Add current playlist, next and previous

Also reuse audio element so slippery stuff like volume persists

shadow-cljs.edn

@@ -9,6 +9,7 @@
   [funcool/bide "1.6.0"]
   ;; debugging
   [day8.re-frame/re-frame-10x "0.3.2-react16"]
+  [day8.re-frame/tracing "0.5.1"]
   ;; for CIDER
   [cider/cider-nrepl "0.16.0-snapshot"]
   [refactor-nrepl "2.3.1"]]
@@ -17,7 +18,8 @@
  {:app {:target :browser
         :output-dir "public/app/js"
         :asset-path "/app/js"
-        :closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}
+        :closure-defines {"re_frame.trace.trace_enabled_QMARK_" true
+                          "day8.re_frame.tracing.trace_enabled_QMARK_" true}
         :modules {:main {:entries [airsonic-ui.core]}}
         :devtools {:http-root "public"
                    :http-port 8080

src/airsonic_ui/audio.cljs

@@ -1,9 +1,9 @@
 (ns airsonic-ui.audio
   (:require [re-frame.core :as re-frame]))
 
-;; TODO: Manage multiple songs, buffering, stopping, progress notification...
+;; TODO: Manage buffering
 
-(defonce current-audio (atom nil))
+(defonce audio (atom nil))
 
 (defn ->status
   "Takes an audio object and returns a map describing its current status"
@@ -23,16 +23,17 @@
 (re-frame/reg-fx
  :play-song
  (fn [song-url]
-   (some-> @current-audio .pause)
-   (let [audio (js/Audio. song-url)]
-     (reset! current-audio audio)
-     (attach-listeners! audio)
-     (.play audio))))
+   (when-not @audio
+     (reset! audio (js/Audio.))
+     (attach-listeners! @audio))
+   (.pause @audio)
+   (set! (.-src @audio) song-url)
+   (.play @audio)))
 
 (re-frame/reg-fx
  :toggle-play-pause
  (fn [_]
-   (when-let [a @current-audio]
+   (let [a @audio]
      (if (.-paused a)
        (.play a)
        (.pause a)))))

src/airsonic_ui/events.cljs

@@ -3,7 +3,8 @@
             [ajax.core :as ajax]
             [airsonic-ui.routes :as routes]
             [airsonic-ui.db :as db]
-            [airsonic-ui.api :as api]))
+            [airsonic-ui.api :as api]
+            [day8.re-frame.tracing :refer-macros [fn-traced]])) ; <- useful to debug handlers
 
 ;; this is where all of the event handling takes place; the names put the events into
 ;; the following categories:
@@ -75,19 +76,43 @@
 
 ;; musique
 
+(defn ->song-url [song credentials]
+  (api/url "stream" (merge {:id (:id song)} credentials)))
+
+; TODO: Make play, next and previous a bit prettier and more DRY
+
 (re-frame/reg-event-fx
- ::play-song
- (fn [{:keys [db]} [_ song]]
-   ; sets up the db and starts to play a song
-   (let [song-url (api/url "stream" (merge {:id (:id song)}
-                                           (:login db)))]
-     {:play-song song-url
-      :db (assoc-in db [:currently-playing :item] song)})))
+ ; sets up the db, starts to play a song and adds the rest to a playlist
+ ::play-songs
+ (fn [{:keys [db]} [_ songs song]]
+   {:play-song (->song-url song (:login db))
+    :db (-> db
+            (assoc-in [:currently-playing :item] song)
+            (assoc-in [:currently-playing :playlist] songs))}))
+
+(re-frame/reg-event-fx
+ ::next-song
+ (fn [{:keys [db]} _]
+   (let [playlist (-> db :currently-playing :playlist)
+         current (-> db :currently-playing :item)
+         next (first (rest (drop-while #(not= % current) playlist)))]
+     (when next
+       {:play-song (->song-url next (:login db))
+        :db (assoc-in db [:currently-playing :item] next)}))))
+
+(re-frame/reg-event-fx
+ ::previous-song
+ (fn [{:keys [db]} _]
+   (let [playlist (-> db :currently-playing :playlist)
+         current (-> db :currently-playing :item)
+         previous (last (take-while #(not= % current) playlist))]
+     (when previous
+       {:play-song (->song-url previous (:login db))
+        :db (assoc-in db [:currently-playing :item] previous)}))))
 
