from django.db import connection
from apps.transactions.models import Transaction
from apps.rates.models import ExchangeRate
from decimal import Decimal
import datetime

class Calc:
  def ShowDiffRate(self, DayDiff, CurrentRate, Crypto, Fiat):
    with connection.cursor() as cursor:
        sql = """SELECT rate, datetime_valid FROM exchangerate WHERE crypto_currency = %s AND fiat_currency = %s
           AND datetime_valid BETWEEN %s AND %s
           ORDER BY datetime_valid DESC"""
        startDate = datetime.datetime.now() - datetime.timedelta(days=int(DayDiff))
        endDate = startDate + datetime.timedelta(days=1)
        cursor.execute(sql, [Crypto, Fiat, startDate, endDate])
        rateMinusXDay = cursor.fetchone()
        if rateMinusXDay:
            return {"dateRelative": "%s days ago" % (DayDiff,), "date" : rateMinusXDay[1], "rateEUR": rateMinusXDay[0],
                "diffPercentage": (CurrentRate.rate-Decimal(rateMinusXDay[0]))/Decimal(rateMinusXDay[0])*100, "rateUSD": None}
    return None

  def GetCurrentValue(self, userid, crypto, total_investment, current_value, total_tax_free):
    amount_kept = 0
    out = {}
    out["crypto"] = crypto

    with connection.cursor() as cursor:
        sql = """SELECT SUM(amount_after_fee) as after_fee, SUM(amount) as amount FROM `transaction` WHERE amount_after_fee > 0 and crypto_currency=%s and owner_id=%s"""
        cursor.execute(sql, [crypto, userid])
        bought = cursor.fetchone()
        if bought[0]:
          out["bought"] = bought[1]
          total_investment += Decimal(bought[1])
          amount_kept += Decimal(bought[0])
        else:
          out["bought"] = None
    
    with connection.cursor() as cursor:
        sql = """SELECT SUM(amount_before_fee) as before_fee, SUM(amount) as amount FROM `transaction` WHERE amount_before_fee < 0 and crypto_currency=%s and owner_id=%s"""
        cursor.execute(sql, [crypto, userid])
        sold = cursor.fetchone()
        if sold[0]:
          out["sold"] = sold[1]
          total_investment += Decimal(sold[1])
          amount_kept += Decimal(sold[0])
        else:
          out["sold"] = None

    rateEUR = ExchangeRate.objects.filter(crypto_currency=crypto, fiat_currency='EUR').order_by('-datetime_valid').first()
    rateUSD = ExchangeRate.objects.filter(crypto_currency=crypto, fiat_currency='USD').order_by('-datetime_valid').first()

    if rateEUR:
      cv =  Decimal(rateEUR.rate) * amount_kept
      current_value += cv
      out["current_value"] = cv
      out["amount_kept"] = amount_kept
      out["rateEUR"] = rateEUR.rate
    else:
      out["current_value"] = None
      out["amount_kept"] = None
      out["rateEUR"] = None

    out["rates"] = []
    if rateUSD and rateEUR:
        out["rates"].append({"dateRelative": "Now", "date" : rateEUR.datetime_valid, "rateEUR": rateEUR.rate, "diffPercentage": None, "rateUSD": rateUSD.rate})

    if rateEUR:
      for daydiff in ["1", "3", "7", "14", "30"]:
        diffrate = self.ShowDiffRate(daydiff, rateEUR, crypto, 'EUR')
        if diffrate:
          out["rates"].append(diffrate)

    amount_within_past_year = 0
    with connection.cursor() as cursor:
        sql = """SELECT SUM(amount_after_fee) as amount FROM `transaction` WHERE amount > 0 and crypto_currency=%s and owner_id=%s and date_valid>%s"""
        cursor.execute(sql, [crypto, userid, datetime.datetime.now() - datetime.timedelta(days=365)])
        bought = cursor.fetchone()
        out["bought_recently"] = None
        if bought[0]:
          out["bought_recently"] = bought[0]
          amount_within_past_year = Decimal(bought[0])
        amount_available_to_sell = amount_kept - amount_within_past_year
        out["bought_tax_free"] = None
        out["value_tax_free"] = None
        if rateEUR:
          out["bought_tax_free"] = amount_available_to_sell
          out["value_tax_free"] = amount_available_to_sell * rateEUR.rate
          total_tax_free += out["value_tax_free"]

    return (total_investment, current_value, total_tax_free, rateEUR.rate, rateUSD.rate, out)