module ParasitemiaUI.DPICalculator

open System
open System.Windows
open System.Windows.Media
open System.Windows.Markup
open System.Windows.Shapes
open System.Windows.Controls
open System.Diagnostics

open ParasitemiaCore.UnitsOfMeasure
open ParasitemiaCore.Types

type SensorSize = {
    w: float<mm>
    h: float<mm>
    txt: string } with
    override this.ToString () =
        sprintf "%g mm × %g mm%s" this.w this.h (if this.txt = "" then "" else " (" + this.txt + ")")

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

    let sensorSizes = [
        { w = 5.76<mm>; h = 4.29<mm>; txt = "1/2.5″" }
        { w = 7.6<mm>;  h = 5.7<mm>;  txt = "1/1.7″" }
        { w = 8.6<mm>;  h = 6.6<mm>;  txt = "2/3″" }
        { w = 13.2<mm>; h = 8.8<mm>;  txt = "1″" }
        { w = 17.3<mm>; h = 13.<mm>;  txt = "" }
        { w = 20.7<mm>; h = 13.8<mm>; txt = "" }
        { w = 22.2<mm>; h = 14.8<mm>; txt = "" }
        { w = 23.6<mm>; h = 15.7<mm>; txt = "" }
        { w = 28.7<mm>; h = 19.<mm>;  txt = "" }
        { w = 28.7<mm>; h = 19.<mm>;  txt = "" } ]

    for size in 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 errorMess = 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).ToString()
        | Fail mess -> win.txtImageResolution.Text <- mess

    win.butCancel.Click.AddHandler(fun obj args -> win.Root.DialogResult <- Nullable<bool>(false); win.Root.Close())
    win.butOK.Click.AddHandler(fun obj args -> win.Root.DialogResult <- Nullable<bool>(true); win.Root.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.Root.ShowDialog()
    if result.HasValue && result.Value
    then
        match Int32.TryParse win.txtImageResolution.Text with
        | true, res -> Some res
        | _ -> None
    else
        None