/*
 * STATE DERIVED STATUS
 * - What is status?
 */

using System;

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Creating a new bug report.");

        var bug = new BugReportContext("Sally Tester");

        Console.WriteLine(bug.Status);

        bug.Resolve(ResolvedReason.Fixed);

        Console.WriteLine(bug.Status);

        bug.Close(ClosedReason.Verified);

        Console.WriteLine(bug.Status);

        Console.WriteLine("Creating a new bug report.");

        // Second round...

        bug = new BugReportContext("Sally Tester");

        Console.WriteLine(bug.Status);

        bug.Resolve(ResolvedReason.NotABug);

        Console.WriteLine(bug.Status);

        Console.WriteLine("Reopening the bug report.");

        bug.Reopen();

        Console.WriteLine(bug.Status);

        bug.Resolve(ResolvedReason.Fixed);

        Console.WriteLine(bug.Status);

        bug.Close(ClosedReason.Verified);

        Console.WriteLine(bug.Status);
    }
}

public enum ResolvedReason
{
    Fixed,
    NotABug,
    Duplicate
}

public enum ClosedReason
{
    Verified,
    NotABug,
    Duplicate
}

public class BugReportContext
{
    public BugReportContext(string submitter)
    {
        this.Submitter = submitter;
        this.CurrentState = new OpenState();
    }

    public IState CurrentState { get; set; }

    public ResolvedReason? ResolvedReason { get; set; }

    public ClosedReason? ClosedReason { get; set; }

    public string Status
    {
        get
        {
            return this.CurrentState.Status(this);
        }
    }

    public string Owner { get; set; }

    public string Submitter { get; set; }

    public void Assign(string owner)
    {
        this.Owner = owner;
    }

    public void Resolve(ResolvedReason reason)
    {
        this.CurrentState.Resolve(this, reason);
    }

    public void Reopen()
    {
        this.CurrentState.Reopen(this);
    }

    public void Close(ClosedReason reason)
    {
        this.CurrentState.Close(this, reason);
    }
}

public interface IState
{
    void Resolve(BugReportContext context, ResolvedReason reason);
    void Reopen(BugReportContext context);
    void Close(BugReportContext context, ClosedReason reason);
    string Status(BugReportContext context);
}

public class OpenState : IState
{
    public void Resolve(BugReportContext context, ResolvedReason reason)
    {
        context.Owner = context.Submitter;
        context.ResolvedReason = reason;
        context.CurrentState = new ResolvedState();
    }

    public void Reopen(BugReportContext context)
    {
        return;
    }

    public void Close(BugReportContext context, ClosedReason reason)
    {
        if (reason == ClosedReason.Verified)
        {
            Console.WriteLine("You cannot verify and close a bug report that has not been resolved!");
            return;
        }

        context.ClosedReason = reason;
        context.CurrentState = new ResolvedState();
    }

    public string Status(BugReportContext context)
    {
        if (string.IsNullOrEmpty(context.Owner))
        {
            return "The bug report is open and unassigned.";
        }

        return string.Format("The bug report is open and assigned to {0}.", context.Owner);
    }
}

public class ResolvedState : IState
{
    public void Resolve(BugReportContext context, ResolvedReason reason)
    {
        return;
    }

    public void Reopen(BugReportContext context)
    {
        context.Owner = null;
        context.ResolvedReason = null;
        context.CurrentState = new OpenState();
    }

    public void Close(BugReportContext context, ClosedReason reason)
    {
        if (reason == ClosedReason.Verified && context.ResolvedReason != ResolvedReason.Fixed)
        {
            Console.WriteLine("You cannot verify and close a bug report that has not been fixed!");
            return;
        }

        context.ClosedReason = reason;
        context.CurrentState = new ClosedState();
    }

    public string Status(BugReportContext context)
    {
        return string.Format("The bug report is resolved as {0} and assigned to {0}.", context.ResolvedReason, context.Owner);
    }
}

public class ClosedState : IState
{
    public void Resolve(BugReportContext context, ResolvedReason reason)
    {
        Console.WriteLine("You cannot resolve a bug report that has been closed!");
    }

    public void Reopen(BugReportContext context)
    {
        context.ResolvedReason = null;
        context.ClosedReason = null;
        context.CurrentState = new OpenState();
    }

    public void Close(BugReportContext context, ClosedReason reason)
    {
        return;
    }

    public string Status(BugReportContext context)
    {
        return string.Format("The bug report is closed because it was {0}.", context.ClosedReason);
    }
}