cmake_minimum_required(VERSION 3.14)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

project(essim
  LANGUAGES CXX
  VERSION 0.1
  DESCRIPTION "System digital twin."
)

include(FetchContent)

# Shared CMake helpers (essim_add_frontend — per-frontend target boilerplate).
list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
include(EssimFrontend)

# ----------------------------------------------------------------- core deps
# libbsdl — standalone BSDL parser (LGPL-2.1), dynamically linked (EUPL-1.2,
# which the LGPL permits). Override its path with -DBSDL_DIR=...
set(BSDL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../libbsdl" CACHE PATH "libbsdl source tree")
set(BSDL_BUILD_CLI   OFF CACHE BOOL "" FORCE)
set(BSDL_BUILD_TESTS OFF CACHE BOOL "" FORCE)
add_subdirectory(${BSDL_DIR} ${CMAKE_BINARY_DIR}/libbsdl)

find_package(libzip REQUIRED)
find_package(pugixml REQUIRED)

# =============================================================== essim_core
# All business logic — domain model, importers, application operations
# (src/core/{domain,imports,app}). Frontend-agnostic: it links NO GUI/TUI
# toolkit, so every frontend and the test suite share the exact same core.
file(GLOB_RECURSE CORE_SOURCES "src/core/*.cpp")
add_library(essim_core STATIC ${CORE_SOURCES})
target_include_directories(essim_core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/src)
target_link_libraries(essim_core
  PUBLIC
    libzip::zip
    pugixml::pugixml
    bsdl::bsdl
)

# =============================================================== frontend(s)
# Pick the GUI/TUI frontend to build the `essim` binary against. Each frontend
# is a self-contained src/frontends/<name>/ (own CMakeLists, GUI toolkit, and
# main.cpp) that links essim_core. "none" builds the core + tests only — no GUI
# toolkit is fetched. To add a frontend (e.g. a Qt GUI), create
# src/frontends/gui/ and configure with -DESSIM_FRONTEND=gui.
set(ESSIM_FRONTEND "tui" CACHE STRING
    "Frontend to build: a directory name under src/frontends/, or 'none'")
set_property(CACHE ESSIM_FRONTEND PROPERTY STRINGS tui wx none)

if(ESSIM_FRONTEND STREQUAL "none")
  message(STATUS "essim: ESSIM_FRONTEND=none — core + tests only (no frontend, no GUI toolkit)")
elseif(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/src/frontends/${ESSIM_FRONTEND}/CMakeLists.txt")
  message(STATUS "essim: building frontend '${ESSIM_FRONTEND}'")
  # Shared, GUI-toolkit-free frontend support: the abstract Frontend interface
  # (header-only) and the frontend-agnostic launcher frontend_main(). Every
  # frontend's main() links this and forwards argv to it.
  add_library(essim_frontend STATIC
    "${CMAKE_CURRENT_SOURCE_DIR}/src/frontends/frontend_main.cpp")
  target_include_directories(essim_frontend PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/src)
  add_subdirectory(src/frontends/${ESSIM_FRONTEND})
else()
  message(FATAL_ERROR
    "Unknown ESSIM_FRONTEND '${ESSIM_FRONTEND}' — expected "
    "src/frontends/${ESSIM_FRONTEND}/CMakeLists.txt, or 'none'.")
endif()

# =============================================================== tests (core)
# The suite exercises essim_core only — no frontend, no GUI toolkit.
include(CTest)
if(BUILD_TESTING)
  set(CMAKE_POLICY_VERSION_MINIMUM 3.5)
  FetchContent_Declare(doctest
    GIT_REPOSITORY https://github.com/doctest/doctest.git
    GIT_TAG v2.4.11
    GIT_SHALLOW TRUE
  )
  FetchContent_MakeAvailable(doctest)
  unset(CMAKE_POLICY_VERSION_MINIMUM)

  # Core tests — exercise essim_core only (tests/*.cpp, non-recursive, so the
  # per-frontend tests under tests/<frontend>/ are not pulled in here).
  file(GLOB TEST_SOURCES "tests/*.cpp")
  if(TEST_SOURCES)
    add_executable(essim_tests ${TEST_SOURCES})
    target_link_libraries(essim_tests PRIVATE essim_core doctest::doctest)
    add_test(NAME essim_tests COMMAND essim_tests)
  endif()

  # Per-frontend tests — tests/<frontend>/*.cpp, built and linked against that
  # frontend's library only when the frontend itself is built.
  if(TARGET essim_tui)
    file(GLOB TUI_TEST_SOURCES "tests/tui/*.cpp")
    if(TUI_TEST_SOURCES)
      add_executable(essim_tui_tests
        "${CMAKE_CURRENT_SOURCE_DIR}/tests/doctest_main.cpp" ${TUI_TEST_SOURCES})
      target_link_libraries(essim_tui_tests PRIVATE essim_tui doctest::doctest)
      add_test(NAME essim_tui_tests COMMAND essim_tui_tests)
    endif()
  endif()
endif()

# =============================================================== documentation
# Doxygen → XML → gen_api_md.py → doc/api/, plus `essim --commands-md`. Needs the
# `essim` binary, so it's only wired when a frontend that provides one is built.
find_package(Doxygen COMPONENTS doxygen)
find_package(Python3 COMPONENTS Interpreter)

if(TARGET essim AND DOXYGEN_FOUND AND Python3_Interpreter_FOUND)
  set(DOXYGEN_OUTPUT_DIR "${CMAKE_BINARY_DIR}/doc")
  file(MAKE_DIRECTORY "${DOXYGEN_OUTPUT_DIR}")
  configure_file(
    "${CMAKE_SOURCE_DIR}/doc/Doxyfile.in"
    "${DOXYGEN_OUTPUT_DIR}/Doxyfile"
    @ONLY)

  set(DOC_API_DIR "${CMAKE_SOURCE_DIR}/doc/api")
  set(DOC_USER_DIR "${CMAKE_SOURCE_DIR}/doc/user")
  add_custom_target(doc
    DEPENDS essim
    COMMAND ${CMAKE_COMMAND} -E rm -rf "${DOC_API_DIR}"
    COMMAND ${CMAKE_COMMAND} -E make_directory "${DOC_API_DIR}/classes"
    COMMAND ${CMAKE_COMMAND} -E make_directory "${DOC_API_DIR}/files"
    COMMAND ${CMAKE_COMMAND} -E make_directory "${DOC_USER_DIR}"
    COMMAND ${DOXYGEN_EXECUTABLE} "${DOXYGEN_OUTPUT_DIR}/Doxyfile"
    COMMAND ${Python3_EXECUTABLE}
            "${CMAKE_SOURCE_DIR}/doc/gen_api_md.py"
            "${DOXYGEN_OUTPUT_DIR}/xml"
            "${DOC_API_DIR}"
    COMMAND $<TARGET_FILE:essim> --commands-md "${DOC_USER_DIR}/commands.md"
    WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
    COMMENT "Generating documentation (doxygen → gen_api_md.py → doc/api/, essim --commands-md → doc/user/commands.md)"
    VERBATIM)
elseif(NOT TARGET essim)
  message(STATUS "doc: no `essim` binary (ESSIM_FRONTEND=none) — `doc` target disabled.")
elseif(NOT DOXYGEN_FOUND)
  message(STATUS "doc: Doxygen not found — `doc` target disabled.")
else()
  message(STATUS "doc: Python 3 interpreter not found — `doc` target disabled.")
endif()