"""Expose budget metrics."""
import os
import calendar
import datetime

import pytz
import requests
import dateutil.parser


header = {"Authorization": "Bearer " + os.environ.get('FIREFLY_PERSONAL_ACCESS_TOKEN')}
host = os.environ.get('FIREFLY_API_HOST')


def _get_budgets():
    budgets_req = requests.get(
        host + "/api/v1/budgets", headers=header
    )
    budgets_json = budgets_req.json()
    budgets = budgets_json.get('data')
    while "next" in budgets_json.get('links'):
        budgets_json = requests.get(
            budgets_json.get('links').get('next'), headers=header
        ).json()
        budgets.extend(budgets_json.get('data'))
    return budgets


def _get_current_limit(budget_id):
    budgets_json = requests.get(
        host + "/api/v1/budgets/{}/limits".format(budget_id), headers=header
    ).json()
    budgets = budgets_json.get('data')
    while "next" in budgets_json.get('links'):
        budget_json = requests.get(
            budgets_json.get('links').get('next'), headers=header
        ).json()
        budgets.extend(budget_json.get('data'))

    today = datetime.datetime.combine(datetime.date.today(), datetime.datetime.min.time()).replace(tzinfo=pytz.UTC)
    return [
        budget for budget in budgets
        if today >= dateutil.parser.parse(budget.get('attributes').get('start')) and today <= dateutil.parser.parse(budget.get('attributes').get('end'))
    ][0]


def _get_current_transactions(budget_id):
    limit_id = _get_current_limit(budget_id).get('id')
    transactions_req = requests.get(
        host + "/api/v1/budgets/{}/limits/{}/transactions".format(
            budget_id,
            limit_id
        ), headers=header
    )
    transactions_json = transactions_req.json()
    transactions = transactions_json.get('data')
    while 'next' in transactions_json:
        transactions_json = requests.get(
            transactions_json.get('links').get('next'), headers=header
        ).json()
        transactions.extend(transactions_json.get('data'))
    return transactions


def _get_current_spent_amount(budget_id):
    transactions = _get_current_transactions(budget_id)
    spent_amount = 0.0
    for transaction in transactions:
        for detail in transaction.get('attributes').get('transactions'):
            if detail.get('type') == "withdrawal":
                spent_amount += float(detail.get('amount'))
            elif detail.get('type') == "deposit":
                spent_amount -= float(detail.get('amount'))
    return spent_amount


def get_budget_metrics():
    out = ""
    for budget in _get_budgets():
        budget_id = budget.get('id')
        budget_name = budget.get('attributes').get('name')
        budget_limit = _get_current_limit(budget_id).get('attributes').get('amount')
        budget_spent = str(_get_current_spent_amount(budget.get('id')))

        out += 'firefly_budget_limit{{budget_id="{}",budget_name="{}",year="{}",month="{}"}} {}\n'.format(
            budget_id,
            budget_name,
            datetime.datetime.today().year,
            datetime.datetime.today().month,
            budget_limit,
        )
        out += 'firefly_budget_spent{{budget_id="{}",budget_name="{}",year="{}",month="{}"}} {}\n'.format(
            budget_id,
            budget_name,
            datetime.datetime.today().year,
            datetime.datetime.today().month,
            budget_spent,
        )
    return out