// Remote FS server

#include "net.h"
#include "remotefs.h"
#include "eluarpc.h"
#include "serial.h"
#include "server.h"
#include "type.h"
#include "log.h"
#include "os_io.h"
#include <stdio.h>
#include <limits.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "rfs.h"
#include "deskutils.h"
#include "rfs_transports.h"

// ****************************************************************************
// Local variables


u8 rfs_buffer[ MAX_PACKET_SIZE + ELUARPC_WRITE_REQUEST_EXTRA ];
const RFS_TRANSPORT_DATA *p_transport_data; 

// ****************************************************************************
// Serial transport implementation

static ser_handler ser;

static void flush_serial()
{
  // Flush all data in serial port
  while( ser_read_byte( ser, SER_NO_TIMEOUT ) != -1 );
}

// Read a packet from the serial port
static void ser_read_request_packet()
{
  u16 temp16;
  u32 readbytes;

  while( 1 )
  {
    // First read the length
    if( ( readbytes = ser_read( ser, rfs_buffer, ELUARPC_START_OFFSET, SER_INF_TIMEOUT ) ) != ELUARPC_START_OFFSET )
    {
      log_msg( "read_request_packet: ERROR reading packet length. Requested %d bytes, got %d bytes\n", ELUARPC_START_OFFSET, readbytes );
      flush_serial();
      continue;
    }

    if( eluarpc_get_packet_size( rfs_buffer, &temp16 ) == ELUARPC_ERR )
    {
      log_msg( "read_request_packet: ERROR getting packet size.\n" );
      flush_serial();
      continue;
    }

    // Then the rest of the data
    if( ( readbytes = ser_read( ser, rfs_buffer + ELUARPC_START_OFFSET, temp16 - ELUARPC_START_OFFSET, SER_INF_TIMEOUT ) ) != temp16 - ELUARPC_START_OFFSET )
    {
      log_msg( "read_request_packet: ERROR reading full packet, got %u bytes, expected %u bytes\n", ( unsigned )readbytes, ( unsigned )temp16 - ELUARPC_START_OFFSET );
      flush_serial();
      continue;
    }
    else
      break;
  }
}

// Send a packet to the serial port
static void ser_send_response_packet()
{
  u16 temp16;

  // Send request
  if( eluarpc_get_packet_size( rfs_buffer, &temp16 ) != ELUARPC_ERR )
  {
    log_msg( "send_response_packet: sending response packet of %u bytes\n", ( unsigned )temp16 );
    ser_write( ser, rfs_buffer, temp16 );
  }
}

static int ser_server_init( const char *portname, int serspeed, int flow )
{
  // Setup serial port
  if( ( ser = ser_open( portname ) ) == SER_HANDLER_INVALID )
  {
    log_err( "Cannot open port %s\n", portname );
    return 0;
  }
  if( ser_setup( ser, ( u32 )serspeed, SER_DATABITS_8, SER_PARITY_NONE, SER_STOPBITS_1, flow ) != SER_OK )
  {
    log_err( "Unable to initialize serial port\n" );
    return 0;
  }  
  flush_serial();
  
  // User report
  log_msg( "Running RFS server on serial port %s (%u baud).\n", portname, ( unsigned )serspeed );
  return 1; 
}

static void ser_cleanup()
{
  ser_close( ser );
}

const RFS_TRANSPORT_DATA ser_transport_data = { ser_read_request_packet, ser_send_response_packet, ser_cleanup };

// ****************************************************************************
// UDP transport implementation

static NET_SOCKET trans_socket = INVALID_SOCKET_VALUE;
static struct sockaddr_in trans_from;

// Helper: read (blocking) the specified number of bytes

static void udp_read_helper( u8 *dest, u32 size )
{
  socklen_t fromlen;
  int readbytes;

  while( size )
  {
    fromlen = sizeof( trans_from );
    readbytes = net_recvfrom( trans_socket, ( char* )dest, size, 0, ( struct sockaddr* )&trans_from, &fromlen, NET_INF_TIMEOUT );
    size -= readbytes;
    if( size == 0 )
      break;
    dest += readbytes;
  }
}

static void udp_read_request_packet()
{
  u16 temp16;
 
  while( 1 )
  {
    // First read the length
    udp_read_helper( rfs_buffer, ELUARPC_START_OFFSET );

    if( eluarpc_get_packet_size( rfs_buffer, &temp16 ) == ELUARPC_ERR )
    {
      log_msg( "read_request_packet: ERROR getting packet size.\n" );
      continue;
    }

