#include "generate_preview.h"

void generate_preview_init(GeneratePreview* self, Anm2* anm2, Anm2Reference* reference, Resources* resources, Settings* settings)
{
    self->anm2 = anm2;
    self->reference = reference;
    self->resources = resources;
    self->settings = settings;

    canvas_init(&self->canvas, GENERATE_PREVIEW_SIZE);
}

void generate_preview_draw(GeneratePreview* self)
{
    static auto& columns = self->settings->generateColumns;
    static auto& count = self->settings->generateCount;
    static GLuint& shaderTexture = self->resources->shaders[SHADER_TEXTURE];
    const mat4 transform = canvas_transform_get(&self->canvas, {}, CANVAS_ZOOM_DEFAULT, ORIGIN_CENTER);
 
    vec2 startPosition = {self->settings->generateStartPosition.x, self->settings->generateStartPosition.y};
    vec2 size = {self->settings->generateSize.x, self->settings->generateSize.y};
    vec2 pivot = {self->settings->generatePivot.x, self->settings->generatePivot.y};

    canvas_bind(&self->canvas);
    canvas_viewport_set(&self->canvas);
    canvas_clear(self->settings->previewBackgroundColor);
 
    Anm2Item* item = anm2_item_from_reference(self->anm2, self->reference);

    if (item)
    {
        if (Anm2Spritesheet* spritesheet = map_find(self->anm2->spritesheets, self->anm2->layers[self->reference->itemID].spritesheetID))
        {
            Texture& texture = spritesheet->texture;

            const s32 index = std::clamp((s32)(self->time * count), 0, count);
            const s32 row = index / columns;
            const s32 column = index % columns;
            vec2 crop = startPosition + vec2(size.x * column, size.y * row);

            vec2 textureSize = vec2(texture.size);
            vec2 uvMin = (crop + vec2(0.5f)) / textureSize;
            vec2 uvMax = (crop + size - vec2(0.5f)) / textureSize;
            f32 vertices[] = UV_VERTICES(uvMin, uvMax);

            mat4 generateTransform = transform * quad_model_get(size, {}, pivot);
            canvas_texture_draw(&self->canvas, shaderTexture, texture.id, generateTransform, vertices, COLOR_OPAQUE, COLOR_OFFSET_NONE);
        }
    }
           
    canvas_unbind();
}

void generate_preview_free(GeneratePreview* self)
{
    canvas_free(&self->canvas);
}