# give info about target
SET(CMAKE_SYSTEM_NAME Generic)
SET(CMAKE_SYSTEM_PROCESSOR avr)

# find tools
find_program(AVR_CC avr-gcc)
find_program(AVR_CXX avr-g++)
find_program(AVR_OBJCOPY avr-objcopy)
find_program(AVR_OBJDUMP avr-objdump)
find_program(AVR_SIZE_TOOL avr-size)

# set compiler (globally)
SET(CMAKE_C_COMPILER ${AVR_CC})
SET(CMAKE_CXX_COMPILER ${AVR_CXX})
SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS)


if(NOT AVR_UPLOADTOOL)
    set(
            AVR_UPLOADTOOL avrdude
            CACHE STRING "Set default upload tool: avrdude"
    )
    find_program(AVR_UPLOADTOOL avrdude)
endif(NOT AVR_UPLOADTOOL)

# default upload tool port
if(NOT AVR_UPLOADTOOL_PORT)
    set(
            AVR_UPLOADTOOL_PORT usb
            CACHE STRING "Set default upload tool port: usb"
    )
endif(NOT AVR_UPLOADTOOL_PORT)

# default programmer (hardware)
if(NOT AVR_PROGRAMMER)
    set(
            AVR_PROGRAMMER atmelice_isp
            CACHE STRING "Set default programmer hardware model: avrispmkII"
    )
endif(NOT AVR_PROGRAMMER)

# prepare base flags for upload tool
set(AVR_UPLOADTOOL_BASE_OPTIONS -p ${AVR_MCU} -c ${AVR_PROGRAMMER} -B5)

add_definitions(-mmcu=${AVR_MCU} -D__${AVR_MCU}__ -DF_CPU=8000000 --std=c99)

function(add_avr_executable EXECUTABLE_NAME)

   if(NOT ARGN)
      message(FATAL_ERROR "No source files given for ${EXECUTABLE_NAME}.")
   endif(NOT ARGN)

   # set file names
   set(elf_file ${EXECUTABLE_NAME})
   set(hex_file ${EXECUTABLE_NAME}.hex)
   set(lst_file ${EXECUTABLE_NAME}.lst)
   set(map_file ${EXECUTABLE_NAME}.map)
   set(eeprom_image ${EXECUTABLE_NAME}_eeprom.hex)

   # elf file
   add_executable(${elf_file} EXCLUDE_FROM_ALL ${ARGN})

   set_target_properties(
      ${elf_file}
      PROPERTIES
         COMPILE_FLAGS "-mmcu=${AVR_MCU}"
         LINK_FLAGS "-mmcu=${AVR_MCU} -Wl,--gc-sections -mrelax -Wl,-Map,${map_file}"
   )

   add_custom_command(
      OUTPUT ${hex_file}
      COMMAND
         ${AVR_OBJCOPY} -j .text -j .data -O ihex ${elf_file} ${hex_file}
      COMMAND
         ${AVR_SIZE_TOOL} ${AVR_SIZE_ARGS} ${elf_file}
      DEPENDS ${elf_file}
   )

   add_custom_command(
      OUTPUT ${lst_file}
      COMMAND
         ${AVR_OBJDUMP} -d ${elf_file} > ${lst_file}
      DEPENDS ${elf_file}
   )

   # eeprom
   add_custom_command(
      OUTPUT ${eeprom_image}
      COMMAND
         ${AVR_OBJCOPY} -j .eeprom --set-section-flags=.eeprom=alloc,load
            --change-section-lma .eeprom=0 --no-change-warnings
            -O ihex ${elf_file} ${eeprom_image}
      DEPENDS ${elf_file}
   )

   add_custom_target(
      build_${EXECUTABLE_NAME}
      ALL
      DEPENDS ${hex_file} ${lst_file} ${eeprom_image}
   )

   set_target_properties(
      build_${EXECUTABLE_NAME}
      PROPERTIES
         OUTPUT_NAME "${elf_file}"
   )

   # upload - with avrdude
   add_custom_target(
      upload_${EXECUTABLE_NAME}
      ${AVR_UPLOADTOOL} ${AVR_UPLOADTOOL_BASE_OPTIONS} ${AVR_UPLOADTOOL_OPTIONS}
         -U flash:w:${hex_file}
         -P ${AVR_UPLOADTOOL_PORT}
      DEPENDS ${hex_file}
      COMMENT "Uploading ${hex_file} to ${AVR_MCU} using ${AVR_PROGRAMMER}"
   )

   # clean
   get_directory_property(clean_files ADDITIONAL_MAKE_CLEAN_FILES)
   set_directory_properties(
      PROPERTIES
         ADDITIONAL_MAKE_CLEAN_FILES "${map_file}"
   )
endfunction(add_avr_executable)