from __future__ import absolute_import
from __future__ import print_function

import numpy as np
from sklearn import metrics


# for decompensation, in-hospital mortality

def print_metrics_binary(y_true, predictions, verbose=1):
    predictions = np.array(predictions)
    if len(predictions.shape) == 1:
        predictions = np.stack([1 - predictions, predictions]).transpose((1, 0))

    cf = metrics.confusion_matrix(y_true, predictions.argmax(axis=1))
    if verbose:
        print("confusion matrix:")
        print(cf)
    cf = cf.astype(np.float32)

    acc = (cf[0][0] + cf[1][1]) / np.sum(cf)
    prec0 = cf[0][0] / (cf[0][0] + cf[1][0])
    prec1 = cf[1][1] / (cf[1][1] + cf[0][1])
    rec0 = cf[0][0] / (cf[0][0] + cf[0][1])
    rec1 = cf[1][1] / (cf[1][1] + cf[1][0])
    auroc = metrics.roc_auc_score(y_true, predictions[:, 1])

    (precisions, recalls, thresholds) = metrics.precision_recall_curve(y_true, predictions[:, 1])
    auprc = metrics.auc(recalls, precisions)
    minpse = np.max([min(x, y) for (x, y) in zip(precisions, recalls)])

    if verbose:
        print("accuracy = {}".format(acc))
        print("precision class 0 = {}".format(prec0))
        print("precision class 1 = {}".format(prec1))
        print("recall class 0 = {}".format(rec0))
        print("recall class 1 = {}".format(rec1))
        print("AUC of ROC = {}".format(auroc))
        print("AUC of PRC = {}".format(auprc))
        print("min(+P, Se) = {}".format(minpse))

    return {"acc": acc,
            "prec0": prec0,
            "prec1": prec1,
            "rec0": rec0,
            "rec1": rec1,
            "auroc": auroc,
            "auprc": auprc,
            "minpse": minpse}


# for length of stay

def mean_absolute_percentage_error(y_true, y_pred):
    return np.mean(np.abs((y_true - y_pred) / (y_true + 0.1))) * 100


def print_metrics_regression(y_true, predictions, verbose=1):
    predictions = np.array(predictions)
    predictions = np.maximum(predictions, 0).flatten()
    y_true = np.array(y_true)

    y_true_bins = [get_bin_custom(x, CustomBins.nbins) for x in y_true]
    prediction_bins = [get_bin_custom(x, CustomBins.nbins) for x in predictions]
    cf = metrics.confusion_matrix(y_true_bins, prediction_bins)
    if verbose:
        print("Custom bins confusion matrix:")
        print(cf)

    kappa = metrics.cohen_kappa_score(y_true_bins, prediction_bins,
                                      weights='linear')
    mad = metrics.mean_absolute_error(y_true, predictions)
    mse = metrics.mean_squared_error(y_true, predictions)
    mape = mean_absolute_percentage_error(y_true, predictions)

    if verbose:
        print("Mean absolute deviation (MAD) = {}".format(mad))
        print("Mean squared error (MSE) = {}".format(mse))
        print("Mean absolute percentage error (MAPE) = {}".format(mape))
        print("Cohen kappa score = {}".format(kappa))

    return {"mad": mad,
            "mse": mse,
            "mape": mape,
            "kappa": kappa}


class LogBins:
    nbins = 10
    means = [0.611848, 2.587614, 6.977417, 16.465430, 37.053745,
             81.816438, 182.303159, 393.334856, 810.964040, 1715.702848]


def get_bin_log(x, nbins, one_hot=False):
    binid = int(np.log(x + 1) / 8.0 * nbins)
    if binid < 0:
        binid = 0
    if binid >= nbins:
        binid = nbins - 1

    if one_hot:
        ret = np.zeros((LogBins.nbins,))
        ret[binid] = 1
        return ret
    return binid


def get_estimate_log(prediction, nbins):
    bin_id = np.argmax(prediction)
    return LogBins.means[bin_id]


def print_metrics_log_bins(y_true, predictions, verbose=1):
    y_true_bins = [get_bin_log(x, LogBins.nbins) for x in y_true]
    prediction_bins = [get_bin_log(x, LogBins.nbins) for x in predictions]
    cf = metrics.confusion_matrix(y_true_bins, prediction_bins)
    if verbose:
        print("LogBins confusion matrix:")
        print(cf)
    return print_metrics_regression(y_true, predictions, verbose)


class CustomBins:
    inf = 1e18
    bins = [(-inf, 1), (1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 7), (7, 8), (8, 14), (14, +inf)]
    nbins = len(bins)
    means = [11.450379, 35.070846, 59.206531, 83.382723, 107.487817,
             131.579534, 155.643957, 179.660558, 254.306624, 585.325890]


def get_bin_custom(x, nbins, one_hot=False):
    for i in range(nbins):
        a = CustomBins.bins[i][0] * 24.0
        b = CustomBins.bins[i][1] * 24.0
        if a <= x < b:
            if one_hot:
                ret = np.zeros((CustomBins.nbins,))
                ret[i] = 1
                return ret
            return i
    return None


def get_estimate_custom(prediction, nbins):
    bin_id = np.argmax(prediction)
    assert 0 <= bin_id < nbins
    return CustomBins.means[bin_id]


def print_metrics_custom_bins(y_true, predictions, verbose=1):
    return print_metrics_regression(y_true, predictions, verbose)