# include "psastroInternal.h"
# define dMag 0.1
// XXX put this in config?

static void pmLumFuncFree (pmLumFunc *func) {

  if (func == NULL) return;

  return;
}

pmLumFunc *pmLumFuncAlloc () {

  pmLumFunc *func = (pmLumFunc *) psAlloc(sizeof(pmLumFunc));
  psMemSetDeallocator(func, (psFreeFunc) pmLumFuncFree);

  func->mMin = 0.0;
  func->mMax = 0.0;
  func->slope = 0.0;
  func->offset = 0.0;

  func->mPeak = 0.0;
  func->nPeak = 0;

  return func;
}

pmLumFunc *psastroLuminosityFunction (psArray *stars) {

  // determine the max and min magnitude for the array of stars
  pmAstromObj *star = stars->data[0];
  double mMin = star->Mag;
  double mMax = star->Mag;
  for (int i = 0; i < stars->n; i++) {
    star = stars->data[i];
    mMin = PS_MIN (star->Mag, mMin);
    mMax = PS_MAX (star->Mag, mMax);
  }

  int nBin = 1 + (mMax - mMin) / dMag;
  if (nBin <= 1) {
    psLogMsg ("psastro", 4, "insufficient valid stars for this readout\n");
    return NULL;
  }

  // create a histogram of the magnitudes
  // bin[0] = mMin : mMin + dMag
  // bin[i] = mMin + i*dMag : mMin + (i+1)*dMag
  psVector *nMags = psVectorAlloc (nBin, PS_TYPE_F32);
  psVectorInit (nMags, 0);

  for (int i = 0; i < stars->n; i++) {
    star = stars->data[i];
    if (!isfinite(star->Mag)) continue;
    int bin = (star->Mag - mMin) / dMag;
    if (bin < 0) psAbort("bin cannot be negative!");
    if (bin >= nBin) psAbort("bin cannot be > %d!", nBin);
    nMags->data.F32[bin] += 1.0;
  }

  // find the peak and position
  int iPeak = 0;
  int nPeak = 0;
  for (int i = 0; i < nMags->n; i++) {
    if (nMags->data.F32[i] < nPeak) continue;
    iPeak = i;
    nPeak = nMags->data.F32[i];
  }

  psVector *lnMag = psVectorAllocEmpty (nBin, PS_TYPE_F32);
  psVector *Mag = psVectorAllocEmpty (nBin, PS_TYPE_F32);

  // create 2 vectors represnting the dlogN/dlogS line
  // exclude bins with no stars
  // exclude points after the peak with N < 0.8*peak
  int n = 0;
  for (int i = 0; i < nMags->n; i++) {
    if (nMags->data.F32[i] < 1) continue;
    if ((i > iPeak) && (nMags->data.F32[i] < 0.8*nPeak)) continue;
    lnMag->data.F32[n] = log10 (nMags->data.F32[i]);
    Mag->data.F32[n] = mMin + (i + 0.5)*dMag;
    n++;
  }
  lnMag->n = n;
  Mag->n = n;
  psLogMsg ("psastro", 4, "fitting %d points to luminosity function\n", n);

  psVector *mask = psVectorAlloc (Mag->n, PS_TYPE_MASK);
  psVectorInit (mask, 0);

  psPolynomial1D *line = psPolynomial1DAlloc (PS_POLYNOMIAL_ORD, 1);
  psStats *stats = psStatsAlloc (PS_STAT_SAMPLE_MEDIAN | PS_STAT_SAMPLE_STDEV);
  stats->clipSigma = 3.0;
  stats->clipIter = 3;

  if (!psVectorClipFitPolynomial1D(line, stats, mask, 0xff, lnMag, NULL, Mag)) {
      psLogMsg ("psastro", 4, "Failed to fit the luminosity function\n");
      return(NULL);
  }

  // find min and max unmasked magnitudes
  double mMinValid = NAN;
  double mMaxValid = NAN;
  for (int i = 0; i < Mag->n; i++) {
    if (mask->data.U8[i]) continue;
    if (isnan(mMinValid) || (Mag->data.F32[i] < mMinValid)) {
      mMinValid = Mag->data.F32[i];
    }
    if (isnan(mMaxValid) || (Mag->data.F32[i] > mMaxValid)) {
      mMaxValid = Mag->data.F32[i];
    }
  }

  psLogMsg ("psastro", 4, "logN = %f + %f mag\n", line->coeff[0], line->coeff[1]);
  psLogMsg ("psastro", 4, "logN vs mag residuals: %f +/- %f\n", stats->sampleMedian, stats->sampleStdev);

  pmLumFunc *lumFunc = pmLumFuncAlloc ();
  lumFunc->mMin = mMinValid;
  lumFunc->mMax = mMaxValid;
  lumFunc->offset = line->coeff[0];
  lumFunc->slope = line->coeff[1];
  lumFunc->mPeak = mMin + (iPeak + 0.5)*dMag;
  lumFunc->nPeak = nPeak;

  psFree (lnMag);
  psFree (nMags);
  psFree (Mag);
  psFree (mask);
  psFree (line);
  psFree (stats);

  return (lumFunc);
}


