import datetime
import random
import numpy as np
import matplotlib.pyplot as plt

# sudo apt-get install python-tk
# pip2 install numpy matplotlib


class RetargetTest():
    # experiment with the number of work packages
    def __init__(self):
        self.current_time = datetime.datetime.now()
        self.works_to_create = 3
        self.generate_blocks = 100
        self.current_height = 0
        self.blockchain = []
        self.work_packages = []
        self.base_target = 0x000000ffffffffffffffffffffffffff
        self.stretch_number_pows = True
        self.do_not_randomize_block_times_but_do_always_60_sec = True
        self.new_miner_every_xth_second = 10
        self.how_many_miners_come_or_go = 70242
        self.initial_miners = 50
        self.miners_kick_in_at_block=50
        self.miners_drop_at = 0
        self.miners_drop_for=20
        self.jitter_size = 0

    def seeder(self, hasher):
        random.seed(hasher)

    def randomize_params(self):
        self.generate_blocks = random.randint(80,500)
        self.new_miner_every_xth_second = random.randint(5,50)
        self.how_many_miners_come_or_go = random.randint(0,1000000)
        self.initial_miners = random.randint(0,1000000) 
        self.miners_kick_in_at_block = random.randint(0,40) 
        self.jitter_size = random.randint(1,7) 
        self.miners_drop_at = random.randint(self.generate_blocks/2,self.generate_blocks)
        pass

    def create_block(self,timestamp, num_pow):
        return {'time_stamp' : timestamp, 'num_pow' : num_pow, 'first_work_factor':0}

    def create_work(self,idx, factor, target):
        return {'id': idx, 'base_executions_per_second' : factor, 'target' : target}

    def addSecs(self,tm, secs):
        fulldate = tm + datetime.timedelta(seconds=secs)
        return fulldate

    def randomDuration(self):
        if self.do_not_randomize_block_times_but_do_always_60_sec:
            return 60
        else:
            return int(random.uniform(25, 120))

    def currently_active_miners(self,current_height):
        if self.current_height<self.miners_kick_in_at_block:
            return 0

        if self.current_height>=self.miners_drop_at and self.current_height<=self.miners_drop_at+self.miners_drop_for:
            return 0
        # get the current active number of miners in relation of blockchain height,
        # but the number of miners increases by 1 every 10 blocks
        increases = int(self.current_height/self.new_miner_every_xth_second) * self.how_many_miners_come_or_go
        return self.initial_miners+increases

    def miner_pows_based_on_target(self,work, height, dur):
        current_target = work["target"]
        factor = (current_target / self.base_target) * 1.0*dur/60.0
        actual_pow_mined = work["base_executions_per_second"]
        # random jitter
        actual_pow_mined = abs((actual_pow_mined - self.jitter_size) + random.uniform(self.jitter_size,2*self.jitter_size)) * self.currently_active_miners(height)
        if actual_pow_mined < 0:
            actual_pow_mined = 0
        actual_pow_mined = actual_pow_mined *factor
        # rate limit to 20 pows per block
        if actual_pow_mined > 20:
            actual_pow_mined = 20
        if actual_pow_mined < 0:
            actual_pow_mined = 0
        return actual_pow_mined
    def kimoto(self,x):
        return  1 + (0.7084 * pow(((x)/(144)), -1.228));
        
def retarget_work(self,block, x):
        targetI = x["target"]
        pastMass = 0
        counter = 0
        current_block = block
        current_block_timestamp = self.blockchain[current_block]["time_stamp"]
        adjustment = 0
        isFull = True
        fullCnt = 0
        isEmpty = True
        max_block_reading = 144
        emptyCnt = 0
        while isFull or isEmpty:
            if isFull and self.blockchain[current_block]["num_pow"][x["id"]] == 20:
                fullCnt += 1
            else:
                isFull = False
            if isEmpty and self.blockchain[current_block]["num_pow"][x["id"]] == 0:
                emptyCnt += 1
            else:
                isEmpty = False
            current_block -= 1
            if current_block < 1:
                break
        current_block = block
        while True:
            counter += 1
            pastMass += self.blockchain[current_block]["num_pow"][x["id"]]
            if current_block_timestamp < self.blockchain[current_block-1]["time_stamp"]:
                current_block_timestamp = self.blockchain[current_block-1]["time_stamp"]
            seconds_passed = (current_block_timestamp - self.blockchain[current_block-1]["time_stamp"]).seconds
            current_block -= 1
            if seconds_passed < 1:
                seconds_passed = 1
            trs_per_second = float(pastMass) / float(seconds_passed)
            target_per_second = 10.0 / 60.0
            if trs_per_second > 0:
                adjustment = target_per_second / trs_per_second
                kim = self.kimoto(pastMass * 1000)
                if adjustment > kim or adjustment < (1.0/kim):
                    break
            else:
                adjustment = 1
            if current_block < 1 or counter == max_block_reading:
                break

        if fullCnt > 1:
            adjustment = adjustment / (1 << fullCnt)
        if emptyCnt > 1:
            adjustment = adjustment * (2 << emptyCnt)
        targetI = targetI * adjustment
        if targetI>self.base_target:
                targetI = self.base_target
        if x["id"] == 0:
                self.blockchain[block]["first_work_factor"] = adjustment
        x["target"] = targetI
        #print "Retarget using",counter,"blocks","fullcnt",fullCnt,"emptyCnt",emptyCnt



    def retarget_works(self,block):
        for x in self.work_packages:
            self.retarget_work(block,x)


    def reset_chain(self):
        self.blockchain = []
        self.work_packages = []
        self.current_height = 0
        self.current_time = datetime.datetime.now()

