//+------------------------------------------------------------------+
//| MarketStateBoard_Fuzzy.mqh                                       |
//| PATCH-09 - FUZZY MEMBERSHIP LAYER                                |
//+------------------------------------------------------------------+
// PATCH-09 semantics (frozen by specification):
//  * Membership is a mathematical degree of membership. It is NOT a
//    probability, confidence, forecast accuracy or signal-strength
//    probability.
//  * The four directional oscillators (RSI, Stochastic, CCI, MACD) each
//    produce a bullish/neutral/bearish membership. For valid data:
//    bullish + neutral + bearish == 1.
//  * This layer is independent from PATCH-05 evidence, PATCH-06 agreement,
//    PATCH-07 alignment and PATCH-08 panel representation. It computes no
//    dynamic weights, no composite score, no confidence and no trading
//    signal.
//
// CALIBRATION GOVERNANCE:
//  The sensitivity/reference-scale constants in this file are PLACEHOLDERS
//  required for compilation only. None of them is an authorized calibration.
//  They must NOT be optimized, backtested, swept, or tuned to market
//  observations. Replacement values require a separate authorization.
//  Exceptions (fixed by the PATCH-09 specification itself):
//   - FUZZY_EPS         validation tolerance
//   - FUZZY_RSI_PIVOT   RSI neutral center (equals PATCH-05 OSC_RSI_NEUTRAL)
//   - FUZZY_RSI_DENOM   RSI domain mapping [0,100] -> [-1,+1]

// Invariant-check tolerance for the sum-to-one rule (spec section 6).
const double FUZZY_EPS = 1.0e-12;

// <CALIBRATION_PENDING> - unvalidated placeholders, NOT authorized calibration.
const double K_RSI                 = 1.0;    // RSI sensitivity k  (spec sections 9/10)
const double STOCH_REFERENCE_SCALE = 20.0;   // stochastic reference scale (spec section 11)
const double CCI_REFERENCE_SCALE   = 100.0;  // CCI reference scale (spec section 12)
const double MACD_ATR_SCALE        = 1.0;    // MACD/ATR sensitivity (spec section 13)
// </CALIBRATION_PENDING>

const double FUZZY_RSI_PIVOT = 50.0;   // RSI neutral center (PATCH-05: OSC_RSI_NEUTRAL)
const double FUZZY_RSI_DENOM = 50.0;   // (RSI - 50) / 50 maps [0,100] to [-1,+1]

//==============================================================
// 1. STRUCTURES
//==============================================================
struct MSB_FuzzyMembership
{
   double bullish;   // degree of bullish membership in [0,1]
   double neutral;   // degree of neutral membership in [0,1]
   double bearish;   // degree of bearish membership in [0,1]
   bool   valid;     // false when the source oscillator is unavailable/invalid
};

struct MSB_FuzzyOscillatorSet
{
   MSB_FuzzyMembership rsi;
   MSB_FuzzyMembership stoch;
   MSB_FuzzyMembership cci;
   MSB_FuzzyMembership macd;
};

//==============================================================
// 2. HELPERS
//==============================================================
bool FuzzyFinite(double v)
{
   return (v == v) && (v < DBL_MAX) && (v > -DBL_MAX);
}

// Deterministic invalid-data storage (spec section 7):
// valid = false with zeroed memberships. The storage is never interpreted
// as neutral (valid=false never implies neutral=1).
MSB_FuzzyMembership InvalidMembership()
{
   MSB_FuzzyMembership m;
   m.bullish = 0.0;
   m.neutral = 0.0;
   m.bearish = 0.0;
   m.valid   = false;
   return m;
}

// Numerically stable tanh: tanh(x) = 1 - 2/(exp(2x)+1).
//   x -> -inf : exp(2x) -> 0   => result -> -1
//   x -> +inf : exp(2x) -> inf => result -> +1
double FuzzyTanh(double x)
{
   double e = MathExp(2.0 * x);
   return 1.0 - 2.0 / (e + 1.0);
}

// Membership construction from a signed signal (spec section 14):
//   1) validate input, 2) reject NaN/invalid values,
//   3) construct memberships, 4) clamp to [0,1] (numerical safety only),
//   5) verify the sum-to-one invariant.
// An unexpected invariant failure yields valid=false and is NEVER silently
// renormalized.
MSB_FuzzyMembership MembershipFromSignedSignal(double s)
{
   if(!FuzzyFinite(s))
      return InvalidMembership();

