psi.fs

open System

type Cylinder = 
    | FourFourEight
    | SixSixTwelve
    | ThreeThreeSix
    | TwoTwoTwo

type CylinderMeasurement = 
    { WidthA: float
      WidthB: float
      Height: float
      Id: int
      LoadPounds: int
      Psi: double
      Cylinder: Cylinder }
    
module calcPsi = 
    // Update the PSI, and return the original cylinder information.
    let calculatePsi cyl = 
        let wa, wb, h = cyl.WidthA, cyl.WidthB, cyl.Height
        
        let basearea = 
            match cyl.Cylinder with
            | FourFourEight -> Math.PI * ((wa + wb) / 2.) / 2. * ((wa + wb) / 2. / 2.)
            | SixSixTwelve -> Math.PI * ((wa + wb) / 2.) / 2. * ((wa + wb) / 2. / 2.)
            | ThreeThreeSix -> wa * wb
            | TwoTwoTwo -> ((wa + wb) / 2.) * ((wa + wb) / 2.)
        
        let ratio = 
            if (h > 0. && (wa + wb > 0.)) 
            then Some(Math.Round(h / ((wa + wb) / 2.), 2))
            else None
        
        let tFactor = 
            match ratio with
            | Some r when r > 1.94 || r < 1. -> 1.
            | _ -> 0.979

        { cyl with Psi = Math.Round((float) cyl.LoadPounds / basearea / 1000. * tFactor, 2) * 1000. }
    
    let getPsi = Array.Parallel.map calculatePsi