# set_default
#
# Define a variable to a default value if otherwise unset.
#
# Priority for new value is:
# - Existing cmake value (ie set with cmake -D, or already set in CMakeLists)
# - Value of any non-empty environment variable of the same name
# - Default value as provided to function
#
function(set_default variable default_value)
    if(NOT ${variable})
        if($ENV{${variable}})
            set(${variable} $ENV{${variable}} PARENT_SCOPE)
        else()
            set(${variable} ${default_value} PARENT_SCOPE)
        endif()
    endif()
endfunction()

# spaces2list
#
# Take a variable whose value was space-delimited values, convert to a cmake
# list (semicolon-delimited)
#
# Note: if using this for directories, keeps the issue in place that
# directories can't contain spaces...
#
# TODO: look at cmake separate_arguments, which is quote-aware
function(spaces2list variable_name)
    string(REPLACE " " ";" tmp "${${variable_name}}")
    set("${variable_name}" "${tmp}" PARENT_SCOPE)
endfunction()


# lines2list
#
# Take a variable with multiple lines of output in it, convert it
# to a cmake list (semicolon-delimited), one line per item
#
function(lines2list variable_name)
    string(REGEX REPLACE "\r?\n" ";" tmp "${${variable_name}}")
    string(REGEX REPLACE ";;" ";" tmp "${tmp}")
    set("${variable_name}" "${tmp}" PARENT_SCOPE)
endfunction()


# move_if_different
#
# If 'source' has different md5sum to 'destination' (or destination
# does not exist, move it across.
#
# If 'source' has the same md5sum as 'destination', delete 'source'.
#
# Avoids timestamp updates for re-generated files where content hasn't
# changed.
function(move_if_different source destination)
    set(do_copy 1)
    file(GLOB dest_exists ${destination})
    if(dest_exists)
        file(MD5 ${source} source_md5)
        file(MD5 ${destination} dest_md5)
        if(source_md5 STREQUAL dest_md5)
            set(do_copy "")
        endif()
    endif()

    if(do_copy)
        message("Moving ${source} -> ${destination}")
        file(RENAME ${source} ${destination})
    else()
        message("Not moving ${source} -> ${destination}")
        file(REMOVE ${source})
    endif()

endfunction()


# add_compile_options variant for C++ code only
#
# This adds global options, set target properties for
# component-specific flags
function(add_cxx_compile_options)
    foreach(option ${ARGV})
        # note: the Visual Studio Generator doesn't support this...
        add_compile_options($<$<COMPILE_LANGUAGE:CXX>:${option}>)
    endforeach()
endfunction()

# add_compile_options variant for C code only
#
# This adds global options, set target properties for
# component-specific flags
function(add_c_compile_options)
    foreach(option ${ARGV})
        # note: the Visual Studio Generator doesn't support this...
        add_compile_options($<$<COMPILE_LANGUAGE:C>:${option}>)
    endforeach()
endfunction()


# target_add_binary_data adds binary data into the built target,
# by converting it to a generated source file which is then compiled
# to a binary object as part of the build
function(target_add_binary_data target embed_file embed_type)

    get_filename_component(embed_file "${embed_file}" ABSOLUTE)

    get_filename_component(name "${embed_file}" NAME)
    set(embed_srcfile "${CMAKE_BINARY_DIR}/${name}.c")

    add_custom_command(OUTPUT "${embed_srcfile}"
        COMMAND "${CMAKE_COMMAND}"
        -D "DATA_FILE=${embed_file}"
        -D "SOURCE_FILE=${embed_srcfile}"
        -D "FILE_TYPE=${embed_type}"
        -P "${IDF_PATH}/tools/cmake/scripts/data_file_to_c.cmake"
        MAIN_DEPENDENCY "${embed_file}"
        WORKING_DIRECTORY "${CMAKE_BINARY_DIR}")

    set_property(DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES "${embed_srcfile}")

    target_sources("${target}" PRIVATE "${embed_srcfile}")
endfunction()

macro(include_if_exists path)
    if(EXISTS "${path}")
        include("${path}")
    endif()
endmacro()

# Append a single line to the file specified
# The line ending is determined by the host OS
function(file_append_line file line)
    if(ENV{MSYSTEM} OR CMAKE_HOST_WIN32)
        set(line_ending "\r\n")
    else() # unix
        set(line_ending "\n")
    endif()
    file(READ ${file} existing)
    string(FIND ${existing} ${line_ending} last_newline REVERSE)
    string(LENGTH ${existing} length)
    math(EXPR length "${length}-1")
    if(NOT length EQUAL last_newline) # file doesn't end with a newline
        file(APPEND "${file}" "${line_ending}")
    endif()
    file(APPEND "${file}" "${line}${line_ending}")
endfunction()