cmake_minimum_required(VERSION 3.20)

set(PROJECT_NAME "conformallab_core")
project(${PROJECT_NAME} LANGUAGES C CXX)

message(STATUS "Configuring ${PROJECT_NAME}...")

# ── Build modes ────────────────────────────────────────────────────────────────
#
#   Default (CI / tests-only): only Eigen + GTest are required.
#
#   -DWITH_CGAL=ON   builds the conformallab_core CLI app (needs CGAL).
#                    Automatically enables WITH_VIEWER because the app uses
#                    the viewer library for mesh visualisation.
#
#   -DWITH_VIEWER=ON builds the viewer library standalone (libigl/GLFW/GLAD).
#
# ──────────────────────────────────────────────────────────────────────────────
option(WITH_CGAL   "Build conformallab_core app (requires CGAL + Viewer)" OFF)
option(WITH_VIEWER "Build viewer library (libigl / GLFW / GLAD)"          OFF)

# The CLI app always needs the viewer; enable it implicitly.
if(WITH_CGAL AND NOT WITH_VIEWER)
    message(STATUS "WITH_CGAL implies WITH_VIEWER – enabling automatically.")
    set(WITH_VIEWER ON CACHE BOOL "" FORCE)
endif()

# ── Standard settings ──────────────────────────────────────────────────────────
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

if(NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Build type" FORCE)
endif()

if(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
  add_compile_options(-Wall -Wextra -Wpedantic)

  # AddressSanitizer only in Debug (gtest_discover_tests runs the binary at
  # configure time and hangs with ASan enabled).
  if(CMAKE_BUILD_TYPE STREQUAL "Debug" AND NOT BUILD_TESTING)
    add_compile_options(-fsanitize=address -fno-omit-frame-pointer)
    add_link_options(-fsanitize=address)
  endif()
endif()

# ── GTest (always – tests are always built) ────────────────────────────────────
include(FetchContent)
include(CTest)
enable_testing()

FetchContent_Declare(
    googletest
    GIT_REPOSITORY https://github.com/google/googletest.git
    GIT_TAG        v1.14.0
)
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
set(INSTALL_GTEST          OFF CACHE BOOL "" FORCE)
set(BUILD_GMOCK            OFF CACHE BOOL "" FORCE)
FetchContent_MakeAvailable(googletest)

# ── External deps (lazy tarball extraction) ────────────────────────────────────
add_subdirectory(deps)

# ── Viewer library (optional) ──────────────────────────────────────────────────
if(WITH_VIEWER)
    add_subdirectory(deps/glfw-3.4)

    add_library(glad STATIC
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/libigl-glad/src/glad.c)
    target_include_directories(glad PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/libigl-glad/include)

    add_library(viewer STATIC src/viewer/simple_viewer.cpp)
    target_include_directories(viewer PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/libigl-2.6.0/include
        ${CMAKE_CURRENT_SOURCE_DIR}/include
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/libigl-glad/include
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/eigen-3.4.0/)
    target_link_libraries(viewer PUBLIC glad glfw)
endif()

# ── Core CLI app (optional, requires CGAL + Viewer) ───────────────────────────
if(WITH_CGAL)
    # CGAL 6.x still needs Boost.Config headers unconditionally.
    # Install via: brew install boost  (macOS)
    #              apt install libboost-dev  (Debian/Ubuntu)
    find_package(Boost REQUIRED)

    add_executable(${PROJECT_NAME} src/apps/v0/conformallab_cli.cpp)
    target_include_directories(${PROJECT_NAME} SYSTEM PRIVATE
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/single_includes
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/eigen-3.4.0/
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/CGAL-6.1.1/include
        ${CMAKE_CURRENT_SOURCE_DIR}/deps/libigl-2.6.0/include
        ${Boost_INCLUDE_DIRS})
    target_include_directories(${PROJECT_NAME} PRIVATE
        ${CMAKE_CURRENT_SOURCE_DIR}/include)
    target_compile_definitions(${PROJECT_NAME} PRIVATE
        CGAL_DISABLE_GMP CGAL_DISABLE_MPFR)
    target_link_libraries(${PROJECT_NAME} PRIVATE viewer)
    set_target_properties(${PROJECT_NAME} PROPERTIES
        RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/bin)
endif()

# ── Example programs (require WITH_CGAL; viewer example also needs WITH_VIEWER) ─
if(WITH_CGAL)
    add_subdirectory(examples)
endif()

# ── Tests (always) ────────────────────────────────────────────────────────────
add_subdirectory(tests)