/*-------------------------------------------------------------------------------
 * ez.cpp
 * EZPWD R-S bridge and ISCH map lookup
 *
 * original copyrights for portions used below (OP25, EZPWD)
 *
 * LWVMOBILE
 * 2022-09 DSD-FME Florida Man Edition
 *-----------------------------------------------------------------------------*/

#include "dsd.h"
#include "ezpwd/rs"
#include <map>

std::vector<uint8_t> ESS_A(28,0); // ESS_A and ESS_B are hexbits vectors
std::vector<uint8_t> ESS_B(16,0);
ezpwd::RS<63,35> rs28;
std::vector<uint8_t> HB(63,0);
std::vector<uint8_t> HBS(63,0);
std::vector<uint8_t> HBL(63,0);
std::vector<int> Erasures;

//Reed-Solomon Correction of ESS section
int ez_rs28_ess (int payload[96], int parity[168])
{
  //do something

  uint8_t a, b, i, j, k;
  k = 0;
  for (i = 0; i < 16; i++)
  {
    b = 0;
    for (j = 0; j < 6; j++)
    {
      b = b << 1;
      b = b + payload[k]; //convert bits to hexbits.
      k++;
    }
    ESS_B[i] = b;
    // fprintf (stderr, " %X", ESS_B[i]);
  }

  k = 0;
  for (i = 0; i < 28; i++)
  {
    a = 0;
    for (j = 0; j < 6; j++)
    {
      a = a << 1;
      a = a + parity[k]; //convert bits to hexbits.
      k++;
    }
    ESS_A[i] = a;
    // fprintf (stderr, " %X ", ESS_A[i]);
  }

  int ec;

  ec = rs28.decode (ESS_B, ESS_A);
  // fprintf (stderr, "\n EC = %d \n", ec);

  //convert ESS_B back to bits
  k = 0;
  for (i = 0; i < 16; i++)
  {
    b = 0;
    for (j = 0; j < 6; j++)
    {
      b = (ESS_B[i] >> (5-j) & 0x1);
      payload[k] = b;
      k++;
    }
    // fprintf (stderr, " %X", ESS_B[i]);
  }

  return(ec);

}

//Reed-Solomon Correction of FACCH section
int ez_rs28_facch (int payload[156], int parity[114])
{
  //do something!
  int ec = -2;
  int i, j, k, b;

  //init HB
  for (i = 0; i < 64; i++)
  {
	HB[i] = 0;
  }

  //Erasures for FACCH
  Erasures = {0,1,2,3,4,5,6,7,8,54,55,56,57,58,59,60,61,62};

  //convert bits to hexbits, 156 for payload, 114 parity
  j = 9; //starting position according to OP25
  for (i = 0; i < 156; i += 6)
  {
		HB[j] = (payload[i] << 5) + (payload[i+1] << 4) + (payload[i+2] << 3) + (payload[i+3] << 2) + (payload[i+4] << 1) + payload[i+5];
		j++;
	}
  //j should continue from its last increment
  for (i = 0; i < 114; i += 6)
  {
		HB[j] = (parity[i] << 5) + (parity[i+1] << 4) + (parity[i+2] << 3) + (parity[i+3] << 2) + (parity[i+4] << 1) + parity[i+5];
		j++;
	}

  ec = rs28.decode(HB, Erasures);

  //convert HB back to bits
  //fprintf (stderr, "\n");
  k = 0;
  for (i = 0; i < 26; i++) //26*6=156 bits
  {
    b = 0;
    for (j = 0; j < 6; j++)
    {
      b = (HB[i+9] >> (5-j) & 0x1); //+9 to mach our starting position
      payload[k] = b;
      //fprintf (stderr, "%d", payload[k]);
      k++;
    }

  }

  return (ec);
}

//Reed-Solomon Correction of SACCH section
int ez_rs28_sacch (int payload[180], int parity[132])
{
  //do something!
  int ec = -2;
  int i, j, k, b;

  //init HBS
  for (i = 0; i < 64; i++)
  {
	HBS[i] = 0;
  }

  //Erasures for SACCH
  Erasures = {0,1,2,3,4,57,58,59,60,61,62};

  //convert bits to hexbits, 156 for payload, 114 parity
  j = 5; //starting position according to OP25
  for (i = 0; i < 180; i += 6)
  {
		HBS[j] = (payload[i] << 5) + (payload[i+1] << 4) + (payload[i+2] << 3) + (payload[i+3] << 2) + (payload[i+4] << 1) + payload[i+5];
		j++;
	}
  //j should continue from its last increment
  for (i = 0; i < 132; i += 6)
  {
		HBS[j] = (parity[i] << 5) + (parity[i+1] << 4) + (parity[i+2] << 3) + (parity[i+3] << 2) + (parity[i+4] << 1) + parity[i+5];
		j++;
	}

  ec = rs28.decode(HBS, Erasures);