    // Then the rest of the data
    udp_read_helper( rfs_buffer + ELUARPC_START_OFFSET, temp16 - ELUARPC_START_OFFSET );
    break;
  }
}

static void udp_send_response_packet()
{
  u16 temp16;
  
  // Send request
  if( eluarpc_get_packet_size( rfs_buffer, &temp16 ) != ELUARPC_ERR )
  {
    log_msg( "send_response_packet: sending response packet of %u bytes\n", ( unsigned )temp16 );
    net_sendto( trans_socket, ( char* )rfs_buffer, temp16, 0, ( struct sockaddr* )&trans_from, sizeof( trans_from ) );
  }  
}

static int udp_server_init( unsigned server_port )
{
  int length;
  struct sockaddr_in server;
     
  if( ( trans_socket = net_create_socket( AF_INET, SOCK_DGRAM, 0 ) ) == INVALID_SOCKET_VALUE )
  {
    log_err( "Unable to create socket\n" );
    return 1;
  }
  length = sizeof( server );
  memset( &server, 0, sizeof( server ) );
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = INADDR_ANY;
  server.sin_port = htons( server_port );
  if( bind( net_socket( trans_socket ), ( struct sockaddr * )&server, length ) < 0 )
  {
   log_err( "Unable to bind socket\n" );
   return 0; 
  }
  log_msg( "Running RFS server on UDP port %u.\n", ( unsigned )server_port );
  return 1;    
}

static void udp_cleanup()
{
  net_close( trans_socket );
}

const RFS_TRANSPORT_DATA udp_transport_data = { udp_read_request_packet, udp_send_response_packet, udp_cleanup };

// ****************************************************************************
// Memory transport implementation

// Read state machine
enum
{
  MEM_STATE_READ_LENGTH,
  MEM_STATE_READ_REQUEST,
  MEM_STATE_REQUEST_DONE
};

static int mem_read_len;
static int mem_expected_len;
static int mem_read_state;
static int mem_response_flag;

void rfs_mem_start_request()
{
  mem_read_state = MEM_STATE_READ_LENGTH;
  mem_read_len = mem_expected_len = 0;
  mem_response_flag = 0;
}

int rfs_mem_read_request_packet( int c )
{
  u16 temp16;
  int res = 1;
  
  if( c == -1 )
  {
    rfs_mem_start_request();
    return 0;
  }
  
  switch( mem_read_state )
  {
    case MEM_STATE_READ_LENGTH:
      rfs_buffer[ mem_read_len ++ ] = c;
      if( mem_read_len == ELUARPC_START_OFFSET )
      {
        mem_read_len = 0;
        if( eluarpc_get_packet_size( rfs_buffer, &temp16 ) == ELUARPC_ERR )
        {
          log_msg( "RFS read_request_packet: ERROR getting packet size.\n" );
          mem_read_state = MEM_STATE_REQUEST_DONE;
          res = 0;
        }
        else
        {
          mem_read_state = MEM_STATE_READ_REQUEST;
          mem_expected_len = temp16 - ELUARPC_START_OFFSET;
        }        
      }
      break;
      
    case MEM_STATE_READ_REQUEST:
      rfs_buffer[ ELUARPC_START_OFFSET + mem_read_len ] = c;
      mem_read_len ++;
      if( mem_read_len == mem_expected_len )  
      {
        mem_read_state = MEM_STATE_REQUEST_DONE;
        mem_response_flag = 1;
      }     
      break;
  }
  
  return res;
}

int rfs_mem_has_response()
{
  return mem_response_flag;
}

void rfs_mem_write_response( u16 *plen, u8 **pdata )
{  
  // Execute request  
  server_execute_request( rfs_buffer );
  
