#pragma once
#include "rtt.h"
#include "texture.h"
#include "shader.h"
#include "shape.h"
#include "brush.h"

NS_START

class Canvas
{
public:
    int m_width;
    int m_height;
    std::vector<Layer> m_layers;
    std::vector<Stroke> m_strokes;
    std::unique_ptr<Layer> m_tmp;
    Stroke* m_current_stroke = nullptr;
    int m_current_layer_idx = 0;
    RTT m_fb;
    Sampler m_sampler;
    Plane m_plane;
    BrushMesh m_mesh;
    bool m_use_instanced = false;
    std::minstd_rand prng;
    bool create(int width, int height)
    {
        m_width = width;
        m_height = height;
        m_tmp = std::make_unique<Layer>();
        m_tmp->create(width, height, "tmp");
        m_fb.create(width, height);
        m_sampler.create();
        m_plane.create<1>(1, 1);
        m_mesh.create();
        return true;
    }
    void resize(int width, int height)
    {
        m_width = width;
        m_height = height;
        m_tmp->create(width, height, "tmp");
        m_fb.create(width, height);
    }
    void layer_add(std::string name)
    {
        m_layers.emplace_back();
        m_layers.back().create(m_width, m_height, name);
    }
    void stroke_start(glm::vec2 point, float pressure, const ui::Brush& brush)
    {
        prng.seed(0);
        m_strokes.emplace_back();
        m_strokes.back().start(point, pressure, brush);
        m_current_stroke = &m_strokes.back();
    }
    void stroke_update(glm::vec2 point, float pressure)
    {
        m_current_stroke->add_point(point, pressure);

        m_fb.bindFramebuffer();

        GLint vp[4];
        GLfloat cc[4];
        glGetIntegerv(GL_VIEWPORT, vp);
        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);

        glViewport(0, 0, m_width, m_height);
        glEnable(GL_BLEND);

        auto proj = glm::ortho(0.f, (float)m_width, (float)m_height, 0.f, -1.f, 1.f);
        auto m_brush = m_current_stroke->m_brush;
        auto samples = m_current_stroke->compute_samples();
        auto& tex = TextureManager::get(m_brush.m_tex_id);
        tex.bind();
        m_sampler.bind(0);

        if (m_use_instanced)
        {
            m_mesh.shader.use();
            m_mesh.shader.u_vec4(kShaderUniform::Col, m_brush.m_tip_color);
            m_mesh.shader.u_int(kShaderUniform::Tex, 0);
            m_mesh.draw(samples, proj);
        }
        else
        {
            ShaderManager::use("stroke");
            ShaderManager::u_vec4(kShaderUniform::Col, m_brush.m_tip_color);
            ShaderManager::u_int(kShaderUniform::Tex, 0);
            for (const auto& s : samples)
            {
                auto mvp = proj *
                    glm::translate(glm::vec3(s.pos, 0)) *
                    glm::scale(glm::vec3(s.size, s.size, 1)) *
                    glm::eulerAngleZ(s.angle);

                ShaderManager::u_mat4(kShaderUniform::MVP, mvp);
                ShaderManager::u_float(kShaderUniform::Alpha, s.flow);
                m_plane.draw_fill();
            }
        }

        m_sampler.unbind();
        tex.unbind();

        glDisable(GL_BLEND);

        glViewport(vp[0], vp[1], vp[2], vp[3]);
        glClearColor(cc[0], cc[1], cc[2], cc[3]);

        m_fb.unbindFramebuffer();
    }
    void stroke_end()
    {
        m_current_stroke = nullptr;
    }
    void clear()
    {
        m_fb.bindFramebuffer();

        GLint vp[4];
        GLfloat cc[4];
        glGetIntegerv(GL_VIEWPORT, vp);
        glGetFloatv(GL_COLOR_CLEAR_VALUE, cc);

        glClearColor(1, 1, 1, 1);
        glClear(GL_COLOR_BUFFER_BIT);
        glViewport(0, 0, m_width, m_height);

        //

        glViewport(vp[0], vp[1], vp[2], vp[3]);
        glClearColor(cc[0], cc[1], cc[2], cc[3]);

        m_fb.unbindFramebuffer();
    }
};

NS_END