--!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 - 2019, TBOOX Open Source Group.
--
-- @author      ruki
-- @file        environment.lua
--

-- imports
import("core.project.config")
import("core.platform.environment")
import("core.package.package", {alias = "core_package"})
import("lib.detect.find_tool")
import("package")

-- enter the package environments
function _enter_package(package_name, envs, installdir)

    -- save the old environments
    _g._OLDENVS = _g._OLDENVS or {}
    local oldenvs = _g._OLDENVS[package_name]
    if not oldenvs then
        oldenvs = {}
        _g._OLDENVS[package_name] = oldenvs
    end

    -- add the new environments
    oldenvs.PATH = os.getenv("PATH") 
    for name, values in pairs(envs) do
        oldenvs[name] = oldenvs[name] or os.getenv(name)
        if name == "PATH" then
            for _, value in ipairs(values) do
                if path.is_absolute(value) then
                    os.addenv(name, value)
                else
                    os.addenv(name, path.join(installdir, value))
                end
            end
        else
            os.addenv(name, unpack(table.wrap(values)))
        end
    end
end

-- leave the package environments
function _leave_package(package_name)
    _g._OLDENVS = _g._OLDENVS or {}
    local oldenvs = _g._OLDENVS[package_name]
    if oldenvs then
        for name, values in pairs(oldenvs) do
            os.setenv(name, values)
        end
        _g._OLDENVS[package_name] = nil
    end
end

-- enter environment of the given binary packages, git, 7z, ..
function _enter_packages(...)
    for _, name in ipairs({...}) do
        for _, manifest_file in ipairs(os.files(path.join(core_package.installdir(), name:sub(1, 1), name, "*", "*", "manifest.txt"))) do
            local manifest = io.load(manifest_file) 
            if manifest and manifest.plat == os.host() and manifest.arch == os.arch() then
                _enter_package(name, manifest.envs, path.directory(manifest_file))
            end
        end
    end
end

-- leave environment of the given binary packages, git, 7z, ..
function _leave_packages(...)
    for _, name in ipairs({...}) do
        _leave_package(name)
    end
end

-- enter environment
--
-- ensure that we can find some basic tools: git, unzip, ...
--
-- If these tools not exist, we will install it first.
--
function enter()

    -- set search pathes of toolchains 
    environment.enter("toolchains")

    -- unzip is necessary
    if not find_tool("unzip") then
        raise("unzip not found! we need install it first")
    end

    -- enter the environments of git and 7z
    _enter_packages("git", "7z")

    -- git not found? install it first
    local packages = {}
    if not find_tool("git") then
        table.join2(packages, package.install_packages("git"))
    end

    -- missing the necessary unarchivers for *.gz, *.7z? install them first, e.g. gzip, 7z, tar ..
    if not ((find_tool("gzip") and find_tool("tar")) or find_tool("7z")) then
        table.join2(packages, package.install_packages("7z"))
    end

    -- enter the environments of installed packages 
    for _, instance in ipairs(packages) do
        instance:envs_enter()
    end
    _g._PACKAGES = packages
end

-- leave environment
function leave()

    -- leave the environments of installed packages 
    for _, instance in irpairs(_g._PACKAGES) do
        instance:envs_leave()
    end
    _g._PACKAGES = nil

    -- leave the environments of git and 7z
    _leave_packages("7z", "git")

    -- restore search pathes of toolchains
    environment.leave("toolchains")
end