edx-module4.fs

open System
open System.IO

let gravity = 9.81

let angleOfReach speed distance = 0.5 * Math.Asin((gravity * distance) / Math.Pow(speed, 2.0))

let distanceTravelled speed angle = Math.Pow(speed, 2.0) * Math.Sin(2.0 * angle) / gravity

let angle x y = Math.Atan(y / x)

type Entity =
    { X : float
      Y : float
      Speed : float
      Distance : float
      Name : string }

type Result = 
    { DistanceTravelled : double
      Hits : bool
      ActualAngle : double
      RequiredAngle : double }

let calcResult entity =
    let actualAngle = angle entity.X entity.Y
    let actualDistance = distanceTravelled entity.Speed actualAngle
    let requiredAngle = angleOfReach entity.Speed entity.Distance
    { DistanceTravelled = actualDistance
      Hits = actualDistance = entity.Distance
      ActualAngle = actualAngle
      RequiredAngle = requiredAngle }

let GetFile =
    Console.Write("Enter the full path to the name of the input file: ")
    Console.ReadLine()

[<EntryPoint>]    
let main argv =
    try
        use input =
            new StreamReader(match argv.Length with
                             | 0 -> GetFile    
                             | _ -> argv.[0])    

        let entities =
            [ while not input.EndOfStream do
                  let raw = input.ReadLine()
                  let values = raw.Split(',')
                  yield { X = float values.[0]
                          Y = float values.[1]
                          Speed = float values.[2]
                          Distance = float values.[3]
                          Name = values.[4] } ]

        let tuples =             
            seq {
                for entity in entities ->
                    (entity, calcResult(entity))
            }

        Console.WriteLine("The results are: ")
        for (entity, result) in tuples do
            match result with
            | {Hits = true} -> Console.WriteLine("{0} hits", entity.Name)    
            | _ -> Console.WriteLine("{0} misses, actual angle: {1}, required angle: {2}", entity.Name, result.ActualAngle, result.RequiredAngle)    
        Console.ReadKey()
        0

    with
    | :? System.IO.FileNotFoundException ->
        Console.Write("File Not Found. Press a key to exit")
        Console.ReadKey()
        -1
    | _ ->
        Console.Write("Something else happened")
        Console.ReadKey()
        -1