# For target_compile_features
cmake_minimum_required(VERSION 3.1.0 FATAL_ERROR)
project(platform_folders VERSION 3.2.0 LANGUAGES CXX)

# Since it's off, the library will be static by default
option(BUILD_SHARED_LIBS "Build shared instead of static." OFF)

add_library(platform_folders
	sago/platform_folders.cpp
)

# Defines standardized defaults for install paths
include(GNUInstallDirs)
# Where to search for the header while building
target_include_directories(platform_folders PUBLIC
	$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/sago>
	# Controls where #include <sago/platform_folders.h> starts to look from
	# So /usr/include/<sago/platform_folders.h>
	# or C:\Program Files\platform_folders\include\<sago/platform_folders.h>
	$<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
)

# Define the header as public for installation
set_target_properties(platform_folders PROPERTIES
	PUBLIC_HEADER "sago/platform_folders.h"
)

# cxx_std_11 requires v3.8
if(CMAKE_VERSION VERSION_LESS "3.8.0")
	# Use old method of forcing C++11
	set(CMAKE_CXX_STANDARD 11)
	set(CMAKE_CXX_STANDARD_REQUIRED true)
else()
	# Require (minimum) C++11 when using header
	# PRIVATE means only at compile time
	target_compile_features(platform_folders PUBLIC cxx_std_11)
endif()

# cxx_nullptr exists in v3.1
target_compile_features(platform_folders PRIVATE cxx_nullptr)

# Apple requires linking to CoreServices
# Check sys name instead of "APPLE" for cross-compilation
if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
	# Find the framework
	# ref: https://developer.apple.com/library/content/documentation/MacOSX/Conceptual/OSX_Technology_Overview/SystemFrameworks/SystemFrameworks.html
	find_library(_CoreServices_FRAMEWORK
		NAMES "CoreServices.framework" "CoreServices"
		PATH_SUFFIXES "CoreServices"
		PATHS "/System/Library/Frameworks"
	)
	# Make sure it was found
	if(NOT _CoreServices_FRAMEWORK)
		message(FATAL_ERROR "Could not find the CoreServices framework!")
	endif()
	# Link to the CoreServices framework. This also sets the correct linking options
	# "If the library file is in a Mac OSX framework, the Headers directory of the framework will also be processed as a usage requirement."
	target_link_libraries(platform_folders PRIVATE "${_CoreServices_FRAMEWORK}")
endif()

if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
	# You can pass these when calling Cmake, so don't override if the user does
	if(NOT _WIN32_WINNT AND NOT WINVER)
		target_compile_definitions(platform_folders PRIVATE
			_WIN32_WINNT=0x0601
			WINVER=0x0601
		)
	endif()
endif()


# Cmake's find_package search path is different based on the system
# See https://cmake.org/cmake/help/latest/command/find_package.html for the list
if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
	# Controls where the exports, config, and configversion files install to
	set(_PROJECT_INSTALL_CMAKE_DIR "${CMAKE_INSTALL_PREFIX}/cmake")
else()
	# When calling find_package(<name>)
	# it looks for /usr/lib/cmake/<name>/<name>Config.cmake
	set(_PROJECT_INSTALL_CMAKE_DIR "${CMAKE_INSTALL_LIBDIR}/cmake/platform_folders")
endif()

# Gives "Make install" esque operations a location to install to...
# and creates a .cmake file to be exported
install(TARGETS platform_folders
	EXPORT "platform_folders-targets"
	LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
	ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
	# Tells it where to put the header files
	PUBLIC_HEADER DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/sago"
)

# "The install(TARGETS) and install(EXPORT) commands work together to install a target and a file to help import it"
# Installs a cmake file which external projects can import.
install(EXPORT "platform_folders-targets"
	NAMESPACE sago::
	DESTINATION "${_PROJECT_INSTALL_CMAKE_DIR}"
)

# "The export command is used to generate a file exporting targets from a project build tree"
# Creates an import file for external projects which are aware of the build tree.
# May be useful for cross-compiling
export(TARGETS platform_folders
	FILE "platform_folders-exports.cmake"
)

# For the config and configversion macros
include(CMakePackageConfigHelpers)

configure_package_config_file("platform_foldersConfig.cmake.in"
	"${CMAKE_CURRENT_BINARY_DIR}/platform_foldersConfig.cmake"
	# Tells the config file where it will be installed, so it can be correctly imported
	INSTALL_DESTINATION "${_PROJECT_INSTALL_CMAKE_DIR}"
)

# Creates the project's ConfigVersion.cmake file
# This allows for find_package() to use a version in the call
write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/platform_foldersConfigVersion.cmake"
	# This'll require versioning in the project() call
	VERSION ${CMAKE_PROJECT_VERSION}
	# Just assuming Semver is followed
	COMPATIBILITY SameMajorVersion
)

# Install the ConfigVersion file, which is located in the build dir
install(FILES
		"${CMAKE_CURRENT_BINARY_DIR}/platform_foldersConfig.cmake"
		"${CMAKE_CURRENT_BINARY_DIR}/platform_foldersConfigVersion.cmake"
	DESTINATION "${_PROJECT_INSTALL_CMAKE_DIR}"
)

# A module for testing the library
include(CTest)
# BUILD_TESTING is defined (default ON) in CTest
if(BUILD_TESTING)
	add_subdirectory(test)
	add_executable(platform_folders_sample platform_folders.cpp)
	target_link_libraries(platform_folders_sample PRIVATE platform_folders)
endif()