#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;

	LabPangoRendererParams params;

};

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

put_ft_bitmap_mono(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_row = bitmap.buffer + by*bitmap.pitch;

	const int src_row_end = bx + w;

	for(const Color *end = dst_pixel + pitch*h; dst_pixel != end; dst_pixel += dst_row_step, src_row += bitmap.pitch)

		for(int src_x = bx; src_x < src_row_end; ++dst_pixel, ++src_x)

			if (src_row[src_x/8] & (128 >> (src_x%8)))

				*dst_pixel = color;

}

static void

lab_pango_renderer_draw_glyph(

	PangoRenderer *renderer,

	PangoFont     *font,

	PangoGlyph     glyph,

	double         x,

	double         y )

{

	const LabPangoRendererParams ¶ms = ((LabPangoRenderer*)renderer)->params;

	if (!params.surface)

		return;

	Vector3 pos = params.matrix*Vector3(x, y, 1);

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

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

	int ix = fx / 64;

	int iy = fy / 64;

	FT_Vector vec = {};

	vec.x = fx % 64;

	vec.y = fy % 64;

	if (params.hinting) {

		if (vec.x >= 32) ++ix;

		if (vec.y >= 32) ++iy;

		vec.x = 0;

		vec.y = 0;

	}

	vec.y = -vec.y;

	FT_Matrix mat = {};

	mat.xx = (int)round( params.glyph_matrix.m00*65536);

	mat.xy = (int)round(-params.glyph_matrix.m10*65536);

	mat.yx = (int)round(-params.glyph_matrix.m01*65536);

	mat.yy = (int)round( params.glyph_matrix.m11*65536);

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

	FT_Set_Transform(face, &mat, &vec);

	if (!FT_Load_Glyph(face, glyph, params.hinting ? FT_LOAD_DEFAULT : FT_LOAD_NO_HINTING)) {

		if (!FT_Render_Glyph(face->glyph, params.antialiasing ? FT_RENDER_MODE_NORMAL : FT_RENDER_MODE_MONO)) {

			if (params.antialiasing) {

				put_ft_bitmap(

					*params.surface,

					face->glyph->bitmap,

					face->glyph->bitmap_left + ix,

					iy - face->glyph->bitmap_top,

					params.color );

			} else {

				put_ft_bitmap_mono(

					*params.surface,

					face->glyph->bitmap,

					face->glyph->bitmap_left + ix,

					iy - face->glyph->bitmap_top,

					params.color );

			}

		}

	}

	pango_fc_font_unlock_face((PangoFcFont*)font);

}

static void

lab_pango_renderer_init(LabPangoRenderer *renderer) {

	memset(&renderer->params, 0, sizeof(renderer->params));

	renderer->params = LabPangoRendererParams();

}

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_set_substitute(FcPattern *pattern, gpointer data) {

	const int &args = *(const int*)data;

	FcPatternDel(pattern, FC_HINTING);

	FcPatternDel(pattern, FC_ANTIALIAS);

	FcPatternAddBool(pattern, FC_HINTING, (args & 1) ? FcTrue : FcFalse);

	FcPatternAddBool(pattern, FC_ANTIALIAS, (args & 2) ? FcTrue : FcFalse);

}

PangoRenderer*

lab_pango_renderer_new(LabPangoRendererParams *params) {

	PangoRenderer *renderer = (PangoRenderer*)g_object_new(LAB_TYPE_PANGO_RENDERER, nullptr);

	lab_pango_renderer_set_params((LabPangoRenderer*)renderer, params);

	return renderer;

}

void

lab_pango_renderer_set_params(LabPangoRenderer *renderer, LabPangoRendererParams *params)

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

void

lab_pango_renderer_get_params(LabPangoRenderer *renderer, LabPangoRendererParams *params)

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

PangoFontMap*

lab_pango_font_map_new(bool hinting, bool antialiasing) {

	static int args[4] { 0, 1, 2, 3 }; // to avoid encoding of int into pointer

	PangoFontMap *font_map = pango_ft2_font_map_new();

	pango_ft2_font_map_set_default_substitute(

		(PangoFT2FontMap*)font_map,

		lab_pango_fc_pattern_set_substitute,

		args + (hinting ? 1 : 0) + (antialiasing ? 2 : 0),

		nullptr );

	return font_map;

}