open System
open System.IO
open FSharp.Charting

let group = [|
    [|1.0; 1.1|];
    [|1.0; 1.0|];
    [|0.0; 0.0|];
    [|0.0; 0.1|]; |]

let labels = [| "A"; "A"; "B"; "B" |]

let inline last (arr:_[]) = arr.[arr.Length - 1]

let vecDist a b =
    Array.map2 (fun x1 x2 -> (x1 - x2) ** 2.0) a b
    |> Array.sum
    |> sqrt


let classify0 inX dataSet labels k =
    dataSet
    |> Array.map (fun item -> vecDist item inX)
    |> Array.zip labels
    |> Array.sortBy snd
    |> Array.toSeq
    |> Seq.take k
    |> Seq.groupBy fst
    |> Seq.maxBy (fun g -> Seq.length (snd g))

let fileToMatrix fileName =
    let processEntry (s: string) =
        let elems = s.Trim().Split '\t'
        let nums = elems.[0..2] |> Array.map System.Double.Parse
        let label = last elems
        (nums, label)

    File.ReadAllLines fileName
    |> Array.map processEntry
    |> Array.unzip


let display data labels =
    let charts =
        Array.zip data labels
        |> Array.groupBy snd
        |> Array.map (fun group ->
                        fst group, snd group
                                    |> Array.map fst
                                    |> Array.map (fun (nums : double[]) -> nums.[0], nums.[1]))
        |> Array.map (fun series -> Chart.Point(snd series, Name = (fst series)).WithLegend())
        |> Array.toSeq
        |> Chart.Combine

    use form = new System.Windows.Forms.Form(Width=400, Height=300, Visible=true, Text="Hello charting")
    charts.ShowChart() |> ignore
    System.Windows.Forms.Application.Run(form)


[<EntryPoint>]
let main argv =
    let x = [| 0.0; 0.0 |]
    let y = [| 3.0; 4.0; 5.0 |]
    let k = 3

    let r = classify0 x group labels 3

    printfn "%A" r

    let bData, bLabels = fileToMatrix "datingTestSet.txt"

    display bData bLabels |> ignore

    printfn "result: %A" (classify0 y bData bLabels k)

    0 // return an integer exit code