--!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        compile_commands.lua
--

-- imports
import("core.tool.compiler")
import("core.project.project")
import("core.language.language")

-- escape path
function _escape_path(p)
    return os.args(p, {escape = true, nowrap = true})
end

-- translate external/system include flags, because some tools (vscode) do not support them yet.
-- https://github.com/xmake-io/xmake/issues/1050
function _translate_arguments(arguments)
    local args = {}
    for _, arg in ipairs(arguments) do
        if arg:find("-isystem", 1, true) then
            arg = arg:replace("-isystem", "-I")
        elseif arg:find("[%-/]external:I") then
            arg = arg:gsub("[%-/]external:I", "-I")
        elseif arg:find("[%-/]external:W") or arg:find("[%-/]experimental:external") then
            arg = nil
        end
        if arg then
            table.insert(args, arg)
        end
    end
    return args
end

-- make the object
function _make_object(jsonfile, target, sourcefile, objectfile)

    -- get the source file kind
    local sourcekind = language.sourcekind_of(sourcefile)

    -- make the object for the *.o/obj? ignore it directly
    if sourcekind == "obj" or sourcekind == "lib" then
        return
    end

    -- get compile arguments
    local arguments = table.join(compiler.compargv(sourcefile, objectfile, {target = target, sourcekind = sourcekind}))

    -- translate some unsupported arguments
    arguments = _translate_arguments(arguments)

    -- escape '"', '\'
    local arguments_escape = {}
    for _, arg in ipairs(arguments) do
        table.insert(arguments_escape, _escape_path(arg))
    end

    -- make body
    jsonfile:printf(
[[%s{
  "directory": "%s",
  "arguments": ["%s"],
  "file": "%s"
}]], (_g.firstline and "" or ",\n"), _escape_path(os.projectdir()), table.concat(arguments_escape, "\", \""), _escape_path(sourcefile))

    -- clear first line marks
    _g.firstline = false
end

-- make objects
function _make_objects(jsonfile, target, sourcekind, sourcebatch)
    for index, objectfile in ipairs(sourcebatch.objectfiles) do
        _make_object(jsonfile, target, sourcebatch.sourcefiles[index], objectfile)
    end
end

-- make target
function _make_target(jsonfile, target)

    -- TODO
    -- disable precompiled header first
    target:set("pcheader", nil)
    target:set("pcxxheader", nil)

    -- build source batches
    for _, sourcebatch in pairs(target:sourcebatches()) do
        local sourcekind = sourcebatch.sourcekind
        if sourcekind then
            _make_objects(jsonfile, target, sourcekind, sourcebatch)
        end
    end
end

-- make all
function _make_all(jsonfile)

    -- make header
    jsonfile:print("[")

    -- make commands
    _g.firstline = true
    for _, target in pairs(project.targets()) do
        if not target:isphony() then
            _make_target(jsonfile, target)
        end
    end

    -- make tailer
    jsonfile:print("]")
end

-- generate compilation databases for clang-based tools(compile_commands.json)
--
-- references:
--  - https://clang.llvm.org/docs/JSONCompilationDatabase.html
--  - https://sarcasm.github.io/notes/dev/compilation-database.html
--  - http://eli.thegreenplace.net/2014/05/21/compilation-databases-for-clang-based-tools
--
function make(outputdir)

    -- enter project directory
    local oldir = os.cd(os.projectdir())

    -- open the jsonfile
    local jsonfile = io.open(path.join(outputdir, "compile_commands.json"), "w")

    -- make all
    _make_all(jsonfile)

    -- close the jsonfile
    jsonfile:close()

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