        # Here we create up to three different work objects
        if self.works_to_create>=1:
            self.work_packages.append(self.create_work(0, 20, self.base_target))
        if self.works_to_create>=2:
            self.work_packages.append(self.create_work(1, 60, self.base_target))
        if self.works_to_create>=3:
            self.work_packages.append(self.create_work(2, 35, self.base_target))

    def generate_chain(self):
        while self.current_height < self.generate_blocks:
            if self.current_height%1000==0:
                print "  -> generated block",self.current_height
            dur = self.randomDuration()
            self.current_time = self.addSecs(self.current_time,dur) # random block generation time
            block_pows = {}
            for x in self.work_packages:
                num_pow = self.miner_pows_based_on_target(x, self.current_height, dur) # mine some POW depending on the current difficulty
                block_pows[x["id"]] = num_pow
            self.blockchain.append(self.create_block(self.current_time, block_pows))
            self.retarget_works(self.current_height) # This retargeting method is the "critical part here"
            self.current_height = self.current_height + 1

    def get_total_error(self):
        values = []
        ideal = []
        for idx in range(len(self.blockchain)):
            if idx == 0:
                continue
            x = self.blockchain[idx]
            x_minus_one = self.blockchain[idx-1]
            time_passed = (x["time_stamp"] - x_minus_one["time_stamp"]).seconds
            strech_normalizer = time_passed / 60.0
           
            sum_x = 0
            for y in x["num_pow"]:
                sum_x += x["num_pow"][y]

            if sum_x == 0:
                ideal.append(0)
            else:
                if self.stretch_number_pows == False:
                    ideal.append(self.works_to_create*10*strech_normalizer)
                else:
                    ideal.append(self.works_to_create*10)


            if self.stretch_number_pows == False:
                values.append(sum_x)
            else:
                values.append(sum_x/strech_normalizer)
        #print values
        #print ideal
        total_error = 0
        for x in range(len(values)):
            soll = ideal[x]
            ist = values[x]
            total_error += abs(soll-ist)
        return total_error/len(values)

    def plot(self,run):
        values = []
        target_factors = []
        ideal = []
        for idx in range(len(self.blockchain)):
            if idx == 0:
                continue
            x = self.blockchain[idx]
            x_minus_one = self.blockchain[idx-1]
            time_passed = (x["time_stamp"] - x_minus_one["time_stamp"]).seconds
            strech_normalizer = time_passed / 60.0
            
            sum_x = 0
            for y in x["num_pow"]:
                sum_x += x["num_pow"][y]

            if sum_x == 0:
                ideal.append(0)
            else:
                if self.stretch_number_pows == False:
                    ideal.append(self.works_to_create*10*strech_normalizer)
                else:
                    ideal.append(self.works_to_create*10)

            if self.stretch_number_pows == False:
                values.append(sum_x)
            else:
                values.append(sum_x/strech_normalizer)
        x = range(self.generate_blocks)[1:]
        y = values

        #print "LEN: x",len(x),"y",len(y),"ideal",len(ideal)

        #fig = plt.figure()
        ax0 = plt.subplot(211)
        if self.stretch_number_pows:
            ax0.set_ylabel('POW rate per 60s', color='b')
        else:
            ax0.set_ylabel('POWs per Block', color='b')
        ax0.set_xlabel('Block height')
        ax0.plot(x,y,'-o',x,ideal,'r--')
        values = []
        ideal = []
        target_factors = []
        for idx in range(len(self.blockchain)):
            if idx == 0:
                continue
            x = self.blockchain[idx]
            x_minus_one = self.blockchain[idx-1]
            time_passed = (x["time_stamp"] - x_minus_one["time_stamp"]).seconds
            strech_normalizer = time_passed / 60.0
            
            sum_x = 0
            sum_x += x["num_pow"][0]

            if sum_x == 0:
                ideal.append(0)
            else:
                if self.stretch_number_pows == False:
                    ideal.append(10*strech_normalizer)
                else:
                    ideal.append(10)

            #print "sumx",sum_x
            if self.stretch_number_pows == False:
                values.append(sum_x)
            else:
                values.append(sum_x/strech_normalizer)
        x = range(self.generate_blocks)[1:]
        y = values
        plt.title('All Works: Total POWs')
        #print "LEN: x",len(x),"y",len(y),"ideal",len(ideal)

        ax1 = plt.subplot(212)
        ax1.plot(x,y,'-o',x,ideal,'r--')
        ax1.set_xlabel('Block Height')
        # Make the y-axis label and tick labels match the line color.
        if self.stretch_number_pows:
            ax1.set_ylabel('POW rate per 60s', color='b')
        else:
            ax1.set_ylabel('POWs per Block', color='b')

        for tl in ax1.get_yticklabels():
            tl.set_color('b')



        ax2 = ax1.twinx()
        ax2.set_ylim(0.4, 1.6)
        ax2.bar(x,[x["first_work_factor"] for x in self.blockchain][1:],0.45,color='#deb0b0', alpha=0.2)
        ax2.set_ylabel('Retargeting Factor', color='r')
        for tl in ax2.get_yticklabels():
            tl.set_color('r')
        plt.title('First Work: POWs + Retargeting Factor')

        plt.savefig('render-' + str(run) + '.png')
        plt.close()