Edx - F# - Patterns

// Learn more about F# at http://fsharp.org
// See the 'F# Tutorial' project for more help.

// Link to Solution can be found here - http://xxx

type MyRecord = {
        IP : string
        MAC : string
        FriendlyName : string
        ID : int }

type GunState =
    {
        X: double
        Y: double
        Speed: double
        ExpectedDistance: double
        Name: string
    }

type ShotResult =
| ShotSuccess
| ShotFailure of double
| ShotImpossible

type GunResult =
    {
        Name: string
        Result: ShotResult
    }

open System
open System.IO

[<EntryPoint>]
let main argv =

    // Koan

//    type MyRecord =
//        { IP : string
//          MAC : string
//          FriendlyName : string
//          ID : int }
//
//    let IsMatchByName record1 name =
//        match record with
//        | { FriendlyName = nameFound; ID = _; IP = _ } if nameFound = name yield Some((id,ip))
//        | _ -> None
//
//    let checkmatch input =
//        match input with
//        | x, y -> printfn "%A" x
//        | None -> printfn "%A" "Sorry no match"

    let IsMatchByName record name =
        match record with
        | { FriendlyName = nameFound; ID = _; IP = _ } -> if nameFound = name then Some((record.ID, record.IP))
                                                          else None
        | _ -> None

    let checkmatch input =
        match input with
        | Some((x, y)) -> printfn "%A" x
        | None -> printfn "%A" "Sorry no match"

//    let record = {IP ="127.0.0.1"; MAC ="FF:FF:FF:FF:FF:FF"; FriendlyName = "Home";ID = 229229}
    let record = {IP = "10.1.1.1"; MAC = "FF:FF:FF:FF:FF:FF"; FriendlyName = "ServerFailure";ID = 0}

    printf "Enter name "
    let name = Console.ReadLine()

    let m = IsMatchByName record name
    checkmatch m

    // Problem

    let angle_of_reach d v =
        let x = 9.81 * d / Math.Pow(v, 2.0)
        if Math.Abs(x) <= 1.0 then
            Some (0.5 * Math.Asin(x))
        else
            None
    let distance_travelled angle v = Math.Pow(v, 2.0) * Math.Sin(2.0 * angle) / 9.81
    let angle x y = Math.Atan(y / x)

    let GetFile =
        Console.Write("Enter the full path to the name of the input file: ")
        Console.ReadLine()
    try
        use input =
            new StreamReader(match argv.Length with
                             | 0 -> GetFile
                             | _ -> argv.[0])
        // By using sequences file and memory access will be efficient
        let data = seq {while not input.EndOfStream do
                            let raw = input.ReadLine()
                            let values = raw.Split(',')
                            yield {
                                    X = double values.[0]
                                    Y = double values.[1]
                                    Speed = double values.[2]
                                    ExpectedDistance = double values.[3]
                                    Name = values.[4]
                                }
                        }
        let results = seq {
                            // Correction factor to deal with
                            // accumulated floating point errors
                            let epsilon = 0.005
                            for gun in data do
                                let angle = Math.Atan2(gun.Y, gun.X)
                                let d = distance_travelled angle gun.Speed
                                if Math.Abs(d - gun.ExpectedDistance) < epsilon then
                                    yield {
                                            Name = gun.Name
                                            Result = ShotSuccess
                                          }
                                else
                                    yield {
                                        Name = gun.Name
                                        Result = match angle_of_reach gun.ExpectedDistance gun.Speed with
                                                 | Some expected_angle -> ShotFailure expected_angle
                                                 | None                -> ShotImpossible
                                        }
                            }
        for r in results do
            let msg =
                match r.Result with
                | ShotFailure expected_angle -> "failed since angle should be " + expected_angle.ToString()
                | ShotSuccess _                       -> "hits the target"
                | ShotImpossible                      -> "target is too far"
            printfn "Gun %s %s" r.Name msg
        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