# Copyright (c) 2024 Intel Corporation
# SPDX-License-Identifier: Apache-2.0

# This script generates a tarball containing all headers and flags necessary to
# build an llext extension. It does so by copying all headers accessible from
# INTERFACE_INCLUDE_DIRECTORIES and generating a Makefile.cflags file (and a
# cmake.cflags one) with all flags necessary to build the extension.
#
# The tarball can be extracted and used in the extension build system to include
# all necessary headers and flags. File paths are made relative to a few key
# directories (build/zephyr, zephyr base, west top dir and application source
# dir), to avoid leaking any information about the host system.
#
# The script expects a build_info.yml file in the project binary directory.
# This file should contain the following entries:
#  - cmake application source-dir
#  - cmake board name
#  - cmake board qualifiers
#  - cmake board revision
#  - cmake llext-edk cflags
#  - cmake llext-edk file
#  - cmake llext-edk include-dirs
#  - west topdir

cmake_minimum_required(VERSION 3.20.0)

# initialize the same paths as the main CMakeLists.txt for consistency
set(PROJECT_BINARY_DIR ${CMAKE_BINARY_DIR})
set(ZEPHYR_BASE ${CMAKE_CURRENT_LIST_DIR}/../)
list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/modules")

include(extensions)
include(yaml)

# Usage:
#   relative_dir(<dir> <relative_out> <bindir_out>)
#
# Helper function to generate relative paths to a few key directories
# (PROJECT_BINARY_DIR, ZEPHYR_BASE, WEST_TOPDIR and APPLICATION_SOURCE_DIR).
# The generated path is relative to the key directory, and the bindir_out
# output variable is set to TRUE if the path is relative to PROJECT_BINARY_DIR.
#
function(relative_dir dir relative_out bindir_out)
    cmake_path(IS_PREFIX PROJECT_BINARY_DIR ${dir} NORMALIZE to_prj_bindir)
    cmake_path(IS_PREFIX ZEPHYR_BASE ${dir} NORMALIZE to_zephyr_base)
    if("${WEST_TOPDIR}" STREQUAL "")
        set(to_west_topdir FALSE)
    else()
        cmake_path(IS_PREFIX WEST_TOPDIR ${dir} NORMALIZE to_west_topdir)
    endif()
    cmake_path(IS_PREFIX APPLICATION_SOURCE_DIR ${dir} NORMALIZE to_app_srcdir)

    # Overall idea is to place included files in the destination dir based on the source:
    # files coming from build/zephyr/generated will end up at
    # <install-dir>/include/zephyr/include/generated, files coming from zephyr base at
    # <install-dir>/include/zephyr/include, files from west top dir (for instance, hal modules),
    # at <install-dir>/include and application ones at <install-dir>/include/<application-dir>.
    # Finally, everything else (such as external libs not at any of those places) will end up
    # at <install-dir>/include/<full-path-to-external-include>, so we avoid any external lib
    # stepping at any other lib toes.
    if(to_prj_bindir)
        cmake_path(RELATIVE_PATH dir BASE_DIRECTORY ${PROJECT_BINARY_DIR} OUTPUT_VARIABLE dir_tmp)
        set(dest ${llext_edk_inc}/zephyr/${dir_tmp})
    elseif(to_zephyr_base)
        cmake_path(RELATIVE_PATH dir BASE_DIRECTORY ${ZEPHYR_BASE} OUTPUT_VARIABLE dir_tmp)
        set(dest ${llext_edk_inc}/zephyr/${dir_tmp})
    elseif(to_west_topdir)
        cmake_path(RELATIVE_PATH dir BASE_DIRECTORY ${WEST_TOPDIR} OUTPUT_VARIABLE dir_tmp)
        set(dest ${llext_edk_inc}/${dir_tmp})
    elseif(to_app_srcdir)
        cmake_path(GET APPLICATION_SOURCE_DIR FILENAME app_dir)
        cmake_path(RELATIVE_PATH dir BASE_DIRECTORY ${APPLICATION_SOURCE_DIR} OUTPUT_VARIABLE dir_tmp)
        set(dest ${llext_edk_inc}/${app_dir}/${dir_tmp})
    else()
        set(dest ${llext_edk_inc}/${dir})
    endif()

    set(${relative_out} ${dest} PARENT_SCOPE)
    if(to_prj_bindir)
        set(${bindir_out} TRUE PARENT_SCOPE)
    else()
        set(${bindir_out} FALSE PARENT_SCOPE)
    endif()
endfunction()

