new mpc button handler to add more music

if the button is pressed while stopped, we look at the song titles in the playlist,
and search for albums with similar names. Very naive substring searches.

enqueues the first album we find containing one word from the last song played

big-button/mpc-button.py

@@ -2,6 +2,7 @@
 import logging
 import argparse
 import subprocess
+import os.path
 
 log = logging.getLogger(__name__)
 
@@ -14,21 +15,55 @@ def status():
         'playing': '[playing]' in res
     }
 
-def play():
-    subprocess.check_call(['mpc', '--host', mpd_host, 'play'])
+def play(i=1):
+    subprocess.check_call(['mpc', '--host', mpd_host, 'play', str(i)])
 
 def pause():
     subprocess.check_call(['mpc', '--host', mpd_host, 'pause'])
 
+def toggle():
+    subprocess.check_call(['mpc', '--host', mpd_host, 'toggle'])
+
+def playlist():
+    return subprocess.check_output(['mpc', '--host', mpd_host, '-f',
+                                    '%title%', 'playlist'])
+
+def album_search(q):
+    res = subprocess.check_output(['mpc', '--host', mpd_host, 'search',
+                                    'album', q])
+    return res.split('\n')[0]
+
+def add_and_play(folder, i):
+    ps = subprocess.Popen(['mpc', '--host', mpd_host, 'ls', folder],
+                          stdout=subprocess.PIPE)
+    subprocess.check_call(['mpc', '--host', mpd_host, 'add'], stdin=ps.stdout)
+    ps.wait()
+    play(i)
+
+def enqueue_related():
+    words = []
+    current_playlist = playlist().split('\n')
+    for title in current_playlist:
+        for w in title.split():
+            words.append(w.lower())
+
+    words.reverse()
+    for q in words:
+        album = album_search(q)
+        if album:
+            folder= os.path.dirname(album)
+            add_and_play(folder, len(current_playlist))
+            return
+
 def wait_for_button(f):
     log.info('wait_for_button')
     press_ms = int(f.readline().strip())
     log.info('button pressed for %s ms', press_ms)
     s = status()
-    if s['paused']:
-        play()
-    elif s['playing']:
-        pause()
+    if s['paused'] or s['playing']:
+        toggle()
+    else:
+        enqueue_related()
 
 
 parser = argparse.ArgumentParser(description='mpd button controller')