// Main class of the Viewer

#ifndef IGL_VIEWER_H
#define IGL_VIEWER_H

#include <AntTweakBar.h>

#include <vector>
#include <string>
#include <cstdint>

#define IGL_MOD_SHIFT           0x0001
#define IGL_MOD_CONTROL         0x0002
#define IGL_MOD_ALT             0x0004
#define IGL_MOD_SUPER           0x0008

#ifdef ENABLE_XML_SERIALIZATION
  #define IGL_HEADER_ONLY
  #include <igl/xml/XMLSerializer.h>
  #include <igl/xml/XMLSerialization.h>
#endif

#include <Eigen/Core>

namespace igl
{

  class Plugin_manager;

  class Viewer
  {
  public:

    void launch(std::string filename = "");
    void init(Plugin_manager* pm);

    class Options
    #ifdef ENABLE_XML_SERIALIZATION
    : public ::igl::XMLSerialization
    #endif
    {
    public:
      Options()
      #ifdef ENABLE_XML_SERIALIZATION
      : XMLSerialization("Options")
      #endif
      {};
      void InitSerialization();

      // Shape material
      float shininess;

      // Colors
      Eigen::Vector3f background_color;
      Eigen::Vector3f line_color;

      // Lighting
      Eigen::Vector3f light_position;

      // Trackball angle (quaternion)
      Eigen::Vector4f trackball_angle;

      // Model viewing parameters
      float model_zoom;
      Eigen::Vector3f model_translation;

      // Model viewing paramters (uv coordinates)
      float model_zoom_uv;
      Eigen::Vector3f model_translation_uv;

      // Camera parameters
      float camera_zoom;
      bool orthographic;
      Eigen::Vector3f camera_eye;
      Eigen::Vector3f camera_up;
      Eigen::Vector3f camera_center;
      float camera_view_angle;
      float camera_dnear;
      float camera_dfar;

      // Visualization options
      bool show_overlay;
      bool show_overlay_depth;
      bool show_texture;
      bool show_faces;
      bool show_lines;
      bool show_vertid;
      bool show_faceid;
      bool invert_normals;

      // Point size / line width
      float point_size;
      float line_width;

      // Enable per-face colors and normals
      bool face_based;
    };

    enum DirtyFlags
    {
      DIRTY_NONE           = 0x0000,
      DIRTY_POSITION       = 0x0001,
      DIRTY_UV             = 0x0002,
      DIRTY_NORMAL         = 0x0004,
      DIRTY_AMBIENT        = 0x0008,
      DIRTY_DIFFUSE        = 0x0010,
      DIRTY_SPECULAR       = 0x0020,
      DIRTY_TEXTURE        = 0x0040,
      DIRTY_FACE           = 0x0080,
      DIRTY_MESH           = 0x00FF,
      DIRTY_OVERLAY_LINES  = 0x0100,
      DIRTY_OVERLAY_POINTS = 0x0200,
      DIRTY_ALL            = 0x03FF
    };

    class Data
    #ifdef ENABLE_XML_SERIALIZATION
    : public ::igl::XMLSerialization
    #endif
    {
    public:
      Data()
      #ifdef ENABLE_XML_SERIALIZATION
      : XMLSerialization("Data"), dirty(DIRTY_ALL)
      #endif
      {};

      void InitSerialization();

      Eigen::MatrixXd V; // Vertices of the current mesh (#V x 3)
      Eigen::MatrixXi F; // Faces of the mesh (#F x 3)

      // Per face attributes
      Eigen::MatrixXd F_normals; // One normal per face

      Eigen::MatrixXd F_material_ambient; // Per face ambient color
      Eigen::MatrixXd F_material_diffuse; // Per face diffuse color
      Eigen::MatrixXd F_material_specular; // Per face specular color

      // Per vertex attributes
      Eigen::MatrixXd V_normals; // One normal per vertex

      Eigen::MatrixXd V_material_ambient; // Per vertex ambient color
      Eigen::MatrixXd V_material_diffuse; // Per vertex diffuse color
      Eigen::MatrixXd V_material_specular; // Per vertex specular color

