--!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, Xmake Open Source Community.
--
-- @author      ruki
-- @file        configfiles.lua
--

-- imports
import("core.base.option")
import("core.base.semver")
import("core.project.config")
import("core.project.depend")
import("core.project.project")
import("core.platform.platform")
import("lib.detect.find_tool")

-- get all configuration files
function _get_configfiles()
    local configfiles = {}
    for _, target in table.orderpairs(project.targets()) do
        if target:is_enabled() then

            -- get configuration files for target
            local srcfiles, dstfiles, fileinfos = target:configfiles()
            for idx, srcfile in ipairs(srcfiles) do

                -- get destinate file and file info
                local dstfile  = dstfiles[idx]
                local fileinfo = fileinfos[idx]

                -- get source info
                local srcinfo = configfiles[dstfile]
                if not srcinfo then
                    srcinfo = {}
                    configfiles[dstfile] = srcinfo
                end

                -- save source file
                if srcinfo.srcfile then
                    assert(path.absolute(srcinfo.srcfile) == path.absolute(srcfile), "file(%s) and file(%s) are writing a same file(%s)", srcfile, srcinfo.srcfile, dstfile)
                else
                    srcinfo.srcfile  = srcfile
                    srcinfo.fileinfo = fileinfo
                end

                -- we use first target to get dependfile path
                -- @see https://github.com/xmake-io/xmake/issues/3321
                if not srcinfo.dependfile then
                    srcinfo.dependfile = target:dependfile(srcfile)
                end

                -- always update?
                local always_update = target:policy("build.always_update_configfiles")
                if always_update == nil then
                    always_update = project.policy("build.always_update_configfiles")
                end
                srcinfo.always_update = always_update

                -- save targets
                srcinfo.targets = srcinfo.targets or {}
                table.insert(srcinfo.targets, target)

                -- save preprocessors
                local preprocessor = fileinfo and fileinfo.preprocessor
                if preprocessor then
                    srcinfo.preprocessors = srcinfo.preprocessors or {}
                    table.insert(srcinfo.preprocessors, preprocessor)
                end
            end
        end
    end
    return configfiles
end

-- get the builtin variables
function _get_builtinvars_target(target)

    -- get version variables
    local builtinvars = {}
    local version, version_build = target:version()
    if version then
        builtinvars.VERSION = version
        try {function ()
            local v = semver.new(version)
            if v then
                builtinvars.VERSION_MAJOR = v:major()
                builtinvars.VERSION_MINOR = v:minor()
                builtinvars.VERSION_ALTER = v:patch()
            end
        end}
        if version_build then
            builtinvars.VERSION_BUILD = version_build
        end
    end
    return builtinvars
end

-- get the git builtin variables
function _get_builtinvars_git(builtinvars)
    local cmds =
    {
        GIT_TAG         = {"describe", "--tags"},
        GIT_TAG_LONG    = {"describe", "--tags", "--long"},
        GIT_BRANCH      = {"rev-parse", "--abbrev-ref", "HEAD"},
        GIT_COMMIT      = {"rev-parse", "--short", "HEAD"},
        GIT_COMMIT_LONG = {"rev-parse", "HEAD"},
        GIT_COMMIT_DATE = {"log", "-1", "--date=format:%Y%m%d%H%M%S", "--format=%ad"}
    }
    for name, argv in pairs(cmds) do
        builtinvars[name] = function ()
            local result
            local git = find_tool("git")
            if git then
                result = try {function ()
                    return os.iorunv(git.program, argv)
                end}
            end
            if not result then
                result = "none"
            end
            return result:trim()
        end
    end
end

-- get the global builtin variables
function _get_builtinvars_global()
    local builtinvars = _g.builtinvars_global
    if builtinvars == nil then
        builtinvars =
        {
            arch  = config.get("arch") or os.arch()
        ,   plat  = config.get("plat") or os.host()
        ,   host  = os.host()
        ,   mode  = config.get("mode") or "release"
        ,   debug = is_mode("debug") and 1 or 0
        ,   os    = platform.os()
        }
        local builtinvars_upper = {}
        for name, value in pairs(builtinvars) do
            builtinvars_upper[name:upper()] = type(value) == "string" and value:upper() or value
        end
        table.join2(builtinvars, builtinvars_upper)
        _get_builtinvars_git(builtinvars)
        _g.builtinvars_global = builtinvars
    end
    return builtinvars
end

function _preprocess_define_value(name, value, opt)
    opt = opt or {}
    local extraconf = opt.extraconf
    if value == nil then
        value = ("/* #undef %s */"):format(name)
    elseif type(value) == "boolean" then
        if value then
            value = ("#define %s 1"):format(name)
        else
            value = ("/* #define %s 0 */"):format(name)
        end
    elseif type(value) == "number" then
        value = ("#define %s %d"):format(name, value)
    elseif type(value) == "string" then
        local quote = true
        local escape = false
        if extraconf then
            -- disable to wrap quote, @see https://github.com/xmake-io/xmake/issues/1694
            if extraconf.quote == false then
                quote = false
            end
            -- escape path separator when with quote, @see https://github.com/xmake-io/xmake/issues/1872
            if quote and extraconf.escape then
                escape = true
            end
        end
        if quote then
            if escape then
                value = value:gsub("\\", "\\\\")
            end
            value = ("#define %s \"%s\""):format(name, value)
        else
            value = ("#define %s %s"):format(name, value)
        end
    else
        raise("unknown variable(%s) type: %s", name, type(value))
    end
    return value
end

function _preprocess_default_value(name, value, opt)
    opt = opt or {}
    local default = table.unpack(opt.argv or {})
    assert(default ~= nil, "please set default value for variable(%s)", variable)

    if value == nil then
        value = default
    else
        value = tostring(value)
    end
    return value
end

function _preprocess_define_export_value(name, value, opt)
    value = ([[#ifdef %s_STATIC
#  define %s_EXPORT
#else
#  if defined(_WIN32)
#    define %s_EXPORT __declspec(dllexport)
#  elif defined(__GNUC__) && ((__GNUC__ >= 4) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 3))
#    define %s_EXPORT __attribute__((visibility("default")))
#  else
#    define %s_EXPORT
#  endif
#endif
]]):format(name, name, name, name, name)
    return value
end

