module ParasitemiaUI.PPICalculator

open System
open System.Windows

open ParasitemiaUIControls
open ParasitemiaCore.Types
open ParasitemiaCore.UnitsOfMeasure

open Types

let showWindow (parent : Window) : int option =
    let win = PPICalculatorWindow ()
    win.Owner <- parent
    win.Left <- parent.Left + parent.ActualWidth / 2. - win.Width / 2.
    win.Top <- parent.Top + parent.ActualHeight / 2. - win.Height / 2.

    for size in Utils.sensorSizes do
        win.cmbSensorSize.Items.Add (size) |> ignore
    win.cmbSensorSize.SelectedIndex <- 0

    let resolution (w_p : float<px>) (w_mm : float<mm>) (zoom : float) : float<ppi> =
        w_p * zoom / mmToInch w_mm

    let updateCurrentResolution () =
        let { w = w; h = h } = win.cmbSensorSize.SelectedValue :?> SensorSize
        let ratio = h / w

        let parseDouble (txt : string) (errorMess : string) = match Double.TryParse (txt) with true, value -> Success value | _ -> Fail errorMess

        match
            (result {
                let! sensorResolution = parseDouble win.txtSensorResolution.Text "The sensor resolution is not valid"
                let! zoom = parseDouble win.txtZoom.Text "The zoom is not valid"
                let wPixel = 1.<px> * sqrt (sensorResolution * 1e6 / ratio)
                return! Success (float <| resolution wPixel w zoom)
            }) with
        | Success res -> win.txtImageResolution.Text <- int (res / 1000.) * 1000 |> string
        | Fail mess -> win.txtImageResolution.Text <- mess

    win.butCancel.Click.AddHandler (fun obj args -> win.DialogResult <- Nullable<bool> (false); win.Close ())
    win.butOK.Click.AddHandler (fun obj args -> win.DialogResult <- Nullable<bool> (true); win.Close ())

    win.cmbSensorSize.SelectionChanged.AddHandler (fun obj arg -> updateCurrentResolution ())
    win.txtSensorResolution.TextChanged.AddHandler (fun obj arg -> updateCurrentResolution ())
    win.txtZoom.TextChanged.AddHandler (fun obj arg -> updateCurrentResolution ())

    let result = win.ShowDialog ()
    if result.HasValue && result.Value then
        match Int32.TryParse win.txtImageResolution.Text with
        | true, res -> Some res
        | _ -> None
    else
        None