   // The signed signal must stay inside the fuzzy domain [-1,+1]. The small
   // tolerance covers only floating-point representation edge cases such as
   // tanh(x) rounding exactly to 1.0.
   if(s < -1.0 - FUZZY_EPS || s > 1.0 + FUZZY_EPS)
      return InvalidMembership();

   double bull = MathMax(0.0,  s);
   double bear = MathMax(0.0, -s);
   double neut = 1.0 - MathAbs(s);

   bull = MathMin(1.0, MathMax(0.0, bull));
   neut = MathMin(1.0, MathMax(0.0, neut));
   bear = MathMin(1.0, MathMax(0.0, bear));

   if(MathAbs((bull + neut + bear) - 1.0) > FUZZY_EPS)
      return InvalidMembership();

   MSB_FuzzyMembership m;
   m.bullish = bull;
   m.neutral = neut;
   m.bearish = bear;
   m.valid   = true;
   return m;
}

//==============================================================
// 3. PER-OSCILLATOR MEMBERSHIP
//==============================================================
// RSI (spec section 10):
//   z_RSI = clamp((RSI - 50.0) / 50.0, -1, +1)   // clamp is defensive only
//   s_RSI = tanh(K_RSI * z_RSI)
// RSI == 50 is the neutral center (PATCH-05: EV_NEUTRAL).
MSB_FuzzyMembership ComputeRsiMembership(double rsi)
{
   if(!FuzzyFinite(rsi))
      return InvalidMembership();

   double z = (rsi - FUZZY_RSI_PIVOT) / FUZZY_RSI_DENOM;
   z = MathMin( 1.0, MathMax(-1.0, z));
   return MembershipFromSignedSignal(FuzzyTanh(K_RSI * z));
}

// Stochastic (spec section 11):
//   d_Stoch = K - D
//   z_Stoch = clamp(d_Stoch / STOCH_REFERENCE_SCALE, -1, +1)
//   s_Stoch = tanh(z_Stoch)                 // common fuzzy transformation
// K == D is the neutral center (PATCH-05: EV_NEUTRAL).
// No 80/20 thresholds and no crossover events.
MSB_FuzzyMembership ComputeStochasticMembership(double k, double d)
{
   if(!FuzzyFinite(k) || !FuzzyFinite(d))
      return InvalidMembership();

   double dStoch = k - d;
   double z = dStoch / STOCH_REFERENCE_SCALE;
   z = MathMin( 1.0, MathMax(-1.0, z));
   return MembershipFromSignedSignal(FuzzyTanh(z));
}

// CCI (spec section 12):
//   s_CCI = tanh(CCI / CCI_REFERENCE_SCALE)
// CCI == 0 is the neutral center (PATCH-05: EV_NEUTRAL).
// No +/-100 direction thresholds and no slope/crossover logic.
MSB_FuzzyMembership ComputeCciMembership(double cci)
{
   if(!FuzzyFinite(cci))
      return InvalidMembership();

   return MembershipFromSignedSignal(FuzzyTanh(cci / CCI_REFERENCE_SCALE));
}

// MACD (spec section 13):
//   MACD_DELTA = MAIN - SIGNAL
//   s_MACD = tanh(MACD_DELTA / (MACD_ATR_SCALE * ATR))
// MAIN == SIGNAL is the neutral center (PATCH-05: EV_NEUTRAL).
// ATR must be finite and strictly positive (same timeframe, same selected
// candle, same ATR handle already used by the indicator). Invalid ATR yields
// valid=false; it is NEVER converted to neutral. No MAIN > 0 condition.
MSB_FuzzyMembership ComputeMacdMembership(double macdMain, double macdSignal, double atr)
{
   if(!FuzzyFinite(macdMain) || !FuzzyFinite(macdSignal) || !FuzzyFinite(atr))
      return InvalidMembership();

   if(atr <= 0.0)
      return InvalidMembership();

   double delta = macdMain - macdSignal;
   return MembershipFromSignedSignal(FuzzyTanh(delta / (MACD_ATR_SCALE * atr)));
}