-- get variable value
function _get_variable_value(variables, name, opt)
    opt = opt or {}
    local preprocessor_name = opt.preprocessor_name
    local preprocessor_argv = opt.preprocessor_argv
    local configfile = opt.configfile
    local value = variables[name]
    local extraconf = variables["__extraconf_" .. name]
    if preprocessor_name then
        local preprocessed = false
        if opt.preprocessors then
            for _, preprocessor in ipairs(opt.preprocessors) do
                value = preprocessor(preprocessor_name, name, value, {argv = preprocessor_argv, extraconf = extraconf})
                if value ~= nil then
                    preprocessed = true
                    break
                end
            end
        end
        if not preprocessed then
            local preprocessors = _g._preprocessors
            if preprocessors == nil then
                preprocessors = {
                    define = _preprocess_define_value,
                    default = _preprocess_default_value,
                    define_export = _preprocess_define_export_value
                }
                _g._preprocessors = preprocessors
            end
            local preprocessor = preprocessors[preprocessor_name]
            if preprocessor == nil then
                raise("unknown variable keyword, ${%s %s}", preprocessor_name, name)
            end
            value = preprocessor(name, value, {argv = preprocessor_argv, extraconf = extraconf})
        end
        assert(value ~= nil, "cannot get variable(%s %s) in %s.", preprocessor_name, name, configfile)
    else
        assert(value ~= nil, "cannot get variable(%s) in %s.", name, configfile)
    end
    dprint("  > replace %s -> %s", name, value)
    if type(value) == "table" then
        dprint("invalid variable value", value)
    end
    return value
end

-- generate the configuration file
function _generate_configfile(srcfile, dstfile, fileinfo, targets, preprocessors)

    -- trace
    if option.get("verbose") then
        cprint("${dim}generating %s to %s ..", srcfile, dstfile)
    end

    -- only copy it?
    if fileinfo.onlycopy then
        if os.mtime(srcfile) > os.mtime(dstfile) then
            os.cp(srcfile, dstfile)
        end
    else
        -- generate to the temporary file first
        local dstfile_tmp = os.tmpfile(srcfile)
        os.tryrm(dstfile_tmp)
        os.cp(srcfile, dstfile_tmp)

        -- get all variables
        local variables = fileinfo.variables or {}
        for _, target in ipairs(targets) do

            -- get variables from the target
            for name, value in pairs(target:get("configvar")) do
                local value = value
                if variables[name] == nil then
                    value = table.unwrap(value)
                    variables[name] = value
                    variables["__extraconf_" .. name] = target:extraconf("configvar." .. name, value)
                end
            end

            -- get variables from the target.options
            for _, opt in ipairs(target:orderopts()) do
                for name, value in pairs(opt:get("configvar")) do
                    if variables[name] == nil then
                        variables[name] = table.unwrap(value)
                        variables["__extraconf_" .. name] = opt:extraconf("configvar." .. name, value)
                    end
                end
            end

            -- get the builtin variables from the target
            for name, value in pairs(_get_builtinvars_target(target)) do
                local value = value
                if type(value) == "function" then
                    value = value()
                end
                if variables[name] == nil then
                    variables[name] = value
                end
            end
        end
        -- get the global builtin variables
        for name, value in pairs(_get_builtinvars_global()) do
            local value = value
            if type(value) == "function" then
                value = value()
            end
            if variables[name] == nil then
                variables[name] = value
            end
        end

        -- replace all variables
        local pattern = fileinfo.pattern or "%${([^\n]-)}"
        io.gsub(dstfile_tmp, "(" .. pattern .. ")", function(_, variable)
            variable = variable:trim()

            local preprocessor_argv
            local preprocessor_name
            local parts = variable:split("%s")
            if #parts > 1 then
                preprocessor_name = parts[1]
                variable = parts[2]
                preprocessor_argv = table.slice(parts, 3)
            end

            return _get_variable_value(variables, variable, {preprocessor_name = preprocessor_name,
                preprocessor_argv = preprocessor_argv, configfile = srcfile, preprocessors = preprocessors})
        end)

        -- update file if the content is changed
        if os.isfile(dstfile_tmp) then
            os.cp(dstfile_tmp, dstfile, {copy_if_different = true})
        end
    end

    -- trace
    cprint("generating %s ... ${color.success}${text.success}", srcfile)
end

-- the main entry function
function main(opt)

    -- enter project directory
    opt = opt or {}
    local oldir = os.cd(project.directory())

    -- generate all configuration files
    local configfiles = _get_configfiles()
    for dstfile, srcinfo in pairs(configfiles) do
        depend.on_changed(function ()
            _generate_configfile(srcinfo.srcfile, dstfile, srcinfo.fileinfo, srcinfo.targets, srcinfo.preprocessors)
        end, {files = srcinfo.srcfile,
              lastmtime = os.mtime(dstfile),
              dependfile = srcinfo.dependfile,
              changed = opt.force or srcinfo.always_update})
    end

    -- leave project directory
    os.cd(oldir)
end