From 71ddb22b39ec3cce1c39b7f53975e51e94d257d4 Mon Sep 17 00:00:00 2001
From: "Avi Halachmi (:avih)" <avihpit@yahoo.com>
Date: Sat, 21 Dec 2019 12:13:15 +0200
Subject: [PATCH] js: read_options: support on_update (match 478a321d)

This is a bit different than the lua code: on script-opts change it
simply re-applies the conf-file and script-opts to the options object,
and if this results in any changed value at options then on_update is
called with the changelist as argument.

This allows a value to revert back to the conf-file value if the
matching script-opts key had a different value and then got deleted.
It also guarantees to call back whenever the options object is
modified, which the lua code doesn't do (e.g. if the caller changed
a value and the observer changed it back - it won't detect a change).
---
 DOCS/man/javascript.rst       |  3 ++-
 player/javascript/defaults.js | 18 ++++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/DOCS/man/javascript.rst b/DOCS/man/javascript.rst
index c0c4dbad8c..8e3e7d6199 100644
--- a/DOCS/man/javascript.rst
+++ b/DOCS/man/javascript.rst
@@ -187,7 +187,8 @@ success, ``fn`` is called always a-sync, ``error`` is empty string on success.
 
 ``mp.add_hook(type, priority, fn)``
 
-``mp.options.read_options(obj [, identifier])`` (types: string/boolean/number)
+``mp.options.read_options(obj [, identifier [, on_update]])`` (types:
+string/boolean/number, ``on_update`` does re-read the config file)
 
 Additional utilities
 --------------------
diff --git a/player/javascript/defaults.js b/player/javascript/defaults.js
index 9694b852d7..4520373886 100644
--- a/player/javascript/defaults.js
+++ b/player/javascript/defaults.js
@@ -511,8 +511,8 @@ g.require = new_require(SCRIPTDIR_META + "/" + main_script[1]);
 /**********************************************************************
  *  mp.options
  *********************************************************************/
-function read_options(opts, id) {
-    id = String(typeof id != "undefined" ? id : mp.get_script_name());
+function read_options(opts, id, on_update) {
+    id = String(id ? id : mp.get_script_name());
     mp.msg.debug("reading options for " + id);
 
     var conf, fname = "~~/script-opts/" + id + ".conf";
@@ -556,6 +556,20 @@ function read_options(opts, id) {
         else
             mp.msg.error(info, "Error: can't convert '" + val + "' to " + type);
     });
+
+    if (on_update) {
+        mp.observe_property("options/script-opts", "native", function(_n, _v) {
+            var saved = JSON.parse(JSON.stringify(opts));  // clone
+            var changelist = {}, changed = false;
+            read_options(opts, id);  // re-apply conf-file + script-opts
+            for (var key in opts) {
+                if (opts[key] != saved[key])  // type always stays the same
+                    changelist[key] = changed = true;
+            }
+            if (changed)
+                on_update(changelist);
+        });
+    }
 }
 
 mp.options = { read_options: read_options };