"""MC2-P1: Market simulator.

Copyright 2018, Georgia Institute of Technology (Georgia Tech)
Atlanta, Georgia 30332
All Rights Reserved

Template code for CS 4646/7646

Georgia Tech asserts copyright ownership of this template and all derivative
works, including solutions to the projects assigned in this course. Students
and other users of this template code are advised not to share it with others
or to make it available on publicly viewable websites including repositories
such as github and gitlab.  This copyright statement should not be removed
or edited.

We do grant permission to share solutions privately with non-students such
as potential employers. However, sharing with other current or future
students of CS 7646 is prohibited and subject to being investigated as a
GT honor code violation.

-----do not edit anything above this line---

Student Name: Tucker Balch (replace with your name)
GT User ID: felixm (replace with your User ID)
GT ID: 1337 (replace with your GT ID)
"""

import pandas as pd
from util import get_data, plot_data
from optimize_something.optimization import calculate_stats


def read_orders(orders_file):
    """
    Parser orders into the form:

        Date      datetime64[ns]
        Symbol            object
        Order             object
        Shares             int32

    This is how the order book looks like:

        Date,Symbol,Order,Shares
        2011-01-10,AAPL,BUY,1500
        2011-01-10,AAPL,SELL,1500
    """
    orders = pd.read_csv(orders_file,
                         index_col=['Date'],
                         dtype='|str, str, str,  i4',
                         parse_dates=['Date'])
    orders.sort_values(by="Date", inplace=True)
    return orders


def get_order_book_info(orders):
    """Return start_date, end_date, and symbols (as a list)."""
    start_date = orders.index[0]
    end_date = orders.index[-1]
    symbols = sorted(list((set(orders.Symbol.tolist()))))
    return start_date, end_date, symbols


def get_portfolio_value(holding, prices):
    """Calculate the current portofolio value."""
    value = 0
    for ticker, shares in holding.items():
        if ticker == 'cash':
            value += shares
        else:
            value += shares * prices[ticker]
    return value


def handle_order(date, order, holding, prices, commission, impact):
    """Process the order."""
    symbol, order, shares = order
    if shares == 0 and order == "":
        return  # empty order
    if pd.isnull(shares):
        return  # shares is nan

    # Allow indicating buying and selling via shares. If shares is positive we
    # buy and if it is negative we sell.
    if shares > 0 and order == "":
        order = "BUY"
    elif shares < 0 and order == "":
        order = "SELL"
        shares = abs(shares)

    adj_closing_price = prices[symbol]
    cost = shares * adj_closing_price
    # Charge commission and deduct impact penalty
    holding['cash'] -= (commission + impact * adj_closing_price * shares)
    if order.upper() == "BUY":
        # print(f"Buy  {shares:6} of {symbol:4} on {date}")
        holding['cash'] -= cost
        holding[symbol] += shares
    elif order.upper() == "SELL":
        # print(f"Sell {shares:6} of {symbol:4} on {date}")
        holding['cash'] += cost
        holding[symbol] -= shares
    else:
        raise Exception("Unexpected order type.")


def compute_portvals(orders_file, start_val=1000000, commission=9.95, impact=0.005):
    if isinstance(orders_file, pd.DataFrame):
        orders = orders_file
    else:
        orders = read_orders(orders_file)

    start_date, end_date, symbols = get_order_book_info(orders)

    # Tickers in the orderbook over the date_range in the order book.
    prices = get_data(symbols, pd.date_range(start_date, end_date))
    prices['Portval'] = pd.Series(0.0, index=prices.index)

    # A dictionary to keep track of the assets we are holding.
    holding = {s: 0 for s in symbols}
    holding['cash'] = start_val

    # Iterate over all trading days that are in the (inclusive) range of the
    # order book dates. This implicitly ignores orders placed on non-trading
    # days.
    for date, values in prices.iterrows():
        # Process orders for that day.
        for date, order in orders.loc[date:date].iterrows():
            handle_order(date, order, holding, values, commission, impact)
        # Compute portfolio value at the end of day.
        values['Portval'] = get_portfolio_value(holding, values)

    return prices[['Portval']]


def test_code():
    of = "./orders/orders-02.csv"
    sv = 1000000

    portvals = compute_portvals(orders_file=of, start_val=sv)

    if isinstance(portvals, pd.DataFrame):
        portvals = portvals[portvals.columns[0]]  # just get the first column
    else:
        raise Exception("warning, code did not return a DataFrame")

    start_date = portvals.index[0]
    end_date = portvals.index[-1]
    cum_ret, avg_daily_ret, \
        std_daily_ret, sharpe_ratio = calculate_stats(portvals.to_frame(), [1])

    spy = get_data(['SPY'], pd.date_range(start_date, end_date))
    cum_ret_SPY, avg_daily_ret_SPY, \
        std_daily_ret_SPY, sharpe_ratio_SPY = calculate_stats(spy, [1])

    # Compare portfolio against $SPY
    print(f"Date Range: {start_date} to {end_date}")
    print()
    print(f"Sharpe Ratio of Fund: {sharpe_ratio}")
    print(f"Sharpe Ratio of SPY : {sharpe_ratio_SPY}")
    print()
    print(f"Cumulative Return of Fund: {cum_ret}")
    print(f"Cumulative Return of SPY : {cum_ret_SPY}")
    print()
    print(f"Standard Deviation of Fund: {std_daily_ret}")
    print(f"Standard Deviation of SPY : {std_daily_ret_SPY}")
    print()
    print(f"Average Daily Return of Fund: {avg_daily_ret}")
    print(f"Average Daily Return of SPY : {avg_daily_ret_SPY}")
    print()
    print(f"Final Portfolio Value: {portvals[-1]}")


def author():
    return 'felixm'


if __name__ == "__main__":
    test_code()