# Usage:
#   edk_escape(<target> <str_in> <str_out>)
#
# Escape problematic characters in the string <str_in> and store the result in
# <str_out>. The escaping is done to make the string suitable for <target>.
function(edk_escape target str_in str_out)
    string(REPLACE "\\" "\\\\" str_escaped "${str_in}")
    string(REPLACE "\"" "\\\"" str_escaped "${str_escaped}")
    set(${str_out} "${str_escaped}" PARENT_SCOPE)
endfunction()

# Usage:
#   edk_write_header(<target>)
#
# Initialize the file associated with <target> and write its header.
function(edk_write_header target)
    file(WRITE ${edk_file_${target}} "")
endfunction()

# Usage:
#   edk_write_comment(<target> <text>)
#
# Write to the file associated with <target> the string <text> as a comment.
function(edk_write_comment target text)
    file(APPEND ${edk_file_${target}} "\n# ${text}\n")
endfunction()

# Usage:
#   edk_write_var(<target> <var_name> <var_value>)
#
# Write to the file associated with <target> an entry where <var_name> is
# assigned the value <var_value>.
function(edk_write_var target var_name var_value)
    if(target STREQUAL "CMAKE")
        # CMake: export assignments of the form:
        #
        #   set(var "value1;value2;...")
        #
        set(DASHIMACROS "-imacros\${CMAKE_CURRENT_LIST_DIR}/")
        set(DASHI "-I\${CMAKE_CURRENT_LIST_DIR}/")
        edk_escape(${target} "${var_value}" var_value)
        string(CONFIGURE "${var_value}" exp_var_value @ONLY)
        # The list is otherwise exported verbatim, surrounded by quotes.
        file(APPEND ${edk_file_${target}} "set(${var_name} \"${exp_var_value}\")\n")
    elseif(target STREQUAL "MAKEFILE")
        # Makefile: export assignments of the form:
        #
        #   var = "value1" "value2" ...
        #
        set(DASHIMACROS "-imacros\$(${install_dir_var})/")
        set(DASHI "-I\$(${install_dir_var})/")
        edk_escape(${target} "${var_value}" var_value)
        string(CONFIGURE "${var_value}" exp_var_value @ONLY)
        # Each element of the list is wrapped in quotes and is separated by a space.
        list(JOIN exp_var_value "\" \"" exp_var_value_str)
        file(APPEND ${edk_file_${target}} "${var_name} = \"${exp_var_value_str}\"\n")
    endif()
endfunction()


# read in computed build configuration
import_kconfig(CONFIG ${PROJECT_BINARY_DIR}/.config)

if (CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID)
  message(FATAL_ERROR
    "The LLEXT EDK is not compatible with CONFIG_LLEXT_EXPORT_BUILTINS_BY_SLID.")
endif()

set(build_info_file ${PROJECT_BINARY_DIR}/../build_info.yml)
yaml_load(FILE ${build_info_file} NAME build_info)

yaml_get(llext_edk_cflags NAME build_info KEY cmake llext-edk cflags)
yaml_get(llext_edk_file NAME build_info KEY cmake llext-edk file)
yaml_get(INTERFACE_INCLUDE_DIRECTORIES NAME build_info KEY cmake llext-edk include-dirs)
yaml_get(APPLICATION_SOURCE_DIR NAME build_info KEY cmake application source-dir)
yaml_get(WEST_TOPDIR NAME build_info KEY west topdir)

yaml_get(board_name NAME build_info KEY cmake board name)
yaml_get(board_qualifiers NAME build_info KEY cmake board qualifiers)
yaml_get(board_revision NAME build_info KEY cmake board revision)
zephyr_build_string(normalized_board_target
    BOARD ${board_name}
    BOARD_QUALIFIERS ${board_qualifiers})

set(llext_edk_name ${CONFIG_LLEXT_EDK_NAME})
set(llext_edk ${PROJECT_BINARY_DIR}/${llext_edk_name})
set(llext_edk_inc ${llext_edk}/include)

zephyr_string(SANITIZE TOUPPER var_prefix ${llext_edk_name})
set(install_dir_var "${var_prefix}_INSTALL_DIR")

set(make_relative FALSE)
foreach(flag ${llext_edk_cflags})
    # Detect all combinations of 'imacros' flag:
    # - with one or two preceding dashes
    # - separated from the argument, joined by '=', or joined (no separator)
    if(flag MATCHES "^--?imacros$")
        # imacros followed by a space, convert next argument
        set(make_relative TRUE)
        continue()
    elseif(flag MATCHES "^--?imacros=?([^=].*)$")
        # imacros=<stuff> or imacros<stuff>, immediately convert <stuff>
        set(flag ${CMAKE_MATCH_1})
        set(make_relative TRUE)
    endif()

