// Collect RF12 packets and send them on as UDP collectd packets on Ethernet.
// 2010-05-20 <jc@wippler.nl> http://opensource.org/licenses/mit-license.php

// This sketch is derived from RF12eth.pde (and etherNode.ino):
// May 2010, Andras Tucsni, http://opensource.org/licenses/mit-license.php

#include <EtherCard.h>
#include <JeeLib.h>
#include <avr/eeprom.h>

#define DEBUG   1   // set to 1 to display free RAM on web page
#define SERIAL  1   // set to 1 to show incoming requests on serial port

#define CONFIG_EEPROM_ADDR ((byte*) 0x10)

// configuration, as stored in EEPROM
struct Config {
  byte band;
  byte group;
  byte collect;
  word port;
  byte valid; // keep this as last byte
} config;

// ethernet interface mac address - must be unique on your network
static byte mymac[] = { 0x74,0x69,0x69,0x2D,0x30,0x31 };

// buffer for an outgoing data packet
static byte outBuf[RF12_MAXDATA], outDest;
static char outCount = -1;

// this buffer will be used to construct a collectd UDP packet
static byte collBuf [200], collPos;

#define NUM_MESSAGES  3     // Number of messages saved in history
#define MESSAGE_TRUNC 15    // Truncate message payload to reduce memory use

static BufferFiller bfill;  // used as cursor while filling the buffer

static byte history_rcvd[NUM_MESSAGES][MESSAGE_TRUNC+1]; //history record
static byte history_len[NUM_MESSAGES]; // # of RF12 messages+header in history
static byte next_msg;       // pointer to next rf12rcvd line
static word msgs_rcvd;      // total number of lines received modulo 10,000

byte Ethernet::buffer[700];   // tcp/ip send and receive buffer

static void loadConfig () {
  for (byte i = 0; i < sizeof config; ++i)
    ((byte*) &config)[i] = eeprom_read_byte(CONFIG_EEPROM_ADDR + i);
  if (config.valid != 253) {
    config.valid = 253;
    config.band = 8;
    config.group = 1;
    config.collect = 1;
    config.port = 25827;
  }
  byte freq = config.band == 4 ? RF12_433MHZ :
              config.band == 8 ? RF12_868MHZ :
                                 RF12_915MHZ;
  rf12_initialize(31, freq, config.group);
}

static void saveConfig () {
  for (byte i = 0; i < sizeof config; ++i)
    eeprom_write_byte(CONFIG_EEPROM_ADDR + i, ((byte*) &config)[i]);
}

#if DEBUG
static int freeRam () {
extern int __heap_start, *__brkval; 
int v; 
return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval); 
}
#endif

void setup (){
  Serial.begin(57600);
  Serial.println("\n[JeeUdp]");
  loadConfig();
  if (ether.begin(sizeof Ethernet::buffer, mymac) == 0) 
    Serial.println( "Failed to access Ethernet controller");
  if (!ether.dhcpSetup())
    Serial.println("DHCP failed");
  ether.printIp("IP: ", ether.myip);
}

const char okHeader[] PROGMEM = 
  "HTTP/1.0 200 OK\r\n"
  "Content-Type: text/html\r\n"
  "Pragma: no-cache\r\n"
;

static void homePage (BufferFiller& buf) {
  word mhz = config.band == 4 ? 433 : config.band == 8 ? 868 : 915;
  buf.emit_p(PSTR("$F\r\n"
    "<title>RF12 JeeUdp</title>" 
    "<h2>RF12 JeeUdp @ $D - RF12 @ $D.$D</h2>"
        "<a href='c'>Configure</a> - <a href='s'>Send Packet</a>"
    "<h3>Last $D messages:</h3>"
    "<pre>"), okHeader, config.port, mhz, config.group, NUM_MESSAGES);
  for (byte i = 0; i < NUM_MESSAGES; ++i) {
    byte j = (next_msg + i) % NUM_MESSAGES;
    if (history_len[j] > 0) {
      word n = msgs_rcvd - NUM_MESSAGES + i;
      buf.emit_p(PSTR("\n$D$D$D$D: OK"), // hack, to show leading zero's
                          n/1000, (n/100) % 10, (n/10) % 10, n % 10);
      for (byte k = 0; k < history_len[j]; ++k)
        buf.emit_p(PSTR(" $D"), history_rcvd[j][k]);
    }
  }
  long t = millis() / 1000;
  word h = t / 3600;
  byte m = (t / 60) % 60;
  byte s = t % 60;
  buf.emit_p(PSTR(
    "</pre>"
    "Uptime is $D$D:$D$D:$D$D"), h/10, h%10, m/10, m%10, s/10, s%10);
#if DEBUG
  buf.emit_p(PSTR(" ($D bytes free)"), freeRam());
#endif
}

