/*
Open Asset Import Library (assimp)
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*/

/** @file IRRLoader.h
 *  @brief Declaration of the .irrMesh (Irrlight Engine Mesh Format)
 *  importer class.
 */
#ifndef AI_IRRLOADER_H_INCLUDED
#define AI_IRRLOADER_H_INCLUDED

#include "AssetLib/Irr/IRRShared.h"
#include "Common/Importer.h"

#include <assimp/SceneCombiner.h>
#include <assimp/StringUtils.h>
#include <assimp/anim.h>

namespace Assimp {

// ---------------------------------------------------------------------------
/** Irr importer class.
 *
 * Irr is the native scene file format of the Irrlight engine and its editor
 * irrEdit. As IrrEdit itself is capable of importing quite many file formats,
 * it might be a good file format for data exchange.
 */
class IRRImporter : public BaseImporter, public IrrlichtBase {
public:
    IRRImporter();
    ~IRRImporter() override;

    // -------------------------------------------------------------------
    /** Returns whether the class can handle the format of the given file.
     *  See BaseImporter::CanRead() for details.
     */
    bool CanRead(const std::string &pFile, IOSystem *pIOHandler,
            bool checkSig) const override;

protected:
    const aiImporterDesc *GetInfo() const override;
    void InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) override;
    void SetupProperties(const Importer *pImp) override;

private:
    /** Data structure for a scene-graph node animator
     */
    struct Animator {
        // Type of the animator
        enum AT {
            UNKNOWN = 0x0,
            ROTATION = 0x1,
            FLY_CIRCLE = 0x2,
            FLY_STRAIGHT = 0x3,
            FOLLOW_SPLINE = 0x4,
            OTHER = 0x5

        } type;

        explicit Animator(AT t = UNKNOWN) :
                type(t), speed(ai_real(0.001)), direction(ai_real(0.0), ai_real(1.0), ai_real(0.0)), circleRadius(ai_real(1.0)), tightness(ai_real(0.5)), loop(true), timeForWay(100) {
        }

        // common parameters
        ai_real speed;
        aiVector3D direction;

        // FLY_CIRCLE
        aiVector3D circleCenter;
        ai_real circleRadius;

        // FOLLOW_SPLINE
        ai_real tightness;
        std::vector<aiVectorKey> splineKeys;

        // ROTATION (angles given in direction)

        // FLY STRAIGHT
        // circleCenter = start, direction = end
        bool loop;
        int timeForWay;
    };

    /** Data structure for a scene-graph node in an IRR file
     */
    struct Node {
        // Type of the node
        enum ET {
            LIGHT,
            CUBE,
            MESH,
            SKYBOX,
            DUMMY,
            CAMERA,
            TERRAIN,
            SPHERE,
            ANIMMESH
        } type;

        explicit Node(ET t) :
                type(t), scaling(1.0, 1.0, 1.0) // assume uniform scaling by default
                ,
                parent(),
                framesPerSecond(0.0),
                id(),
                sphereRadius(1.0),
                spherePolyCountX(100),
                spherePolyCountY(100) {

            // Generate a default name for the node
            char buffer[128];
            static int cnt;
            ai_snprintf(buffer, 128, "IrrNode_%i", cnt++);
            name = std::string(buffer);

            // reserve space for up to 5 materials
            materials.reserve(5);

            // reserve space for up to 5 children
            children.reserve(5);
        }

        // Transformation of the node
        aiVector3D position, rotation, scaling;

        // Name of the node
        std::string name;

        // List of all child nodes
        std::vector<Node *> children;

        // Parent node
        Node *parent;

        // Animated meshes: frames per second
        // 0.f if not specified
        ai_real framesPerSecond;

        // Meshes: path to the mesh to be loaded
        std::string meshPath;
        unsigned int id;

        // Meshes: List of materials to be assigned
        // along with their corresponding material flags
        std::vector<std::pair<aiMaterial *, unsigned int>> materials;

