#pragma once

#include"k3.h"
#include"k3batch.h"
#include<string.h>

#define k3_FONT_ALIGN_LEFT 0
#define k3_FONT_ALIGN_CENTER 1
#define k3_FONT_ALIGN_RIGHT 2

struct k3FontGlyph {
	uint32_t cp;
	uint16_t x;
	uint16_t y;
	uint16_t width;
	uint16_t height;
	int16_t xoffset;
	int16_t yoffset;
	uint16_t xadvance;
	uint8_t page;
	uint8_t chnl;
};

struct k3Font {
	void *ud;
	
	float lineScale;
	
	uint16_t baseline;
	
	uint16_t texW, texH;
	
	size_t glyphCount;
	struct k3FontGlyph *glyphs;
	
	size_t pageCount;
	struct k3Tex **pages;
};

typedef struct k3Tex*(*k3FontTexLoader)(struct k3Font*, const char *name);

struct k3Font *k3FontCreate();
int k3FontLoad(struct k3Font*, const uint8_t *buf, size_t len, k3FontTexLoader);

void k3FontSz(struct k3Font*, float sz, const char *txt, float wall, struct k3RectF *ret);
void k3FontDraw(struct k3Font*, float x, float y, float sz, const char *txt, float wall, int alignment, vec4 color);

struct k3FontGlyph *k3FontGetGlyph(struct k3Font*, uint32_t cp);

static inline int k3UTF8Encode(uint32_t cp, uint8_t ret[static 4]) {
	if(cp < 0x80) {
		ret[0] = cp;
		return 1;
	} else if(cp < 0x800) {
		ret[0] = 192 | (cp >> 6);
		ret[1] = 128 | (cp & 63);
		return 2;
	} else if(cp < 0x10000) {
		ret[0] = 224 | (cp >> 12);
		ret[1] = 128 | ((cp >> 6) & 63);
		ret[2] = 128 | (cp & 63);
		return 3;
	} else if(cp < 0x110000) {
		ret[0] = 240 | (cp >> 18);
		ret[1] = 128 | ((cp >> 12) & 63);
		ret[2] = 128 | ((cp >> 6) & 63);
		ret[3] = 128 | (cp & 63);
		return 4;
	}
	return 0;
}

static inline const char *k3UTF8LastCodepointZ(const char *txt) {
	size_t len = strlen(txt);
	while(len--) {
		if((txt[len] & 0xC0) != 0x80) {
			return &txt[len];
		}
	}
	return NULL;
}