#ifndef SOCKS_TTY_H_
#define SOCKS_TTY_H_

#include <socks/status.h>
#include <socks/device.h>
#include <socks/queue.h>
#include <socks/object.h>
#include <stdint.h>

#define TTY_DEVICE(dev) ((dev)->dev_type == DEV_TYPE_CHAR ? (dev)->chr.c_tty : NULL)
#define TTY_DRIVER(drv) ((struct tty_driver *)((char *)drv - offsetof(struct tty_driver, tty_base)))

#define TTY_INPUT_QUEUE_SIZE 256

struct kext;

/* The TTY system.

   TTYs are an enhanced version of the console object. Rather than a simple output
   device for log messages, TTYs are intended to support fully-featured interactive
   user sessions, including advanced display manipulation (if applicable) and
   buffered user input.

   A TTY object is split into 2 parts:
     - struct tty: This represents the terminal session, and tracks things like the cursor
       position, input buffer, flags, etc.
     - struct tty_driver: This is a set of function callbacks that the TTY can use to
       manipulate the output device. This could represent a char-based framebuffer
       device, a serial port, etc.
*/

#ifdef __cplusplus
extern "C" {
#endif

enum tty_driver_type {
	/* For TTYs operating on simple IO devices like serial ports.
	   Allows writing characters, receiving characters, and not much else. */
	TTY_DRIVER_SIMPLE,
	/* For TTYs operating on more capable display interfaces.
	   Allows putting characters at arbitrary locations, scrolling, etc */
	TTY_DRIVER_FULL,
};

/* TTY cursor status. The extra cursor styles are just for completeness,
   the important one to support (if possible), is TTY_CURSOR_NONE.
   The others can be interpreted as "just turn on a cursor of any style". */
enum tty_cursor {
	TTY_CURSOR_ULINE,
	TTY_CURSOR_BLOCK,
	TTY_CURSOR_NONE,
};

/* direction to use for scrolling. The important one to support is
   TTY_SCROLL_DOWN for when output overflows the display */
enum tty_scroll_dir {
	TTY_SCROLL_DOWN,
	TTY_SCROLL_UP,
};

enum tty_modifier_key {
	TTY_KEY_OTHER = 0x00u,
	TTY_KEY_CTRL = 0x01u,
	TTY_KEY_ALT = 0x02u,
	TTY_KEY_SHIFT = 0x04u,
};

/* character attribute. this could be as simple as VGA's 16-colour palette
   plus an extra bit for bright, or a full 24-bit RGB value with bold and underline
   support, depending on what the driver supports. */
typedef uint64_t tty_attrib_t;

struct tty_driver_ops {
	void (*tty_init)(struct device *dev);
	void (*tty_deinit)(struct device *dev);
	void (*tty_clear)(struct device *dev, int x, int y, int width, int height);
	void (*tty_putc)(struct device *dev, int c, int xpos, int ypos, tty_attrib_t attrib);
	void (*tty_set_cursor)(struct device *dev, enum tty_cursor cur);
	void (*tty_move_cursor)(struct device *dev, int x, int y);
	void (*tty_scroll)(struct device *dev, enum tty_scroll_dir dir, int lines);
};

struct tty_driver {
	struct driver tty_base;

	char tty_name[16];
	enum tty_driver_type tty_type;
	struct queue_entry tty_head;

	struct tty_driver_ops *tty_ops;
};

struct tty_ldisc {
	char name[OBJECT_NAME_MAX];
	void(*write)(struct device *, const struct input_event *);
};

struct tty_device {
	unsigned int tty_xcells, tty_ycells;
	unsigned int tty_xcur, tty_ycur;
	unsigned int tty_iflag, tty_oflag, tty_lflag;
	tty_attrib_t tty_curattrib;

	enum tty_modifier_key tty_modstate;

	struct tty_ldisc *tty_ldisc;

	/* input characters processed from tty_events, returned by tty_read()  */
	struct ringbuffer tty_input;
};

extern kern_status_t tty_bootstrap(void);
extern struct tty_ldisc *tty_default_line_discipline(void);

extern struct device *tty_device_create(void);
extern kern_status_t tty_device_register(struct device *dev, struct tty_driver *owner, struct device *parent);

extern void tty_set_foreground(struct device *tty);
extern kern_status_t tty_connect_foreground_input_device(struct device *input);

extern struct tty_driver *tty_driver_create(struct kext *self, const char *name);
extern kern_status_t tty_driver_destroy(struct tty_driver *drv);
extern kern_status_t tty_driver_register(struct tty_driver *drv);
extern kern_status_t tty_driver_unregister(struct tty_driver *drv);
static inline struct driver *tty_driver_base(struct tty_driver *drv)
{
	return &drv->tty_base;
}

extern kern_status_t tty_read(struct device *tty, void *buf, size_t max, size_t *nr_read, socks_flags_t flags);
extern kern_status_t tty_write(struct device *tty, const void *buf, size_t len, size_t *nr_written, socks_flags_t flags);
extern kern_status_t tty_report_event(struct device *tty, const struct input_event *ev);

#ifdef __cplusplus
}
#endif

#endif