-- this file provides project_add_extern_libs, which takes care of the
-- dirty details of adding the libraries' include and lib paths.
--
-- TYPICAL TASK: add new library. Instructions:
-- 1) add a new extern_lib_defs entry
-- 2) add library name to extern_libs tables in premake.lua for all 'projects' that want to use it

-- directory in which OS-specific library subdirectories reside.
if os.istarget("macosx") then
	libraries_dir = rootdir.."/libraries/osx/"
elseif os.istarget("windows") then
	libraries_dir = rootdir.."/libraries/win32/"
else
	-- No Unix-specific libs yet (use source directory instead!)
end
-- directory for shared, bundled libraries
libraries_source_dir = rootdir.."/libraries/source/"
third_party_source_dir = rootdir.."/source/third_party/"

local function add_default_lib_paths(extern_lib)
	libdirs { libraries_dir .. extern_lib .. "/lib" }
end

local function add_source_lib_paths(extern_lib)
	libdirs { libraries_source_dir .. extern_lib .. "/lib" }
end

local function add_default_include_paths(extern_lib)
	sysincludedirs { libraries_dir .. extern_lib .. "/include" }
end

local function add_source_include_paths(extern_lib)
	sysincludedirs { libraries_source_dir .. extern_lib .. "/include" }
end

local function add_third_party_include_paths(extern_lib)
	sysincludedirs { third_party_source_dir .. extern_lib .. "/include" }
end

pkgconfig = require "pkgconfig"


local function add_delayload(name, suffix, def)

	if def["no_delayload"] then
		return
	end

	-- currently only supported by VC; nothing to do on other platforms.
	if not os.istarget("windows") then
		return
	end

	-- no extra debug version; use same library in all configs
	if suffix == "" then
		linkoptions { "/DELAYLOAD:"..name..".dll" }
	-- extra debug version available; use in debug config
	else
		local dbg_cmd = "/DELAYLOAD:" .. name .. suffix .. ".dll"
		local cmd     = "/DELAYLOAD:" .. name .. ".dll"

		filter "Debug"
			linkoptions { dbg_cmd }
		filter "Release"
			linkoptions { cmd }
		filter { }
	end

end

local function add_default_links(def)

	-- careful: make sure to only use *_names when on the correct platform.
	local names = {}
	if os.istarget("windows") then
		if def.win_names then
			names = def.win_names
		end
	elseif _OPTIONS["android"] and def.android_names then
		names = def.android_names
	elseif os.istarget("linux") and def.linux_names then
		names = def.linux_names
	elseif os.istarget("macosx") and (def.osx_names or def.osx_frameworks) then
		if def.osx_names then
			names = def.osx_names
		end
		-- OS X "Frameworks" are added to the links as "name.framework"
		if def.osx_frameworks then
			for i,name in pairs(def.osx_frameworks) do
				links { name .. ".framework" }
			end
		end
	elseif os.istarget("bsd") and def.bsd_names then
		names = def.bsd_names
	elseif def.unix_names then
		names = def.unix_names
	end

	local suffix = "d"
	-- library is overriding default suffix (typically "" to indicate there is none)
	if def["dbg_suffix"] then
		suffix = def["dbg_suffix"]
	end
	-- non-Windows doesn't have the distinction of debug vs. release libraries
	-- (to be more specific, they do, but the two are binary compatible;
	-- usually only one type - debug or release - is installed at a time).
	if not os.istarget("windows") then
		suffix = ""
	end

	for i,name in pairs(names) do
		filter "Debug"
			links { name .. suffix }
		filter "Release"
			links { name }
		filter { }

