import math
import scipy
import numpy
import sklearn.kernel_ridge

import sys
import os
sys.path.append(os.path.join(os.path.abspath(os.path.dirname(__file__)),os.pardir))
import helperFunctions

class ClassifierPrototype:

    def __init__(self, sigmaN=0.01, gamma=None, kernel='rbf', configFile=None, probSampleRuns=1000):

        self.sigmaN = helperFunctions.getConfig(configFile, 'activeLearning', 'sigmaN', sigmaN, 'float', True)
        self.kernel = helperFunctions.getConfig(configFile, 'activeLearning', 'kernel', kernel, 'str', True)
        self.gamma = helperFunctions.getConfig(configFile, 'activeLearning', 'gamma', gamma, 'float', True)
        self.numKernelCores = helperFunctions.getConfig(configFile, 'activeLearning', 'numKernelCores', 1, 'int', True)
        self.probSampleRuns = helperFunctions.getConfig(configFile, 'activeLearning', 'probSampleRuns', probSampleRuns, 'float', True)

        self.K = []
        self.alpha = []
        self.X = []
        self.y = []
        self.yBin = []
        self.yUni = []

        self.allowedKernels = ['rbf', 'sigmoid', 'polynomial', 'poly', 'linear', 'cosine']

        if self.kernel not in self.allowedKernels:
            raise Exception('Unknown kernel %s!'%self.kernel)


    def kernelFunc(self, x1, x2=None, gamma=None):

        if gamma is not None:
            self.gamma = gamma

        if self.kernel in ['rbf']:
            return numpy.asmatrix(sklearn.kernel_ridge.pairwise_kernels(x1, x2, metric=self.kernel, gamma=self.gamma, n_jobs=self.numKernelCores), dtype=numpy.float)
        else:
            return numpy.asmatrix(sklearn.kernel_ridge.pairwise_kernels(x1, x2, metric=self.kernel, n_jobs=self.numKernelCores), dtype=numpy.float)


    def checkModel(self):

        if not numpy.all(numpy.isfinite(self.K)):
            raise Exception('not numpy.all(numpy.isfinite(self.K))')

        if not numpy.all(numpy.isfinite(self.alpha)):
            raise Exception('not numpy.all(numpy.isfinite(self.alpha))')

        if not numpy.all(numpy.isfinite(self.X)):
            raise Exception('not numpy.all(numpy.isfinite(self.X))')

        if not numpy.all(numpy.isfinite(self.y)):
            raise Exception('not numpy.all(numpy.isfinite(self.y))')


    def train2(self, X, y, sigmaN=None):

        self.train(X[0,:],y[0,:],sigmaN)
        for idx in range(1,X.shape[0]):
            self.update(X[idx,:],y[idx,:])


    def train(self, X, y, sigmaN=None, gamma=None, kernel=None, numKernelCores=None):

        if sigmaN is not None:
            self.sigmaN = sigmaN

        if gamma is not None:
            self.gamma = gamma

        if kernel is not None and kernel in self.allowedKernels:
            self.kernel = kernel

        if numKernelCores is not None:
            self.numKernelCores = numKernelCores

        self.X = X
        self.y = y

        self.yUni = numpy.asmatrix(numpy.unique(numpy.asarray(self.y)))

        tmpVec = numpy.asmatrix(numpy.empty([self.y.shape[0],1]))
        self.yBin = numpy.asmatrix(numpy.empty([self.y.shape[0],self.yUni.shape[1]]))
        for cls in range(self.yUni.shape[1]):
            mask = (self.y == self.yUni[0,cls])
            tmpVec[mask == True] = 1
            tmpVec[mask == False] = -1
            self.yBin[:,cls] = tmpVec

        self.K = numpy.dot(X,X.T)
        self.alpha = numpy.linalg.solve(numpy.add(self.K, numpy.identity(self.X.shape[0], dtype=numpy.float)*self.sigmaN), self.yBin)

        self.checkModel()


    def update(self, x, y):

        # update for known classes
        binY = numpy.asmatrix(numpy.ones((1,self.alpha.shape[1])))*(-1)

        if self.alpha.shape[1] > 1:
            binY[0,numpy.asarray(numpy.squeeze(numpy.asarray(y == self.yUni)))] = 1
        elif y == self.yUni:
            binY[0,0] = 1

        # get new kernel columns
        k = self.kernelFunc(self.X, x)
        selfK = self.getSelfK(x)

        # update alpha
        term1 = 1.0 / (self.sigmaN + self.calcSigmaF(x, k, selfK).item(0))

        term2 = numpy.asmatrix(numpy.ones((self.X.shape[0] + 1,x.shape[0])), dtype=numpy.float) * (-1.0)
        term2[0:self.X.shape[0],:] = numpy.linalg.solve(numpy.add(self.K, numpy.identity(self.X.shape[0], dtype=numpy.float)*self.sigmaN), k)

        term3 = self.infer(x, k=k) - binY

        self.alpha = numpy.add(numpy.append(self.alpha, numpy.zeros((1,self.alpha.shape[1])), axis=0), numpy.dot(numpy.dot(term1,term2),term3))

        # update K
        self.K = numpy.append(numpy.append(self.K, k, axis=1), numpy.append(k.T, selfK, axis=1), axis=0)

        # update samples
        self.X = numpy.append(self.X, x, axis=0)
        self.y = numpy.append(self.y, y, axis=0)

        # update binary labels for knwon class
        if (self.yUni == y).any():
            mask = (y == self.yUni)
            tmpVec = numpy.empty([self.yBin.shape[1], 1])
            tmpVec[mask.T == True] = 1
            tmpVec[mask.T == False] = -1
            self.yBin = numpy.append(self.yBin, tmpVec.T, axis=0)

