/* Routines for Text encoding of vote messages.
 * Wire Format:
 *   "Voting <v|i> [R]  <candidate ID>  <count>"
 */
#include <string.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "Practical.h"
#include "VoteProtocol.h"

static const char *MAGIC = "Voting";
static const char *VOTESTR = "v";
static const char *INQSTR = "i";
static const char *RESPONSESTR = "R";
static const char *DELIMSTR = " ";
enum {
  BASE = 10
};

/* Encode voting message info as a text string.
 * WARNING: Message will be silently truncated if buffer is too small!
 * Invariants (e.g. 0 <= candidate <= 1000) not checked.
 */
size_t Encode(const VoteInfo *v, uint8_t *outBuf, const size_t bufSize) {
  uint8_t *bufPtr = outBuf;
  long size = (size_t) bufSize;
  int rv = snprintf((char *) bufPtr, size, "%s %c %s %d", MAGIC,
      (v->isInquiry ? 'i' : 'v'), (v->isResponse ? "R" : ""), v->candidate);
  bufPtr += rv;
  size -= rv;
  if (v->isResponse) {
    rv = snprintf((char *) bufPtr, size, " %llu", v->count);
    bufPtr += rv;
  }
  return (size_t) (bufPtr - outBuf);
}

/* Extract message information from given buffer.
 * Note: modifies input buffer.
 */
bool Decode(uint8_t *inBuf, const size_t mSize, VoteInfo *v) {

  char *token;
  token = strtok((char *) inBuf, DELIMSTR);
  // Check for magic
  if (token == NULL || strcmp(token, MAGIC) != 0)
    return false;

  // Get vote/inquiry indicator
  token = strtok(NULL, DELIMSTR);
  if (token == NULL)
    return false;

  if (strcmp(token, VOTESTR) == 0)
    v->isInquiry = false;
  else if (strcmp(token, INQSTR) == 0)
    v->isInquiry = true;
  else
    return false;

  // Next token is either Response flag or candidate ID
  token = strtok(NULL, DELIMSTR);
  if (token == NULL)
    return false; // Message too short

  if (strcmp(token, RESPONSESTR) == 0) { // Response flag present
    v->isResponse = true;
    token = strtok(NULL, DELIMSTR); // Get candidate ID
    if (token == NULL)
      return false;
  } else { // No response flag; token is candidate ID;
    v->isResponse = false;
  }
  // Get candidate #
  v->candidate = atoi(token);
  if (v->isResponse) { // Response message should contain a count value
    token = strtok(NULL, DELIMSTR);
    if (token == NULL)
      return false;
    v->count = strtoll(token, NULL, BASE);
  } else {
    v->count = 0L;
  }
  return true;
}