		add_delayload(name, suffix, def)
	end

end

-- Library definitions
-- In a perfect world, libraries would have a common installation template,
-- i.e. location of include directory, naming convention for .lib, etc.
-- this table provides a means of working around each library's differences.
--
-- The basic approach is defining two functions per library:
--
-- 1. compile_settings
-- This function should set all settings requred during the compile-phase like
-- includedirs, defines etc...
--
-- 2. link_settings
-- This function should set all settings required during the link-phase like
-- libdirs, linkflag etc...
--
-- The main reason for separating those settings is different linking behaviour
-- on osx and xcode. For more details, read the comment in project_add_extern_libs.
--
-- There are some helper functions for the most common tasks. You should use them
-- if they can be used in your situation to make the definitions more consistent and
-- use their default beviours as a guideline.
--
--
-- add_default_lib_paths(extern_lib)
--      Description: Add '<libraries root>/<libraryname>/lib'to the libpaths
--      Parameters:
--          * extern_lib: <libraryname> to be used in the libpath.
--
-- add_default_include_paths(extern_lib)
--      Description: Add '<libraries root>/<libraryname>/include' to the includepaths
--      Parameters:
--          * extern_lib: <libraryname> to be used in the libpath.
--
-- add_default_links
--      Description: Adds links to libraries and configures delayloading.
--      If the *_names parameter for a plattform is missing, no linking will be done
--      on that plattform.
--      The default assumptions are:
--      * debug import library and DLL are distinguished with a "d" suffix
--      * the library should be marked for delay-loading.
--      Parameters:
--      * win_names: table of import library / DLL names (no extension) when
--        running on Windows.
--      * unix_names: as above; shared object names when running on non-Windows.
--      * osx_names, osx_frameworks: for OS X specifically; if any of those is
--        specified, unix_names is ignored. Using both is possible if needed.
--          * osx_names: as above.
--          * osx_frameworks: as above, for system libraries that need to be linked
--            as "name.framework".
--      * bsd_names: as above; for BSD specifically (overrides unix_names if both are
--        specified)
--      * linux_names: ditto for Linux (overrides unix_names if both given)
--      * dbg_suffix: changes the debug suffix from the above default.
--        can be "" to indicate the library doesn't have a debug build;
--        in that case, the same library (without suffix) is used in
--        all build configurations.
--      * no_delayload: indicate the library is not to be delay-loaded.
--        this is necessary for some libraries that do not support it,
--        e.g. Xerces (which is so stupid as to export variables).

extern_lib_defs = {
	boost = {
		compile_settings = function()
			if os.istarget("windows") then
				-- Force the autolink to use the vc140 libs even on VS2017
				defines { 'BOOST_LIB_TOOLSET="vc140"' }
				add_default_include_paths("boost")
			elseif os.istarget("macosx") then
				-- Suppress all the Boost warnings on OS X by including it as a system directory
				buildoptions { "-isystem../" .. libraries_dir .. "boost/include" }
			end
			-- TODO: This actually applies to most libraries we use on BSDs, make this a global setting.
			if os.istarget("bsd") then
				sysincludedirs { "/usr/local/include" }
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				if os.istarget("windows") then
					defines { 'BOOST_LIB_TOOLSET="vc140"' }
				end
				add_default_lib_paths("boost")
			end
			add_default_links({
				-- The following are not strictly link dependencies on all systems, but
				-- are included for compatibility with different versions of Boost
				android_names = { "boost_filesystem-gcc-mt", "boost_system-gcc-mt" },
				unix_names = { os.findlib("boost_filesystem-mt") and "boost_filesystem-mt" or "boost_filesystem", os.findlib("boost_system-mt") and "boost_system-mt" or "boost_system" },
				osx_names = { "boost_filesystem", "boost_system" },
			})
		end,
	},
	comsuppw = {
		link_settings = function()
			add_default_links({
				win_names = { "comsuppw" },
				dbg_suffix = "d",
				no_delayload = 1,
			})
		end,
	},
	cxxtest = {
		compile_settings = function()
			sysincludedirs { libraries_source_dir .. "cxxtest-4.4" }
		end,
	},
	enet = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("enet")
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("enet")
			end
			add_default_links({
				win_names  = { "enet" },
				unix_names = { "enet" },
			})
		end,
	},
	fcollada = {
		compile_settings = function()
			add_source_include_paths("fcollada")
		end,
		link_settings = function()
			add_source_lib_paths("fcollada")
			if os.istarget("windows") then
				filter "Debug"
					links { "FColladaD" }
				filter "Release"
					links { "FCollada" }
				filter { }
			else
				filter "Debug"
					links { "FColladaSD" }
				filter "Release"
					links { "FColladaSR" }
				filter { }
			end
		end,
	},
	fmt = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("fmt")
			end

