/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2019 - Francisco Javier Trujillo Mata
 *
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <malloc.h>
#include <gsKit.h>
#include <dmaKit.h>
#include <gsToolkit.h>
#include <encodings/utf.h>

#include "../common/ps2_common.h"

#include "../font_driver.h"

#include "../../configuration.h"
#include "../../verbosity.h"

typedef struct
{
   GSTEXTURE *texture;
   const font_renderer_driver_t* font_driver;
   void* font_data;
} ps2_font_t;

static void* ps2_font_init(void* data, const char* font_path,
      float font_size, bool is_threaded)
{
   uint32_t j;
   int text_size, clut_size;
   uint8_t *tex8;
   uint32_t *clut32;
   const struct font_atlas* atlas = NULL;
   ps2_font_t* font = (ps2_font_t*)calloc(1, sizeof(*font));

   if (!font)
      return NULL;

   if (!font_renderer_create_default(
            &font->font_driver,
            &font->font_data, font_path, font_size))
   {
      RARCH_WARN("Couldn't initialize font renderer.\n");
      free(font);
      return NULL;
   }

   atlas                  = font->font_driver->get_atlas(font->font_data);
   font->texture          = (GSTEXTURE*)calloc(1, sizeof(GSTEXTURE));
   font->texture->Width   = atlas->width;
   font->texture->Height  = atlas->height;
   font->texture->PSM     = GS_PSM_T8;
   font->texture->ClutPSM = GS_PSM_CT32;
   font->texture->Filter  = GS_FILTER_NEAREST;

   /* Convert to 8bit texture */
   text_size           = gsKit_texture_size_ee(atlas->width, atlas->height, GS_PSM_T8);
   tex8                = (uint8_t*)malloc(text_size);
   for (j = 0; j <  atlas->width * atlas->height; j++ )
      tex8[j]          = atlas->buffer[j] & 0x000000FF;
   font->texture->Mem  = (u32 *)tex8;

   /* Create 8bit CLUT */
   clut_size           = gsKit_texture_size_ee(16, 16, GS_PSM_CT32);
   clut32              = (uint32_t*)malloc(clutSize);
   for (j = 0; j < 256; j++)
      clut32[j]        = 0x01010101 * j;
   font->texture->Clut = (u32 *)clut32;

   return font;
}

static void ps2_font_free(void* data, bool is_threaded)
{
   ps2_font_t* font = (ps2_font_t*)data;

   if (!font)
      return;

   if (font->font_driver && font->font_data)
      font->font_driver->free(font->font_data);

   if (font->texture->Clut)
      free(font->texture->Clut);

   if (font->texture->Mem)
      free(font->texture->Mem);

   if (font->texture)
      free(font->texture);
}

static int ps2_font_get_message_width(void* data, const char* msg,
                                      unsigned msg_len, float scale)
{
   const struct font_glyph* glyph_q = NULL;
   unsigned i;
   int delta_x      = 0;
   ps2_font_t* font = (ps2_font_t*)data;

   if (!font)
      return 0;

   glyph_q = font->font_driver->get_glyph(font->font_data, '?');

   for (i = 0; i < msg_len; i++)
   {
      const struct font_glyph* glyph;
      const char* msg_tmp            = &msg[i];
      unsigned code                  = utf8_walk(&msg_tmp);
      unsigned skip                  = msg_tmp - &msg[i];

      if (skip > 1)
         i += skip - 1;

      /* Do something smarter here ... */
      if (!(glyph =
         font->font_driver->get_glyph(font->font_data, code)))
         if (!(glyph = glyph_q))
            continue;

      delta_x += glyph->advance_x;
   }

   return delta_x * scale;
}

static void ps2_font_render_line(
      ps2_video_t *ps2,
      ps2_font_t* font, const char* msg, unsigned msg_len,
      float scale, const unsigned int color, float pos_x,
      float pos_y,
      unsigned width, unsigned height, unsigned text_align)
{
   unsigned i;
   const struct font_glyph* glyph_q = NULL;
   int x            = roundf(pos_x * width);
   int y            = roundf((1.0f - pos_y) * height);
   int delta_x      = 0;
   int delta_y      = 0;
   /* We need to >> 1, because GS_SETREG_RGBAQ expects 0x80 as max color */
   int color_a      = (int)(((color & 0xFF000000) >> 24) >> 2);
   int color_b      = (int)(((color & 0x00FF0000) >> 16) >> 1);
   int color_g      = (int)(((color & 0x0000FF00) >> 8)  >> 1);
   int color_r      = (int)(((color & 0x000000FF) >> 0)  >> 1);

