type SchemeType = { Value: decimal; Rate: decimal }

module ITax =
    let relu = max 0m

    let calc scheme x =
        let rec calcRecursive scheme agg =
            match scheme with
            | [ y ] -> agg + (relu ((x - y.Value) * y.Rate))
            | lb :: ub :: rest ->
                if x <= ub.Value then
                    agg + (relu ((x - lb.Value) * lb.Rate))
                else
                    calcRecursive (ub :: rest) (agg + (relu ((ub.Value - lb.Value) * lb.Rate)))
            | _ -> agg

        (calcRecursive (scheme |> List.sortBy (fun x -> x.Value)) 0m)
        / 100m

let tryDecimal x =
    try
        x |> decimal |> Some
    with _ -> None

[<EntryPoint>]
let main argv =
    let scheme =
        [ { Value = 2_50_000m; Rate = 5m }
          { Value = 5_00_000m; Rate = 10m }
          { Value = 7_50_000m; Rate = 15m }
          { Value = 10_00_000m; Rate = 20m }
          { Value = 12_50_000m; Rate = 25m }
          { Value = 15_00_000m; Rate = 30m } ]

    let incomeTaxCalculator = ITax.calc scheme

    argv
    |> Seq.choose tryDecimal
    |> Seq.iter (fun x -> printfn "Income tax for ammount- Rs. %.3f = Rs. %.3f Only/-" x (x |> incomeTaxCalculator))

    0