#include "text.h"

#include <cstddef>
#include <cstring>

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

static void wayc_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 wayc_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 wayc_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,
                                       struct sg_shader shader) {
  wayc_notnull(desc);

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

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

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

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

enum font_context_error_e wayc_font_context_init(
    struct font_context_s* context) {
  wayc_notnull(context);
  memset(context, 0, sizeof(*context));
  bool success = false;

  FT_Library ft;
  FT_Error fterr = FT_Init_FreeType(&ft);
  if (fterr) return FONT_CONTEXT_ERROR_LOAD_LIBRARY;
  wayc_defer_cond(FT_Done_FreeType(ft), success, true);

  struct sg_shader shader =
      sg_make_shader(text_shader_desc(sg_query_backend()));
  if (sg_query_shader_state(shader) != SG_RESOURCESTATE_VALID)
    return FONT_CONTEXT_ERROR_CREATE_SHADER;
  wayc_defer_cond(sg_destroy_shader(shader), success, true);

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

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

  struct sg_sampler sampler = sg_make_sampler(&sampler_desc);
  if (sg_query_sampler_state(sampler) != SG_RESOURCESTATE_VALID)
    return FONT_CONTEXT_ERROR_CREATE_SAMPLER;

  wayc_defer_cond(sg_destroy_sampler(sampler), success, true);

  struct sg_pipeline pipeline = sg_make_pipeline(&pipeline_desc);
  if (sg_query_pipeline_state(pipeline) != SG_RESOURCESTATE_VALID)
    return FONT_CONTEXT_ERROR_CREATE_PIPELINE;

  context->ft = ft;
  context->sampler = sampler;
  context->pipeline = pipeline;

  success = true;

  return FONT_CONTEXT_ERROR_NONE;
}

void wayc_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);
}

enum font_error_e wayc_font_init(struct font_s* font,
                                 struct font_context_s* context,
                                 const char* path, u32 font_size,
                                 u32 atlas_width, u32 atlas_height) {
  wayc_notnull(font);
  wayc_notnull(context);
  memset(font, 0, sizeof(*font));
  bool success = false;

  FT_Face face;
  FT_Error fterr = FT_New_Face(context->ft, path, 0, &face);
  if (fterr) return FONT_ERROR_LOAD_FACE;

  wayc_defer_cond(FT_Done_Face(face), success, true);

  struct atlas_s atlas;
  enum atlas_error_e aterr =
      wayc_atlas_init(&atlas, atlas_width, atlas_height, SG_PIXELFORMAT_R8);
  if (aterr) return FONT_ERROR_LOAD_FACE;

  font->face = face;
  font->font_size = font_size;
  font->atlas = atlas;

  success = true;
  return FONT_ERROR_NONE;
}

void wayc_font_deinit(struct font_s* font) {
  wayc_notnull(font);

  wayc_atlas_deinit(&font->atlas);
  FT_Done_Face(font->face);
}