from copy import copy
import json
import numpy as np
import random
from numpngw import write_apng

class Instrument:

    def __init__(self):
        self.context = {}
        self.events = []

    def under(self, ctx):
        self.context = {}

    def emit(self, event):
        self.events.append((self.context, copy(event)))

    def report(self):
        for el in self.dump():
            print(json.dumps(_ctx))

    def dump(self):
        for ctx, el in self.events:
            _ctx = copy(ctx)
            _ctx['event'] = el
            yield _ctx

instrument = Instrument()

def quickSort(alist):
    quickSortHelper(alist,0,len(alist)-1)

def quickSortHelper(alist,first,last):
    if first<last:

        splitpoint = partition(alist,first,last)

        quickSortHelper(alist,first,splitpoint-1)
        quickSortHelper(alist,splitpoint+1,last)


def partition(alist,first,last):
    pivotvalue = alist[first]

    leftmark = first+1
    rightmark = last

    done = False
    while not done:

        while leftmark <= rightmark and alist[leftmark] <= pivotvalue:
            leftmark = leftmark + 1

        while alist[rightmark] >= pivotvalue and rightmark >= leftmark:
            rightmark = rightmark -1

        if rightmark < leftmark:
            done = True
        else:
            temp = alist[leftmark]
            alist[leftmark] = alist[rightmark]
            alist[rightmark] = temp
            instrument.emit(alist)

    temp = alist[first]
    alist[first] = alist[rightmark]
    alist[rightmark] = temp
    instrument.emit(alist)

    return rightmark

def gen_alist():
    A = 0
    B = 255
    COUNT = 255
    return random.sample(range(A,B+1),COUNT)

def main():
    alist = gen_alist()
    instrument.under({'line': 1})
    instrument.emit(alist)
    quickSort(alist)
    seq = []
    for e in instrument.dump():
        a = np.zeros((100, 255), dtype=np.uint8)
        for index, alist_el in enumerate(e['event']):
            a[:, index] = alist_el
        seq.append(a)

    write_apng("demo.png", seq, delay=50, use_palette=True)

if __name__ == '__main__':
    main()