#include "widget_render.h"

extern SimpleMesh mesh_quad1_ui;

static inline void
_Widget_get_aabb (Widget *self, vec2 aabb[2])
{
  glm_vec2_copy ((vec2) { self->position[0], self->position[1] }, aabb[0]);
  glm_vec2_copy ((vec2) { self->position[0] + self->size[0], self->position[1] + self->size[1] }, aabb[1]);
}

static inline void
_Widget_render_text_line(const char *text, TextAlignment alignment, ivec2 position,
			 ivec2 size, int max_width, const vec4 color, mat4 projection)
{
  program_use (PMPRG ("uitext"));
  program_set_mat4 (PMPRG ("uitext"), "projection", projection);
  program_set_vec4 (PMPRG ("uitext"), "color", color);

  int nchars = g_utf8_strlen (text, -1);
  int total_w = nchars * size[0];

  int xoff = 0.0;
    
  switch (alignment)
    {
    case TEXT_ALIGN_CENTER:
      xoff = (max_width - total_w) * 0.5;
      break;
    case TEXT_ALIGN_RIGHT:
      xoff = max_width - total_w;
      break;
    case TEXT_ALIGN_LEFT:
    default:
      xoff = 0;
    }

  const char *p = text;
  while (*p)
    {
      gunichar ch = g_utf8_get_char (p);
      program_set_float (PMPRG ("uitext"), "character", ch);
	
      mat3 model;
      glm_translate2d_make (model, (vec2) { position[0] + xoff, position[1] });
      glm_scale2d (model, (vec2) { size[0], size[1] });
      program_set_mat3 (PMPRG ("uitext"), "model", model);
	
      SimpleMesh_render (&mesh_quad1_ui, FALSE);
	
      xoff += size[0];
      p    = g_utf8_next_char (p);
    }
}

void
Widget_render_base (Widget *self, mat4 projection, int window_height)
{
  if (!self->visible)
    {
      return;
    }

  if (self->parent == NULL)
    {
      SimpleMesh_bind (&mesh_quad1_ui);
    }

  const WidgetStyle *style = self->style;
  
  program_use (PMPRG ("uiwidget"));

  texture_use (style->background_image, 0); /* If it doesn't have a texture, it'll be 0 anyway. */
  texture_use (PMTEX ("icons"), 1);
  
  program_set_int (PMPRG ("uiwidget"), "has_background_image", style->background_image != 0);
  program_set_int (PMPRG ("uiwidget"), "has_icon", self->icon != ICON_NONE);
  program_set_int (PMPRG ("uiwidget"), "has_resize_handle", self->kind == WIDGET_WINDOW);
  
  program_set_vec2 (PMPRG ("uiwidget"), "widget_size", (vec2) { self->size[0], self->size[1] });
  program_set_float (PMPRG ("uiwidget"), "border_width", style->border_width);
  program_set_float (PMPRG ("uiwidget"), "icon_index", self->icon - 1);

  program_set_vec4 (PMPRG ("uiwidget"), "background_color", style->background_color);
  program_set_vec4 (PMPRG ("uiwidget"), "icon_color", style->icon_color);
  program_set_vec4 (PMPRG ("uiwidget"), "border_color", style->border_color);
  program_set_vec4 (PMPRG ("uiwidget"), "resize_handle_color", style->resize_handle_color);
  
  if (self->clicked)
    {
      program_set_vec4 (PMPRG ("uiwidget"), "background_color", style->background_color_clicked);
      program_set_vec4 (PMPRG ("uiwidget"), "icon_color", style->icon_color_clicked);
    }
  else if (self->hovered)
    {
      program_set_vec4 (PMPRG ("uiwidget"), "background_color", style->background_color_hovered);
      program_set_vec4 (PMPRG ("uiwidget"), "icon_color", style->icon_color_hovered);
    }

  mat3 model;
  glm_translate2d_make (model, (vec2) { self->position[0], self->position[1] });
  glm_scale2d (model, (vec2) { self->size[0], self->size[1] });

  program_set_mat3 (PMPRG ("uiwidget"), "model", model);
  program_set_mat4 (PMPRG ("uiwidget"), "projection", projection);