			-- With Linux & BSD, we assume that fmt is installed in a standard location.
			--
			-- It would be nice to not assume, and to instead use pkgconfig: however that
			-- requires fmt 5.3.0 or greater.
			--
			-- Unfortunately (at the time of writing) only 69 out of 95 (~72.6%) of distros
			-- that provide a fmt package meet this, according to
			-- https://repology.org/badge/vertical-allrepos/fmt.svg?minversion=5.3
			--
			-- Whilst that might seem like a healthy majority, this does not include the 2018
			-- Long Term Support and 2019.10 releases of Ubuntu - not only popular and widely
			-- used as-is, but which are also used as a base for other popular distros (e.g.
			-- Mint).
			--
			-- When fmt 5.3 (or better) becomes more widely used, then we can safely use the
			-- following line:
			-- pkgconfig.add_includes("fmt")
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("fmt")
			end

			if os.istarget("windows") then
				add_default_links({
					win_names = { "fmt" },
					dbg_suffix = "d",
					no_delayload = 1,
				})
			else
				add_default_links({
					unix_names = { "fmt" },
				})

				-- See comment above as to why this is commented out.
				-- pkgconfig.add_links("fmt")
			end
		end
	},
	gloox = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("gloox")
			else
				-- Support GLOOX_CONFIG for overriding the default (pkg-config --cflags gloox)
				-- i.e. on OSX where it gets set in update-workspaces.sh
				pkgconfig.add_includes("gloox", os.getenv("GLOOX_CONFIG"))
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("gloox")
				add_default_links({
					win_names  = { "gloox-1.0" },
					no_delayload = 1,
				})
			else
				pkgconfig.add_links("gloox", os.getenv("GLOOX_CONFIG"))

				if os.istarget("macosx") then
					-- Manually add gnutls dependencies, those are not present in gloox's pkg-config
					add_default_lib_paths("nettle")
					add_default_lib_paths("gmp")
					add_default_links({
						osx_names = { "nettle", "hogweed", "gmp" },
					})
				end

