Toggle midi on and off

2 files changed, 125 insertions, 39 deletions

diff --git a/src/.main.clj.swp b/src/.main.clj.swp
new file mode 100644
index 0000000..b91b1b6
--- /dev/null
+++ b/src/.main.clj.swp
diff --git a/src/main.clj b/src/main.clj
index eb0e2d2..7674cc1 100644
--- a/src/main.clj
+++ b/src/main.clj
@@ -2,30 +2,56 @@
   (:require [missionary.core :as m]
             [clojure.set :refer [difference union]]))
 
+(def >portal
+  (m/signal
+   (m/ap
+    (try
+      (m/?<
+       (m/observe
+        (fn [cb]
+          ((m/via m/blk ((requiring-resolve 'portal.api/open))) {} {})
+          (cb :open)
+          (fn []
+            ((m/via m/blk
+                    ((requiring-resolve 'portal.api/close))
+                    ((requiring-resolve 'portal.api/clear))) {} {})))))
+      (catch missionary.Cancelled _
+        (m/amb))))))
+
 ;; How many times per second are output continuous values sampled and turned
 ;; into events?
 (def sample-rate (atom 30))
 
-(defn set-sample-rate [v] (reset! sample-rate v))
+(defn set-sample-rate
+  "Change the output sample rate."
+  [v]
+  (reset! sample-rate v))
 
-;; Temporary atom to explore the concept of note state as a continuous value
 (def notes-on (atom #{}))
 (def >notes-on (m/signal (m/watch notes-on)))
 
-(def playback-enabled? (atom true))
+(def midi-enabled? (atom true))
 
-(defn enable-playback []
-  (reset! playback-enabled? true))
+(defn enable-midi
+  "Enable midi out."
+  []
+  (reset! midi-enabled? true))
 
-(defn disable-playback []
-  (reset! playback-enabled? false))
+(defn disable-midi
+  "Stop all active notes and disable midi out."
+  []
+  (reset! midi-enabled? false))
 
-(defn play-notes [& v]
-  (when @playback-enabled?
+(defn play-notes
+  "Play notes."
+  [& v]
+  (when @midi-enabled?
     (swap! notes-on union (into #{} v))))
 
-(defn stop-notes [& v]
-  (when @playback-enabled?
+(defn stop-notes
+  "Stop notes."
+  [& v]
+  (when @midi-enabled?
     (swap! notes-on difference (into #{} v))))
 
 (def clock
@@ -41,8 +67,9 @@
       :tick
       (recur)))))
 
-;; convert the continuous time >notes-on flow to a series of discrete midi note on and off events
 (def output
+  "Convert the continuous time >notes-on flow to a series of discrete midi note
+  on and off events."
   (m/eduction
    (comp (remove #(= (select-keys % [:note-on :note-off]) {:note-on #{} :note-off #{}}))
          (dedupe))
@@ -61,19 +88,22 @@
                   >notes-on
                   clock))))
 
-(def toggle-playback
+(def process-midi-toggle-events
+  "Listen for changes on midi-enabled?
+  When playback is disabled, send a note-off event for each active note
+  and then zero out notes-on."
   (m/ap
-   (let [local-playback-enabled? (atom nil)
+   (let [local-midi-enabled? (atom nil)
          local-active (atom #{})
          [tag value] (m/amb=
-                      [:playback-enabled? (m/?< (m/watch playback-enabled?))]
+                      [:midi-enabled? (m/?< (m/watch midi-enabled?))]
                       [:note-event (m/?< output)])]
      (case tag
-       :playback-enabled?
-       (let [playback-enabled? value
+       :midi-enabled?
+       (let [midi-enabled? value
              active @local-active]
-         (reset! local-playback-enabled? playback-enabled?)
-         (if (not playback-enabled?)
+         (reset! local-midi-enabled? midi-enabled?)
+         (if (not midi-enabled?)
            (do
              (reset! notes-on #{})
              (reset! local-active #{})
@@ -85,31 +115,87 @@
        (let [{:keys [active]
               :as note-event} value]
          (reset! local-active active)
-         (if @local-playback-enabled?
+         (if @local-midi-enabled?
            note-event
            (m/amb)))))))
 
-(defonce process (atom nil))
-
-(defn start-process []
-  (when (not @process)
-    (reset! process
-            (do (enable-playback)
-                ((m/reduce prn toggle-playback) {} {})))))
+(defonce engine (atom nil))
 
-(defn stop-process []
-  (disable-playback)
-  (@process)
-  (reset! process nil))
+(def set->midi-events
+  "Convert set representation of notes to midi events"
+  (m/ap
+   (let [{:keys [note-on note-off]} (m/?< process-midi-toggle-events)]
+     (m/amb=
+      (loop [notes note-on]
+        (if (first notes)
+          (m/amb [:note-on (first notes)]
+                 (recur (rest notes)))
+          (m/amb)))
+      (loop [notes note-off]
+        (if (first notes)
+          (m/amb [:note-off (first notes)]
+                 (recur (rest notes)))
+          (m/amb)))))))
+
+(def enable-portal-submission? (atom false))
+(def >enable-portal-submission? (m/watch enable-portal-submission?))
+
+(defn enable-portal-submission []
+  (reset! enable-portal-submission? true))
+
+(defn disable-portal-submission []
+  (reset! enable-portal-submission? false))
+
+(def tap-flow
+  (m/ap
+   (let [local-enable-portal-submission? (atom nil)
+         [tag value]
+         (m/amb= [:enable-portal-submission? (m/?< >enable-portal-submission?)]
+                 [:event (m/?< set->midi-events)])]
+     (case tag
+       :enable-portal-submission?
+       (do
+         (reset! local-enable-portal-submission? value)
+         (when value
+           (m/?< >portal))
+         (m/amb))
+       :event
+       (do
+         (when @local-enable-portal-submission?
+           (m/? (m/via m/blk ((requiring-resolve 'portal.api/submit) value))))
+         value)))))
+
+(defn start-engine
+  "Start playback engine."
+  []
+  (when (not @engine)
+    (reset! engine
+            (do (enable-midi)
+                ((m/reduce prn tap-flow) {} {})))))
+
+(defn stop-engine
+  "Stop playback engine."
+  []
+  (disable-midi)
+  (when @engine
+    (@engine)
+    (reset! engine nil)))
 
 (comment
-  (start-process)
-  (stop-process)
-  (set-sample-rate 1)
-  (play-notes 1 2 3 4 5)
-  (stop-notes 3)
+  (start-engine)
+
   (play-notes 1 2 3 4 5)
-  (stop-notes 1 2 3 4 5)
+  (stop-notes 4 5)
+  (enable-portal-submission)
+  (play-notes 1 2 3 4)
+
+  (disable-midi)
+  (play-notes 1 2 3 4)
+  (disable-portal-submission)
+
+  (enable-midi)
+  (play-notes 1 2 3 4)
+  (play-notes 6 7 8)
+  (play-notes 100)
 
-  (enable-playback)
-  (disable-playback))
+  (stop-engine))