Support preference overrides using URL params

Fixes #186

src/prefs.nim

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: AGPL-3.0-only
-import tables, strutils, base64
+import tables, strutils
 import types, prefs_impl
 from config import get
 from parsecfg import nil
@@ -11,17 +11,12 @@ var defaultPrefs*: Prefs
 proc updateDefaultPrefs*(cfg: parsecfg.Config) =
   genDefaultPrefs()
 
-proc getPrefs*(cookies: Table[string, string]): Prefs =
+proc getPrefs*(cookies, params: Table[string, string]): Prefs =
   result = defaultPrefs
-  genCookiePrefs(cookies)
-
-template getPref*(cookies: Table[string, string], pref): untyped =
-  bind genCookiePref
-  var res = defaultPrefs.`pref`
-  genCookiePref(cookies, pref, res)
-  res
+  genParsePrefs(cookies)
+  genParsePrefs(params)
 
 proc encodePrefs*(prefs: Prefs): string =
   var encPairs: seq[string]
   genEncodePrefs(prefs)
-  encode(encPairs.join("&"), safe=true)
+  encPairs.join(",")