			end
		end,
	},
	iconv = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("iconv")
				defines { "HAVE_ICONV_CONST" }
				defines { "ICONV_CONST=const" }
				defines { "LIBICONV_STATIC" }
			elseif os.istarget("macosx") then
				add_default_include_paths("iconv")
				defines { "LIBICONV_STATIC" }
			elseif os.getversion().description == "FreeBSD" then
				defines { "HAVE_ICONV_CONST" }
				defines { "ICONV_CONST=const" }
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("iconv")
			end
			add_default_links({
				win_names  = { "libiconv" },
				osx_names = { "iconv" },
				dbg_suffix = "",
				no_delayload = 1,
			})
			-- glibc (used on Linux and GNU/kFreeBSD) has iconv
			-- FreeBSD 10+ has iconv as a part of libc
			if os.istarget("bsd")
			   and not (os.getversion().description == "FreeBSD" and os.getversion().majorversion >= 10
			            or os.getversion().description == "GNU/kFreeBSD") then
				add_default_links({
					bsd_names = { "iconv" },
				})
			end
		end,
	},
	icu = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("icu")
			else
				-- Support ICU_CONFIG for overriding the default (pkg-config --cflags icu-i18n)
				-- i.e. on OSX where it gets set in update-workspaces.sh
				pkgconfig.add_includes("icu-i18n", os.getenv("ICU_CONFIG"), "--cppflags")
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("icu")
				add_default_links({
					win_names  = { "icuuc", "icuin" },
					dbg_suffix = "",
					no_delayload = 1,
				})
			else
				pkgconfig.add_links("icu-i18n", os.getenv("ICU_CONFIG"), "--ldflags-searchpath --ldflags-libsonly --ldflags-system")
			end
		end,
	},
	libcurl = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("libcurl")
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("libcurl")
			end
			add_default_links({
				win_names  = { "libcurl" },
				unix_names = { "curl" },
				osx_names = { "curl", "z" },
				osx_frameworks = { "Security" }
			})
		end,
	},
	libpng = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("libpng")
			end
			if os.getversion().description == "OpenBSD" then
				sysincludedirs { "/usr/local/include/libpng" }
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("libpng")
			end
			add_default_links({
				win_names  = { "libpng16" },
				unix_names = { "png" },
				-- Otherwise ld will sometimes pull in ancient 1.2 from the SDK, which breaks the build :/
				-- TODO: Figure out why that happens
				osx_names = { "png16" },
			})
		end,
	},
	libsodium = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("libsodium")
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("libsodium")
			end
			add_default_links({
				win_names  = { "libsodium" },
				unix_names = { "sodium" },
			})
		end,
	},
	libxml2 = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("libxml2")
			else
				-- Support XML2_CONFIG for overriding the default (pkg-config --cflags libxml-2.0)
				-- i.e. on OSX where it gets set in update-workspaces.sh
				pkgconfig.add_includes("libxml-2.0", os.getenv("XML2_CONFIG"))
			end
			if os.istarget("macosx") then
				-- libxml2 needs _REENTRANT or __MT__ for thread support;
				-- OS X doesn't get either set by default, so do it manually
				defines { "_REENTRANT" }
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("libxml2")
				filter "Debug"
					links { "libxml2" }
				filter "Release"
					links { "libxml2" }
				filter { }
			else
				pkgconfig.add_links("libxml-2.0", os.getenv("XML2_CONFIG"))
			end
		end,
	},
	miniupnpc = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("miniupnpc")
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("miniupnpc")
			end
			add_default_links({
				win_names  = { "miniupnpc" },
				unix_names = { "miniupnpc" },
			})
		end,
	},
	nvtt = {
		compile_settings = function()
			if not _OPTIONS["with-system-nvtt"] then
				add_source_include_paths("nvtt")
			end
			defines { "NVTT_SHARED=1" }
		end,
		link_settings = function()
			if not _OPTIONS["with-system-nvtt"] then
				add_source_lib_paths("nvtt")
			end
			add_default_links({
				win_names  = { "nvtt" },
				unix_names = { "nvcore", "nvmath", "nvimage", "nvtt" },
				osx_names = { "bc6h", "bc7", "nvcore", "nvimage", "nvmath", "nvthread", "nvtt", "squish" },
				dbg_suffix = "", -- for performance we always use the release-mode version
			})
		end,
	},
	openal = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("openal")
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("openal")
			end
			add_default_links({
				win_names  = { "openal32" },
				unix_names = { "openal" },
				osx_frameworks = { "OpenAL" },
				dbg_suffix = "",
				no_delayload = 1, -- delayload seems to cause errors on startup
			})
		end,
	},
	opengl = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("opengl")
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("opengl")
			end
			if _OPTIONS["gles"] then
				add_default_links({
					unix_names = { "GLESv2" },
					dbg_suffix = "",
				})
			else
				add_default_links({
					win_names  = { "opengl32", "gdi32" },
					unix_names = { "GL" },
					osx_frameworks = { "OpenGL" },
					dbg_suffix = "",
					no_delayload = 1, -- delayload seems to cause errors on startup
				})
			end
		end,
	},
	sdl = {
