//
//  Lol Engine
//
//  Copyright © 2010—2019 Sam Hocevar <sam@hocevar.net>
//            © 2014—2015 Benjamin “Touky” Huet <huet.benjamin@gmail.com>
//
//  Lol Engine is free software. It comes without any warranty, to
//  the extent permitted by applicable law. You can redistribute it
//  and/or modify it under the terms of the Do What the Fuck You Want
//  to Public License, Version 2, as published by the WTFPL Task Force.
//  See http://www.wtfpl.net/ for more details.
//

#pragma once

//
// The Scene class
// ---------------
//

#include <memory>
#include <cstdint>

#include "tileset.h"
#include "light.h"
#include "camera.h"
#include "mesh/mesh.h"

#include <lol/gpu/renderer.h>
#include <lol/base/thread.h>

#define LOL_MAX_LIGHT_COUNT 8

namespace lol
{

//-----------------------------------------------------------------------------
class PrimitiveSource
{
    friend class Scene;

public:
    PrimitiveSource() { }
    virtual ~PrimitiveSource() { }
    virtual void Render(Scene& scene);

private:
};

/*
 * A quick and dirty Tile structure for 2D blits
 */

struct Tile
{
    mat4 m_model;
    TileSet *m_tileset;
    int m_id;
};

class PrimitiveRenderer
{
    friend class Scene;

public:
    PrimitiveRenderer() { }
    virtual ~PrimitiveRenderer() { }
    virtual void Render(Scene& scene, std::shared_ptr<PrimitiveSource> primitive);

private:
    bool m_fire_and_forget = false;
};

class SceneDisplay
{
    friend class Scene;

public:
    SceneDisplay() { }
    virtual ~SceneDisplay() { }

    /* pos/size/... methods */
    virtual void set_resolution(ivec2 resolution) { UNUSED(resolution); }
    virtual ivec2 resolution() const { return ivec2(0); }

    virtual void SetPosition(ivec2 position) { UNUSED(position); }

    /* TODO: Should that be there or in Video ? */
    static void Add(SceneDisplay* display);
    static int GetCount();
    static SceneDisplay* GetDisplay(int index = 0);
    static void DestroyAll();

    /* Implement these in the platform section */
    static int GetPhysicalCount();
    static const char* GetPhysicalName(int index = 0);

//protected:
    virtual void Enable();
    virtual void Disable();
};

class Scene
{
    friend class Video;

private:
    static array<Scene*> g_scenes;

    Scene(ivec2 size);
    ~Scene();

public:
    static void AddNew(ivec2 size);
private: //Private because I don't know if we should have it
    static void DestroyScene(Scene* scene);
private:
    static void DestroyAll();
public:
    static int GetCount();
    static bool IsReady(int index = 0);
    static Scene& GetScene(int index = 0);

public:
    //TODO: don't like the name
    void Link(entity* entity);
    bool IsRelevant(entity* entity);

public:
    Camera* GetCamera(int cam_idx = -1);
    int PushCamera(Camera *cam);
    void PopCamera(Camera *cam);
    void SetTileCam(int cam_idx);

    void Reset();

    std::shared_ptr<Renderer> get_renderer() { return m_renderer; }

    /* ============================== */
#   define _KEY_IDX (uintptr_t)key /* TOUKY: I don't like that. hash should be fixed to handle these custom stuff */
    /* ============================== */
private:
    int HasPrimitiveSource(uintptr_t key);
    int AddPrimitiveSource(uintptr_t key, std::shared_ptr<class PrimitiveSource> source);
    void SetPrimitiveSource(int index, uintptr_t key, std::shared_ptr<class PrimitiveSource> source);
    void ReleasePrimitiveSource(int index, uintptr_t key);
    void ReleaseAllPrimitiveSources(uintptr_t key);
public:
    /* === Primitive source stuff === */
    /* Returns the number of primitive source set to the given entity */
    template <typename T>
    int HasPrimitiveSource(T* key)
    {
        ASSERT(key);
        return HasPrimitiveSource(_KEY_IDX);
    }
    /* Add a primitive sources linked to the given entity
     * Returns the slot number */
    template <typename T>
    int AddPrimitiveSource(T* key, std::shared_ptr<class PrimitiveSource> source)
    {
        ASSERT(key);
        return AddPrimitiveSource(_KEY_IDX, source);
    }
    /* Update the primitive source at index linked to the given entity
     * Deletes the old one
     * The slot is kept even if source == nullptr */
    template <typename T>
    void SetPrimitiveSource(int index, T* key, std::shared_ptr<class PrimitiveSource> source)
    {
        ASSERT(key);
        SetPrimitiveSource(index, _KEY_IDX, source);
    }
    /* Remove primitive source at index set to the given entity */
    template <typename T>
    void ReleasePrimitiveSource(int index, T* key)
    {
        ASSERT(key);
        ReleasePrimitiveSource(index, _KEY_IDX);
    }
    /* Remove all primitive source set to the given entity */
    template <typename T>
    void ReleaseAllPrimitiveSources(T* key)
    {
        ASSERT(key);
        ReleaseAllPrimitiveSources(_KEY_IDX);
    }

private:
    int HasPrimitiveRenderer(uintptr_t key);

