cmake_minimum_required(VERSION 3.28)

project(fantemp LANGUAGES CXX)

# libavr rides as the pinned submodule; LIBAVR_ROOT (cache or environment)
# overrides it for tandem development against a working tree. The toolchain
# file comes from the submodule via CMakePresets.json either way.
if(NOT LIBAVR_ROOT AND DEFINED ENV{LIBAVR_ROOT})
	set(LIBAVR_ROOT $ENV{LIBAVR_ROOT})
endif()
if(NOT LIBAVR_ROOT)
	set(LIBAVR_ROOT ${CMAKE_CURRENT_SOURCE_DIR}/libavr)
endif()
if(NOT EXISTS ${LIBAVR_ROOT}/CMakeLists.txt)
	message(FATAL_ERROR "libavr not found at ${LIBAVR_ROOT} - run: git submodule update --init libavr")
endif()
# pureboot rides as a pinned submodule too: this board's only way in is its
# resident loader, so the commit that names this firmware names the loader it
# has to hand over to. Consumed for the geometry it exports - the loader links
# the libavr target above, so pureboot's own libavr submodule stays
# uninitialised.
if(NOT EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/pureboot/CMakeLists.txt)
	message(FATAL_ERROR "pureboot not found - run: git submodule update --init pureboot")
endif()
add_subdirectory(${LIBAVR_ROOT} libavr-build)
add_subdirectory(pureboot pureboot-build)
include(${LIBAVR_ROOT}/cmake/checks.cmake)

add_executable(fantemp src/main.cpp)
target_link_libraries(fantemp PRIVATE libavr)
# The raw image is what the loader takes, and what the reachability check
# measures the boot-section clearance against.
add_custom_command(TARGET fantemp POST_BUILD
                   COMMAND ${CMAKE_SIZE} $<TARGET_FILE:fantemp>
                   COMMAND ${CMAKE_OBJCOPY} -O binary -R .eeprom
                           $<TARGET_FILE:fantemp> $<TARGET_FILE_DIR:fantemp>/fantemp.bin
                   COMMAND ${CMAKE_OBJCOPY} -O ihex -R .eeprom
                           $<TARGET_FILE:fantemp> $<TARGET_FILE_DIR:fantemp>/fantemp.hex)

# The board's loader, built here rather than named from memory: consuming
# pureboot for its geometry alone left the one image this deployment cannot be
# recovered without outside the repository that pins it. Every parameter is
# pureboot's own default for this chip - USART0 at 115200 on the 16 MHz crystal
# `src/board.hpp` declares - and that is measured rather than assumed, the
# image being byte-for-byte the 386 B the board's slot reads back. It goes on
# over the wire (`--update-loader`), which is why there is no flash target
# beside it: no programmer has ever been in this board's path.
pureboot_add_loader(pureboot)

enable_testing()
add_subdirectory(test)