		compile_settings = function()
			if os.istarget("windows") then
				includedirs { libraries_dir .. "sdl2/include/SDL" }
			elseif not _OPTIONS["android"] then
				-- Support SDL2_CONFIG for overriding the default (pkg-config sdl2)
				-- i.e. on OSX where it gets set in update-workspaces.sh
				pkgconfig.add_includes("sdl2", os.getenv("SDL2_CONFIG"))
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("sdl2")
			elseif not _OPTIONS["android"] then
				pkgconfig.add_links("sdl2", os.getenv("SDL2_CONFIG"))
			end
		end,
	},
	spidermonkey = {
		compile_settings = function()
			if _OPTIONS["with-system-mozjs"] then
				if not _OPTIONS["android"] then
					pkgconfig.add_includes("mozjs-60")
				end
			else
				if os.istarget("windows") then
					include_dir = "include-win32"
					buildoptions { "/FI\"js/RequiredDefines.h\"" }
				else
					include_dir = "include-unix"
				end
				filter "Debug"
					sysincludedirs { libraries_source_dir.."spidermonkey/"..include_dir.."-debug" }
					defines { "DEBUG" }
				filter "Release"
					sysincludedirs { libraries_source_dir.."spidermonkey/"..include_dir.."-release" }
				filter { }
			end
		end,
		link_settings = function()
			if _OPTIONS["with-system-mozjs"] then
				if _OPTIONS["android"] then
					links { "mozjs-60" }
				else
					pkgconfig.add_links("mozjs-60")
				end
			else
				filter { "Debug" }
					links { "mozjs60-ps-debug" }
				filter { "Release" }
					links { "mozjs60-ps-release" }
				filter { }
				add_source_lib_paths("spidermonkey")
			end
		end,
	},
	tinygettext = {
		compile_settings = function()
			add_third_party_include_paths("tinygettext")
		end,
	},
	valgrind = {
		compile_settings = function()
			add_source_include_paths("valgrind")
		end,
	},
	vorbis = {
		compile_settings = function()
			if os.istarget("windows") then
				add_default_include_paths("vorbis")
			elseif os.istarget("macosx") then
				add_default_include_paths("libogg")
				add_default_include_paths("vorbis")
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				add_default_lib_paths("vorbis")
			elseif os.istarget("macosx") then
				add_default_lib_paths("libogg")
				add_default_lib_paths("vorbis")
			end
			-- TODO: We need to force linking with these as currently
			-- they need to be loaded explicitly on execution
			if os.getversion().description == "OpenBSD" then
				add_default_links({
					unix_names = { "ogg",
						"vorbis" },
				})
			end
			add_default_links({
				win_names  = { "libvorbisfile" },
				unix_names = { "vorbisfile" },
				osx_names = { "vorbis", "vorbisenc", "vorbisfile", "ogg" },
			})
		end,
	},
	wxwidgets = {
		compile_settings = function()
			if os.istarget("windows") then
				includedirs { libraries_dir.."wxwidgets/include/msvc" }
				add_default_include_paths("wxwidgets")
			else
				-- wxwidgets does not come with a definition file for pkg-config,
				-- so we have to use wxwidgets' own config tool
				wx_config_path = os.getenv("WX_CONFIG") or "wx-config"
				pkgconfig.add_includes(nil, wx_config_path, "--unicode=yes --cxxflags")
			end
		end,
		link_settings = function()
			if os.istarget("windows") then
				libdirs { libraries_dir.."wxwidgets/lib/vc_lib" }
			else
				wx_config_path = os.getenv("WX_CONFIG") or "wx-config"
				pkgconfig.add_links(nil, wx_config_path, "--unicode=yes --libs std,gl")
			end
		end,
	},
	x11 = {
		compile_settings = function()
			if not os.istarget("windows") and not os.istarget("macosx") then
				pkgconfig.add_includes("x11")
			end
		end,
		link_settings = function()
			if not os.istarget("windows") and not os.istarget("macosx") then
				pkgconfig.add_links("x11")
			end
		end,
	},
	xcursor = {
		link_settings = function()
			add_default_links({
				unix_names = { "Xcursor" },
			})
		end,
	},
	zlib = {
		compile_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_include_paths("zlib")
			end
		end,
		link_settings = function()
			if os.istarget("windows") or os.istarget("macosx") then
				add_default_lib_paths("zlib")
			end
			add_default_links({
				win_names  = { "zlib1" },
				unix_names = { "z" },
				no_delayload = 1,
			})
		end,
	},
}


-- add a set of external libraries to the project; takes care of
-- include / lib path and linking against the import library.
-- extern_libs: table of library names [string]
-- target_type: String defining the projects kind [string]
function project_add_extern_libs(extern_libs, target_type)

	for i,extern_lib in pairs(extern_libs) do
		local def = extern_lib_defs[extern_lib]
		assert(def, "external library " .. extern_lib .. " not defined")

		if def.compile_settings then
			def.compile_settings()
		end

		-- Linking to external libraries will only be done in the main executable and not in the
		-- static libraries. Premake would silently skip linking into static libraries for some
		-- actions anyway (e.g. vs2010).
		-- On osx using xcode, if this linking would be defined in the static libraries, it would fail to
		-- link if only dylibs are available. If both *.a and *.dylib are available, it would link statically.
		-- I couldn't find any problems with that approach.
		if target_type ~= "StaticLib" and def.link_settings then
			def.link_settings()
		end
	end
end