  //convert HBS back to bits
  // fprintf (stderr, "\n");
  k = 0;
  for (i = 0; i < 30; i++) //30*6=180 bits
  {
    b = 0;
    for (j = 0; j < 6; j++)
    {
      b = (HBS[i+5] >> (5-j) & 0x1); //+5 to mach our starting position
      payload[k] = b;
      // fprintf (stderr, "%d", payload[k]);
      k++;
    }

  }
  return (ec);
}

//std::map <std::uint64_t, int> isch_map;
std::map <uint64_t, int> isch_map; //User Noted GCC potential compiler error fix on BB OP25
void map_isch()
{
	isch_map[0x184229d461ULL] = 0;
	isch_map[0x18761451f6ULL] = 1;
	isch_map[0x181ae27e2fULL] = 2;
	isch_map[0x182edffbb8ULL] = 3;
	isch_map[0x18df8a7510ULL] = 4;
	isch_map[0x18ebb7f087ULL] = 5;
	isch_map[0x188741df5eULL] = 6;
	isch_map[0x18b37c5ac9ULL] = 7;
	isch_map[0x1146a44f13ULL] = 8;
	isch_map[0x117299ca84ULL] = 9;
	isch_map[0x111e6fe55dULL] = 10;
	isch_map[0x112a5260caULL] = 11;
	isch_map[0x11db07ee62ULL] = 12;
	isch_map[0x11ef3a6bf5ULL] = 13;
	isch_map[0x1183cc442cULL] = 14;
	isch_map[0x11b7f1c1bbULL] = 15;
	isch_map[0x1a4a2e239eULL] = 16;
	isch_map[0x1a7e13a609ULL] = 17;
	isch_map[0x1a12e589d0ULL] = 18;
	isch_map[0x1a26d80c47ULL] = 19;
	isch_map[0x1ad78d82efULL] = 20;
	isch_map[0x1ae3b00778ULL] = 21;
	isch_map[0x1a8f4628a1ULL] = 22;
	isch_map[0x1abb7bad36ULL] = 23;
	isch_map[0x134ea3b8ecULL] = 24;
	isch_map[0x137a9e3d7bULL] = 25;
	isch_map[0x13166812a2ULL] = 26;
	isch_map[0x1322559735ULL] = 27;
	isch_map[0x13d300199dULL] = 28;
	isch_map[0x13e73d9c0aULL] = 29;
	isch_map[0x138bcbb3d3ULL] = 30;
	isch_map[0x13bff63644ULL] = 31;
	isch_map[0x1442f705efULL] = 32;
	isch_map[0x1476ca8078ULL] = 33;
	isch_map[0x141a3cafa1ULL] = 34;
	isch_map[0x142e012a36ULL] = 35;
	isch_map[0x14df54a49eULL] = 36;
	isch_map[0x14eb692109ULL] = 37;
	isch_map[0x14879f0ed0ULL] = 38;
	isch_map[0x14b3a28b47ULL] = 39;
	isch_map[0x1d467a9e9dULL] = 40;
	isch_map[0x1d72471b0aULL] = 41;
	isch_map[0x1d1eb134d3ULL] = 42;
	isch_map[0x1d2a8cb144ULL] = 43;
	isch_map[0x1ddbd93fecULL] = 44;
	isch_map[0x1defe4ba7bULL] = 45;
	isch_map[0x1d831295a2ULL] = 46;
	isch_map[0x1db72f1035ULL] = 47;
	isch_map[0x164af0f210ULL] = 48;
	isch_map[0x167ecd7787ULL] = 49;
	isch_map[0x16123b585eULL] = 50;
	isch_map[0x162606ddc9ULL] = 51;
	isch_map[0x16d7535361ULL] = 52;
	isch_map[0x16e36ed6f6ULL] = 53;
	isch_map[0x168f98f92fULL] = 54;
	isch_map[0x16bba57cb8ULL] = 55;
	isch_map[0x1f4e7d6962ULL] = 56;
	isch_map[0x1f7a40ecf5ULL] = 57;
	isch_map[0x1f16b6c32cULL] = 58;
	isch_map[0x1f228b46bbULL] = 59;
	isch_map[0x1fd3dec813ULL] = 60;
	isch_map[0x1fe7e34d84ULL] = 61;
	isch_map[0x1f8b15625dULL] = 62;
	isch_map[0x1fbf28e7caULL] = 63;
	isch_map[0x084d62c339ULL] = 64;
	isch_map[0x08795f46aeULL] = 65;
	isch_map[0x0815a96977ULL] = 66;
	isch_map[0x082194ece0ULL] = 67;
	isch_map[0x08d0c16248ULL] = 68;
