set(CPACK_PACKAGING_INSTALL_PREFIX "/usr")
endif()
set(CPACK_DEBIAN_PACKAGE_NAME         "h5cpp-dev")
set(CPACK_DEBIAN_PACKAGE_SECTION      "libdevel")
set(CPACK_DEBIAN_PACKAGE_DEPENDS      "libhdf5-dev")
set(CPACK_DEBIAN_PACKAGE_RECOMMENDS   "h5cpp-compiler")

# RPM
set(CPACK_RPM_PACKAGE_NAME            "h5cpp-devel")
set(CPACK_RPM_PACKAGE_LICENSE         "MIT")
set(CPACK_RPM_PACKAGE_GROUP           "Development/Libraries")
set(CPACK_RPM_PACKAGE_REQUIRES        "hdf5-devel")
set(CPACK_RPM_PACKAGE_SUGGESTS        "h5cpp-compiler")

# NSIS (Windows installer)
set(CPACK_NSIS_PACKAGE_NAME           "h5cpp ${H5CPP_VERSION}")
set(CPACK_NSIS_DISPLAY_NAME           "H5CPP ${H5CPP_VERSION}")
set(CPACK_NSIS_URL_INFO_ABOUT         "https://h5cpp.org")
set(CPACK_NSIS_ENABLE_UNINSTALL_BEFORE_INSTALL ON)

# productbuild (macOS .pkg)
set(CPACK_PRODUCTBUILD_IDENTIFIER     "org.h5cpp.h5cpp")

# Override the default per-generator filename so that amd64 / arm64 / x86_64 /
# aarch64 / darwin-arm64 / windows-amd64 produce distinct names when collected
# into a single release upload directory.  Without this, multi-arch CI matrix
# builds emit identical filenames and overwrite each other on the Release page.
set(CPACK_PACKAGE_FILE_NAME "${CPACK_PACKAGE_NAME}-v${PROJECT_VERSION}-${CMAKE_SYSTEM_NAME}-${CMAKE_SYSTEM_PROCESSOR}")
string(TOLOWER "${CPACK_PACKAGE_FILE_NAME}" CPACK_PACKAGE_FILE_NAME)

include(CPack)

# ─── Developer convenience targets ───────────────────────────────────────────
find_program(DOXYGEN_EXECUTABLE doxygen)

if(DOXYGEN_EXECUTABLE)
    add_custom_target(docs-doxygen COMMAND ${DOXYGEN_EXECUTABLE} Doxyfile
        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}/doxy
        COMMENT "Building Doxygen API reference → docs/doxygen/html"
        VERBATIM
    )
endif()