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/** @file utMDLImporter_HL1_Nodes.cpp
 *  @brief Half-Life 1 MDL loader nodes tests.
 */

#include "AbstractImportExportBase.h"
#include "AssetLib/MDL/HalfLife/HL1ImportDefinitions.h"
#include "MDLHL1TestFiles.h"
#include "UnitTestPCH.h"
#include <assimp/postprocess.h>
#include <assimp/scene.h>
#include <assimp/Importer.hpp>

using namespace Assimp;

class utMDLImporter_HL1_Nodes : public ::testing::Test {

public:
    /**
    * @note The following tests require a basic understanding
    * of the SMD format. For more information about SMD format,
    * please refer to the SMD importer or go to VDC
    * (Valve Developer Community).
    */

    /*  Given a model with bones that have empty names,
        verify that all the bones of the imported model
        have unique and no empty names.

        ""        <----+---- empty names
        ""        <----+
        ""        <----+
        "Bone_3"       |
        ""        <----+
        "Bone_2"       |
        "Bone_5"       |
        ""        <----+
        ""        <----+
    */
    void emptyBonesNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "unnamed_bones.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_bones_names = {
            "Bone",
            "Bone_0",
            "Bone_1",
            "Bone_3",
            "Bone_4",
            "Bone_2",
            "Bone_5",
            "Bone_6",
            "Bone_7"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_BONES, expected_bones_names);
    }

    /*  Given a model with bodyparts that have empty names,
        verify that the imported model contains bodyparts with
        unique and no empty names.

        $body ""           <----+---- empty names
        $body "Bodypart_1"      |
        $body "Bodypart_5"      |
        $body "Bodypart_6"      |
        $body ""           <----+
        $body "Bodypart_2"      |
        $body ""           <----+
        $body "Bodypart_3"      |
        $body ""           <----+
    */
    void emptyBodypartsNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "unnamed_bodyparts.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_bodyparts_names = {
            "Bodypart",
            "Bodypart_1",
            "Bodypart_5",
            "Bodypart_6",
            "Bodypart_0",
            "Bodypart_2",
            "Bodypart_4",
            "Bodypart_3",
            "Bodypart_7"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_BODYPARTS, expected_bodyparts_names);
    }

    /*  Given a model with bodyparts that have duplicate names,
        verify that the imported model contains bodyparts with
        unique and no duplicate names.

        $body "Bodypart"   <-----+
        $body "Bodypart_1" <--+  |
        $body "Bodypart_2"    |  |
        $body "Bodypart1"     |  |
        $body "Bodypart"   ---|--+
        $body "Bodypart_1" ---+  |
        $body "Bodypart2"        |
        $body "Bodypart"   ------+
        $body "Bodypart_4"
    */
    void duplicateBodypartsNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "duplicate_bodyparts.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_bodyparts_names = {
            "Bodypart",
            "Bodypart_1",
            "Bodypart_2",
            "Bodypart1",
            "Bodypart_0",
            "Bodypart_1_0",
            "Bodypart2",
            "Bodypart_3",
            "Bodypart_4"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_BODYPARTS, expected_bodyparts_names);
    }

    /*  Given a model with several bodyparts that contains multiple
        sub models with the same file name, verify for each bodypart
        sub model of the imported model that they have a unique name.

        $bodygroup "first_bodypart"
        {
            studio "triangle"   <------+ duplicate file names.
            studio "triangle"   -------+
        }                              |
                                       |
        $bodygroup "second_bodypart"   |
        {                              |
            studio "triangle"   -------+ same as first bodypart, but with same file.
            studio "triangle"   -------+
        }

        $bodygroup "last_bodypart"
        {
            studio "triangle2"  <------+ duplicate names.
            studio "triangle2"  -------+
        }
    */
    void duplicateSubModelsNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "duplicate_submodels.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::vector<std::string>> expected_bodypart_sub_models_names = {
            {
                    "triangle",
                    "triangle_0",
            },
            {
                    "triangle_1",
                    "triangle_2",
            },
            {
                    "triangle2",
                    "triangle2_0",
            }
        };

        const aiNode *bodyparts_node = scene->mRootNode->FindNode(AI_MDL_HL1_NODE_BODYPARTS);
        EXPECT_NE(nullptr, bodyparts_node);
        EXPECT_EQ(3u, bodyparts_node->mNumChildren);
        for (unsigned int i = 0; i < bodyparts_node->mNumChildren; ++i) {
            expect_named_children(bodyparts_node->mChildren[i],
                    expected_bodypart_sub_models_names[i]);
        }
    }

    /*  Given a model with sequences that have duplicate names, verify
        that each sequence from the imported model has a unique
        name.