	isch_map[0x08e4fce7dfULL] = 69;
	isch_map[0x08880ac806ULL] = 70;
	isch_map[0x08bc374d91ULL] = 71;
	isch_map[0x0149ef584bULL] = 72;
	isch_map[0x017dd2dddcULL] = 73;
	isch_map[0x011124f205ULL] = 74;
	isch_map[0x0125197792ULL] = 75;
	isch_map[0x01d44cf93aULL] = 76;
	isch_map[0x01e0717cadULL] = 77;
	isch_map[0x018c875374ULL] = 78;
	isch_map[0x01b8bad6e3ULL] = 79;
	isch_map[0x0a456534c6ULL] = 80;
	isch_map[0x0a7158b151ULL] = 81;
	isch_map[0x0a1dae9e88ULL] = 82;
	isch_map[0x0a29931b1fULL] = 83;
	isch_map[0x0ad8c695b7ULL] = 84;
	isch_map[0x0aecfb1020ULL] = 85;
	isch_map[0x0a800d3ff9ULL] = 86;
	isch_map[0x0ab430ba6eULL] = 87;
	isch_map[0x0341e8afb4ULL] = 88;
	isch_map[0x0375d52a23ULL] = 89;
	isch_map[0x03192305faULL] = 90;
	isch_map[0x032d1e806dULL] = 91;
	isch_map[0x03dc4b0ec5ULL] = 92;
	isch_map[0x03e8768b52ULL] = 93;
	isch_map[0x038480a48bULL] = 94;
	isch_map[0x03b0bd211cULL] = 95;
	isch_map[0x044dbc12b7ULL] = 96;
	isch_map[0x0479819720ULL] = 97;
	isch_map[0x041577b8f9ULL] = 98;
	isch_map[0x04214a3d6eULL] = 99;
	isch_map[0x04d01fb3c6ULL] = 100;
	isch_map[0x04e4223651ULL] = 101;
	isch_map[0x0488d41988ULL] = 102;
	isch_map[0x04bce99c1fULL] = 103;
	isch_map[0x0d493189c5ULL] = 104;
	isch_map[0x0d7d0c0c52ULL] = 105;
	isch_map[0x0d11fa238bULL] = 106;
	isch_map[0x0d25c7a61cULL] = 107;
	isch_map[0x0dd49228b4ULL] = 108;
	isch_map[0x0de0afad23ULL] = 109;
	isch_map[0x0d8c5982faULL] = 110;
	isch_map[0x0db864076dULL] = 111;
	isch_map[0x0645bbe548ULL] = 112;
	isch_map[0x06718660dfULL] = 113;
	isch_map[0x061d704f06ULL] = 114;
	isch_map[0x06294dca91ULL] = 115;
	isch_map[0x06d8184439ULL] = 116;
	isch_map[0x06ec25c1aeULL] = 117;
	isch_map[0x0680d3ee77ULL] = 118;
	isch_map[0x06b4ee6be0ULL] = 119;
	isch_map[0x0f41367e3aULL] = 120;
	isch_map[0x0f750bfbadULL] = 121;
	isch_map[0x0f19fdd474ULL] = 122;
	isch_map[0x0f2dc051e3ULL] = 123;
	isch_map[0x0fdc95df4bULL] = 124;
	isch_map[0x0fe8a85adcULL] = 125;
	isch_map[0x0f845e7505ULL] = 126;
	isch_map[0x0fb063f092ULL] = 127;
	isch_map[0x575d57f7ffULL] =  -2; // S-ISCH
}

//I-ISCH Lookup, borrowed from OP25 (now w/ error correction)
int isch_lookup (uint64_t isch)
{
	map_isch(); //initialize the lookup map
	int decoded = -2;

	// Must contain bit errors if no exact match, so
	// look for codeword with smallest hamming distance
	if (isch_map.find(isch) == isch_map.end())
	{
		int popct, popmin = 40;
		for (auto it = isch_map.begin(); it != isch_map.end(); ++it)
		{
			popct = __builtin_popcountll(isch ^ it->first);
			// Encoding is (40, 9, 16) which can correct at most 7 bit-errors
			if ((popct <= 7) && (popct < popmin))
			{
					decoded = it->second;
					popmin = popct;
			}
		}
	return decoded;
	}
	else  // No errors, so simply return the matching value
		decoded = isch_map[isch];

	return decoded;

}