//
// Copyright 2018 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache License.
//

#include "pxr/base/arch/fileSystem.h"
#include "pxr/usd/ndr/filesystemDiscovery.h"
#include "pxr/usd/ndr/filesystemDiscoveryHelpers.h"

#include "pxr/base/tf/stringUtils.h"
#include "pxr/base/tf/envSetting.h"

#include <string>

PXR_NAMESPACE_OPEN_SCOPE

NDR_REGISTER_DISCOVERY_PLUGIN(_NdrFilesystemDiscoveryPlugin)

TF_DEFINE_ENV_SETTING(
    PXR_NDR_FS_PLUGIN_SEARCH_PATHS, "",
    "The paths that should be searched, recursively, for files that represent "
    "nodes. Paths should be separated by either a ':' or a ';' depending on "
    "your platform (it should mimic the PATH attribute).  See "
    "ARCH_PATH_LIST_SEP");

TF_DEFINE_ENV_SETTING(
    PXR_NDR_FS_PLUGIN_ALLOWED_EXTS, "",
    "The extensions on files that define nodes.  Do not include the leading "
    "'.'. Extensions should be separated by a colon.");

TF_DEFINE_ENV_SETTING(
    PXR_NDR_FS_PLUGIN_FOLLOW_SYMLINKS, false,
    "Whether symlinks should be followed while walking the search paths. Set "
    "to 'true' (case sensitive) if they should be followed.");

_NdrFilesystemDiscoveryPlugin::_NdrFilesystemDiscoveryPlugin()
{
    //
    // TODO: This needs to somehow be set up to find the nodes that USD
    //       ships with
    //
    _searchPaths = TfStringSplit(
            TfGetEnvSetting(PXR_NDR_FS_PLUGIN_SEARCH_PATHS),
            ARCH_PATH_LIST_SEP);
    _allowedExtensions = TfStringSplit(
            TfGetEnvSetting(PXR_NDR_FS_PLUGIN_ALLOWED_EXTS), ":");
    _followSymlinks = TfGetEnvSetting(PXR_NDR_FS_PLUGIN_FOLLOW_SYMLINKS);
}

_NdrFilesystemDiscoveryPlugin::_NdrFilesystemDiscoveryPlugin(Filter filter)
    : _NdrFilesystemDiscoveryPlugin()
{
    _filter = std::move(filter);
}

NdrNodeDiscoveryResultVec
_NdrFilesystemDiscoveryPlugin::DiscoverNodes(const Context& context)
{
    auto result = NdrFsHelpersDiscoverNodes(
        _searchPaths, _allowedExtensions, _followSymlinks, &context
    );

    if (_filter) {
        auto j = result.begin();
        for (auto i = j; i != result.end(); ++i) {
            // If we pass the filter and any previous haven't then move.
            if (_filter(*i)) {
                if (j != i) {
                    *j = std::move(*i);
                }
                ++j;
            }
        }
        result.erase(j, result.end());
    }

    return result;
}

PXR_NAMESPACE_CLOSE_SCOPE