      // UV parametrization
      Eigen::MatrixXd V_uv; // UV vertices
      Eigen::MatrixXi F_uv; // optional faces for UVs

      // Texture
      Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic> texture_R;
      Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic> texture_G;
      Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic> texture_B;

      // Overlays

      // Lines plotted over the scene
      // (Every row contains 9 doubles in the following format S_x, S_y, S_z, T_x, T_y, T_z, C_r, C_g, C_b),
      // with S and T the coordinates of the two vertices of the line in global coordinates, and C the color in floating point rgb format
      Eigen::MatrixXd lines;

      // Points plotted over the scene
      // (Every row contains 6 doubles in the following format P_x, P_y, P_z, C_r, C_g, C_b),
      // with P the position in global coordinates of the center of the point, and C the color in floating point rgb format
      Eigen::MatrixXd points;

      // Text labels plotted over the scene
      // Textp contains, in the i-th row, the position in global coordinates where the i-th label should be anchored
      // Texts contains in the i-th position the text of the i-th label
      Eigen::MatrixXd           labels_positions;
      std::vector<std::string > labels_strings;

      // Marks dirty buffers that need to be uploaded to OpenGL
      uint32_t dirty;

      // Caches the two-norm between the min/max point of the bounding box
      float object_scale;
      /*********************************/
    };

    class OpenGL_shader
    {
    public:
      typedef unsigned int GLuint;
      typedef int GLint;

      GLuint vertex_shader;
      GLuint fragment_shader;
      GLuint geometry_shader;
      GLuint program_shader;

      OpenGL_shader() : vertex_shader(0), fragment_shader(0),
        geometry_shader(0), program_shader(0) { }

      // Create a new shader from the specified source strings
      bool init(const std::string &vertex_shader_string,
        const std::string &fragment_shader_string,
        const std::string &fragment_data_name,
        const std::string &geometry_shader_string = "",
        int geometry_shader_max_vertices = 3);

      // Create a new shader from the specified files on disk
      bool init_from_files(const std::string &vertex_shader_filename,
        const std::string &fragment_shader_filename,
        const std::string &fragment_data_name,
        const std::string &geometry_shader_filename = "",
        int geometry_shader_max_vertices = 3);

      // Select this shader for subsequent draw calls
      void bind();

      // Release all OpenGL objects
      void free();

      // Return the OpenGL handle of a named shader attribute (-1 if it does not exist)
      GLint attrib(const std::string &name) const;

      // Return the OpenGL handle of a uniform attribute (-1 if it does not exist)
      GLint uniform(const std::string &name) const;

      // Bind a per-vertex array attribute and refresh its contents from an Eigen amtrix
      GLint bindVertexAttribArray(const std::string &name, GLuint bufferID,
        const Eigen::MatrixXf &M, bool refresh) const;
    };

    class OpenGL_state
    {
    public:
      typedef unsigned int GLuint;

      GLuint vao_mesh;
      GLuint vao_overlay_lines;
      GLuint vao_overlay_points;
      OpenGL_shader shader_mesh;
      OpenGL_shader shader_overlay_lines;
      OpenGL_shader shader_overlay_points;

      GLuint vbo_V; // Vertices of the current mesh (#V x 3)
      GLuint vbo_V_uv; // UV coordinates for the current mesh (#V x 2)
      GLuint vbo_V_normals; // Vertices of the current mesh (#V x 3)
      GLuint vbo_V_ambient; // Ambient material  (#V x 3)
      GLuint vbo_V_diffuse; // Diffuse material  (#V x 3)
      GLuint vbo_V_specular; // Specular material  (#V x 3)

      GLuint vbo_F; // Faces of the mesh (#F x 3)
      GLuint vbo_tex; // Texture

      GLuint vbo_lines_F;         // Indices of the line overlay
      GLuint vbo_lines_V;         // Vertices of the line overlay
      GLuint vbo_lines_V_colors;  // Color values of the line overlay
      GLuint vbo_points_F;        // Indices of the point overlay
      GLuint vbo_points_V;        // Vertices of the point overlay
      GLuint vbo_points_V_colors; // Color values of the point overlay

