(ns unheard.instrument.minilab3
  (:require [missionary.core :as m])
  (:import [javax.sound.midi ShortMessage]))

(def matching-control-change
  (filter (fn [^ShortMessage m] (= (.getCommand m) ShortMessage/CONTROL_CHANGE))))

(defn matching-channel [ch]
  (filter (fn [^ShortMessage m] (= (.getChannel m) ch))))

(defn matching-data-1 [d1]
  (filter (fn [^ShortMessage m] (= (.getData1 m) d1))))

(def get-data-2
  (map (fn [^ShortMessage m] (.getData2 m))))

(defn matching-control
  "Returns a function filtering flow of ShortMessage `f` down to control
  change messages where channel is `ch` and data-1 is `k`, and then returning
  a signal of values for data-2. Initial value of signal will be `init`.

  Though a little esoteric sounding, this is actually quite useful.
  The signal returned by this is useful for representing knobs, faders, and
  pads on a midi controller.
  "
  [init ch k]
  (fn [f]
    (m/signal
     (m/reductions {} init
                   (m/eduction
                    (comp
                     matching-control-change
                     (matching-channel ch)
                     (matching-data-1 k)
                     get-data-2)
                    f)))))

(def minilab3
  {:knob
   {1 (matching-control 0 0 74)
    2 (matching-control 0 0 71)
    3 (matching-control 0 0 76)
    4 (matching-control 0 0 77)
    5 (matching-control 0 0 93)
    6 (matching-control 0 0 18)
    7 (matching-control 0 0 19)
    8 (matching-control 0 0 16)}
   :fader
   {1 (matching-control 0 0 82)
    2 (matching-control 0 0 83)
    3 (matching-control 0 0 85)
    4 (matching-control 0 0 17)}
   :pad
   {1 (matching-control 0 9 36)
    2 (matching-control 0 9 37)
    3 (matching-control 0 9 38)
    4 (matching-control 0 9 39)
    5 (matching-control 0 9 40)
    6 (matching-control 0 9 41)
    7 (matching-control 0 9 42)
    8 (matching-control 0 9 43)}})