Main {

  {{
  static SymbolTable symbolTable;
  static boolean stopSimulation = false;
  }}


  public static void main(String args[]) throws Exception {{

    ClassGraph cg = new ClassGraph(true,false);
    Main m = parse(System.in);

    //System.out.println ("parsed input file");
    //System.out.println(m.get_s());
    //m.universal_trv0(new DisplayVisitor());

    m.run_simulation();
  }}


  public void run_simulation() {{

    Mortgage mort = new Mortgage();
    symbolTable = SymbolTable.parse("");

    System.out.println ("\nInitializing symbol table");
    initSymbolTable(new InitSymbolTableVisitor());

    // Initialize date/state, other required variables.
    // If the user has declared these variables, these will be ignored.
    Symbol start_month      = addDefaultVariable("start_month 1");
    Symbol start_year       = addDefaultVariable("start_year 2000");
    Symbol current_month    = addDefaultVariable("current_month");
    Symbol current_year     = addDefaultVariable("current_year");
    Symbol sumOfAssets      = addDefaultVariable("sum_of_assets");
    Symbol sumOfLiabilities = addDefaultVariable("sum_of_liabilities");
    Symbol startup          = addDefaultVariable("startup 1");
    Symbol savings          = addDefaultVariable("savings 0");

    // Initialize the default columns
    addDefaultColumn("column \"Expenses\" is sum_of_liabilities");
    addDefaultColumn("column \"Income\" is sum_of_assets");
    addDefaultColumn("column \"NetIncome\" is sum_of_assets - sum_of_liabilities");
    addDefaultColumn("column \"Savings\" is savings");
    addDefaultColumn("column \"Month\" is current_month");
    addDefaultColumn("column \"Year\" is current_year");

    // Initialize mortgage-related variables and state
    mort.init();

    System.out.println ("\n\nThe initial symbol table is:");
    symbolTable.allSymbols(new DumpSymbolTableVisitor());

    // This is the catch-all termination date, so that the sim doesn't
    // run forever if the user forgets to declare a STOP event.
    int end_year = 2030; 

    current_month.setValue(start_month.getValue());
    current_year.setValue(start_year.getValue());

    System.out.println ("\n\nStarting the simulation");

    // print table heading
    printColumnTitle();

    // this is used for summing the assets and liabilities
    GetAttributeVisitor attribVisitor = new GetAttributeVisitor();

    // Main loop

    while (current_year.getValue() <= end_year) {
        double year = current_year.getValue();

        while (current_month.getValue() <= 12) {
           double month = current_month.getValue();

           mort.do_processing();

           // Search for events that should be triggered now and 
           // execute their associated statements. Remembers the 
           // names of events that triggers.
           EventVisitor ev = new EventVisitor (year, month);
           doEvents(ev);

           symbolTable.allAttribs(attribVisitor);
           sumOfAssets.setValue(attribVisitor.getAssets());
           sumOfLiabilities.setValue(attribVisitor.getLiabilities());   
           
           savings.setValue(savings.getValue() + 
             sumOfAssets.getValue() - sumOfLiabilities.getValue());

           printColumnValue(ev.getNames());
 
           if (stopSimulation) {
             return;
           }
           current_month.setValue(month + 1.0);
           startup.setValue(0);
        }
        current_month.setValue(1.0);
        current_year.setValue(year + 1.0);
    }
    System.out.println ("Stopping simulation due to date limit");

  }}


  // This is a shortcut for adding a variable to symbol table
  static Symbol addDefaultVariable (String symbolString) {{
    // symbolString has the format <ident> <value>
    Symbol symbol = Symbol.parse(symbolString);

    // check if symbol is in table
    Symbol foundSymbol = Main.symbolTable.findSymbol(symbol.get_varname().toString());
    if (foundSymbol == null) {
      // not in table, so add it
      Main.symbolTable.get_symbol_list().addElement(symbol);
      foundSymbol = symbol;
    }

    return foundSymbol;
  }}

  // This is a shortcut for adding a column to the output
  void addDefaultColumn (String columnString) {{
    // Column = "column" <title> Title [Width] "is" <expr> Expr.
    Column col = Column.parse(columnString);
    get_s().push(col);
  }}



  {{
  // This class encapsulates the mortgage-related computations.
  // The results of the computations are symbols in the symbol table.

  class Mortgage {

    boolean started;
    int     remaining_months;

    Symbol mortgage_rate;
    Symbol mortgage_payment;
    Symbol minimum_percent_down;
    Symbol closing_costs;
    Symbol loan_term;
    Symbol house_price;
    Symbol reserve_savings;
    Symbol term_start;  // corresponds to an event
    Symbol term_end;    // corresponds to an event
    Symbol savings;

    void init() {
      started = false;
      remaining_months = 0;
      house_price          = Main.addDefaultVariable("house_price 200000");
      minimum_percent_down = Main.addDefaultVariable("minimum_percent_down 20");
      closing_costs        = Main.addDefaultVariable("closing_costs 4000");
      reserve_savings      = Main.addDefaultVariable("reserve_savings 10000");
      loan_term            = Main.addDefaultVariable("loan_term 15");
      mortgage_rate        = Main.addDefaultVariable("mortgage_rate 0.090");
      term_start           = Main.addDefaultVariable("term_start 0");
      term_end             = Main.addDefaultVariable("term_end 0");
      mortgage_payment     = Main.addDefaultVariable("mortgage_payment liability 0");
      savings              = Main.symbolTable.findSymbol("savings");
    }

    void do_processing() {
      term_start.setValue(0);  // The user can define events that trigger
      term_end.setValue(0);    // off these symbols.

      if (!started) {
        // determine if we should initiate the loan

        double perc_down     = minimum_percent_down.getValue()/100;
        double upfront_costs = closing_costs.getValue() +
              house_price.getValue() * perc_down;
        if (savings.getValue() >= upfront_costs + reserve_savings.getValue()) {
          // Get that loan!
          double r = mortgage_rate.getValue() / 12;
          double principal = house_price.getValue() * (1-perc_down);
          double y = loan_term.getValue();
          mortgage_payment.setValue((principal*r) / (1 - 1/power((1+r),(int)y*12)));
  
          savings.setValue(savings.getValue() - upfront_costs);
          remaining_months = 12 * (int)y;
          term_start.setValue(1);
          started = true;
        }

      } else {
        // have already started loan
        remaining_months -= 1;
        if (remaining_months == 0) {
          mortgage_payment.setValue(0);
          term_end.setValue(1);
        }        
      }
    }

    // compute base ** exponent
    double power (double base, int exponent) {
      if (exponent <= 0) {
        return 1;
      } else {
        double result = base;
        for (int i=1; i<exponent; i++) {
          result = result * base;
        }
        return result;
      }
    }
  }
  }}
}