namespace AsciiWaveRenderer
open System
open NAudio.Wave
open FSharp

module private AsciiWaveRenderer =
    let garbageSeq =
        let rand = new Random()
        let b = Array.zeroCreate 4
        Seq.initInfinite (fun _ ->
            rand.NextBytes b
            BitConverter.ToSingle (b, 0)
        )
        |> Seq.cache

type AsciiWaveRenderer =
    static member RenderSamples (buffer: float32[], waveFormat: WaveFormat, ?graphHeight) =
        let h = defaultArg graphHeight 10

        let channels = [|
            for ci in 0 .. waveFormat.Channels - 1 -> [|
                for si in 0 .. (buffer.Length / waveFormat.Channels) - 1 ->
                    let i = (si * waveFormat.Channels) + ci
                    buffer.[i]
            |]
        |]

        let cs =
            channels
            |> Array.map (fun samples ->
                let halfh = h/2
                let halfhf = float32 halfh
                [|
                    for hi in halfh .. -1 .. -halfh -> String([|
                        for si in 0 .. samples.Length - 1 ->
                            if hi = (int (round (samples.[si] * halfhf))) then '*' else ' '
                    |])
                |]
            )

        cs

    static member ReadAndRenderSamples ((sampleProvider: ISampleProvider), nSamples, ?buffSize, ?buffOffset, ?graphHeight, ?fillBufferWithGarbage) =
        let count = nSamples * sampleProvider.WaveFormat.Channels
        let buff = Array.zeroCreate<float32> (defaultArg buffSize count)
        let garbage = AsciiWaveRenderer.garbageSeq |> Seq.take buff.Length |> Seq.toArray
        garbage.CopyTo (buff, 0)
        let count' = sampleProvider.Read (buff, defaultArg buffOffset 0, count)
        
        AsciiWaveRenderer.RenderSamples (buff, sampleProvider.WaveFormat, ?graphHeight = graphHeight)

    static member MakeGarbageBufferForSampleReading ((sampleProvider: ISampleProvider), nSamples, ?buffSize) =
        let count = nSamples * sampleProvider.WaveFormat.Channels
        let buff = Array.zeroCreate<float32> (defaultArg buffSize count)
        let garbage = AsciiWaveRenderer.garbageSeq |> Seq.take buff.Length |> Seq.toArray
        garbage.CopyTo (buff, 0)
        
        buff