-- Copyright (C) 1997-2016 Sam Lantinga <slouken@libsdl.org>

--

-- This software is provided 'as-is', without any express or implied

-- warranty.  In no event will the authors be held liable for any damages

-- arising from the use of this software.

--

-- Permission is granted to anyone to use this software for any purpose,

-- including commercial applications, and to alter it and redistribute it

-- freely.

--

-- Meta-build system using premake created and maintained by

-- Benjamin Henning <b.henning@digipen.edu>

--[[

sdl_dependency_checkers.lua

	This script contains a bunch of functions which determine whether certain

	dependencies exist on the current platform. These functions are able to use

	any and all available utilities for trying to determine both whether the

	dependency is available on this platform, and how to build to the dependency.

	There are a few limitations with these functions, but many of the limitations

	can be mitigated by using the dependency definition functions in the project

	definition files.

	Each function in this file, in order to be a valid dependency function, must

	return a table with the following entries:

	'found' = boolean value indicating whether the dependency was found

	'incDirs' = table of include directory strings, or nil if none are needed

	'libDirs' = table of library directory strings, or nil if none are needed

	'libs' = table of libraries to link to, or nil if none are needed

	All functions must be properly registered with the project definition system

	in order to be properly referenced by projects.

]]

-- dependency functions must return the following:

-- table with an element found, incDirs, libDirs, and libs

function openGLDep()

	print("Checking OpenGL dependencies...")

	if SDL_getos() == "macosx" then

		-- mac should always have support for OpenGL...

		return { found = true, libs = { "OpenGL.framework" } }

	elseif SDL_getos() == "ios" then

		--...unless on iOS

		print("Desktop OpenGL is not supported on iOS targets.")

		return { found = false, libs = { "OpenGL.framework" } }

	elseif SDL_getos() == "cygwin" then

		print("OpenGL is not currently supported on Cygwin.")

		return { found = false, libDirs = { }, libs = { "OpenGL32" } }

	end

	local libpath = nil

  local libname = nil

	if SDL_getos() == "windows" or SDL_getos() == "mingw" then

		libpath = os.findlib("OpenGL32")

		libname = "OpenGL32"

	else -- *nix

		libpath = os.findlib("libGL")

		libname = "GL"

	end

	local foundLib = libpath ~= nil

	-- another way to possibly find the dependency on windows

	--if not foundLib then

	--	foundLib, libpath = find_dependency_dir_windows(nil, "C:/Program Files (x86);C:/Program Files", "Microsoft SDKs", "Lib")

	--end

	if not foundLib then return { found = false } end

	if SDL_getos() == "mingw" then

		libpath = libpath:gsub("\\", "/"):gsub("//", "/")

	end

	return { found = foundLib, libDirs = { }, libs = { libname } }

end

function directXDep()

	print("Checking DirectX dependencies...")

	-- enable this for more correct searching, but it's much slower

	local searchPath = nil --os.getenvpath("ProgramFiles", "ProgramFiles(x86)")

	local foundInc, incpath = find_dependency_dir_windows("DXSDK_DIR", searchPath, "DirectX", "Include")

	local foundLib, libpath = find_dependency_dir_windows("DXSDK_DIR", searchPath, "DirectX", "Lib/x86")

	if not foundInc or not foundLib then return { found = false } end

	-- XXX: hacked mingw check...

	if foundInc and SDL_getos() == "mingw" then

		incpath = incpath:gsub("%$%(DXSDK_DIR%)", os.getenv("DXSDK_DIR")):gsub("\\", "/"):gsub("//", "/")

		libpath = libpath:gsub("%$%(DXSDK_DIR%)", os.getenv("DXSDK_DIR")):gsub("\\", "/"):gsub("//", "/")

	end

	if SDL_getos() == "mingw" then

		print("DirectX is not currently supported on MinGW targets.")

		return { found = false, incDirs = { incpath }, libDirs = { libpath } }

	end

	if SDL_getos() == "cygwin" then

		print("DirectX is not currently supported on Cygwin targets.")

		return { found = false, incDirs = { incpath }, libDirs = { libpath } }

	end

	return { found = true, incDirs = { incpath }, libDirs = { libpath } }

end

function dbusDep()

	print("Checking for D-Bus support...")