        $sequence "idle_1" <-------+
        $sequence "idle"   <----+  |
        $sequence "idle_2"      |  |
        $sequence "idle"   -----+  |
        $sequence "idle_0"      |  |
        $sequence "idle_1" -----|--+
        $sequence "idle_3"      |
        $sequence "idle"   -----+
        $sequence "idle_7"
    */
    void duplicateSequenceNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "duplicate_sequences.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_sequence_names = {
            "idle_1",
            "idle",
            "idle_2",
            "idle_4",
            "idle_0",
            "idle_1_0",
            "idle_3",
            "idle_5",
            "idle_7"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_SEQUENCE_INFOS, expected_sequence_names);
    }

    /*  Given a model with sequences that have empty names, verify
        that each sequence from the imported model has a unique
        name.

        $sequence ""            <----+---- empty names
        $sequence "Sequence_1"       |
        $sequence ""            <----+
        $sequence "Sequence_4"       |
        $sequence ""            <----+
        $sequence "Sequence_8"       |
        $sequence ""            <----+
        $sequence "Sequence_2"       |
        $sequence ""            <----+
    */
    void emptySequenceNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "unnamed_sequences.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_sequence_names = {
            "Sequence",
            "Sequence_1",
            "Sequence_0",
            "Sequence_4",
            "Sequence_3",
            "Sequence_8",
            "Sequence_5",
            "Sequence_2",
            "Sequence_6"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_SEQUENCE_INFOS, expected_sequence_names);
    }

    /*  Given a model with sequence groups that have duplicate names,
        verify that each sequence group from the imported model has
        a unique name.

        "default"
        $sequencegroup "SequenceGroup"    <----+
        $sequencegroup "SequenceGroup_1"       |
        $sequencegroup "SequenceGroup_5"  <----|--+
        $sequencegroup "SequenceGroup"    -----+  |
        $sequencegroup "SequenceGroup_0"       |  |
        $sequencegroup "SequenceGroup"    -----+  |
        $sequencegroup "SequenceGroup_5"  --------+
        $sequencegroup "SequenceGroup_6"
        $sequencegroup "SequenceGroup_2"
    */
    void duplicateSequenceGroupNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "duplicate_sequence_groups/duplicate_sequence_groups.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_sequence_names = {
            "default",
            "SequenceGroup",
            "SequenceGroup_1",
            "SequenceGroup_5",
            "SequenceGroup_3",
            "SequenceGroup_0",
            "SequenceGroup_4",
            "SequenceGroup_5_0",
            "SequenceGroup_6",
            "SequenceGroup_2"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_SEQUENCE_GROUPS, expected_sequence_names);
    }

    /*  Given a model with sequence groups that have empty names,
        verify that each sequence group from the imported model has
        a unique name.

        "default"
        $sequencegroup ""                 <----+---- empty names
        $sequencegroup "SequenceGroup_2"       |
        $sequencegroup "SequenceGroup_6"       |
        $sequencegroup ""                 <----+
        $sequencegroup ""                 <----+
        $sequencegroup "SequenceGroup_1"       |
        $sequencegroup "SequenceGroup_5"       |
        $sequencegroup ""                 <----+
        $sequencegroup "SequenceGroup_4"
    */
    void emptySequenceGroupNames() {
        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MDL_HL1_MODELS_DIR "unnamed_sequence_groups/unnamed_sequence_groups.mdl", aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        const std::vector<std::string> expected_sequence_names = {
            "default",
            "SequenceGroup",
            "SequenceGroup_2",
            "SequenceGroup_6",
            "SequenceGroup_0",
            "SequenceGroup_3",
            "SequenceGroup_1",
            "SequenceGroup_5",
            "SequenceGroup_7",
            "SequenceGroup_4"
        };

        expect_named_children(scene, AI_MDL_HL1_NODE_SEQUENCE_GROUPS, expected_sequence_names);
    }

