from threading import Timer
import json
import datetime


def json_time(x): return datetime.datetime.strptime(x, '%Y-%m-%dT%H:%M:%S.%fZ')


def seconds_remaining(r_d): return (
    r_d - datetime.datetime.now()).total_seconds()


class InvoiceData(object):
    """docstring for InvoiceData."""

    def __init__(self, invoice_data):
        super(InvoiceData, self).__init__()
        self.customer_id = invoice_data["customer_id"]
        self.due_date = json_time(invoice_data["invoice_due_date"])
        self.amount = invoice_data["invoice_amount"]
        rem_start = invoice_data["reminder_start"]
        rem_every = invoice_data["reminder_every"]
        self.remind_before = datetime.timedelta(0, int(rem_start))
        self.reminder_interval = datetime.timedelta(0, int(rem_every))

    def __repr__(self):
        return self.customer_id + "#" + self.due_date

    def print_invoice(self):
        invoice_str = "INVOICE FOR CUSTOMER ID : {}\nDATE:{}\nAMOUNT:{}\n"
        print invoice_str.format(self.customer_id, self.due_date, self.amount)

    def print_reminder(self):
        inv_str = "REMINDER FOR CUSTOMER ID : {}\nINVOICE DUE ON :{}\nAMOUNT:{}\n"
        print inv_str.format(self.customer_id, self.due_date, self.amount)

    def schedule_reminders(self):
        current_time = datetime.datetime.now()
        reminder_start = (self.due_date - self.remind_before)
        reminder_time = self.due_date - self.reminder_interval

        def closed_reminder():
            self.print_reminder()
        while (reminder_time >= reminder_start
               and reminder_time < self.due_date
               and seconds_remaining(reminder_time) > 0):
            inv_timer = Timer(seconds_remaining(
                reminder_time), closed_reminder)
            inv_timer.start()
            reminder_time = reminder_time - self.reminder_interval

    def schedule_invoice(self):
        self.schedule_reminders()

        def closed_invoice():
            self.print_invoice()
        if seconds_remaining(self.due_date) > 0:
            inv_timer = Timer(seconds_remaining(self.due_date), closed_invoice)
            inv_timer.start()

    @classmethod
    def from_json(cls, file_name):
        invoice_data = json.load(open(file_name, 'rb'))
        invoice_list = []
        for inv_d in invoice_data:
            invoice_list.append(cls(inv_d))
        return invoice_list

invoices = InvoiceData.from_json("./invoice_data.json")
for inv in invoices:
    inv.print_invoice()
    inv.schedule_invoice()