/*
 * secde -- experimental lightweight Wayland/X11 server
 * Copyright (C) 2019  Samuel Lidén Borell
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#ifndef PROTOHND_H
#define PROTOHND_H

/** Bitmask for the type of a file descriptor */
typedef enum {
    FDF_SOCKET = 0x1, /* uses recv/send */
    FDF_SERVER = 0x2, /* supports accept */
    FDF_READABLE = 0x4 /* supports read/recv and send/write */
} FdFlags;
#define FDTYPE_SERVERSOCK (FDF_SOCKET | FDF_SERVER)
#define FDTYPE_CLIENTSOCK (FDF_SOCKET | FDF_READABLE)
#define FDTYPE_CHARDEV (FDF_READABLE)

/**
 * Type of protocol. Some use sockets with clients
 * also, others use character devices.
 */
typedef enum {
    FDP_UNSPEC = 0,  /* used for client fds in protohnd_fdadded */
    FDP_X11,      /* socket */
    FDP_PULSE,    /* socket */
    FDP_WAYLAND,  /* socket */
    FDP_KMS,      /* character device */
    FDP_FBDEV,    /* character device */
    FDP_EVDEV,    /* character device */
    FDP_ALSA,     /* character device */
    FDP_V4L2,     /* character device */
    FDP_INOTIFY   /* character device */
} FdProtocol;

typedef struct FdInfo FdInfo;


/** Called when the server has begun to start */
void protohnd_initing(void);

/**
 * Called when the server has been initialized.
 * Devices and sockets may be added even after initialization.
 */
void protohnd_inited(void);

/**
 * Returns the FdInfo pointer for a given file descriptor, or
 * NULL if not found.
 */
FdInfo *protohnd_getfdinfo(int fd);

/** Returns the file descriptor from the given FdInfo pointer */
int protohnd_getfd(struct FdInfo *info);

/** Returns the FdFlags mask for a given FdInfo pointer */
FdFlags protohnd_getfdflags(struct FdInfo *info);

/**
 * Called when some type of socket (client or server) or file
 * descriptor (like a character device) has been added.
 *
 * \param server If the new fd is a client, then this is the server
 * \param fd New file descriptor to add
 * \param flags Flags for file descriptor.
 * \param protocol Protocol of file descriptor. FDP_UNSPEC for clients.
 * \return FdInfo pointer, or NULL if the fd should be closed
 */
/* TODO it would be nice to have a "user" parameter here, that was returned and then passed into all places where the serversock is passed */
struct FdInfo *protohnd_fdadded(struct FdInfo *server, int fd,
                                FdFlags flags, FdProtocol protocol
                                /*, cliantaddr, clientaddrsize*/);

/**
 * May be called when a client has closed a connection.
 * There might still be data to read.
 * There is no guarantee that this function will be called.
 */
void protohnd_willclose(struct FdInfo *info);

/**
 * Called when a file descriptor has been completely closed and no more
 * data remains to be read.
 */
void protohnd_closed(struct FdInfo *info);

/** Called when data has been received */
void protohnd_received(struct FdInfo *info, const unsigned char *buff,
                       int numrecv);

/**
 * Called to notify when the fd is ready or no longer
 * ready to send data.
 *
 * \param info FdInfo pointer
 * \param state 1 if ready, 0 if not ready
 */
void protohnd_writeready(struct FdInfo *info, int state);

/**
 * Called when data can be written. Returns the FdInfo structure of
 * the file descriptor to write to, or NULL if there is nothing to
 * write.
 *
 * The buff and length arguments are initialized to point to a static buffer
 * and the length of it, but may be changed to point to a longer buffer.
 *
 * Set clientmore if there is more data to write to the returned fd.
 *
 * Writes may or may not succeed. The protohnd_written function will be
 * called with the write status, and with the same FdInfo pointer.
 */
struct FdInfo *protohnd_getwrite(unsigned char **buff, int *length,
                                 int *clientmore);

/**
 * Called when data has been written, or when a write has failed.
 * Result is set to: 0 for success, 1 for error, and -1 if one should try again.
 */
void protohnd_written(struct FdInfo *info, int numwritten,
                      int remaining, int result);

#endif