--!A cross-platform build utility based on Lua
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
--     http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
--
-- Copyright (C) 2015-present, TBOOX Open Source Group.
--
-- @author      ruki
-- @file        has_flags.lua
--

-- imports
import("core.cache.detectcache")
import("core.language.language")

-- is linker?
function _islinker(flags, opt)

    -- the flags is "-Wl,<arg>" or "-Xlinker <arg>"?
    local flags_str = table.concat(flags, " ")
    if flags_str:startswith("-Wl,") or flags_str:startswith("-Xlinker ") then
        return true
    end

    -- the tool kind is ld or sh?
    local toolkind = opt.toolkind or ""
    return toolkind == "ld" or toolkind == "sh" or toolkind:endswith("-ld") or toolkind:endswith("-sh")
end

-- try running
function _try_running(program, argv, opt)
    local errors = nil
    return try { function () os.runv(program, argv, opt); return true end, catch { function (errs) errors = (errs or ""):trim() end }}, errors
end

-- attempt to check it from the argument list
function _check_from_arglist(flags, opt, islinker)

    -- check for the builtin flags
    local builtin_flags = {["-code"] = true,
                           ["--gpu-code"] = true,
                           ["-gencode"] = true,
                           ["--generate-code"] = true,
                           ["-arch"] = true,
                           ["--gpu-architecture"] = true,
                           ["-cudart=none"] = true,
                           ["--cudart=none"] = true}
    if builtin_flags[flags[1]] then
        return true
    end

    -- check for the builtin flag=value
    local cudart_flags = {none = true, shared = true, static = true}
    local builtin_flags_pair = {["-cudart"] = cudart_flags,
                                ["--cudart"] = cudart_flags}
    if #flags > 1 and builtin_flags_pair[flags[1]] and builtin_flags_pair[flags[1]][flags[2]] then
        return true
    end

    -- check from the `--help` menu, only for linker
    if islinker or #flags > 1 then
        return
    end

    -- make cache key
    local key = "detect.tools.nvcc.has_flags"

    -- make flags key
    local flagskey = opt.program .. "_" .. (opt.programver or "")

    -- get all flags from argument list
    local allflags = detectcache:get2(key, flagskey)
    if not allflags then

        -- get argument list
        allflags = {}
        local arglist = os.iorunv(opt.program, {"--help"})
        if arglist then
            for arg in arglist:gmatch("%s+(%-[%-%a%d]+)%s+") do
                allflags[arg] = true
            end
        end

        -- save cache
        detectcache:set2(key, flagskey, allflags)
        detectcache:save()
    end
    return allflags[flags[1]]
end

-- try running to check flags
function _check_try_running(flags, opt, islinker)

    -- make an stub source file
    local snippet = opt.snippet or "int main(int argc, char** argv)\n{return 0;}"
    local sourcefile = os.tmpfile("nvcc_has_flags:" .. snippet) .. ".cu"
    if not os.isfile(sourcefile) then
        io.writefile(sourcefile, snippet)
    end

    local args = table.join("-o", os.nuldev(), sourcefile)
    if not islinker then
        table.insert(args, 1, "-c")
    end

    -- avoid recursion
    if flags[1] ~= "-allow-unsupported-compiler" then
        -- add -allow-unsupported-compiler if supported to suppress error of unsupported compiler,
        -- which caused all checks failed.
        local allow_unsupported_compiler = _has_flags({"-allow-unsupported-compiler"}, opt)
        if allow_unsupported_compiler then
            table.insert(args, 1, "-allow-unsupported-compiler")
        end
    end

    -- add architecture flags if cross compiling
    if not is_arch(os.arch()) then
        if is_arch(".+64.*") then
            table.insert(args, 1, "-m64")
        else
            table.insert(args, 1, "-m32")
        end
    end

    -- check flags
    return _try_running(opt.program, table.join(flags, args), opt)
end

-- has_flags(flags)?
--
-- @param opt   the argument options, e.g. {toolname = "", program = "", programver = "", toolkind = "cu"}
--
-- @return      true or false
--
function _has_flags(flags, opt)

    -- is linker?
    local islinker = _islinker(flags, opt)

    -- attempt to check it from the argument list
    if _check_from_arglist(flags, opt, islinker) then
        return true
    end

    -- try running to check it
    return _check_try_running(flags, opt, islinker)
end

function main(...)
    return _has_flags(...)
end

