import matplotlib.pyplot as plt
import numpy as np
import json
import sys
import argparse
__author__ = 'm3x1m0m'

class c_settings_extractor:
    def __init__(self, fname):
        with open(fname, "r") as rf:
            settings = json.load(rf)
            kilometer_price_ccar = settings["ccar"]["litres_per_kilometer"] * settings["petrol_litre_price"]
            self.labels = [settings["ecar"]["label"], settings["ccar"]["label"]]
            self.purchase = np.array([settings["ecar"]["price"], settings["ccar"]["price"]])
            self.taxes = np.array([settings["ecar"]["taxes"], settings["ccar"]["taxes"]])
            self.insurance = np.array([settings["ecar"]["insurance"], settings["ccar"]["insurance"]])
            kilometer_price_ecar =  (   settings["ecar"]["charging_behaviour"]["percent_home_charges"] * settings["kwh_price_home"]
                                      + settings["ecar"]["charging_behaviour"]["percent_commercial_charges"] * settings["kwh_price_commercial"]) / 100.0
            self.driving = np.array([kilometer_price_ecar * settings["kilometers_per_year"], kilometer_price_ccar * settings["kilometers_per_year"]])
            self.maintenance = np.array([settings["ecar"]["maintenance"], settings["ecar"]["maintenance"]])
    def get_labels(self):
        return self.labels
    def get_purchase(self):
        return self.purchase
    def get_taxes(self):
        return self.taxes
    def get_insurance(self):
        return self.insurance
    def get_driving(self):
        return self.driving
    def get_maintenance(self):
        return self.maintenance
    
class c_ecar_comparator:
    def __init__(self, fname):
        self.settings_extractor = c_settings_extractor(fname)
    def calculate_costs_a_year(self):
        taxes = self.settings_extractor.get_taxes()
        insurance = self.settings_extractor.get_insurance()
        driving = self.settings_extractor.get_driving()
        maintenance = self.settings_extractor.get_maintenance()
        return taxes + insurance + driving + maintenance
    def calculate_costs(self, years, months):
        months_a_year = 12.0
        costs_a_year = self.calculate_costs_a_year()
        return costs_a_year * (years + months/months_a_year)
    def calculate_break_even(self):
        total_costs = self.settings_extractor.get_purchase()
        months_a_year = 12.0
        increment = self.calculate_costs_a_year() / months_a_year
        months = 0
        while total_costs[0] > total_costs[1]:
            total_costs += increment 
            months += 1
        return [months/months_a_year, months%months_a_year] # years, months

def main():
    parser = argparse.ArgumentParser(description='This script allows to calculate if an electric car makes sense financially for you')
    parser.add_argument('-a','--settings', help='Settings file', required=True, metavar=('FILENAME'))
    parser.add_argument('-b','--break_even', help='Calculate the break even point. (When does the EV become cheaper)', action='store_true')
    parser.add_argument('-c','--savings_per_year', help='Calculate savings per year', action='store_true')
    parser.add_argument('-d','--savings_per_month', help='Calculate savings per month', action='store_true')
    parser.add_argument('-e','--plot', help='Visualize costs over one or multiple years', type=int, metavar=('YEARS'))
    args = parser.parse_args()
    if not args.break_even and not args.savings_per_year and not args.savings_per_month and not args.plot:
        sys.exit("Please choose one or multiple options")
    comparator = c_ecar_comparator(args.settings)
    extractor = c_settings_extractor(args.settings)
    if args.plot:
        width = 0.3
        labels = extractor.get_labels()
        purchase = extractor.get_purchase()
        taxes = extractor.get_taxes()
        insurance = extractor.get_insurance()
        driving = extractor.get_driving()
        maintenance = extractor.get_maintenance()
        fig, ax = plt.subplots()
        ax.bar(labels, purchase, width, label = "Price", color = "gray")
        current_y = extractor.get_purchase()
        y = 0

    for i in range(args.plot):
        ax.bar(labels, taxes, width, bottom = current_y, label = "Taxes".format(y), color = "darkgreen")
        current_y = current_y + taxes
        ax.bar(labels, insurance, width, bottom = current_y, label = "Insurance".format(y), color = "royalblue")
        current_y = current_y + insurance
        ax.bar(labels, driving, width, bottom = current_y, label = "Driving".format(y), color = "midnightblue")
        current_y = current_y + driving
        ax.bar(labels, maintenance, width, bottom = current_y, label = "Maintenance".format(y), color = "lavender")
        current_y = current_y + maintenance
        y += 1
    ecar_top = current_y[0]
    #ax.plot(np.linspace(-0.2, 1.2, 10), [ecar_top]*10, "--", color = "firebrick", label = "Break even")
    #ax.text(0.3, ecar_top * 0.95, "Break even: {} years, {} kilometers".format(y, y*settings["kilometers_per_year"]))
    ax.set_ylabel("CHF")
    ax.set_title("Comparision of economics electric vs. combustion car")
    ax.legend(["Price", "Taxes", "Insurance", "Driving", "Maintenance"])
    ax.grid(axis = "y")
    #print("Break even after {} years and {} kilometers. {}".format(y, y*settings["kilometers_per_year"], current_y[0]-current_y[1]))
    plt.show()

if __name__ == "__main__":
    main()