#include <cstring></cstring>

#include <freetype2 ft2build.h=""></freetype2>

#include FT_BITMAP_H

#include <pango pangoft2.h=""></pango>

#include "surface.h"

#include "matrix.h"

#include "labpangorenderer.h"

struct _LabPangoRenderer {

	PangoRenderer parent_instance;

	Surface *surface;

	Color color;

	Matrix matrix;

};

struct _LabPangoRendererClass {

  PangoRendererClass parent_class;

};

G_DEFINE_TYPE(LabPangoRenderer, lab_pango_renderer, PANGO_TYPE_RENDERER)

static void

put_ft_bitmap(Surface &surface, FT_Bitmap &bitmap, int x, int y, const Color &color) {

	if (x >= surface.width() || y >= surface.height())

		return;

	if (x + (int)bitmap.width <= 0 || y + (int)bitmap.rows <= 0)

		return;

	const int bx = std::max(0, -x);

	const int by = std::max(0, -y);

	x = std::max(0, x);

	y = std::max(0, y);

	const int w = std::min(surface.width() - x, (int)bitmap.width - bx);

	const int h = std::min(surface.height() - y, (int)bitmap.rows - by);

	const int pitch = surface.pitch();

	Color *dst_pixel = &surface[y][x];

	const int dst_row_step = pitch - w;

	const unsigned char *src_pixel = bitmap.buffer + by*bitmap.pitch + bx;

	const int src_row_step = bitmap.pitch - w;

	for(const Color *end = dst_pixel + pitch*h; dst_pixel != end; dst_pixel += dst_row_step, src_pixel += src_row_step) {

		for(const Color *row_end = dst_pixel + w; dst_pixel != row_end; ++dst_pixel, ++src_pixel) {

			Real a = *src_pixel * (1/255.0);

			*dst_pixel = *dst_pixel*(1-a) + color*a;

		}

	}

}

static void

lab_pango_renderer_draw_glyph(

	PangoRenderer *renderer,

	PangoFont     *font,

	PangoGlyph     glyph,

	double         x,

	double         y )

{

	LabPangoRenderer *lab_renderer = (LabPangoRenderer*)renderer;

	if (!lab_renderer->surface)

		return;

	Vector3 pos = lab_renderer->matrix*Vector3(x, y, 1);

	const int fx = (int)round(pos.x*64);

	const int fy = (int)round(pos.y*64);

	const int ix = fx / 64;

	const int iy = fy / 64;

	FT_Vector vec = {};

	vec.x = fx % 64;

	vec.y = fy % 64;

	FT_Face face = pango_fc_font_lock_face((PangoFcFont*)font);

	FT_Set_Transform(face, nullptr, &vec);

	if (!FT_Load_Glyph(face, glyph, FT_LOAD_NO_HINTING)) {

		if (!FT_Render_Glyph(face->glyph, FT_RENDER_MODE_NORMAL)) {

			put_ft_bitmap(

				*lab_renderer->surface,

				face->glyph->bitmap,

				face->glyph->bitmap_left + ix,

				iy - face->glyph->bitmap_top,

				lab_renderer->color );

		}

	}

	pango_fc_font_unlock_face((PangoFcFont*)font);

}

static void

lab_pango_renderer_init(LabPangoRenderer *renderer) {

	memset( renderer + sizeof(renderer->parent_instance), 0,

			sizeof(*renderer) - sizeof(renderer->parent_instance) );

	renderer->matrix = Matrix();

}

static void

lab_pango_renderer_class_init(LabPangoRendererClass *klass)

{

	PangoRendererClass *renderer_class = PANGO_RENDERER_CLASS(klass);

	renderer_class->draw_glyph = lab_pango_renderer_draw_glyph;

}

static void

lab_pango_fc_pattern_unset_hinting(FcPattern *pattern, gpointer)

	{ FcPatternDel(pattern, FC_HINTING); }

static void

lab_pango_fc_pattern_set_hinting(FcPattern *pattern, gpointer) {

	FcPatternDel(pattern, FC_HINTING);

	FcPatternAddBool(pattern, FC_HINTING, FcFalse);

}

PangoRenderer*

lab_pango_renderer_new()

	{ return (PangoRenderer*)g_object_new(LAB_TYPE_PANGO_RENDERER, nullptr); }

void

lab_pango_renderer_set_matrix(LabPangoRenderer *renderer, Matrix *matrix)

	{ renderer->matrix = matrix ? *matrix : Matrix(); }

void

lab_pango_renderer_get_matrix(LabPangoRenderer *renderer, Matrix *matrix)

	{ if (matrix) *matrix = renderer->matrix; }

void

lab_pango_renderer_set_color(LabPangoRenderer *renderer, Color *color)

	{ renderer->color = color ? *color : Color(); }

void

lab_pango_renderer_get_color(LabPangoRenderer *renderer, Color *color)

	{ if (color) *color = renderer->color; }

void

lab_pango_renderer_set_surface(LabPangoRenderer *renderer, Surface *surface)

	{ renderer->surface = surface; }

Surface*

lab_pango_renderer_get_surface(LabPangoRenderer *renderer)

	{ return renderer->surface; }

PangoFontMap*

lab_pango_font_map_new(bool hinting) {

	PangoFontMap *font_map = pango_ft2_font_map_new();

	pango_ft2_font_map_set_default_substitute(

		(PangoFT2FontMap*)font_map,

		hinting ? &lab_pango_fc_pattern_set_hinting

				: &lab_pango_fc_pattern_unset_hinting,

		nullptr,

		nullptr );

	return font_map;

}