// [snippet:Assembly references for FSI]
// We can use the kRPC C# client library in F#.

#r @"mscorlib"
#r @"System.Runtime" // in my GAC
#r @"DLLs/Google.Protobuf.dll" // from https://www.nuget.org/packages/Google.Protobuf
#r @"DLLs/KRPC.Client.dll" // from kRPC 0.2.1 (in the client folder)
// [/snippet]


// [snippet:Connecting to the Server]
let connection = new KRPC.Client.Connection (name= "FSI Example")
// [/snippet]


// [snippet:Interacting with the Server (version information)]
open KRPC.Client.Services.KRPC
do printfn "Version: %A." (connection.KRPC().GetStatus().Version)
// [/snippet]


// [snippet:Interacting with the Server (name of active vessel)]
open KRPC.Client.Services.SpaceCenter
let spacecenter = connection.SpaceCenter ()
let vessel = spacecenter.ActiveVessel
do printfn "Name of vessel: %A." (vessel.Name)
// [/snippet]


// [snippet:Streaming Data from the Server (straight)]
let refframe = vessel.Orbit.Body.ReferenceFrame

/// Calculate Kerbin altitude in meters.
/// Note: Assumes the reference frame is Kerbin.
let altOfPos (x,y,z) =
  sqrt( x*x + y*y + z*z ) - 600000.

let pos0 = vessel.Position refframe

do printfn "Altitude of position: %.0f." (altOfPos pos0)
// [/snippet]


// [snippet:Streaming Data from the Server (lambda)]
open System.Threading
open System.Linq.Expressions
open Microsoft.FSharp.Linq.RuntimeHelpers.LeafExpressionConverter

let positionstream: KRPC.Client.Stream<float*float*float> =
    let quotation = <@ vessel.Position refframe @>
    let body =  quotation |> QuotationToExpression
    let lambda = Expression.Lambda(body, Seq.empty)
    connection.AddStream lambda

let getAltitude () =
    positionstream.Get () |> altOfPos

let writeAltitude obj =
    do printfn "Altitude: %7.1f m." (getAltitude ())

do writeAltitude ()

let myTimer = new Timer (new TimerCallback (writeAltitude), (), 5000, 2500)
// do myTimer.Dispose ()  // dispose will kill the timer
// [/snippet]