/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * chardev_client.h — kernel-bridge client for the daedalus-v4l2 daemon.
 *
 * Opens /dev/daedalus-v4l2, runs a blocking read() / write() loop,
 * and invokes the daemon's REQ_* handlers.  Phase 8.4 understands
 * REQ_DECODE; future phases extend the dispatch table.
 */
#ifndef DAEDALUS_V4L2_CHARDEV_CLIENT_H
#define DAEDALUS_V4L2_CHARDEV_CLIENT_H

#include <signal.h>
#include <stddef.h>
#include <stdint.h>

#include "daedalus_v4l2_proto.h"

struct ffmpeg_loader;
struct daedalus_decoder;

/**
 * struct chardev_client - daemon-side chardev state
 * @fd:		open /dev/daedalus-v4l2 descriptor (-1 if not open)
 * @loader:	dlopen'd FFmpeg loader (borrowed; not owned)
 * @decoder:	per-codec AVCodecContext cache (owned)
 * @stop_flag:	set non-zero from a signal handler to break the loop
 */
struct chardev_client {
	int				 fd;
	struct ffmpeg_loader		*loader;
	struct daedalus_decoder		*decoder;
	volatile sig_atomic_t		*stop_flag;
};

/**
 * chardev_client_open - open /dev/daedalus-v4l2 O_RDWR
 *
 * @cli:	caller-allocated; cleared on entry
 * @loader:	borrowed FFmpeg loader (must outlive the client)
 * @stop_flag:	pointer the signal handler sets to ask the loop to stop
 *
 * Return: 0 on success; negative errno on failure.
 */
int  chardev_client_open(struct chardev_client *cli,
			 struct ffmpeg_loader *loader,
			 volatile sig_atomic_t *stop_flag);

/**
 * chardev_client_run - blocking event loop
 *
 * Reads one message at a time, dispatches to the matching
 * handler, writes the corresponding response.  Returns when
 * *@stop_flag is set, on chardev EOF, or on an unrecoverable
 * error.
 *
 * Return: 0 on clean shutdown; negative errno on a fatal error.
 */
int  chardev_client_run(struct chardev_client *cli);

/**
 * chardev_client_close - close the chardev and free decoder state
 */
void chardev_client_close(struct chardev_client *cli);

#endif /* DAEDALUS_V4L2_CHARDEV_CLIENT_H */