  // Send response
  if( eluarpc_get_packet_size( rfs_buffer, plen ) != ELUARPC_ERR )
  {
    log_msg( "send_response_packet: sending response packet of %u bytes\n", ( unsigned )*plen );
    *pdata = rfs_buffer;    
  } 
  else
  {
    log_msg( "ERROR in send_response_packet!\n" );
    *plen = 0;
  }
}

static int mem_server_init()
{
  rfs_mem_start_request();  
  log_msg( "RFS: using memory transport.\n" );
  return 1;   
}

const RFS_TRANSPORT_DATA mem_transport_data = { NULL, NULL, NULL };

// ****************************************************************************
// Helper functions

// Transport parser
static int parse_transport_and_init( const char* s )
{
  const char *c, *c2;
  char *temps, *tempb;
  long tempi = 0;
  int flow;
  
  if( strstr( s, "ser:" ) == s )
  {
    p_transport_data = &ser_transport_data;
    s += strlen( "ser:" );
    if( ( c = strchr( s, ',' ) ) == NULL )
    {
      log_err( "Invalid serial transport syntax\n" );
      return 0;
    }
    temps = l_strndup( s, c - s );
    if( ( c2 = strchr( c + 1, ',' ) ) == NULL )
    {
      log_err( "Invalid serial transport syntax.\n" );
      return 0;
    }
    tempb = l_strndup( c + 1, c2 - c - 1 );
    if( secure_atoi( tempb, &tempi ) == 0 )
    {
      log_err( "Invalid port speed\n" );
      return 0;
    }
    free( tempb );   
    if( !strcmp( c2 + 1, "none" ) )
      flow = SER_FLOW_NONE;
    else if( !strcmp( c2 + 1, "rtscts" ) )
      flow = SER_FLOW_RTSCTS;
    else
    {
      log_err( "Invalid flow control type.\n" );
      return 0;
    }
    tempi = ser_server_init( temps, tempi, flow );
    free( temps );    
    return tempi;
  }
  else if( strstr( s, "udp:" ) == s )
  {
    p_transport_data = &udp_transport_data;
    s += strlen( "udp:" );
    if( secure_atoi( s, &tempi ) == 0 )
    {
      log_err( "Invalid port number\n" );
      return 0;
    }    
    if( net_init() == 0 )
    { 
      log_err( "Unable to initialize network\n" );
      return 0;
    }
    return udp_server_init( tempi );   
  }
  else if( !strcmp( s, "mem" ) )
  {
    // Direct memory transport, only used with mux in rfsmux mode
    p_transport_data = &mem_transport_data;
    return mem_server_init( tempi ); 
  }  
  log_err( "Error: unsupported transport\n" );
  return 0;
}

// *****************************************************************************
// Entry point

#define TRANSPORT_ARG_IDX     1
#define DIRNAME_ARG_IDX       2
#define VERBOSE_ARG_IDX       3
#define MIN_ARGC_COUNT        3
#define VERBOSE_ARGC_COUNT    4

int rfs_init( int argc, const char **argv )
{
  setvbuf( stdout, NULL, _IONBF, 0 );
  if( argc < MIN_ARGC_COUNT )
  {
    log_err( "Usage: %s <transport> <dirname> [-v]\n", argv[ 0 ] );
    log_err( "  Serial transport: 'ser:<sername>,<serspeed>,<flow> ('flow' defines the flow control and can be either 'none' or 'rtscts')\n" );
    log_err( "  UDP transport: 'udp:<port>'\n" );
    log_err( "Use -v for verbose output.\n" );
    return 1;
  }
  
  if( ( argc >= VERBOSE_ARGC_COUNT ) && !strcmp( argv[ VERBOSE_ARG_IDX ], "-v" ) )
    log_init( LOG_ALL );
  else
    log_init( LOG_NONE );  
  
  if( !os_isdir( argv[ DIRNAME_ARG_IDX ] ) )
  {
    log_err( "Invalid directory %s\n", argv[ DIRNAME_ARG_IDX ] );
    return 1;
  }  
  if( parse_transport_and_init( argv[ TRANSPORT_ARG_IDX ] ) == 0 )
    return 1;
    
    // Setup RFS server
  server_setup( argv[ DIRNAME_ARG_IDX ] );   
  log_msg( "Sharing directory %s\n", argv[ DIRNAME_ARG_IDX ] );
  return 0;
}