package trading_game;

import java.util.ArrayList;
import java.util.List;

import exceptions.InsufficientFundsException;
import exceptions.InsufficientSharesException;
import game.BaseTradingStrategy;
import game.DailyInput;
import game.DailyOutput;

public class TradingStrategy extends BaseTradingStrategy {

	public TradingStrategy (){
		// Initialise any variables needed.

	}

	// input starts from the most recent day
	public double crossoverEMA(List<DailyInput> l){
		double ema = 0;
		Double[] alphas = new Double[l.size()];
		double a = 2 / (1 + l.size());
		double divider = 0;
		for (int i = 0; i < l.size(); i++) {
			alphas[i] = Math.pow(1 - a, i);
			divider += alphas[i];
		}
		assert divider != 0;
		// calculate the ema
		double sum = 0;
		for (int i = 0; i < l.size(); i++) {
			// get the avg
			DailyInput in = l.get(i);
			double avg = (in.getClose() + in.getOpen() + in.getHigh() + in.getLow() ) / 4;
			sum += alphas[i] * avg;
		}
		return sum / divider;
	}
	// list of a COMPANY stock (each element represents the stocks of one company)
	List<DailyInput> pastStock  = new ArrayList<DailyInput>();
	@Override
	public DailyOutput makeDailyTrade(DailyInput input) throws InsufficientFundsException, InsufficientSharesException {
		// add the most recent day from
		if(input.getRemainingDays() == 0){
			pastStock  = new ArrayList<DailyInput>();
			pastStock.add(0, input);
		}
		else
			pastStock.add(0, input);

		//get the Exponential Moving Average for the stock chart
		double crossover = crossoverEMA(pastStock);

		// compare with closing price
		double crossprice = input.getClose() - crossover;

		System.out.println(crossprice);

		DailyOutput output;
		if (input.getDay() % 2 == 0) {
			output = tradingManager.buyMaxNumberOfShares(input);

		} else {
			output = tradingManager.sellAllShares(input);
		}

		return output;
	}
}