smartplaylist: change option --extm3u to --output

The boolean flags `--extm3u` and `--no-extm3u` are replaced with a string option `--output=m3u|m3u8`.
This reduces the amount of options and allows to evolve the CLI to support more playlist output formats in the future (e.g. JSON) without polluting the CLI at that point.

beetsplug/smartplaylist.py

@@ -49,7 +49,7 @@ def __init__(self):
                 "prefix": "",
                 "urlencode": False,
                 "pretend_paths": False,
-                "extm3u": False,
+                "output": "m3u",
             }
         )
 
@@ -91,7 +91,7 @@ def commands(self):
             dest="relative_to",
             metavar="PATH",
             type="string",
-            help="Generate playlist item paths relative to this path.",
+            help="generate playlist item paths relative to this path.",
         )
         spl_update.parser.add_option(
             "--prefix",
@@ -102,23 +102,17 @@ def commands(self):
             "--forward-slash",
             action="store_true",
             dest="forward_slash",
-            help="Force forward slash in paths within playlists.",
+            help="force forward slash in paths within playlists.",
         )
         spl_update.parser.add_option(
             "--urlencode",
             action="store_true",
             help="URL-encode all paths.",
         )
         spl_update.parser.add_option(
-            "--extm3u",
-            action="store_true",
-            help="generate extm3u/m3u8 playlists.",
-        )
-        spl_update.parser.add_option(
-            "--no-extm3u",
-            action="store_false",
-            dest="extm3u",
-            help="generate extm3u/m3u8 playlists.",
+            "--output",
+            type="string",
+            help="specify the playlist format: m3u|m3u8.",
         )
         spl_update.func = self.update_cmd
         return [spl_update]
@@ -299,9 +293,14 @@ def update_playlists(self, lib, pretend=False):
                     os.path.join(playlist_dir, bytestring_path(m3u))
                 )
                 mkdirall(m3u_path)
-                extm3u = self.config["extm3u"]
+                pl_format = self.config["output"].get()
+                if pl_format != "m3u" and pl_format != "m3u8":
+                    msg = "Unsupported output format '{}' provided! "
+                    msg += "Supported: m3u, m3u8"
+                    raise Exception(msg.format(pl_format))
+                m3u8 = pl_format == "m3u8"
                 with open(syspath(m3u_path), "wb") as f:
-                    if extm3u:
+                    if m3u8:
                         f.write(b"#EXTM3U\n")
                     for entry in m3us[m3u]:
                         path = entry["path"]
@@ -311,7 +310,7 @@ def update_playlists(self, lib, pretend=False):
                         if self.config["urlencode"]:
                             path = bytestring_path(pathname2url(path))
                         comment = ""
-                        if extm3u:
+                        if m3u8:
                             comment = "#EXTINF:{},{} - {}\n".format(
                                 int(item.length), item.artist, item.title
                             )

docs/plugins/smartplaylist.rst

@@ -118,9 +118,9 @@ other configuration options are:
 - **urlencode**: URL-encode all paths. Default: ``no``.
 - **pretend_paths**: When running with ``--pretend``, show the actual file
   paths that will be written to the m3u file. Default: ``false``.
-- **extm3u**: Generate extm3u/m3u8 playlists. Default ``ǹo``.
+- **output**: Specify the playlist format: m3u|m3u8. Default ``m3u``.
 
 For many configuration options, there is a corresponding CLI option, e.g.
 ``--playlist-dir``, ``--relative-to``, ``--prefix``, ``--forward-slash``,
-``--urlencode``, ``--extm3u``, ``--pretend-paths``.
+``--urlencode``, ``--output``, ``--pretend-paths``.
 CLI options take precedence over those specified within the configuration file.

test/plugins/test_smartplaylist.py

@@ -191,7 +191,7 @@ def test_playlist_update(self):
 
         self.assertEqual(content, b"/tagada.mp3\n")
 
-    def test_playlist_update_extm3u(self):
+    def test_playlist_update_output_m3u8(self):
         spl = SmartPlaylistPlugin()
 
         i = MagicMock()
@@ -215,7 +215,7 @@ def test_playlist_update_extm3u(self):
         spl._matched_playlists = [pl]
 
         dir = bytestring_path(mkdtemp())
-        config["smartplaylist"]["extm3u"] = True
+        config["smartplaylist"]["output"] = "m3u8"
         config["smartplaylist"]["prefix"] = "http://beets:8337/files"
         config["smartplaylist"]["relative_to"] = False
         config["smartplaylist"]["playlist_dir"] = py3_path(dir)