    /*  Verify that mOffsetMatrix applies the correct
        inverse bind pose transform. */
    void offsetMatrixUnappliesTransformations() {

        const float TOLERANCE = 0.01f;

        Assimp::Importer importer;
        const aiScene *scene = importer.ReadFile(MDL_HL1_FILE_MAN, aiProcess_ValidateDataStructure);
        EXPECT_NE(nullptr, scene);

        aiNode *scene_bones_node = scene->mRootNode->FindNode(AI_MDL_HL1_NODE_BONES);

        const aiMatrix4x4 identity_matrix;

        for (unsigned int i = 0; i < scene->mNumMeshes; ++i) {
            aiMesh *scene_mesh = scene->mMeshes[i];
            for (unsigned int j = 0; j < scene_mesh->mNumBones; ++j) {
                aiBone *scene_mesh_bone = scene_mesh->mBones[j];

                // Store local node transforms.
                aiNode *n = scene_bones_node->FindNode(scene_mesh_bone->mName);
                std::vector<aiMatrix4x4> bone_matrices = { n->mTransformation };
                while (n->mParent != scene->mRootNode) {
                    n = n->mParent;
                    bone_matrices.push_back(n->mTransformation);
                }

                // Compute absolute node transform.
                aiMatrix4x4 transform;
                for (auto it = bone_matrices.rbegin(); it != bone_matrices.rend(); ++it)
                    transform *= *it;

                // Unapply the transformation using the offset matrix.
                aiMatrix4x4 unapplied_transform = scene_mesh_bone->mOffsetMatrix * transform;

                // Ensure that we have, approximately, the identity matrix.
                expect_equal_matrices(identity_matrix, unapplied_transform, TOLERANCE);
            }
        }
    }

private:
    void expect_named_children(const aiNode *parent_node, const std::vector<std::string> &expected_names) {
        EXPECT_NE(nullptr, parent_node);
        EXPECT_EQ(expected_names.size(), parent_node->mNumChildren);

        for (unsigned int i = 0; i < parent_node->mNumChildren; ++i)
            EXPECT_EQ(expected_names[i], parent_node->mChildren[i]->mName.C_Str());
    }

    void expect_named_children(const aiScene *scene, const char *node_name, const std::vector<std::string> &expected_names) {
        expect_named_children(scene->mRootNode->FindNode(node_name), expected_names);
    }

    void expect_equal_matrices(const aiMatrix4x4 &expected, const aiMatrix4x4 &actual, float abs_error) {
        for (int i = 0; i < 4; ++i) {
            for (int j = 0; j < 4; ++j)
                EXPECT_NEAR(expected[i][j], actual[i][j], abs_error);
        }
    }
};

TEST_F(utMDLImporter_HL1_Nodes, emptyBonesNames) {
    emptyBonesNames();
}

TEST_F(utMDLImporter_HL1_Nodes, emptyBodypartsNames) {
    emptyBodypartsNames();
}

TEST_F(utMDLImporter_HL1_Nodes, duplicateBodypartsNames) {
    duplicateBodypartsNames();
}

TEST_F(utMDLImporter_HL1_Nodes, duplicateSubModelsNames) {
    duplicateSubModelsNames();
}

TEST_F(utMDLImporter_HL1_Nodes, emptySequenceNames) {
    emptySequenceNames();
}

TEST_F(utMDLImporter_HL1_Nodes, duplicateSequenceNames) {
    duplicateSequenceNames();
}

TEST_F(utMDLImporter_HL1_Nodes, emptySequenceGroupNames) {
    emptySequenceGroupNames();
}

TEST_F(utMDLImporter_HL1_Nodes, duplicateSequenceGroupNames) {
    duplicateSequenceGroupNames();
}

TEST_F(utMDLImporter_HL1_Nodes, offsetMatrixUnappliesTransformations) {
    offsetMatrixUnappliesTransformations();
}