      // Temporary copy of the content of each VBO
      Eigen::MatrixXf V_vbo;
      Eigen::MatrixXf V_normals_vbo;
      Eigen::MatrixXf V_ambient_vbo;
      Eigen::MatrixXf V_diffuse_vbo;
      Eigen::MatrixXf V_specular_vbo;
      Eigen::MatrixXf V_uv_vbo;
      Eigen::MatrixXf lines_V_vbo;
      Eigen::MatrixXf lines_V_colors_vbo;
      Eigen::MatrixXf points_V_vbo;
      Eigen::MatrixXf points_V_colors_vbo;

      int tex_u;
      int tex_v;
      Eigen::Matrix<char,Eigen::Dynamic,1> tex;

      Eigen::Matrix<unsigned, Eigen::Dynamic, Eigen::Dynamic> F_vbo;
      Eigen::Matrix<unsigned, Eigen::Dynamic, Eigen::Dynamic> lines_F_vbo;
      Eigen::Matrix<unsigned, Eigen::Dynamic, Eigen::Dynamic> points_F_vbo;

      // Marks dirty buffers that need to be uploaded to OpenGL
      uint32_t dirty;

      // Create a new set of OpenGL buffer objects
      void init();

      // Update contents from a 'Data' instance
      void set_data(const Data &data, bool face_based, bool invert_normals);

      // Bind the underlying OpenGL buffer objects for subsequent mesh draw calls
      void bind_mesh();

      /// Draw the currently buffered mesh (either solid or wireframe)
      void draw_mesh(bool solid);

      // Bind the underlying OpenGL buffer objects for subsequent line overlay draw calls
      void bind_overlay_lines();

      /// Draw the currently buffered line overlay
      void draw_overlay_lines();

      // Bind the underlying OpenGL buffer objects for subsequent point overlay draw calls
      void bind_overlay_points();

      /// Draw the currently buffered point overlay
      void draw_overlay_points();

      // Release the OpenGL buffer objects
      void free();
    };

    // Stores all the viewing options
    Options options;

    // Stores all the data that should be visualized
    Data data;

    // Stores the vbos indices and opengl related settings
    OpenGL_state opengl;

    // Pointer to the plugin_manager (usually it will be a global variable)
    Plugin_manager* plugin_manager;
    void init_plugins();
    void shutdown_plugins();

    // Temporary data stored when the mouse button is pressed
    Eigen::Vector4f down_rotation;
    int current_mouse_x;
    int current_mouse_y;
    int down_mouse_x;
    int down_mouse_y;
    float down_mouse_z;
    Eigen::Vector3f down_translation;
    bool down;

    // Anttweak bar
    TwBar* bar;

    // Window size
    int width;
    int height;

    // Keep track of the global position of the scrollwheel
    float scroll_position;

    // Useful functions
    void compute_normals(); // Computes the normals of the mesh
    void uniform_colors(Eigen::Vector3d ambient, Eigen::Vector3d diffuse, Eigen::Vector3d specular); // assign uniform colors to all faces/vertices
    void grid_texture(); // Generate a default grid texture

    void clear_mesh();      // Clear the mesh data
    void alignCameraCenter(); // Adjust the view to see the entire model

    // Change the visualization mode, invalidating the cache if necessary
    void set_face_based(bool newvalue);