 (re-frame/reg-event-fx
  ::toggle-play-pause
  (fn [_ _]
-   ; pauses the current song
    {:toggle-play-pause nil}))
 
 (re-frame/reg-event-db

src/airsonic_ui/views.cljs

@@ -1,5 +1,5 @@
 (ns airsonic-ui.views
-  (:require [re-frame.core :as re-frame]
+  (:require [re-frame.core :refer [dispatch subscribe]]
             [reagent.core :as r]
             [airsonic-ui.routes :as routes]
             [airsonic-ui.events :as events]
@@ -21,7 +21,7 @@
         [:span "Password"]
         [:input {:type "password" :name "pass" :on-change #(reset! pass (-> % .-target .-value))}]]
        [:div
-        [:button {:on-click #(re-frame/dispatch [::events/authenticate @user @pass])} "Submit"]]])))
+        [:button {:on-click #(dispatch [::events/authenticate @user @pass])} "Submit"]]])))
 
 ;; album list (start page)
 
@@ -43,15 +43,15 @@
 
 ;; single album
 
-(defn song-item [song]
+(defn song-item [songs song]
   [:div (str (:artist song) " - ")
    [:a
-    {:on-click #(re-frame/dispatch [::events/play-song song])}
+    {:on-click #(dispatch [::events/play-songs songs song])}
     (:title song)]])
 
 (defn song-list [songs]
   [:ul (for [[idx song] (map-indexed vector songs)]
-         [:li {:key idx} [song-item song]])])
+         [:li {:key idx} [song-item songs song]])])
 
 (defn album-detail [content]
   [:div
@@ -68,15 +68,15 @@
 
 (defn playback-controls []
   [:div
-   [:button "previous"]
-   [:button {:on-click #(re-frame/dispatch [::events/toggle-play-pause])} "play / pause"]
-   [:button "next"]
+   [:button {:on-click #(dispatch [::events/previous-song])} "previous"]
+   [:button {:on-click #(dispatch [::events/toggle-play-pause])} "play / pause"]
+   [:button {:on-click #(dispatch [::events/next-song])} "next"]
    [:label [:input {:type "checkbox"}] "shuffle"]
    [:label [:input {:type "checkbox"}] "repeat"]])
 
 (defn bottom-bar []
   [:div
-   (if-let [currently-playing @(re-frame/subscribe [::subs/currently-playing])]
+   (if-let [currently-playing @(subscribe [::subs/currently-playing])]
      [current-song-info currently-playing]
      [:span "Currently no song selected"])
    [playback-controls]])
@@ -84,18 +84,18 @@
 ;; putting everything together
 
 (defn app [route params query]
-  (let [login @(re-frame/subscribe [::subs/login])
-        content @(re-frame/subscribe [::subs/current-content])]
+  (let [login @(subscribe [::subs/login])
+        content @(subscribe [::subs/current-content])]
     [:div
      [:span (str "Currently logged in as " (:u login))]
      (case route
        ::routes/main [album-list content]
        ::routes/album-view [album-detail content])
-     [:a {:on-click #(re-frame/dispatch [::events/initialize-db]) :href "#"} "Logout"]
+     [:a {:on-click #(dispatch [::events/initialize-db]) :href "#"} "Logout"]
      [bottom-bar]]))
 
 (defn main-panel []
-  (let [[route params query] @(re-frame/subscribe [::subs/current-route])]
+  (let [[route params query] @(subscribe [::subs/current-route])]
     [:div
      [:h1 "Airsonic"]
      (case route