    if(make_relative)
        set(make_relative FALSE)
        cmake_path(GET flag PARENT_PATH parent)
        cmake_path(GET flag FILENAME name)
        relative_dir(${parent} dest bindir)
        cmake_path(RELATIVE_PATH dest BASE_DIRECTORY ${llext_edk} OUTPUT_VARIABLE dest_rel)
        if(bindir)
            list(APPEND imacros_gen "@DASHIMACROS@${dest_rel}/${name}")
        else()
            list(APPEND imacros "@DASHIMACROS@${dest_rel}/${name}")
        endif()
    else()
        list(APPEND new_cflags ${flag})
    endif()
endforeach()
set(llext_edk_cflags ${new_cflags})

list(APPEND base_flags ${llext_edk_cflags} ${imacros})

file(MAKE_DIRECTORY ${llext_edk_inc})
foreach(dir ${INTERFACE_INCLUDE_DIRECTORIES})
    if (NOT EXISTS ${dir})
        continue()
    endif()

    relative_dir(${dir} dest bindir)
    # Use destination parent, as the last part of the source directory is copied as well
    cmake_path(GET dest PARENT_PATH dest_p)

    file(MAKE_DIRECTORY ${dest_p})
    file(COPY ${dir} DESTINATION ${dest_p} FILES_MATCHING PATTERN "*.h")

    cmake_path(RELATIVE_PATH dest BASE_DIRECTORY ${llext_edk} OUTPUT_VARIABLE dest_rel)
    if(bindir)
        list(APPEND gen_inc_flags "@DASHI@${dest_rel}")
    else()
        list(APPEND inc_flags "@DASHI@${dest_rel}")
    endif()
    list(APPEND all_inc_flags "@DASHI@${dest_rel}")
endforeach()

list(APPEND all_flags ${base_flags} ${imacros_gen} ${all_inc_flags})

if(CONFIG_LLEXT_EDK_USERSPACE_ONLY)
    # Copy syscall headers from edk directory, as they were regenerated there.
    file(COPY ${PROJECT_BINARY_DIR}/edk/include/generated/ DESTINATION ${llext_edk_inc}/zephyr/include/generated)
endif()

#
# Generate the EDK flags files
#

set(edk_targets MAKEFILE CMAKE)
set(edk_file_MAKEFILE ${llext_edk}/Makefile.cflags)
set(edk_file_CMAKE ${llext_edk}/cmake.cflags)

foreach(target ${edk_targets})
    edk_write_header(${target})

    edk_write_comment(${target} "Target information")
    edk_write_var(${target} "${var_prefix}_BOARD_NAME" "${board_name}")
    edk_write_var(${target} "${var_prefix}_BOARD_QUALIFIERS" "${board_qualifiers}")
    edk_write_var(${target} "${var_prefix}_BOARD_REVISION" "${board_revision}")
    edk_write_var(${target} "${var_prefix}_BOARD_TARGET" "${normalized_board_target}")

    edk_write_comment(${target} "Compile flags")
    edk_write_var(${target} "LLEXT_CFLAGS" "${all_flags}")
    edk_write_var(${target} "LLEXT_ALL_INCLUDE_CFLAGS" "${all_inc_flags}")
    edk_write_var(${target} "LLEXT_INCLUDE_CFLAGS" "${inc_flags}")
    edk_write_var(${target} "LLEXT_GENERATED_INCLUDE_CFLAGS" "${gen_inc_flags}")
    edk_write_var(${target} "LLEXT_BASE_CFLAGS" "${base_flags}")
    edk_write_var(${target} "LLEXT_GENERATED_IMACROS_CFLAGS" "${imacros_gen}")
endforeach()

if(CONFIG_LLEXT_EDK_FORMAT_TAR_XZ)
  set(llext_edk_format FORMAT gnutar COMPRESSION XZ)
elseif(CONFIG_LLEXT_EDK_FORMAT_TAR_ZSTD)
  set(llext_edk_format FORMAT gnutar COMPRESSION Zstd)
elseif(CONFIG_LLEXT_EDK_FORMAT_ZIP)
  set(llext_edk_format FORMAT zip)
else()
  message(FATAL_ERROR "Unsupported LLEXT_EDK_FORMAT choice")
endif()

# Generate the tarball
file(ARCHIVE_CREATE
    OUTPUT ${llext_edk_file}
    PATHS ${llext_edk}
    ${llext_edk_format}
)

file(REMOVE_RECURSE ${llext_edk})