  /* Before we render, we calculate the scissor box based on the
     parents. */

  vec2 self_aabb[2], parent_aabb[2], clipped_aabb[2];
  _Widget_get_aabb (self, self_aabb);
  /* We copy it, in case there's no parent. */
  _Widget_get_aabb (self, parent_aabb);

  if (self->parent != NULL)
    {
      _Widget_get_aabb (self->parent, parent_aabb);
    }

  glm_aabb2d_crop (self_aabb, parent_aabb, clipped_aabb);

  int x = roundf (clipped_aabb[0][0]);
  int y = roundf (window_height - clipped_aabb[1][1]);
  int w = roundf (clipped_aabb[1][0] - clipped_aabb[0][0]);
  int h = roundf (clipped_aabb[1][1] - clipped_aabb[0][1]);
  
  /* X, Y is the lower left corner of the box. */
  glScissor (x, y, w, h);
  SimpleMesh_render (&mesh_quad1_ui, FALSE);
}

void
Widget_render_label (Widget *self, mat4 projection, int window_height)
{
  Widget_render_base (self, projection, window_height);

  int char_w = self->size[1] * (9.0f / 20.0f);
  ivec2 pos = { self->position[0], self->position[1] };

  const WidgetStyle *style = self->style;
  texture_use (PMTEX ("font0"), 0);
  _Widget_render_text_line (self->label.text->str, self->label.text_alignment,
			    pos, (ivec2) { char_w, self->size[1] }, self->size[0],
			    self->clicked ? style->text_color_clicked : self->hovered
			    ? style->text_color_hovered : style->text_color, projection);
}

void
Widget_render_scrollbar (Widget *self, mat4 projection, int window_height)
{
  program_use (PMPRG ("uiwidget"));
  program_set_int (PMPRG ("uiwidget"), "has_scrollbar", TRUE);

  const WidgetStyle *style = self->style;

  program_set_vec4 (PMPRG ("uiwidget"), "scrollbar_color", style->scrollbar_color);

  if (self->clicked)
    {
      program_set_vec4 (PMPRG ("uiwidget"), "scrollbar_color", style->scrollbar_color_clicked);
    }
  else if (self->hovered)
    {
      program_set_vec4 (PMPRG ("uiwidget"), "scrollbar_color", style->scrollbar_color_hovered);
    }
  
  /* Calculate the scrollbar size. */
  unsigned int idx = self->scrollbar.horizontal ? 0 : 1;
      
  Widget *scr = self->scrollbar.target;

  int content_size = scr->scrollable.content_size[idx];
  int scroll_pos = scr->scrollable.scroll_position[idx];
  int view_size = scr->size[idx];
  int thumb_size_norm = view_size / content_size;
  int thumb_pos_norm = scroll_pos / content_size;

  program_set_vec2 (PMPRG ("uiwidget"), "scrollbar_position", self->scrollbar.horizontal
		    ? (vec2) { thumb_pos_norm, 0.0f }
		    : (vec2) { 0.0f, thumb_pos_norm });

  program_set_vec2 (PMPRG ("uiwidget"), "scrollbar_size", self->scrollbar.horizontal
		    ? (vec2) { thumb_size_norm, 1.0f }
		    : (vec2) { 1.0f, thumb_size_norm });

  Widget_render_base (self, projection, window_height);
  program_set_int (PMPRG ("uiwidget"), "has_scrollbar", FALSE);
}

void
Widget_render_progress (Widget *self, mat4 projection, int window_height)
{
  program_use (PMPRG ("uiwidget"));
  program_set_int (PMPRG ("uiwidget"), "has_progress", TRUE);

  float bar_size = (*self->progress.ptr - self->progress.min) / (self->progress.max - self->progress.min);
  bar_size = glm_clamp (bar_size, 0.0, 1.0);

  program_set_vec4 (PMPRG ("uiwidget"), "progress_color", self->style->progress_color);
  
  program_set_vec2 (PMPRG ("uiwidget"), "progress_size", self->progress.horizontal
		    ? (vec2) { bar_size, 1.0f }
		    : (vec2) { 1.0f, bar_size });

