(ns unheard.theory
  (:require [missionary.core :as m]
            [clojure.set :refer [union]]))

(defn note [>clock start duration >value]
  (m/cp
    (let [[c v] (m/?< (m/latest vector >clock >value))]
      (if (<= start c (dec (+ start duration))) 
        #{v}
        #{}))))

(defn poly [& notes]
  (m/signal
   (m/cp
     (apply union (m/?< (apply m/latest vector notes))))))

;; TODO: Group could actually wrap note, rather than using explicitly
;; WIll introduce a lot of GC churn, though
(defn group
  [clock start end content]
  (m/cp
   (let [content (m/signal content)]
     (if (m/?< (m/latest #(<= start % end) clock))
       (m/?< content)
       (m/amb #{})))))

;; TODO:
;; - Note literals turn into numbers
;; - Represent keyboard as byte array of shorts
;; - play a note increments, stop a note decrements
;; - Multiple instruments
;; - Mapping inputs to vars
;; - Inputs get declared at the top of a track
;; - Devices get mapped to declared inputs
;; - Notion of scenes that change mapping of inputs to vars
;; - Loops