#include "pch.h"
#include "log.h"
#include "canvas.h"

void ui::Canvas::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();
}
void ui::Canvas::stroke_end()
{
    m_current_stroke = nullptr;
}
void ui::Canvas::stroke_draw()
{
    if (!(m_current_stroke && m_current_stroke->has_sample()))
        return;

    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 ui::Canvas::stroke_update(glm::vec2 point, float pressure)
{
    m_current_stroke->add_point(point, pressure);
}
void ui::Canvas::stroke_start(glm::vec2 point, float pressure, const ui::Brush& brush)
{
    m_strokes.emplace_back();
    m_strokes.back().start(brush);
    m_strokes.back().add_point(point, pressure);
    m_current_stroke = &m_strokes.back();
}
void ui::Canvas::layer_add(std::string name)
{
    m_layers.emplace_back();
    m_layers.back().create(m_width, m_height, name);
}
void ui::Canvas::resize(int width, int height)
{
    m_width = width;
    m_height = height;
    m_tmp->create(width, height, "tmp");
    m_fb.create(width, height);
}
bool ui::Canvas::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;
}