        // Spheres: radius of the sphere to be generates
        ai_real sphereRadius;

        // Spheres: Number of polygons in the x,y direction
        unsigned int spherePolyCountX, spherePolyCountY;

        // List of all animators assigned to the node
        std::list<Animator> animators;
    };

    /** Data structure for a vertex in an IRR skybox
     */
    struct SkyboxVertex {
        SkyboxVertex() = default;

        //! Construction from single vertex components
        SkyboxVertex(ai_real px, ai_real py, ai_real pz,
                ai_real nx, ai_real ny, ai_real nz,
                ai_real uvx, ai_real uvy)

                :
                position(px, py, pz), normal(nx, ny, nz), uv(uvx, uvy, 0.0) {}

        aiVector3D position, normal, uv;
    };

    // -------------------------------------------------------------------
    // Parse <node> tag from XML file and extract child node
    // @param node XML node
    // @param guessedMeshesContained number of extra guessed meshes
    IRRImporter::Node *ParseNode(pugi::xml_node &node, BatchLoader& batch);

    // -------------------------------------------------------------------
    // Parse <attributes> tags within <node> tags and apply to scene node
    // @param attributeNode XML child node
    // @param nd Attributed scene node
    void ParseNodeAttributes(pugi::xml_node &attributeNode, IRRImporter::Node *nd, BatchLoader& batch);

    // -------------------------------------------------------------------
    // Parse an <animator> node and attach an animator to a node
    // @param animatorNode XML animator node
    // @param nd Animated scene node
    void ParseAnimators(pugi::xml_node &animatorNode, IRRImporter::Node *nd);

    // -------------------------------------------------------------------
    /// Fill the scene-graph recursively
    void GenerateGraph(Node *root, aiNode *rootOut, aiScene *scene,
            BatchLoader &batch,
            std::vector<aiMesh *> &meshes,
            std::vector<aiNodeAnim *> &anims,
            std::vector<AttachmentInfo> &attach,
            std::vector<aiMaterial *> &materials,
            unsigned int &defaultMatIdx);

    // -------------------------------------------------------------------
    /// Generate a mesh that consists of just a single quad
    aiMesh *BuildSingleQuadMesh(const SkyboxVertex &v1,
            const SkyboxVertex &v2,
            const SkyboxVertex &v3,
            const SkyboxVertex &v4);

    // -------------------------------------------------------------------
    /// Build a sky-box
    ///
    /// @param meshes Receives 6 output meshes
    /// @param materials The last 6 materials are assigned to the newly
    ///                  created meshes. The names of the materials are adjusted.
    void BuildSkybox(std::vector<aiMesh *> &meshes,
            std::vector<aiMaterial *> materials);

    // -------------------------------------------------------------------
    /** Copy a material for a mesh to the output material list
     *
     *  @param materials Receives an output material
     *  @param inmaterials List of input materials
     *  @param defMatIdx Default material index - UINT_MAX if not present
     *  @param mesh Mesh to work on
     */
    void CopyMaterial(std::vector<aiMaterial *> &materials,
            std::vector<std::pair<aiMaterial *, unsigned int>> &inmaterials,
            unsigned int &defMatIdx,
            aiMesh *mesh);

    // -------------------------------------------------------------------
    /** Compute animations for a specific node
     *
     *  @param root Node to be processed
     *  @param anims The list of output animations
     */
    void ComputeAnimations(Node *root, aiNode *real,
            std::vector<aiNodeAnim *> &anims);

private:
    /// Configuration option: desired output FPS
    double fps;

    /// Configuration option: speed flag was set?
    bool configSpeedFlag;

    std::vector<aiCamera*> cameras;
    std::vector<aiLight*> lights;
    unsigned int guessedMeshCnt;
    unsigned int guessedMatCnt;
    unsigned int guessedAnimCnt;
};

} // end of namespace Assimp

#endif // AI_IRRIMPORTER_H_INC