   /* Enable Alpha for font */
   gsKit_set_primalpha(ps2->gsGlobal, GS_SETREG_ALPHA(0, 1, 0, 1, 0), 0);
   ps2->gsGlobal->PrimAlphaEnable = GS_SETTING_ON;
   gsKit_set_test(ps2->gsGlobal, GS_ATEST_ON);

   switch (text_align)
   {
      case TEXT_ALIGN_RIGHT:
         x -= ps2_font_get_message_width(font, msg, msg_len, scale);
         break;

      case TEXT_ALIGN_CENTER:
         x -= ps2_font_get_message_width(font, msg, msg_len, scale) / 2;
         break;
   }

   glyph_q = font->font_driver->get_glyph(font->font_data, '?');

   for (i = 0; i < msg_len; i++)
   {
      const struct font_glyph* glyph;
      int off_x, off_y, tex_x, tex_y, width, height;
      float x1, y1, u1, v1, x2, y2, u2, v2;
      const char* msg_tmp            = &msg[i];
      unsigned code                  = utf8_walk(&msg_tmp);
      unsigned skip                  = msg_tmp - &msg[i];

      if (skip > 1)
         i += skip - 1;

      /* Do something smarter here ... */
      if (!(glyph =
               font->font_driver->get_glyph(font->font_data, code)))
         if (!(glyph = glyph_q))
            continue;

      off_x  = glyph->draw_offset_x;
      off_y  = glyph->draw_offset_y;
      tex_x  = glyph->atlas_offset_x;
      tex_y  = glyph->atlas_offset_y;
      width  = glyph->width;
      height = glyph->height;

      /* The -0.5 is needed to achieve pixel perfect. 
       * More info here (PS2 GSKit uses same logic as Direct3D9)
       * https://docs.microsoft.com/en-us/windows/win32/direct3d10/d3d10-graphics-programming-guide-resources-coordinates
      */
      x1     = -0.5f + x + (off_x + delta_x) * scale;
      y1     = -0.5f + y + (off_y + delta_y) * scale;
      u1     = tex_x;
      v1     = tex_y;
      x2     = x1 + width * scale;
      y2     = y1 + height * scale;
      u2     = u1 + width;
      v2     = v1 + height;

      gsKit_prim_sprite_texture(ps2->gsGlobal, font->texture,
            x1,                /* X1 */
            y1,                /* Y1 */
            u1,                /* U1 */
            v1,                /* V1 */
            x2,                /* X2 */
            y2,                /* Y2 */
            u2,                /* U2 */
            v2,                /* V2 */
            5,                 /* Z  */
            GS_SETREG_RGBAQ(color_r, color_g, color_b, color_a, 0x00));

      delta_x += glyph->advance_x;
      delta_y += glyph->advance_y;
   }
}

static void ps2_font_render_message(
      ps2_video_t *ps2,
      ps2_font_t* font, const char* msg, float scale,
      const unsigned int color, float pos_x, float pos_y,
      unsigned width, unsigned height, unsigned text_align)
{
   struct font_line_metrics *line_metrics = NULL;
   int lines                              = 0;
   float line_height;

   if (!msg || !*msg)
      return;

   /* If font line metrics are not supported just draw as usual */
   if (!font->font_driver->get_line_metrics ||
       !font->font_driver->get_line_metrics(font->font_data, &line_metrics))
   {
      ps2_font_render_line(ps2, font, msg, strlen(msg),
                           scale, color, pos_x, pos_y,
                           width, height, text_align);
      return;
   }

   line_height = (float)line_metrics->height * scale / (float)height;

   for (;;)
   {
      const char* delim = strchr(msg, '\n');
      unsigned msg_len  = delim ?
         (unsigned)(delim - msg) : strlen(msg);

