#pragma once

#include <stdint.h>

/* for shared objects */
#if __GNUC__ >= 4
 #define SO_IMPORT __attribute__((visibility("default")))
#else
 #define SO_IMPORT
#endif

#ifdef __cplusplus
extern "C" {
#endif

/* Colors (see struct tb_cell's fg and bg fields). */
#define TB_DEFAULT 0x00
#define TB_BLACK   0x01
#define TB_RED     0x02
#define TB_GREEN   0x03
#define TB_YELLOW  0x04
#define TB_BLUE    0x05
#define TB_MAGENTA 0x06
#define TB_CYAN    0x07
#define TB_WHITE   0x08

/* Attributes, it is possible to use multiple attributes by combining them
 * using bitwise OR ('|'). Although, colors cannot be combined. But you can
 * combine attributes and a single color. See also struct tb_cell's fg and bg
 * fields.
 */
#define TB_BOLD      0x0100
#define TB_UNDERLINE 0x0200
#define TB_REVERSE   0x0400

/* A cell, single conceptual entity on the terminal screen. The terminal screen
 * is basically a 2d array of cells. It has the following fields:
 *  - 'ch' is a unicode character
 *  - 'fg' foreground color and attributes
 *  - 'bg' background color and attributes
 */
struct tb_cell {
    uint32_t ch;
    uint16_t fg;
    uint16_t bg;
};

/* Error codes returned by tb_init(). All of them are self-explanatory, except
 * the pipe trap error. Termbox uses unix pipes in order to deliver a message
 * from a signal handler (SIGWINCH) to the main event reading loop. Honestly in
 * most cases you should just check the returned code as < 0.
 */
#define TB_EUNSUPPORTED_TERMINAL -1
#define TB_EFAILED_TO_OPEN_TTY   -2

/* Initializes the termbox library. This function should be called before any
 * other functions. After successful initialization, the library must be
 * finalized using the tb_shutdown() function.
 */
SO_IMPORT int tb_init(void);
SO_IMPORT void tb_resize(void);
SO_IMPORT void tb_shutdown(void);

/* Returns the size of the internal back buffer (which is the same as
 * terminal's window size in characters). The internal buffer can be resized
 * after tb_clear() or tb_present() function calls. Both dimensions have an
 * unspecified negative value when called before tb_init() or after
 * tb_shutdown().
 */
SO_IMPORT int tb_width(void);
SO_IMPORT int tb_height(void);

/* Clears the internal back buffer using TB_DEFAULT color or the
 * color/attributes set by tb_set_clear_attributes() function.
 */
SO_IMPORT void tb_clear(void);
SO_IMPORT void tb_set_clear_attributes(uint16_t fg, uint16_t bg);

/* Synchronizes the internal back buffer with the terminal. */
SO_IMPORT void tb_present(void);

#define TB_HIDE_CURSOR -1

/* Sets the position of the cursor. Upper-left character is (0, 0). If you pass
 * TB_HIDE_CURSOR as both coordinates, then the cursor will be hidden. Cursor
 * is hidden by default.
 */
SO_IMPORT void tb_set_cursor(int cx, int cy);

/* Changes cell's parameters in the internal back buffer at the specified
 * position.
 */
SO_IMPORT void tb_put_cell(int x, int y, const struct tb_cell *cell);
SO_IMPORT void tb_change_cell(int x, int y, uint32_t ch, uint16_t fg, uint16_t bg);

/* Returns a pointer to internal cell back buffer. You can get its dimensions
 * using tb_width() and tb_height() functions. The pointer stays valid as long
 * as no tb_clear() and tb_present() calls are made. The buffer is
 * one-dimensional buffer containing lines of cells starting from the top.
 */
SO_IMPORT struct tb_cell *tb_cell_buffer(void);

#define TB_OUTPUT_CURRENT   0
#define TB_OUTPUT_NORMAL    1
#define TB_OUTPUT_256       2
#define TB_OUTPUT_216       3
#define TB_OUTPUT_GRAYSCALE 4

/* Sets the termbox output mode. Termbox has three output options:
 * 1. TB_OUTPUT_NORMAL     => [1..8]
 *    This mode provides 8 different colors:
 *      black, red, green, yellow, blue, magenta, cyan, white
 *    Shortcut: TB_BLACK, TB_RED, ...
 *    Attributes: TB_BOLD, TB_UNDERLINE, TB_REVERSE
 *
 *    Example usage:
 *        tb_change_cell(x, y, '@', TB_BLACK | TB_BOLD, TB_RED);
 *
 * 2. TB_OUTPUT_256        => [0..256]
 *    In this mode you can leverage the 256 terminal mode:
 *    0x00 - 0x07: the 8 colors as in TB_OUTPUT_NORMAL
 *    0x08 - 0x0f: TB_* | TB_BOLD
 *    0x10 - 0xe7: 216 different colors
 *    0xe8 - 0xff: 24 different shades of grey
 *
 *    Example usage:
 *        tb_change_cell(x, y, '@', 184, 240);
 *        tb_change_cell(x, y, '@', 0xb8, 0xf0);
 *
 * 2. TB_OUTPUT_216        => [0..216]
 *    This mode supports the 3rd range of the 256 mode only.
 *    But you don't need to provide an offset.
 *
 * 3. TB_OUTPUT_GRAYSCALE  => [0..23]
 *    This mode supports the 4th range of the 256 mode only.
 *    But you dont need to provide an offset.
 *
 * Execute build/src/demo/output to see its impact on your terminal.
 *
 * If 'mode' is TB_OUTPUT_CURRENT, it returns the current output mode.
 *
 * Default termbox output mode is TB_OUTPUT_NORMAL.
 */
SO_IMPORT int tb_select_output_mode(int mode);

#ifdef __cplusplus
}
#endif