    // Helpers that can draw the most common meshes
    void set_mesh(const Eigen::MatrixXd& V, const Eigen::MatrixXi& F);
    void set_normals(const Eigen::MatrixXd& N);
    // Set the color of the mesh
    //
    // Inputs:
    //   C  #V|#F|1 by 3 list of colors
    void set_colors(const Eigen::MatrixXd &C);
    void set_uv(const Eigen::MatrixXd& UV);
    void set_uv(const Eigen::MatrixXd& UV_V, const Eigen::MatrixXi& UV_F);
    void set_texture(
                      const Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic>& R,
                      const Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic>& G,
                      const Eigen::Matrix<char,Eigen::Dynamic,Eigen::Dynamic>& B);

    void add_points(const Eigen::MatrixXd& P,  const Eigen::MatrixXd& C);
    void add_edges (const Eigen::MatrixXd& P1, const Eigen::MatrixXd& P2, const Eigen::MatrixXd& C);
    void add_label (const Eigen::VectorXd& P,  const std::string& str);

    // Save the OpenGL transformation matrices used for the previous rendering pass
    Eigen::Matrix4f view;
    Eigen::Matrix4f model;
    Eigen::Matrix4f proj;

    Eigen::Vector4f viewport;

    // UI Enumerations
    enum MouseButton {IGL_LEFT, IGL_MIDDLE, IGL_RIGHT};
    enum MouseMode { NOTHING, ROTATION, ZOOM, PAN, TRANSLATE} mouse_mode;
    enum KeyModifier { NO_KEY = TW_KMOD_NONE, SHIFT = TW_KMOD_SHIFT, CTRL =TW_KMOD_CTRL, ALT = TW_KMOD_ALT } key_modifier;

    Viewer();
    ~Viewer();

    // Mesh IO
    bool load_mesh_from_file(const char* mesh_file_name);
    bool save_mesh_to_file(const char* mesh_file_name);

    // Callbacks
    bool key_down(unsigned char key, int modifier);
    bool key_up(unsigned char key, int modifier);

    bool mouse_down(MouseButton button, int modifier);
    bool mouse_up(MouseButton button, int modifier);

    bool mouse_move(int mouse_x, int mouse_y);
    bool mouse_scroll(float delta_y);

    // Scene IO
    bool load_scene();
    bool save_scene();

    // Determines how much to zoom and shift such that the mesh fills the unit
    // box (centered at the origin)
    static void get_scale_and_shift_to_fit_mesh(const Eigen::MatrixXd& vertices,
                                                float & zoom,
                                                Eigen::Vector3f& shift);


    // Init opengl shaders and VBOs
    void init_opengl();
    void free_opengl();

    // Draw everything
    void draw();

    // OpenGL context resize
    void resize(int w, int h);


    // C-style callbacks
    bool (*callback_pre_draw)(Viewer& viewer);
    bool (*callback_post_draw)(Viewer& viewer);
    bool (*callback_mouse_down)(Viewer& viewer, int button, int modifier);
    bool (*callback_mouse_up)(Viewer& viewer, int button, int modifier);
    bool (*callback_mouse_move)(Viewer& viewer, int mouse_x, int mouse_y);
    bool (*callback_mouse_scroll)(Viewer& viewer, float delta_y);
    bool (*callback_key_down)(Viewer& viewer, unsigned char key, int modifiers);
    bool (*callback_key_up)(Viewer& viewer, unsigned char key, int modifiers);

    /********* AntTweakBar callbacks *********/
    static void TW_CALL snap_to_canonical_quaternion_cb(void *clientData);
    static void TW_CALL save_scene_cb(void *clientData);
    static void TW_CALL load_scene_cb(void *clientData);
    static void TW_CALL open_dialog_mesh(void *clientData);
    static void TW_CALL align_camera_center_cb(void *clientData);
    static void TW_CALL set_face_based_cb(const void *param, void *clientData);
    static void TW_CALL get_face_based_cb(void *param, void *clientData);
    static void TW_CALL set_invert_normals_cb(const void *param, void *clientData);
    static void TW_CALL get_invert_normals_cb(void *param, void *clientData);
  };


  // Abstract class for plugins
  // All plugins MUST have this class as their parent and implement all the callbacks
  // For an example of a basic plugins see plugins/skeleton.h
  //
  // Return value of callbacks: returning true to any of the callbacks tells Preview3D that the event has been
  // handled and that it should not be passed to other plugins or to other internal functions of Preview3D

  class Viewer_plugin
  #ifdef ENABLE_XML_SERIALIZATION
  : public ::igl::XMLSerialization
  #endif
  {
  public:
    Viewer_plugin()
    #ifdef ENABLE_XML_SERIALIZATION
    : XMLSerialization("dummy")
    #endif
    {plugin_name = "dummy";};

