package edu.brown.cs.student.term.parsing;

import edu.brown.cs.student.term.hub.Holder;
import edu.brown.cs.student.term.trade.Trade;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

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


/**
 * This class represents the transaction data from the xml file.
 */
public class Transaction {
  private Document doc;
  private final List<Trade> trades;
  private final String personName;
  private final int id;
  private final String ticker;

  /**
   * Constructor that represents the transaction from the document.
   * @param document The document parsed from the xml file.
   */
  public Transaction(Document document) {
    // TODO: add log comments
    System.err.println("LOG: Entered constructor for: " + getClass());
    doc = document;
    trades = new ArrayList<>();

    personName = personName();
    id = id();
    ticker = ticker();

    // There are two types of transactions within the xml - derivative and non derivative.
    // We only look at non-derivative
    NodeList nonDerivative = document.getElementsByTagName("nonDerivativeTransaction");
    System.err.println("LOG: Called processTransaction in constructor for: " + getClass());
    processTransactions(nonDerivative);
  }

  /**
   * Takes a transaction as a node list, then processes and stores them into trades.
   * @param tradesAsNodes The trades within the transaction as a nodelist.
   */
  private void processTransactions(NodeList tradesAsNodes) {
    int numTrades = tradesAsNodes.getLength();
    for(int i = 0; i < numTrades; i++) {
      // Convert to an element to extract specific info.
      // I know there is a cast, but this how it is done and is checked with the assertion.
      Node trade = tradesAsNodes.item(i);
      assert trade.getNodeType() == Node.ELEMENT_NODE;
      Element tradeValues = (Element) trade;

      // This stages the params for the trade.
      // TODO: update with real timestamp
      double ts = getDate(tradeValues).hashCode();
      int isBuy = getIsBuy(tradeValues);
      int numShares = getNumShares(tradeValues);
      // TODO: update id? unique for each holder?
      Holder holder = new Holder(id, personName);
      double pricePerShare = getPriceShares(tradeValues);

      if (pricePerShare != 0 && numShares != -1 && pricePerShare != -1 && isBuy != -1) {
        trades.add(new Trade(id, ticker, ts, isBuy, numShares, holder, pricePerShare));
      }
    }

    doc = null;
  }

  /**
   * Extracts the id of the transaction from the document.
   * @return The id.
   */
  private int id() {
    // Id of transaction
    NodeList idNode = doc.getElementsByTagName("rptOwnerCik");
    // TODO: add error parsing
    return Integer.parseInt(idNode.item(0).getTextContent());
  }

  /**
   * Extracts the person's name of the transaction from the document.
   * @return The person's name.
   */
  private String personName() {
    // Name of person
    NodeList nameNode = doc.getElementsByTagName("rptOwnerName");
    return nameNode.item(0).getTextContent();
  }

  /**
   * Extracts the security ticker of the transaction from the document
   * @return The ticker.
   */
  private String ticker() {
    // Ticker of security
    NodeList idNode = doc.getElementsByTagName("issuerTradingSymbol");
    return idNode.item(0).getTextContent();
  }


  public String getValueFromNode(NodeList dataHolder) {
    // Convert to an element to extract the value form.
    // I know there is a cast, but this how it is done and is checked with the assertion.
    Node dataNode = dataHolder.item(0);
    assert dataNode.getNodeType() == Node.ELEMENT_NODE;
    Element data = (Element) dataNode;

    // Only one field within the value holding the value...
    NodeList value = data.getElementsByTagName("value");
    if (value.getLength() == 0) {
      // If market trade, some values don't have fields...
      return "";
    }
    return value.item(0).getTextContent();
  }

  /**
   * Extracts the trade date from a trade node.
   * @param values The value array representing the trade.
   * @return The date in mm-dd-yyyy format as a string.
   */
  public String getDate(Element values) {
    NodeList date = values.getElementsByTagName("transactionDate");
    return getValueFromNode(date);
  }

  /**
   * Extracts the number of shares moved from the trade.
   * @param values The value array representing the trade.
   * @return The number of shares.
   */
  public int getNumShares(Element values) {
    NodeList numShares = values.getElementsByTagName("transactionShares");
    String num = getValueFromNode(numShares);
    num = num.equals("") ? "<empty>" : num;
    try {
      // Some ints have training zeros, so need to parse Double then truncate.
      return (int) Double.parseDouble(num);
    } catch (NumberFormatException e) {
      System.err.println("WARNING: Num shares in XML bad format: " + num);
      return -1;
    }
  }

  /**
   * Extracts the price each share cost from the trade.
   * @param values The value array representing the trade.
   * @return The price of each share.
   */
  public double getPriceShares(Element values) {
    NodeList priceShares = values.getElementsByTagName("transactionPricePerShare");
    String num = getValueFromNode(priceShares);
    num = num.equals("") ? "<empty>" : num;
    try {
      return Double.parseDouble(num);
    } catch (NumberFormatException e) {
      System.err.println("WARNING: Price shares in XML bad format: " + num);
      return -1;
    }
  }

  /**
   * Determines whether the shares in the trade were bought or sold.
   * @param values The value array representing the trade.
   * @return True if they were bought (acquired). False, if sold.
   */
  public int getIsBuy(Element values) {
    NodeList isBuy = values.getElementsByTagName("transactionAcquiredDisposedCode");
    String value = getValueFromNode(isBuy);
    if (value.equals("A")) {
      return 1;
    } else if (value.equals("D")) {
      return 0;
    } else {
      System.err.println("WARNING: Acquire code not recognized: " + value);
      return -1;
    }
  }

  /**
   * Returns the list of trades that occurred within the transaction.
   * @return A list of trade objects.
   */
  public List<Trade> getTrades() {
    return trades;
  }

  /**
   * Accessor method that returns the id of the transaction.
   * @return The id.
   */
  public int getId() {
    return id;
  }

  /**
   * Accessor method that returns the person's name who did the transaction.
   * @return The name of whom did the transaction.
   */
  public String getPersonName() {
    return personName;
  }
}