static int getIntArg(const char* data, const char* key, int value =-1) {
  char temp[10];
  if (ether.findKeyVal(data + 7, temp, sizeof temp, key) > 0)
    value = atoi(temp);
  return value;
}

static void configPage (const char* data, BufferFiller& buf) {
  // pick up submitted data, if present
  if (data[6] == '?') {
    byte b = getIntArg(data, "b", 8);
    byte g = getIntArg(data, "g", 1);
    byte c = getIntArg(data, "c", 0);
    word p = getIntArg(data, "p", 25827);
    if (1 <= g && g <= 250 && 1024 <= p && p <= 30000) {
      // store values as new settings
      config.band = b;
      config.group = g;
      config.collect = c;
      config.port = p;
      saveConfig();
      // re-init RF12 driver
      loadConfig();
      // clear history
      memset(history_len, 0, sizeof history_len);
      // redirect to the home page
      buf.emit_p(PSTR(
        "HTTP/1.0 302 found\r\n"
        "Location: /\r\n"
        "\r\n"));
      return;
    }
  }
  // else show a configuration form
  buf.emit_p(PSTR("$F\r\n"
    "<h3>Server node configuration</h3>"
    "<form>"
      "<p>"
  "Freq band <input type=text name=b value='$D' size=1> (4, 8, or 9)<br>"
  "Net group <input type=text name=g value='$D' size=3> (1..250)<br>"
  "Collect mode: <input type=checkbox name=c value='1' $S> "
    "(don't send ACKs)<br><br>"
  "UDP Port <input type=text name=p value='$D' size=5> (1024..30000)"
      "</p>"
      "<input type=submit value=Set>"
    "</form>"), okHeader, config.band, config.group,
                config.collect ? "CHECKED" : "",
                config.port);
}

static void sendPage (const char* data, BufferFiller& buf) {
  // pick up submitted data, if present
  const char* p = strstr(data, "b=");
  byte d = getIntArg(data, "d");
  if (data[6] == '?' && p != 0 && 0 <= d && d <= 31) {
    // prepare to send data as soon as possible in loop()
    outDest = d & RF12_HDR_MASK ? RF12_HDR_DST | d : 0;
    outCount = 0;
    // convert the input string to a number of decimal data bytes in outBuf
    ++p;
    while (*p != 0 && *p != '&') {
      outBuf[outCount] = 0;
      while ('0' <= *++p && *p <= '9')
        outBuf[outCount] = 10 * outBuf[outCount] + (*p - '0');
      ++outCount;
    }
#if SERIAL
    Serial.print("Send to ");
    Serial.print(outDest, DEC);
    Serial.print(':');
    for (byte i = 0; i < outCount; ++i) {
      Serial.print(' ');
      Serial.print(outBuf[i], DEC);
    }
    Serial.println();
#endif
    // redirect to home page
    buf.emit_p(PSTR(
      "HTTP/1.0 302 found\r\n"
      "Location: /\r\n"
      "\r\n"));
    return;
  }
  // else show a send form
  buf.emit_p(PSTR("$F\r\n"
    "<h3>Send a wireless data packet</h3>"
    "<form>"
      "<p>"
        "Data bytes <input type=text name=b size=50> (decimal)<br>"
        "Destination node <input type=text name=d size=3> "
          "(1..31, or 0 to broadcast)<br>"
      "</p>"
      "<input type=submit value=Send>"
    "</form>"), okHeader);
}

