#include "text.h"

#include <cstddef>

#include "freetype/freetype.h"
#include "shaders.h"
#include "utils.h"

static void font_context_sampler_desc(struct sg_sampler_desc* desc) {
  wayc_notnull(desc);

  desc->min_filter = SG_FILTER_LINEAR;
  desc->mag_filter = SG_FILTER_LINEAR;
  desc->wrap_u = SG_WRAP_CLAMP_TO_EDGE;
  desc->wrap_v = SG_WRAP_CLAMP_TO_EDGE;
}

static void font_context_layout(struct sg_vertex_layout_state* layout) {
  wayc_notnull(layout);

  layout->buffers[0].stride = sizeof(text_vertex_s);

  layout->attrs[ATTR_text_in_position].format = SG_VERTEXFORMAT_FLOAT2;
  layout->attrs[ATTR_text_in_position].buffer_index = 0;
  layout->attrs[ATTR_text_in_position].offset = offsetof(text_vertex_s, pos);

  layout->attrs[ATTR_text_in_uv].format = SG_VERTEXFORMAT_FLOAT2;
  layout->attrs[ATTR_text_in_uv].buffer_index = 0;
  layout->attrs[ATTR_text_in_uv].offset = offsetof(text_vertex_s, uv);
}

static void font_context_color(struct sg_color_target_state* color) {
  wayc_notnull(color);

  struct sg_blend_state blend = {};
  blend.enabled = true;
  blend.src_factor_rgb = SG_BLENDFACTOR_SRC_ALPHA;
  blend.dst_factor_rgb = SG_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;
  blend.src_factor_alpha = SG_BLENDFACTOR_SRC_ALPHA;
  blend.dst_factor_alpha = SG_BLENDFACTOR_ONE_MINUS_SRC_ALPHA;

  color->blend = blend;
}

static void font_context_pipeline_desc(struct sg_pipeline_desc* desc) {
  wayc_notnull(desc);

  const struct sg_shader_desc* shader_desc =
      text_shader_desc(sg_query_backend());
  struct sg_shader shader = sg_make_shader(shader_desc);

  struct sg_vertex_layout_state vertex_layout = {};
  font_context_layout(&vertex_layout);

  struct sg_color_target_state color = {};
  font_context_color(&color);

  desc->layout = vertex_layout;
  desc->shader = shader;

  desc->colors[0] = color;
  desc->color_count = 1;
}

enum font_context_error_e font_context_init(struct font_context_s* context) {
  wayc_notnull(context);

  FT_Library ft;
  FT_Error fterr = FT_Init_FreeType(&ft);
  if (fterr) return FONT_CONTEXT_ERROR_LOAD_LIBRARY;

  struct sg_sampler_desc sampler_desc = {};
  font_context_sampler_desc(&sampler_desc);

  struct sg_pipeline_desc pipeline_desc = {};
  font_context_pipeline_desc(&pipeline_desc);

  context->ft = ft;
  context->sampler = sg_make_sampler(&sampler_desc);
  context->pipeline = sg_make_pipeline(&pipeline_desc);

  return FONT_CONTEXT_ERROR_NONE;
}

void font_context_deinit(struct font_context_s* context) {
  wayc_notnull(context);

  sg_destroy_pipeline(context->pipeline);
  sg_destroy_sampler(context->sampler);
  FT_Done_FreeType(context->ft);
}