CMakeLists.txt

cmake_minimum_required(VERSION 3.21)

# Set extension name here
set(TARGET_NAME duck_dggs)

set(EXTENSION_NAME ${TARGET_NAME}_extension)
set(LOADABLE_EXTENSION_NAME ${TARGET_NAME}_loadable_extension)

project(${TARGET_NAME}
    VERSION 0.1.0
    LANGUAGES CXX C
    DESCRIPTION "DuckDB extension — DGGRID discrete global grid functions"
)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

include_directories(src/include)

# --------------------------------------------------------------------------
# DGGRID submodule at third_party/DGGRID
# --------------------------------------------------------------------------
set(DGGRID_DIR "${CMAKE_CURRENT_SOURCE_DIR}/third_party/DGGRID")

if(NOT EXISTS "${DGGRID_DIR}/CMakeLists.txt")
    message(FATAL_ERROR
        "DGGRID submodule not found at ${DGGRID_DIR}.\n"
        "Run: git submodule update --init --recursive")
endif()

option(WITH_GDAL "Build DGGRID with GDAL support" OFF)
set(DGGRID_SKIP_INSTALL ON CACHE BOOL "" FORCE)

# On Windows, M_PI is not defined by default — not by MSVC and not by MinGW/GCC
# either (MinGW skips the if(MSVC) block in DGGRID's CMakeLists.txt).
# add_compile_definitions here is directory-scoped: it propagates into the
# DGGRID add_subdirectory below, so dglib itself also gets the define.
if(WIN32)
    add_compile_definitions(_USE_MATH_DEFINES)
endif()

add_subdirectory("${DGGRID_DIR}" "third_party/DGGRID" EXCLUDE_FROM_ALL)

set(DGLIB_INCLUDE_DIR "${DGGRID_DIR}/src/lib/dglib/include")

# --------------------------------------------------------------------------
# Z7 core library + authalic latitude conversion (submodule at
# third_party/igeo7_duckdb, upstream: https://github.com/allixender/igeo7_duckdb).
# We compile the Z7 core files under src/z7/ and the auth/ math (Karney 2022
# Fourier series) and register our own DuckDB scalar-function wrappers.
# --------------------------------------------------------------------------
set(IGEO7_DIR "${CMAKE_CURRENT_SOURCE_DIR}/third_party/igeo7_duckdb/src")
set(Z7_DIR "${IGEO7_DIR}/z7")
set(AUTH_DIR "${IGEO7_DIR}/auth")

if(NOT EXISTS "${Z7_DIR}/library.h")
    message(FATAL_ERROR
        "igeo7_duckdb submodule not found at ${Z7_DIR}.\n"
        "Run: git submodule update --init --recursive")
endif()

if(NOT EXISTS "${AUTH_DIR}/authalic.hpp")
    message(FATAL_ERROR
        "igeo7_duckdb authalic source not found at ${AUTH_DIR}.\n"
        "The submodule pointer is older than the authalic commit; run:\n"
        "  git submodule update --remote third_party/igeo7_duckdb")
endif()

# --------------------------------------------------------------------------
# Extension sources
# --------------------------------------------------------------------------
set(EXTENSION_SOURCES
    src/duck_dggs_extension.cpp
    src/dggrid_transform.cpp
    src/igeo7_functions.cpp
    "${Z7_DIR}/library.cpp"
    "${AUTH_DIR}/authalic.cpp"
)

# Set LINKED_LIBS so the WASM (Emscripten) post-build emcc command can find
# dglib.  Without this, the emcc -sSIDE_MODULE=2 step does not link dglib and
# static symbols like DgGeoSphRF::icosaEdgeRads_ are left undefined.
set(DUCKDB_EXTENSION_DUCK_DGGS_LINKED_LIBS $<TARGET_FILE:dglib>)

build_static_extension(${TARGET_NAME} ${EXTENSION_SOURCES})
build_loadable_extension(${TARGET_NAME} "" ${EXTENSION_SOURCES})

target_include_directories(${EXTENSION_NAME} PRIVATE "${DGLIB_INCLUDE_DIR}" "${Z7_DIR}" "${IGEO7_DIR}")
target_include_directories(${LOADABLE_EXTENSION_NAME} PRIVATE "${DGLIB_INCLUDE_DIR}" "${Z7_DIR}" "${IGEO7_DIR}")

add_dependencies(${EXTENSION_NAME} dglib)
add_dependencies(${LOADABLE_EXTENSION_NAME} dglib)
target_link_libraries(${EXTENSION_NAME} $<TARGET_FILE:dglib>)
target_link_libraries(${LOADABLE_EXTENSION_NAME} $<TARGET_FILE:dglib>)

# On Linux, the GCC linker (including aarch64) treats duplicate COMDAT symbols
# (C++17 inline statics like LogicalType::DOUBLE) as hard errors when linking
# extension object files against libduckdb_static.a.  These symbols are
# identical across all TUs so multiple definitions are safe to merge.
# INTERFACE on the static extension propagates the flag to the final test
# binary that DuckDB's build system links (libduck_dggs_extension.a +
# libduckdb_static.a).  PRIVATE on the loadable extension covers the .so link.
if((UNIX AND NOT APPLE) OR MINGW)
    target_link_options(${EXTENSION_NAME} INTERFACE -Wl,--allow-multiple-definition)
    target_link_options(${LOADABLE_EXTENSION_NAME} PRIVATE -Wl,--allow-multiple-definition)
endif()


install(
  TARGETS ${EXTENSION_NAME}
  EXPORT "${DUCKDB_EXPORT_SET}"
  LIBRARY DESTINATION "${INSTALL_LIB_DIR}"
  ARCHIVE DESTINATION "${INSTALL_LIB_DIR}")