    ~Viewer_plugin(){};

    // This function is called when the viewer is initialized (no mesh will be loaded at this stage)
    virtual void init(igl::Viewer *_viewer)
    {
      viewer = _viewer;
    }

    // This function is called before shutdown
    virtual void shutdown()
    {
    }

    // This function is called before a mesh is loaded
    virtual bool load(std::string filename)
    {
      return false;
    }

    // This function is called before a mesh is saved
    virtual bool save(std::string filename)
    {
      return false;
    }

    // Runs immediately after a new mesh had been loaded.
    virtual bool post_load()
    {
      return false;
    }

    // This function is called before the draw procedure of Preview3D
    virtual bool pre_draw()
    {
      return false;
    }

    // This function is called after the draw procedure of Preview3D
    virtual bool post_draw()
    {
      return false;
    }

    // This function is called when the mouse button is pressed
    // - button can be GLUT_LEFT_BUTTON, GLUT_MIDDLE_BUTTON or GLUT_RIGHT_BUTTON
    // - modifiers is a bitfield that might one or more of the following bits Preview3D::NO_KEY, Preview3D::SHIFT, Preview3D::CTRL, Preview3D::ALT;
    virtual bool mouse_down(int button, int modifier)
    {
      return false;
    }

    // This function is called when the mouse button is released
    // - button can be GLUT_LEFT_BUTTON, GLUT_MIDDLE_BUTTON or GLUT_RIGHT_BUTTON
    // - modifiers is a bitfield that might one or more of the following bits Preview3D::NO_KEY, Preview3D::SHIFT, Preview3D::CTRL, Preview3D::ALT;
    virtual bool mouse_up(int button, int modifier)
    {
      return false;
    }

    // This function is called every time the mouse is moved
    // - mouse_x and mouse_y are the new coordinates of the mouse pointer in screen coordinates
    virtual bool mouse_move(int mouse_x, int mouse_y)
    {
      return false;
    }

    // This function is called every time the scroll wheel is moved
    // Note: this callback is not working with every glut implementation
    virtual bool mouse_scroll(float delta_y)
    {
      return false;
    }

    // This function is called when a keyboard key is pressed
    // - modifiers is a bitfield that might one or more of the following bits Preview3D::NO_KEY, Preview3D::SHIFT, Preview3D::CTRL, Preview3D::ALT;
    virtual bool key_down(unsigned char key, int modifiers)
    {
      return false;
    }

    // This function is called when a keyboard key is release
    // - modifiers is a bitfield that might one or more of the following bits Preview3D::NO_KEY, Preview3D::SHIFT, Preview3D::CTRL, Preview3D::ALT;
    virtual bool key_up(unsigned char key, int modifiers)
    {
      return false;
    }

    // Priority of the plugin (use only positive numbers, negative are reserved for internal use)
    // The plugins will be initialized in increasing priority
    virtual int priority()
    {
      return 0;
    }

    std::string plugin_name;
  protected:
    // Pointer to the main Preview3D class
    Viewer *viewer;
  };

  // Keeps the lists of plugins
  class Plugin_manager
  {
  public:

    Plugin_manager() {}

    /** Registers a new plugin. A call to this function should be
     implemented in the constructor of all classes derived from PreviewPlugin. */
    bool register_plugin(Viewer_plugin* p)
    {
      auto it = plugin_list.begin();
      while(it != plugin_list.end() && (*it)->priority() < p->priority())
        ++it;

      plugin_list.insert(it,p);
      return true;
    }

    std::vector<Viewer_plugin*> plugin_list;
  };


} // end namespace

#ifdef IGL_HEADER_ONLY
#  include "Viewer.cpp"
#endif

#endif