	if not check_include_directories("/usr/include/dbus-1.0", "/usr/lib/x86_64-linux-gnu/dbus-1.0/include") then

		print("Warning: D-Bus unsupported!")

		return { found = false }

	end

	return { found = true, incDirs = { "/usr/include/dbus-1.0", "/usr/lib/x86_64-linux-gnu/dbus-1.0/include" } }

end

function alsaDep()

	print("Checking for ALSA support...")

	if not check_include_files("alsa/asoundlib.h")

			or os.findlib("asound") == nil

			or not check_library_exists_lookup("asound", "snd_pcm_open", "alsa/asoundlib.h")

			or not SDL_assertdepfunc("DLOpen") then

		print("Warning: ALSA unsupported!")

		return { found = false }

	end

	return { found = true }

end

function pulseAudioDep()

	print("Checking for PulseAudio support...")

	if os.findlib("libpulse-simple") == nil

			or not SDL_assertdepfunc("DLOpen") then

		print("Warning: PulseAudio unsupported!")

		return { found = false }

	end

	return { found = true }

end

function esdDep()

	print("Checking for ESD support...")

	if os.findlib("esd") == nil

			or not SDL_assertdepfunc("DLOpen") then

		print("Warning: ESD unsupported!")

		return { found = false }

	end

	return { found = true }

end

function nasDep()

	print("Checking for NAS support...")

	if not check_include_file("audio/audiolib.h")

			or not SDL_assertdepfunc("DLOpen") then

		print("Warning: NAS unsupported!")

		return { found = false }

	end

	return { found = true }

end

function ossDep()

	print("Checking for OSS support...")

	if not check_cxx_source_compiles([[

				#include <sys/soundcard.h>

				int main() { int arg = SNDCTL_DSP_SETFRAGMENT; return 0; }]])

			and not check_cxx_source_compiles([[

				#include <soundcard.h>

				int main() { int arg = SNDCTL_DSP_SETFRAGMENT; return 0; }]]) then

		print("Warning: OSS unsupported!")

		return { found = false }

	end

	return { found = true }

end

function dlOpenDep()

	print("Checking for DLOpen support...")

	if not check_library_exists_multiple("dlopen", "dlfcn.h", "dl", "tdl") then

		print("Warning: DLOpen unsupported!")

		return { found = false }

	end

	return { found = true, libs = { "dl" } }

end

function x11Dep()

	print("Checking for X11 support...")

	for _, v in ipairs { "X11", "Xext", "Xcursor", "Xinerama", "Xi", "Xrandr", "Xrender", "Xss", "Xxf86vm" } do

		if os.findlib(v) == nil then

			print("Warning: X11 unsupported!")

			return { found = false }

		end

	end

	if not check_include_files("X11/Xcursor/Xcursor.h", "X11/extensions/Xinerama.h",

			"X11/extensions/XInput2.h", "X11/extensions/Xrandr.h", "X11/extensions/Xrender.h",

			"X11/extensions/scrnsaver.h", "X11/extensions/shape.h", "X11/Xlib.h",

			"X11/extensions/xf86vmode.h") then

		print("Warning: X11 unsupported!")

		return { found = false }

	end

	if not SDL_assertdepfunc("DLOpen") then

		print("Warning: X11 unsupported!")

		return { found = false }

	end

	-- XXX: shared memory check...

	-- there's a LOT more to check to properly configure X11...

	return { found = true, libs = { "X11" } }

end

-- register all of these dependency functions with the definition system

SDL_registerDependencyChecker("OpenGL", openGLDep)

SDL_registerDependencyChecker("DirectX", directXDep)

SDL_registerDependencyChecker("DBus", dbusDep)

SDL_registerDependencyChecker("ALSA", alsaDep)

SDL_registerDependencyChecker("PulseAudio", pulseAudioDep)

SDL_registerDependencyChecker("ESD", esdDep)

SDL_registerDependencyChecker("NAS", nasDep)

SDL_registerDependencyChecker("OSS", ossDep)

SDL_registerDependencyChecker("DLOpen", dlOpenDep)

SDL_registerDependencyChecker("X11", x11Dep)