Statement

This exercise is a port from the Rectoring 2 book exercise that can be found into the free chapter.

Background

Imagine a company of theatrical players who go out to various events performing plays. Typically, a customer will request a few plays and the company charges them based on the size of the audience and the kind of play they perform. There are currently two kinds of plays that the company performs: tragedies and comedies. As well as providing a bill for the performance, the company gives its customers “volume credits” which they can use for discounts on future performances—think of it as a customer loyalty mechanism. The performers store data about their plays in a simple JSON file that looks something like this:

// plays.json…

{
  "hamlet": {"name": "Hamlet", "type": "tragedy"},
  "as-like": {"name": "As You Like It", "type": "comedy"},
  "othello": {"name": "Othello", "type": "tragedy"}
}

The data for their bills also comes in a JSON file:

// invoices.json…

[
  {
    "customer": "BigCo",
    "performances": [
      {
        "playID": "hamlet",
        "audience": 55
      },
      {
        "playID": "as-like",
        "audience": 35
      },
      {
        "playID": "othello",
        "audience": 40
      }
    ]
  }
]

The code found in PerformanceBiller.Statement class will create the following output:

Statement for BigCo
 Hamlet: $650.00 (55 seats)
 As You Like It: $580.00 (35 seats)
 Othello: $500.00 (40 seats)
Amount owed is $1,730.00
You earned 47 credits

And the unit test in PerformanceBiller.Tests.StatementTests validates this output.

Exercise

For this exercise, we want you to refactor the PerformanceBiller.Statement in order to make its code cleaner. You can make use of the best practices of OOP, Clean Code and Solid Priciples.