//
// Copyright 2016 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/usd/usdSkel/root.h"
#include "pxr/usd/usd/schemaRegistry.h"
#include "pxr/usd/usd/typed.h"

#include "pxr/usd/sdf/types.h"
#include "pxr/usd/sdf/assetPath.h"

PXR_NAMESPACE_OPEN_SCOPE

// Register the schema with the TfType system.
TF_REGISTRY_FUNCTION(TfType)
{
    TfType::Define<UsdSkelRoot,
        TfType::Bases< UsdGeomBoundable > >();
    
    // Register the usd prim typename as an alias under UsdSchemaBase. This
    // enables one to call
    // TfType::Find<UsdSchemaBase>().FindDerivedByName("SkelRoot")
    // to find TfType<UsdSkelRoot>, which is how IsA queries are
    // answered.
    TfType::AddAlias<UsdSchemaBase, UsdSkelRoot>("SkelRoot");
}

/* virtual */
UsdSkelRoot::~UsdSkelRoot()
{
}

/* static */
UsdSkelRoot
UsdSkelRoot::Get(const UsdStagePtr &stage, const SdfPath &path)
{
    if (!stage) {
        TF_CODING_ERROR("Invalid stage");
        return UsdSkelRoot();
    }
    return UsdSkelRoot(stage->GetPrimAtPath(path));
}

/* static */
UsdSkelRoot
UsdSkelRoot::Define(
    const UsdStagePtr &stage, const SdfPath &path)
{
    static TfToken usdPrimTypeName("SkelRoot");
    if (!stage) {
        TF_CODING_ERROR("Invalid stage");
        return UsdSkelRoot();
    }
    return UsdSkelRoot(
        stage->DefinePrim(path, usdPrimTypeName));
}

/* virtual */
UsdSchemaType UsdSkelRoot::_GetSchemaType() const {
    return UsdSkelRoot::schemaType;
}

/* static */
const TfType &
UsdSkelRoot::_GetStaticTfType()
{
    static TfType tfType = TfType::Find<UsdSkelRoot>();
    return tfType;
}

/* static */
bool 
UsdSkelRoot::_IsTypedSchema()
{
    static bool isTyped = _GetStaticTfType().IsA<UsdTyped>();
    return isTyped;
}

/* virtual */
const TfType &
UsdSkelRoot::_GetTfType() const
{
    return _GetStaticTfType();
}

/*static*/
const TfTokenVector&
UsdSkelRoot::GetSchemaAttributeNames(bool includeInherited)
{
    static TfTokenVector localNames;
    static TfTokenVector allNames =
        UsdGeomBoundable::GetSchemaAttributeNames(true);

    if (includeInherited)
        return allNames;
    else
        return localNames;
}

PXR_NAMESPACE_CLOSE_SCOPE

// ===================================================================== //
// Feel free to add custom code below this line. It will be preserved by
// the code generator.
//
// Just remember to wrap code in the appropriate delimiters:
// 'PXR_NAMESPACE_OPEN_SCOPE', 'PXR_NAMESPACE_CLOSE_SCOPE'.
// ===================================================================== //
// --(BEGIN CUSTOM CODE)--

#include "pxr/usd/usd/primRange.h"
#include "pxr/usd/usdGeom/boundableComputeExtent.h"
#include "pxr/usd/usdGeom/xformCache.h"
#include "pxr/usd/usdSkel/binding.h"
#include "pxr/usd/usdSkel/cache.h"
#include "pxr/usd/usdSkel/skeleton.h"
#include "pxr/usd/usdSkel/skeletonQuery.h"
#include "pxr/usd/usdSkel/skinningQuery.h"
#include "pxr/usd/usdSkel/utils.h"


PXR_NAMESPACE_OPEN_SCOPE


UsdSkelRoot
UsdSkelRoot::Find(const UsdPrim& prim)
{
    for(UsdPrim p = prim; p; p = p.GetParent()) {
        if(p.IsA<UsdSkelRoot>()) {
            return UsdSkelRoot(p);
        }
    }
    return UsdSkelRoot();
}


/// Plugin extent method.
static bool
_ComputeExtent(const UsdGeomBoundable& boundable,
               const UsdTimeCode& time,
               const GfMatrix4d* transform,
               VtVec3fArray* extent)
{
    const UsdSkelRoot skelRoot(boundable);
    if(!TF_VERIFY(skelRoot)) {
        return false;
    }

    UsdSkelCache skelCache;
    skelCache.Populate(skelRoot);

    std::vector<UsdSkelBinding> bindings;
    if (!skelCache.ComputeSkelBindings(skelRoot, &bindings) ||
        bindings.size() == 0) {

        // XXX: The extent of a SkelRoot is intended to bound the set of
        // skinnable prims only. If we have no bindings, then there are no
        // skinnable prims to bound, and the case can be treated as a failed
        // extent computation.
        // We could potentially look for the set of skeletons bound beneath
        // the SkelRoot and compute the union of their extents, but since
        // Skeleton prims are themselves boundable, this seems redundant.
        return false;
    }

    UsdGeomXformCache xfCache;

    GfRange3d bbox;
    VtVec3fArray skelExtent;

    for (const UsdSkelBinding& binding : bindings) {

        UsdSkelSkeletonQuery skelQuery =
            skelCache.GetSkelQuery(binding.GetSkeleton());
        if (!TF_VERIFY(skelQuery))
            return false;

        // Compute skel-space joint transforms.
        // The extent for this skel is based on the pivots of all bones,
        // with some additional padding.
        VtMatrix4dArray skelXforms;
        if(!skelQuery.ComputeJointSkelTransforms(&skelXforms, time))
            continue;

        // Pre-compute a constant padding metric across all prims
        // skinned by this skeleton. 
        float padding = 0;
        VtMatrix4dArray skelRestXforms;
        if(skelQuery.ComputeJointSkelTransforms(
               &skelRestXforms, time, /*atRest*/ true)) {

            for (const auto& skinningQuery : binding.GetSkinningTargets()) {

                const UsdPrim& skinnedPrim = skinningQuery.GetPrim();

                float skelPadding = skinningQuery.ComputeExtentsPadding(
                    skelRestXforms, UsdGeomBoundable(skinnedPrim)); 
                    padding = std::max(padding, skelPadding);
            }
        }

        // Compute the final, padded extents from the skel-space
        // transforms, in the space of the SkelRoot prim.
        bool resetXformStack = false;
        GfMatrix4d skelRootXform =
        xfCache.ComputeRelativeTransform(binding.GetSkeleton().GetPrim(),
                                         skelRoot.GetPrim(),
                                         &resetXformStack);
        if(!resetXformStack && transform) {
            skelRootXform *= *transform;
        }
        UsdSkelComputeJointsExtent(skelXforms, &skelExtent,
                                   padding, &skelRootXform);

        for(const auto& p : skelExtent)
            bbox.UnionWith(p);
    }

    extent->resize(2);
    (*extent)[0] = GfVec3f(bbox.GetMin());
    (*extent)[1] = GfVec3f(bbox.GetMax());

    return true;
}        

TF_REGISTRY_FUNCTION(UsdGeomBoundable)
{
    UsdGeomRegisterComputeExtentFunction<UsdSkelRoot>(_ComputeExtent);
}


PXR_NAMESPACE_CLOSE_SCOPE