    void AddPrimitiveRenderer(uintptr_t key, std::shared_ptr<class PrimitiveRenderer> renderer);
    void SetPrimitiveRenderer(int index, uintptr_t key, std::shared_ptr<class PrimitiveRenderer> renderer);
    void ReleasePrimitiveRenderer(int index, uintptr_t key);
    void ReleaseAllPrimitiveRenderers(uintptr_t key);
public:
    /* === Primitive renderer stuff === */
    /* Returns the number of primitive renderer set to the given entity */
    template <typename T>
    int HasPrimitiveRenderer(T* key)
    {
        ASSERT(key);
        return HasPrimitiveRenderer(_KEY_IDX);
    }
    /* Add a primitive renderer linked to the given entity
     * The primitive is considered as Fire&Forget and
     * will be destroyed at the end of the frame */
    template <typename T>
    void AddPrimitiveRenderer(T* key, std::shared_ptr<class PrimitiveRenderer> renderer)
    {
        ASSERT(key);
        AddPrimitiveRenderer(_KEY_IDX, renderer);
    }
    /* Update the primitive renderer linked to the given entity
     * Deletes the old one
     * Will assert if renderer == nullptr */
    template <typename T>
    void SetPrimitiveRenderer(int index, T* key, std::shared_ptr<class PrimitiveRenderer> renderer)
    {
        ASSERT(key && renderer);
        SetPrimitiveRenderer(index, _KEY_IDX, renderer);
    }
    /* Remove primitive renderer at index set to the given entity */
    template <typename T>
    void ReleasePrimitiveRenderer(int index, T* key)
    {
        ASSERT(key);
        ReleasePrimitiveRenderer(index, _KEY_IDX);
    }
    /* Remove all primitive renderer set to the given entity */
    template <typename T>
    void ReleaseAllPrimitiveRenderers(T* key)
    {
        ASSERT(key);
        ReleaseAllPrimitiveRenderers(_KEY_IDX);
    }
    /* ============================== */
#   undef _KEY_IDX /* (uintptr_t)key *//* TOUKY: I don't like that. hash should be fixed to handle these custom stuff */
    /* ============================== */

    /* FIXME: this should be deprecated -- it doesn't really match
     * the architecture we want to build */
    void AddTile(TileSet *tileset, int id, vec3 pos, vec2 scale, float radians);
    void AddTile(TileSet *tileset, int id, mat4 model);

public:
    void AddLine(vec3 a, vec3 b, vec4 color);
    void AddLine(vec3 a, vec3 b, vec4 color, float duration, int mask);

    void AddLight(Light *light);
    array<Light *> const &GetLights();

    /* === Render stuff === */
    void SetDisplay(SceneDisplay* display);
    void EnableDisplay();
    void DisableDisplay();

    void resize(ivec2 size);

    void pre_render(float seconds);
    void render(float seconds);
    void post_render(float seconds);

private:
    void render_primitives();
    void render_tiles();
    void render_lines(float seconds);

    ivec2 m_size, m_wanted_size;

    std::shared_ptr<Renderer> m_renderer;

    //
    // The old SceneData stuff
    //

    /* Mask ID */
    /* TODO: Do a mask class that handles more than 64 slots */
    static uint64_t g_used_id;
    uint64_t m_mask_id = 0;

    /* Scene display: if none has been set to the scene,
     * the default one created by the app will be used */
    SceneDisplay* m_display = nullptr;

    /** Render buffers: where to render to. */
    std::shared_ptr<Framebuffer> m_renderbuffer[4];

    struct postprocess
    {
        std::shared_ptr<Shader> blit_shader, pp_shader;
        std::shared_ptr<VertexBuffer> quad_vbo;
        std::shared_ptr<VertexDeclaration> quad_vdecl;
        ShaderUniform m_buffer_uni[2][3];
        ShaderAttrib blit_pos_attr, pp_pos_attr;
    }
    m_pp;

    /* Sources are shared by all scenes.
     * Renderers are scene-dependent. They get the primitive in the identical
     * slot to render with the given scene.
     * Primitives and renderers will be kept until:
     * - Updated by entity
     * - Marked Fire&Forget
     * - Scene is destroyed */
    std::map<uintptr_t, array<std::shared_ptr<PrimitiveRenderer>>> m_prim_renderers;
    static std::map<uintptr_t, array<std::shared_ptr<PrimitiveSource>>> g_prim_sources;
    static mutex g_prim_mutex;

    Camera *m_default_cam;
    array<Camera *> m_camera_stack;

    /* Old line API <P0, P1, COLOR, TIME, MASK> */
    struct line_api
    {
        //float m_duration, m_segment_size;
        //vec4 m_color;
        array<vec3, vec3, vec4, float, int, bool, bool> m_lines;
        int /*m_mask,*/ m_debug_mask;
        std::shared_ptr<Shader> m_shader;
        std::shared_ptr<VertexDeclaration> m_vdecl;
    }
    m_line_api;

    /* The old tiles API */
    struct tile_api
    {
        int m_cam;
        array<Tile> m_tiles;
        array<Tile> m_palettes;
        array<Light *> m_lights;

        std::shared_ptr<Shader> m_shader;
        std::shared_ptr<Shader> m_palette_shader;

        std::shared_ptr<VertexDeclaration> m_vdecl;
        array<std::shared_ptr<VertexBuffer>> m_bufs;
    }
    m_tile_api;
};

} /* namespace lol */