#ifndef EL__TERMINAL_SCREEN_H
#define EL__TERMINAL_SCREEN_H


struct screen_char;
struct terminal;

/* The terminal's screen manages */
struct terminal_screen {
	/* This is the screen's image, character by character. */
	struct screen_char *image;

	/* The previous screen's image, used for optimizing actual drawing. */
	struct screen_char *last_image;

	/* The current and the previous cursor positions. */
	int cx, cy;
	int lcx, lcy;

	/* The range of line numbers that are out of sync with the physical
	 * screen. @dirty_from > @dirty_to means not dirty. */
	int dirty_from, dirty_to;
};

/* Mark the screen ready for redrawing. */
static inline void
set_screen_dirty(struct terminal_screen *screen, int from, int to)
{
	int_upper_bound(&screen->dirty_from, from);
	int_lower_bound(&screen->dirty_to, to);
}

/* Initializes a screen. Returns NULL upon allocation failure. */
struct terminal_screen *init_screen(void);

/* Cleans up after the screen. */
void done_screen(struct terminal_screen *screen);

/* Update the size of the previous and the current screen image to hold @x time
 * @y chars. */
void resize_screen(struct terminal *term, int x, int y);

/* Updates the terminal screen. */
void redraw_screen(struct terminal *term);

/* Erases the entire screen and moves the cursor to the upper left corner. */
void erase_screen(struct terminal *term);

/* Meeep! */
void beep_terminal(struct terminal *term);

/* Release private screen drawing utilities. */
void done_screen_drivers(void);

#endif
