#include <asm/errno.h>

#include "intf.h"
#include "trans.h"
#include "debug.h"


static int process_release(struct tsnif_handle *h, struct tsnif_term *term)
{
	if (!h->ops || !h->ops->cb_release)
		return -1;

	term->state = TSNIF_INTF_STATE_DONE;

	TSNIF_DEBUG(FSM, "type %d, idx %d\n", term->type, term->idx);
	return h->ops->cb_release(term);
}

static int process_error(struct tsnif_handle *h, struct tsnif_term *term, int err)
{
	if (!h->ops || !h->ops->cb_err)
		return -1;

	return h->ops->cb_err(term, err);
}

static int process_tgroup(struct tsnif_handle *h, struct tsnif_term *term,
			  int group)
{
	int err;

	err = trans_group(&h->trans, group);
	term->state = err ? TSNIF_INTF_STATE_DONE : TSNIF_INTF_STATE_DATA;

	TSNIF_DEBUG(FSM, "adding group %d, err %d\n", group, err);
	return err;
}

static int process_data(struct tsnif_handle *h,
			struct tsnif_term *term,
			struct trans_msg *msg)
{
	struct tsnif_data data;

	TSNIF_DEBUG(FSM, "type %d, idx %d\n",
			term->type, term->idx);

	if (!h->ops || !h->ops->cb_data)
		return -1;

	data.ptr   = msg->data.ptr;
	data.len   = msg->data.len;
	data.flags = msg->data.flags;
	data.time  = msg->data.time;
	data.ws    = msg->data.ws;

	return h->ops->cb_data(term, &data);
}

static int new(struct tsnif_handle *h,
		struct tsnif_term *term,
		struct trans_msg *msg)
{
	TSNIF_DEBUG(FSM, "got data in the NEW state, something is wrong\n");
	return -1;
}

static int attach(struct tsnif_handle *h,
		  struct tsnif_term *term,
		  struct trans_msg *msg)
{
	int err = 0;

	switch(msg->cmd) {
	case TSNIF_CMD_TGROUP:
		err = process_tgroup(h, term, msg->group);
		break;

	case TSNIF_CMD_ATTACH:
		/* got attach ack, do nothing */
		if (msg->ack)
			break;

		/* got ATTACH cmd without error */
		err = -EINVAL;
		if (!msg->err)
			break;

		err = process_error(h, term, msg->error);
		break;

	default:
		return -1;
	}

	return err;
}

static int detach(struct tsnif_handle *h,
		  struct tsnif_term *term,
		  struct trans_msg *msg)
{
	int err = 0;

	switch(msg->cmd) {
	case TSNIF_CMD_DETACH:
		if (msg->ack)
			return process_release(h, term);

		err = -EINVAL;
		if (!msg->err)
			break;

		err = process_error(h, term, msg->error);
		break;

	case TSNIF_CMD_DATA:
		/* ignore DATA msg when in DETACH state */
		break;

	default:
		return -1;
	}

	return err;
}
static int data(struct tsnif_handle *h,
		struct tsnif_term *term,
		struct trans_msg *msg)
{
	int err = 0;

	/* all ACKs should be ok in this state */
	if (msg->ack)
		return 0;

	switch(msg->cmd) {
	case TSNIF_CMD_DATA:
		err = process_data(h, term, msg);
		break;

	default:
		return -1;
	}

	return err;
}

int fsm_process(struct tsnif_handle *h,
		struct tsnif_term *term,
		struct trans_msg *msg)
{
	TSNIF_DEBUG(FSM, "got cmd %d for term type %d, idx %d, state %d\n",
		msg->cmd, term->type, term->idx, term->state);

	/* we can get the release command in any state,
	 * so let's handle it globaly here */
	if (msg->cmd == TSNIF_CMD_TTY_RELEASE)
		return process_release(h, term);

	switch(term->state) {
	case TSNIF_INTF_STATE_NEW:
		return new(h, term, msg);

	case TSNIF_INTF_STATE_ATTACH:
		return attach(h, term, msg);

	case TSNIF_INTF_STATE_DETACH:
		return detach(h, term, msg);

	case TSNIF_INTF_STATE_DATA:
		return data(h, term, msg);

	default:
		return -1;
	}

	return 0;
}

int fsm_send(struct tsnif_term *term, int cmd)
{
	switch(cmd) {
	case TSNIF_CMD_ATTACH:
		if (term->state != TSNIF_INTF_STATE_NEW)
			return -1;

		term->state = TSNIF_INTF_STATE_ATTACH;
		break;

	case TSNIF_CMD_DETACH:
		if (term->state != TSNIF_INTF_STATE_DATA)
			return -1;

		term->state = TSNIF_INTF_STATE_DETACH;
        }

	return 0;
}