#ifndef GBAEXP_TILES_H
#define GBAEXP_TILES_H

#include <stdarg.h>
#include <stdio.h>

#include "common.h"
#include "bitmap.h"
#include "posprintf.h"
#include "ppu.h"

typedef struct TextEngine {
    // Currently working on tiled backgrounds only. The X and Y positions
    // correspond to the tile X and Y starting from the top left of the screen.
    // For a 240x160 screen, we have 30x20 tiles available.
    size_t cursor_x;
    size_t cursor_y;
    // Pointer to the memory being used for writing to the screen.
    u32 *memory;
    // The font used to render the text.
    u8 color;
} TextEngine;

static TextEngine text_engine = {0};

void
txt_putc(char c) {
    if (c == '\0') {
        return;
    }
    if (c == '\n') {
        text_engine.cursor_x = 0;
        text_engine.cursor_y++;
    } else {
        int x = text_engine.cursor_x;
        int y = text_engine.cursor_y;
        putfontchar(text_engine.memory, x, y, c, text_engine.color);
        text_engine.cursor_x += 1;
        if (text_engine.cursor_x >= 30) {
            text_engine.cursor_x = 0;
            text_engine.cursor_y++;
        }
    }
    if (text_engine.cursor_y >= 20) {
        text_engine.cursor_y = 0;
    }
}

static inline void
txt_puts(char *msg) {
    while (*msg) {
        txt_putc(*msg++);
    }
}

void
txt_init(u8 color, u32 *buf) {
    // Prepare text engine.
    text_engine.color = color;
    text_engine.memory = buf;
}

// Print text to the screen with formatting.
#define txt_printf(msg, ...) \
	{ \
		char buf[256] = {0}; \
		posprintf(buf, msg, ##__VA_ARGS__); \
		txt_puts(buf); \
	}

void
txt_clear_line(void) {
    for (size_t i = 0; i < 30; ++i) {
        int x = text_engine.cursor_x;
        int y = text_engine.cursor_y;
        putfontchar(text_engine.memory, x, y, ' ', text_engine.color);
    }
    text_engine.cursor_x = 0;
}

void
txt_clear_screen(void) {
    for (size_t j = 0; j < 20; ++j) {
        text_engine.cursor_y = j;
        txt_clear_line();
    }
    text_engine.cursor_x = 0;
    text_engine.cursor_y = 0;
}

void
txt_position(size_t tile_x, size_t tile_y) {
    text_engine.cursor_x = tile_x;
    text_engine.cursor_y = tile_y;
}

#endif // GBAEXP_TILES_H