using System;
 
namespace DoFactory.GangOfFour.State.RealWorld
{
	/// 

	/// MainApp startup class for Real-World 
	/// State Design Pattern.
	/// 
  class MainApp
  {
	/// 

	/// Entry point into console application.
	/// 
	static void Main()
    {
      // Open a new account
      Account account = new Account("Jim Johnson");
 
      // Apply financial transactions
      account.Deposit(500.0);
      account.Deposit(300.0);
      account.Deposit(550.0);
      account.PayInterest();
      account.Withdraw(2000.00);
      account.Withdraw(1100.00);
 
      // Wait for user
      Console.ReadKey();
    }
  }
 
	/// 

	/// The 'State' abstract class
	/// 
  abstract class State
  {
    protected Account account;
    protected double balance;
 
    protected double interest;
    protected double lowerLimit;
    protected double upperLimit;
 
    // Properties
    public Account Account
    {
      get { return account; }
      set { account = value; }
    }
 
    public double Balance
    {
      get { return balance; }
      set { balance = value; }
    }
 
    public abstract void Deposit(double amount);
    public abstract void Withdraw(double amount);
    public abstract void PayInterest();
  }
 
 
	/// 

	/// A 'ConcreteState' class
	/// 
	/// Red indicates that account is overdrawn 
	/// 
	/// 
  class RedState : State
  {
    private double _serviceFee;
 
    // Constructor
    public RedState(State state)
    {
      this.balance = state.Balance;
      this.account = state.Account;
      Initialize();
    }
 
    private void Initialize()
    {
      // Should come from a datasource
      interest = 0.0;
      lowerLimit = -100.0;
      upperLimit = 0.0;
      _serviceFee = 15.00;
    }
 
    public override void Deposit(double amount)
    {
      balance += amount;
      StateChangeCheck();
    }
 
    public override void Withdraw(double amount)
    {
      amount = amount - _serviceFee;
      Console.WriteLine("No funds available for withdrawal!");
    }
 
    public override void PayInterest()
    {
      // No interest is paid
    }
 
    private void StateChangeCheck()
    {
      if (balance > upperLimit)
      {
        account.State = new SilverState(this);
      }
    }
  }
 
	/// 

	/// A 'ConcreteState' class
	/// 
	/// Silver indicates a non-interest bearing state
	/// 
	/// 
  class SilverState : State
  {
    // Overloaded constructors
    public SilverState(State state) :
      this(state.Balance, state.Account)
    {
    }
 
    public SilverState(double balance, Account account)
    {
      this.balance = balance;
      this.account = account;
      Initialize();
    }
 
    private void Initialize()
    {
      // Should come from a datasource
      interest = 0.0;
      lowerLimit = 0.0;
      upperLimit = 1000.0;
    }
 
    public override void Deposit(double amount)
    {
      balance += amount;
      StateChangeCheck();
    }
 
    public override void Withdraw(double amount)
    {
      balance -= amount;
      StateChangeCheck();
    }
 
    public override void PayInterest()
    {
      balance += interest * balance;
      StateChangeCheck();
    }
 
    private void StateChangeCheck()
    {
      if (balance < lowerLimit)
      {
        account.State = new RedState(this);
      }
      else if (balance > upperLimit)
      {
        account.State = new GoldState(this);
      }
    }
  }
 
	/// 

	/// A 'ConcreteState' class
	/// 
	/// Gold indicates an interest bearing state
	/// 
	/// 
  class GoldState : State
  {
    // Overloaded constructors
    public GoldState(State state) : this(state.Balance, state.Account)
    {
    }
 
    public GoldState(double balance, Account account)
    {
      this.balance = balance;
      this.account = account;
      Initialize();
    }
 
    private void Initialize()
    {
      // Should come from a database
      interest = 0.05;
      lowerLimit = 1000.0;
      upperLimit = 10000000.0;
    }
 
    public override void Deposit(double amount)
    {
      balance += amount;
      StateChangeCheck();
    }
 
    public override void Withdraw(double amount)
    {
      balance -= amount;
      StateChangeCheck();
    }
 
    public override void PayInterest()
    {
      balance += interest * balance;
      StateChangeCheck();
    }
 
    private void StateChangeCheck()
    {
      if (balance < 0.0)
      {
        account.State = new RedState(this);
      }
      else if (balance < lowerLimit)
      {
        account.State = new SilverState(this);
      }
    }
  }
 
	/// 

	/// The 'Context' class
	/// 
  class Account
  {
    private State _state;
    private string _owner;
 
    // Constructor
    public Account(string owner)
    {
      // New accounts are 'Silver' by default
      this._owner = owner;
      this._state = new SilverState(0.0, this);
    }
 
    // Properties
    public double Balance
    {
      get { return _state.Balance; }
    }
 
    public State State
    {
      get { return _state; }
      set { _state = value; }
    }
 
    public void Deposit(double amount)
    {
      _state.Deposit(amount);
      Console.WriteLine("Deposited {0:C} --- ", amount);
      Console.WriteLine(" Balance = {0:C}", this.Balance);
      Console.WriteLine(" Status = {0}", this.State.GetType().Name);
      Console.WriteLine("");
    }
 
    public void Withdraw(double amount)
    {
      _state.Withdraw(amount);
      Console.WriteLine("Withdrew {0:C} --- ", amount);
      Console.WriteLine(" Balance = {0:C}", this.Balance);
      Console.WriteLine(" Status = {0}\n", this.State.GetType().Name);
    }
 
    public void PayInterest()
    {
      _state.PayInterest();
      Console.WriteLine("Interest Paid --- ");
      Console.WriteLine(" Balance = {0:C}", this.Balance);
      Console.WriteLine(" Status = {0}\n", this.State.GetType().Name);
    }
  }
}