      /* Draw the line */
      ps2_font_render_line(ps2, font, msg, msg_len,
            scale, color, pos_x, pos_y - (float)lines * line_height,
            width, height, text_align);
      if (!delim)
         break;

      msg += msg_len + 1;
      lines++;
   }
}

static void ps2_font_render_msg(
      void *userdata,
      void* data, const char* msg,
      const struct font_params *params)
{
   float x, y, scale, drop_mod, drop_alpha;
   int drop_x, drop_y;
   enum text_alignment text_align;
   unsigned color, r, g, b, alpha;
   ps2_font_t                * font = (ps2_font_t*)data;
   ps2_video_t                *ps2  = (ps2_video_t*)userdata;
   unsigned width                   = ps2->vp.full_width;
   unsigned height                  = ps2->vp.full_height;

   if (!font || !msg || !*msg)
      return;

   if (params)
   {
      x                       = params->x;
      y                       = params->y;
      scale                   = params->scale;
      text_align              = params->text_align;
      drop_x                  = params->drop_x;
      drop_y                  = params->drop_y;
      drop_mod                = params->drop_mod;
      drop_alpha              = params->drop_alpha;

      r                       = FONT_COLOR_GET_RED(params->color);
      g                       = FONT_COLOR_GET_GREEN(params->color);
      b                       = FONT_COLOR_GET_BLUE(params->color);
      alpha                   = FONT_COLOR_GET_ALPHA(params->color);

      color                   = COLOR_ABGR(r, g, b, alpha);
   }
   else
   {
      settings_t *settings    = config_get_ptr();
      float video_msg_pos_x   = settings->floats.video_msg_pos_x;
      float video_msg_pos_y   = settings->floats.video_msg_pos_y;
      float video_msg_color_r = settings->floats.video_msg_color_r;
      float video_msg_color_g = settings->floats.video_msg_color_g;
      float video_msg_color_b = settings->floats.video_msg_color_b;
      x                       = video_msg_pos_x;
      y                       = video_msg_pos_y;
      scale                   = 1.0f;
      text_align              = TEXT_ALIGN_LEFT;

      r                       = (video_msg_color_r * 255);
      g                       = (video_msg_color_g * 255);
      b                       = (video_msg_color_b * 255);
      alpha                   = 255;
      color                   = COLOR_ABGR(r, g, b, alpha);

      drop_x                  = 1;
      drop_y                  = -1;
      drop_mod                = 0.0f;
      drop_alpha              = 0.75f;
   }

   gsKit_TexManager_bind(ps2->gsGlobal, font->texture);

   if (drop_x || drop_y)
   {
      unsigned r_dark         = r * drop_mod;
      unsigned g_dark         = g * drop_mod;
      unsigned b_dark         = b * drop_mod;
      unsigned alpha_dark     = alpha * drop_alpha;
      unsigned color_dark     = COLOR_ABGR(r_dark, g_dark, b_dark, alpha_dark);
      ps2_font_render_message(ps2, font, msg, scale, color_dark,
                              x + scale * drop_x / width, y +
                              scale * drop_y / height,
                              width, height, text_align);
   }

   ps2_font_render_message(ps2, font, msg, scale,
                           color, x, y,
                           width, height, text_align);
}

static const struct font_glyph* ps2_font_get_glyph(
   void* data, uint32_t code)
{
   ps2_font_t* font = (ps2_font_t*)data;
   if (font && font->font_driver && font->font_driver->ident)
      return font->font_driver->get_glyph((void*)font->font_driver, code);
   return NULL;
}

static bool ps2_font_get_line_metrics(void* data, struct font_line_metrics **metrics)
{
   ps2_font_t* font = (ps2_font_t*)data;
   if (font && font->font_driver && font->font_data)
      return font->font_driver->get_line_metrics(font->font_data, metrics);
   return false;
}

font_renderer_t ps2_font = {
   ps2_font_init,
   ps2_font_free,
   ps2_font_render_msg,
   "ps2_font",
   ps2_font_get_glyph,
   NULL,                      /* bind_block */
   NULL,                      /* flush */
   ps2_font_get_message_width,
   ps2_font_get_line_metrics
};