        # create labels and alpha for new class
        else:

            # create bigger matrices
            tmpyBin = numpy.asmatrix(numpy.empty([self.yBin.shape[0] + 1, self.yBin.shape[1] + 1]))
            tmpAlpha = numpy.asmatrix(numpy.empty([self.alpha.shape[0], self.alpha.shape[1] + 1]))

            # index of new class
            tmpIdx = -1

            # check all knwon classes
            for cls in range(self.yUni.shape[1]):

                # just copy all classes with lower label
                if y > self.yUni[0,cls]:
                    tmpyBin[0:-1,cls] = self.yBin[:,cls]
                    tmpyBin[tmpyBin.shape[0] - 1,cls] = -1
                    tmpAlpha[:,cls] = self.alpha[:,cls]
                    tmpIdx = cls

                # copy classes with higher label to shiftet position
                else: # y < self.yUni[cls]
                    tmpyBin[0:-1,cls + 1] = self.yBin[:,cls]
                    tmpyBin[tmpyBin.shape[0] - 1,cls + 1] = -1
                    tmpAlpha[:,cls + 1] = self.alpha[:,cls]

            # add new binary label vector for new class
            tmpyBin[0:-1,tmpIdx + 1] = -1
            tmpyBin[tmpyBin.shape[0] - 1,tmpIdx + 1] = 1

            # set new binary matrix and append new label
            self.yBin = tmpyBin
            self.yUni = numpy.sort(numpy.append(self.yUni, y, axis=1))

            # train new alpha for new class
            tmpAlpha[:,tmpIdx + 1] = numpy.linalg.solve(numpy.add(self.K, numpy.identity(self.X.shape[0], dtype=numpy.float)*self.sigmaN), self.yBin[:,tmpIdx + 1])
            self.alpha = tmpAlpha

        self.checkModel()


    # X.shape = (number of samples, feat dim), loNoise = {0,1}
    def infer(self, x, loNoise=False, k=None):

        if k is None:
            k = self.kernelFunc(self.X, x)

        loNoise = loNoise and (self.yUni == -1).any()

        pred = numpy.asmatrix(numpy.dot(k.T,self.alpha[:,int(loNoise):]))

        if not numpy.all(numpy.isfinite(pred)):
            raise Exception('not numpy.all(numpy.isfinite(pred))')

        return pred


    # X.shape = (number of samples, feat dim)
    def test(self, x, loNoise=False):

        loNoise = loNoise and (self.yUni == -1).any()

        return self.yUni[0,numpy.argmax(self.infer(x, loNoise), axis=1) + int(loNoise)]


    def calcSigmaF(self, x, k=None, selfK=None):

        if k is None:
            k = self.kernelFunc(self.X, x)

        if selfK is None:
            selfK = self.getSelfK(x)

        sigmaF = numpy.subtract(selfK, numpy.sum(numpy.multiply(numpy.linalg.solve(numpy.add(self.K, numpy.identity(self.X.shape[0], dtype=numpy.float)*self.sigmaN), k),k).T, axis=1))

        if not numpy.all(numpy.isfinite(sigmaF)):
            raise Exception('not numpy.all(numpy.isfinite(sigmaF))')

        return sigmaF


    def getSelfK(self, x):

        selfK = numpy.asmatrix(numpy.empty([x.shape[0],1], dtype=numpy.float))
        for idx in range(x.shape[0]):
            selfK[idx,:] = self.kernelFunc(x[idx,:])

        return selfK


    # X.shape = (number of samples, feat dim)
    def calcProbs(self, x, mu=None, sigmaF=None, nmb=None):

        # set number of sampling iterations
        if nmb is None:
            nmb = self.probSampleRuns

        # get mu and sigma
        if mu is None:
            mu = self.infer(x)
        if sigmaF is None:
            sigmaF = self.calcSigmaF(x)

        # prepare
        probs = numpy.asmatrix(numpy.zeros(mu.shape))

        for idx in range(nmb):

            draws = numpy.asmatrix(numpy.random.randn(mu.shape[0],mu.shape[1]))
            draws = numpy.add(numpy.multiply(draws, numpy.repeat(sigmaF, draws.shape[1], axis=1)), mu)

            maxIdx = numpy.argmax(draws, axis=1)

            idxs = (range(len(maxIdx)),numpy.squeeze(maxIdx))
            probs[idxs] = probs[idxs] + 1

        # convert absolute to relative amount
        return probs/float(nmb)


    # x.shape = (feat dim, number of samples)
    def calcAlScores(self, x):

        return None


    # x.shape = (feat dim, number of samples)
    def getAlScores(self, x):

        alScores = self.calcAlScores(x)

        if not numpy.all(numpy.isfinite(alScores)):
            raise Exception('not numpy.all(numpy.isfinite(alScores))')

        if alScores.shape[0] != x.shape[0] or alScores.shape[1] != 1:
            raise Exception('alScores.shape[0] != x.shape[0] or alScores.shape[1] != 1')

        return alScores


    # x.shape = (feat dim, number of samples)
    def chooseSample(self, x):

        return numpy.argmax(self.getAlScores(x), axis=0).item(0)