  Widget_render_base (self, projection, window_height);
  program_set_int (PMPRG ("uiwidget"), "has_progress", FALSE);
}

void
Widget_render_multiline_text (Widget *self, mat4 projection, int window_height)
{
  Widget_render_base (self, projection, window_height);

  texture_use (PMTEX ("font0"), 0);

  int pad = self->layout_padding;
  int row_h = self->multiline_text.line_height;
  int char_w = row_h * (9.0 / 20.0);
  ivec2 pos0   = { self->position[0] + pad, self->position[1] + pad };
  
  for (unsigned int i = 0; i < self->multiline_text.lines->len; ++i)
    {
      GString *line = g_array_index (self->multiline_text.lines, GString *, i);
      ivec2 pos = { pos0[0], pos0[1] + i * row_h };
      _Widget_render_text_line(line->str, self->multiline_text.text_alignment, pos,
			       (ivec2) { char_w, row_h }, self->size[0] - 2 * pad,
			       self->style->text_color, projection);
    }
}

void
Widget_render_entry (Widget *self, mat4 projection, int window_height)
{
  Widget_render_base (self, projection, window_height);

  texture_use (PMTEX ("font0"), 0);
  
  int char_w = self->size[1] * (9.0f / 20.0f);
  int cursor_in_px = self->entry.cursor_position * char_w;
  /* -char_w because we leave space for the cursor at the end of the
      text. */
  int offset = glm_max (0, cursor_in_px - (self->size[0] - char_w));

  if (!self->focused && self->entry.content->len == 0)
    {
      _Widget_render_text_line (self->entry.ghost_text->str, TEXT_ALIGN_LEFT,
				self->position, (ivec2) { char_w, self->size[1] }, self->size[0],
				self->style->ghost_text_color, projection);
    }
  else
    {
      ivec2 pos = { self->position[0] - offset, self->position[1] };
      _Widget_render_text_line (self->entry.content->str, TEXT_ALIGN_LEFT,
				pos, (ivec2) { char_w, self->size[1] }, self->size[0],
				self->style->text_color, projection);
    }

  if (self->focused)
    {
      int x = self->position[0] + cursor_in_px - offset;
      int y = self->position[1];
      int w = 2.0;
      int h = self->size[1];
      
      mat3 model;
      glm_translate2d_make (model, (vec2) { x, y });
      glm_scale2d (model, (vec2) { w, h });

      program_use (PMPRG ("uidummy"));
      program_set_mat3 (PMPRG ("uidummy"), "model", model);
      program_set_mat4 (PMPRG ("uidummy"), "projection", projection);
      program_set_vec4 (PMPRG ("uidummy"), "background_color", self->style->text_color);
      
      SimpleMesh_render (&mesh_quad1_ui, FALSE);
    }
}

void
Widget_render_window (Widget *self, mat4 projection, int window_height)
{
  UNUSED (self,  projection, window_height);
  Widget_render_base (self, projection, window_height);  

  texture_use (PMTEX ("font0"), 0);  

  ivec2 pos = {
    self->position[0] + self->layout_padding,
    self->position[1] + self->layout_padding
  };

  ivec2 siz = {
    self->size[0] - self->layout_padding * 2,
    self->window.titlebar_height
  };

  int char_w = siz[1] * (9.0f / 20.0f);
  
  _Widget_render_text_line (self->window.title->str, TEXT_ALIGN_CENTER,
			    pos, (ivec2) { char_w, siz[1] }, siz[0], self->style->text_color,
			    projection);
}