--
-- Yoink Build System
-- A collection of Lua functions for performing checks.
--
-- Copyright (c) 2011, Charles McGarvey
-- Distributable under the terms and conditions of the 2-clause BSD
-- license; see the file COPYING for a complete text of the license.
--

local M = {}


local util = require "utility"
local print_check = util.printer("checking for %s... ")

-- TODO: Should have check for toolset triplet, compiling arbitrary code,
-- headers, libraries.


local CC  = ""
local CXX = ""


local compile
do
	local cache = {}
	compile = function(compiler, ext, flags, code)
		if type(compiler) ~= "table" then compiler = {compiler} end
		local key = util.concat(compiler, "&") .. ext .. code
		if cache[key] then return cache[key], "cached value" end
		local tmpdir = util.make_tempdir("config.XXXXXX")
		if tmpdir
		then
			local fd, err = io.open(tmpdir .. "/test." .. ext, "w")
			if not fd then die("failed to create temporary file", fd) end
			fd:write(code)
			fd:close()
			--util.print_log("code to be compiled:\n" .. code)
			compiler = util.find_command(compiler, "test." .. ext, tmpdir)
			os.execute("rm -rf " .. tmpdir)
		else
			die("failed to create temporary directory", tmpdir)
		end
		cache[key] = compiler
		if compiler == nil then return nil, "test program could not be compiled" end
		return compiler
	end
end


do
	local cache = {}
	local function cc(...)
		local arg = util.copy(arg, "v", tostring)
		local key = util.concat(arg)
		if cache[key] then return cache[key], "cached value" end
		--print_check("C compiler")
		local cc, err = compile(arg, "c", "", "int main() { return 0; }")
		--if cc then util.print(cc) else util.print("no") end
		cache[key] = cc
		--util.print_info("cccheck:", key, cc)
		if cc == nil then return nil, err end
		return cc
	end
	M.cc = cc

	local function native_cc(triplet)
		local ccenv = os.getenv("CC")
		if ccenv
		then
			local result = cc(ccenv)
			if result then return result end
		end
		if type(triplet) ~= "string" then triplet = util.exec("config.guess") end
		return cc(triplet .. "-gcc", "cc", "gcc")
	end
	M.native_cc = native_cc

	local function cross_cc(triplet)
		return cc(triplet .. "-gcc")
	end
	M.cross_cc = cross_cc
end

do
	local cache = {}
	local function cxx(...)
		local arg = util.copy(arg, "v", tostring)
		local key = util.concat(arg)
		if cache[key] then return cache[key], "cached value" end
		--print_check("C++ compiler")
		local cxx, err = compile(arg, "c++", "", "int main() { return 0; }")
		--if cxx then util.print(cxx) else util.print("no") end
		cache[key] = cxx
		CXX = cxx
		--util.print_info("cxxcheck:", key, cxx)
		if cxx == nil then return nil, err end
		return cxx
	end
	M.cxx = cxx

	local function native_cxx(triplet)
		if type(triplet) ~= "string" then triplet = util.exec("config.guess") end
		return cxx(os.getenv("CXX"), "g++", "c++")
	end
	M.native_cxx = native_cxx

	local function cross_cxx(triplet)
		return cxx(triplet .. "-g++")
	end
	M.cross_cxx = cross_cxx
end

do
	local cache = {}
	local function lib(...)
		--local key = util.concat(arg, ", ")
		--if cache[key] then return cache[key] end
		--print_check(key)
		--local code = ""
		--local result = false
		--for _,header in ipairs(arg)
		--do
			--code = string.format("%s#include <%s>\n", code, header)
		--end
		--code = code .. "int main() { return 0; }\n"
		--if compile({CC}, "c", "", code) or compile({CC}, "c++", "", code)
		--then
			--result = true
			--util.print("yes")
		--else
			--util.print("no")
		--end
		--cache[key] = result
		--return key
		return true
	end
	M.lib = lib
end

do
	local cache = {}
	local function header(...)
		local CC = M.native_cc()
		local key = util.concat(arg, ", ")
		if cache[key] then return cache[key] end
		--print_check(key)
		local code = ""
		local result = false
		for _,header in util.npairs(arg)
		do
			code = string.format("%s#include <%s>\n", code, header)
		end
		code = code .. "int main() { return 0; }\n"
		if compile({CC}, "c", "", code) or compile({CC}, "c++", "", code)
		then
			result = true
			--util.print("yes")
		else
			--util.print("no")
		end
		cache[key] = result
		return key
	end
	M.header = header
end


return M