import pandas as pd
from sklearn.tree import DecisionTreeClassifier
from sklearn.model_selection import train_test_split
from sklearn import metrics
import numpy


header = ["ready", "hydration", "weeds", "planted"]


def check(field):
    if field == 0:
        return [0, 0, 0, 'N']
    elif field == 1:
        return [0, 0, 1, 'N']
    elif field == 2:
        return [0, 0, 0, 'Y']
    elif field == 3:
        return [0, 0, 1, 'Y']
    elif field == 4:
        return [0, 1, 0, 'N']
    elif field == 5:
        return [0, 1, 1, 'N']
    elif field == 6:
        return [0, 1, 0, 'Y']
    elif field == 7:
        return [0, 1, 1, 'Y']
    elif field == 8:
        return [1, 0, 0, 'N']
    else:
        print("wrong field number")


def un_values(rows, col):
    return set([row[col] for row in rows])


def class_counts(rows):
    counts = {}
    for row in rows:
        label = row[-1]
        if label not in counts:
            counts[label] = 0
        counts[label] += 1
    return counts


def is_numeric(value):
    return isinstance(value, int) or isinstance(value, float)


class Question():
    def __init__(self, column, value):
        self.column = column
        self.value = value

    def match(self, example):
        val = example[self.column]
        if is_numeric(val):
            return val == self.value
        else:
            return val != self.value

    def __repr__(self):
        condition = "!="
        if is_numeric(self.value):
            condition = "=="
        return "Is %s %s %s?" %(
            header[self.column], condition, str(self.value)
        )


def partition(rows, question):
    true_rows, false_rows = [], []
    for row in rows:
        if question.match(row):
            true_rows.append(row)
        else:
            false_rows.append(row)
    return true_rows, false_rows


def gini(rows):
    counts = class_counts(rows)
    impurity = 1
    for lbl in counts:
        prob_of_lbl = counts[lbl]/float(len(rows))
        impurity -= prob_of_lbl**2
    return impurity


def info_gain(left, right, current_uncertainty):
    p = float(len(left))/(len(left) + len(right))
    return current_uncertainty - p*gini(left) - (1-p) * gini(right)


def find_best_split(rows):
    best_gain = 0
    best_question = None
    current_uncertainty = gini(rows)
    n_features = len(rows[0]) - 1

    for col in range(n_features):

        values = set([row[col] for row in rows])

        for val in values:
            question = Question(col, val)
            true_rows, false_rows = partition(rows, question)
            if len(true_rows) == 0 or len(false_rows) == 0:
                continue
            gain = info_gain(true_rows,false_rows,current_uncertainty)
            if gain >= best_gain:
                best_gain, best_question = gain, question

    return best_gain, best_question


class Leaf:
    def __init__(self, rows):
        self.predictions = class_counts(rows)


class DecisionNode:
    def __init__(self, question, true_branch, false_branch):
        self.question = question
        self.true_branch = true_branch
        self.false_branch = false_branch


def build_tree(rows):
    gain, question = find_best_split(rows)
    if gain == 0:
        return Leaf(rows)
    true_rows, false_rows = partition(rows, question)

    true_branch = build_tree(true_rows)
    false_branch = build_tree(false_rows)

    return DecisionNode(question, true_branch, false_branch)


def print_tree(node, spacing=""):
    if isinstance(node, Leaf):
        print(spacing + "Predict", node.predictions)
        return

    print(spacing + str(node.question))

    print(spacing + '--> True: ')
    print_tree(node.true_branch, spacing + " ")

    print(spacing + '--> False: ')
    print_tree(node.false_branch, spacing + " ")


def classify(row, node):
    if isinstance(node, Leaf):
        return node.predictions
    if node.question.match(row):
        return classify(row, node.true_branch)
    else:
        return classify(row,node.false_branch)


def print_leaf(counts):
    total = sum(counts.values()) * 1.0
    probs = {}
    for lbl in counts.keys():
        probs[lbl] = str(int(counts[lbl]/total * 100)) + "%"
    return probs


class main():
    def __init__(self,traktor,field,ui,path):
        self.traktor = traktor
        self.field = field
        self.ui = ui
        self.path = path

    def tree(field):
        array = ([[8, 8, 8, 8, 8, 8, 8, 8, 8, 8],
                  [7, 7, 7, 7, 7, 7, 7, 7, 7, 7],
                  [6, 6, 6, 6, 6, 6, 6, 6, 6, 6],
                  [5, 5, 5, 5, 5, 5, 5, 5, 5, 5],
                  [4, 4, 4, 4, 4, 4, 4, 4, 4, 4],
                  [3, 3, 3, 3, 3, 3, 3, 3, 3, 3],
                  [2, 2, 2, 2, 2, 2, 2, 2, 2, 2],
                  [1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
                  [0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
                  [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]])

        testing_data = []

        for i in range(10):
            verse = field[i]
            for j in verse:
                coord = (i, j)
                current_field = check(verse[j])
                testing_data.append(current_field)

        x = build_tree(testing_data)
        print_tree(x)