/*

 * Low-level protocol support for the IPC connection to the engine.

 */

#ifndef IPCCONN_H_

#define IPCCONN_H_

#include <stddef.h>

#include <stdbool.h>

#define IPCCONN_MAPMSG_BYTES 4097

typedef enum {IPC_NOT_CONNECTED, IPC_LISTENING, IPC_CONNECTED} IpcConnState;

struct _flib_ipcconn;

typedef struct _flib_ipcconn *flib_ipcconn;

/**

 * Start an engine connection by listening on a random port. The selected port can

 * be queried with flib_ipcconn_port and has to be passed to the engine.

 *

 * The parameter "recordDemo" can be used to control whether demo recording should

 * be enabled for this connection. The localPlayerName is needed for demo

 * recording purposes.

 *

 * Returns NULL on error. Destroy the created object with flib_ipcconn_destroy.

 *

 * We stop accepting new connections once a connection has been established, so you

 * need to create a new ipcconn in order to start a new connection.

 */

flib_ipcconn flib_ipcconn_create(bool recordDemo, const char *localPlayerName);

uint16_t flib_ipcconn_port(flib_ipcconn ipc);

/**

 * Free resources, close sockets, and set the pointer to NULL.

 */

void flib_ipcconn_destroy(flib_ipcconn *ipcptr);

/**

 * Determine the current connection state

 */

IpcConnState flib_ipcconn_state(flib_ipcconn ipc);

/**

 * Receive a single message (up to 256 bytes) and copy it into the data buffer.

 * Returns the length of the received message, a negative value if no message could

 * be read.

 *

 * The first byte of a message is its content length, which is one less than the returned

 * value.

 *

 * Note: When a connection is closed, you probably want to call this function until

 * no further message is returned, to ensure you see all messages that were sent

 * before the connection closed.

 */

int flib_ipcconn_recv_message(flib_ipcconn ipc, void *data);

/**

 * Try to receive 4097 bytes. This is the size of the reply the engine sends

 * when successfully queried for map data. The first 4096 bytes are a bit-packed

 * twocolor image of the map (256x128), the last byte is the number of hogs that

 * fit on the map.

 */

int flib_ipcconn_recv_map(flib_ipcconn ipc, void *data);

/**

 * Write a single message (up to 255 bytes) to the engine. This call blocks until the

 * message is completely written or the connection is closed or an error occurs.

 *

 * Calling this function in a state other than IPC_CONNECTED will fail immediately.

 * Returns a negative value on failure.

 */

int flib_ipcconn_send_message(flib_ipcconn ipc, void *data, size_t len);

/**

 * Convenience function for sending a 0-delimited string.

 */

int flib_ipcconn_send_messagestr(flib_ipcconn ipc, char *data);

/**

 * Call regularly to allow background work to proceed

 */

void flib_ipcconn_accept(flib_ipcconn ipc);

/**

 * Get a record of the connection. This should be called after

 * the connection is closed and all messages have been received.

 *

 * If demo recording was not enabled, or if the recording failed for some reason,

 * the buffer will be empty.

 *

 * If save=true is passed, the result will be a savegame, otherwise it will be a

 * demo.

 *

 * The buffer is only valid until flib_ipcconn_getsave is called again or the ipcconn

 * is destroyed.

 */

flib_constbuffer flib_ipcconn_getrecord(flib_ipcconn ipc, bool save);

#endif /* IPCCONN_H_ */