static void collectTypeLen (word type, word len) {
  len += 4;
  collBuf[collPos++] = type >> 8;
  collBuf[collPos++] = (byte) type;
  collBuf[collPos++] = len >> 8;
  collBuf[collPos++] = (byte) len;
}

static void collectStr (word type, const char* data) {
  word len = strlen(data) + 1;
  collectTypeLen(type, len);
  strcpy((char*) collBuf + collPos, data);
  collPos += len;
}

static void collectPayload (word type) {
  // Copy the received RF12 data into a as many values as needed.
  byte num = rf12_len / 8 + 1; // this many values will be needed
  collectTypeLen(type, 2 + 9 * num);
  collBuf[collPos++] = 0;
  collBuf[collPos++] = num;
  for (byte i = 0; i < num; ++i)
    collBuf[collPos++] = 0; // counter
  for (char i = 0; i < 8 * num; ++i) // include -1, i.e. the length byte
    collBuf[collPos++] = i <= rf12_len ? rf12_data[i-1] : 0;
}

static void forwardToUDP () {
  static byte destIp[] = { 239,192,74,66 }; // UDP multicast address
  char buf[10];
  
  collPos = 0;
  collectStr(0x0000, "JeeUdp");
  collectStr(0x0002, "RF12");
  word mhz = config.band == 4 ? 433 : config.band == 8 ? 868 : 915;
  sprintf(buf, "%d.%d", mhz, config.group);
  collectStr(0x0003, buf);
  collectStr(0x0004, "OK");
  sprintf(buf, "%d", rf12_hdr);
  collectStr(0x0005, buf);
  collectPayload(0x0006);
  
  ether.sendUdp ((char*) collBuf, collPos, 23456, destIp, config.port);
#if SERIAL
  Serial.println("UDP sent");
#endif
}

void loop (){
  word len = ether.packetReceive();
  word pos = ether.packetLoop(len);
  // check if valid tcp data is received
  if (pos) {
    bfill = ether.tcpOffset();
    char* data = (char *) Ethernet::buffer + pos;
#if SERIAL
    Serial.println(data);
#endif
    // receive buf hasn't been clobbered by reply yet
    if (strncmp("GET / ", data, 6) == 0)
      homePage(bfill);
    else if (strncmp("GET /c", data, 6) == 0)
      configPage(data, bfill);
    else if (strncmp("GET /s", data, 6) == 0)
      sendPage(data, bfill);
    else
      bfill.emit_p(PSTR(
        "HTTP/1.0 401 Unauthorized\r\n"
        "Content-Type: text/html\r\n"
        "\r\n"
        "<h1>401 Unauthorized</h1>"));  
    ether.httpServerReply(bfill.position()); // send web page data
  }

  // RFM12 loop runner, don't report acks
  if (rf12_recvDone() && rf12_crc == 0 && (rf12_hdr & RF12_HDR_CTL) == 0) {
    history_rcvd[next_msg][0] = rf12_hdr;
    for (byte i = 0; i < rf12_len; ++i)
      if (i < MESSAGE_TRUNC) 
        history_rcvd[next_msg][i+1] = rf12_data[i];
    history_len[next_msg] = rf12_len < MESSAGE_TRUNC ? rf12_len+1
                                                     : MESSAGE_TRUNC+1;
    next_msg = (next_msg + 1) % NUM_MESSAGES;
    msgs_rcvd = (msgs_rcvd + 1) % 10000;

    if (RF12_WANTS_ACK && !config.collect) {
#if SERIAL
      Serial.println(" -> ack");
#endif
      rf12_sendStart(RF12_ACK_REPLY, 0, 0);
    }
    
    forwardToUDP();
  }
  
  // send a data packet out if requested
  if (outCount >= 0 && rf12_canSend()) {
    rf12_sendStart(outDest, outBuf, outCount, 1);
    outCount = -1;
  }
}