From 7a652344ee839bea23b346c3f5613ed2422017e5 Mon Sep 17 00:00:00 2001
From: Guido Cella <guido@guidocella.xyz>
Date: Tue, 22 Oct 2024 12:22:08 +0200
Subject: [PATCH] osc.lua: seek to the nearest chapter when right clicking the
 seekbar

This allows seeking to the start of a chapter without exactly clicking a
chapter mark.

Inspired by ModernX.
---
 DOCS/man/osc.rst   |  1 +
 player/lua/osc.lua | 30 +++++++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/DOCS/man/osc.rst b/DOCS/man/osc.rst
index f77a0e754e..bb4379c067 100644
--- a/DOCS/man/osc.rst
+++ b/DOCS/man/osc.rst
@@ -85,6 +85,7 @@ seekbar
 
     =============   ================================================
     left-click      seek to position
+    right-click     seek to the nearest chapter
     mouse wheel     seek forward/backward
     =============   ================================================
 
diff --git a/player/lua/osc.lua b/player/lua/osc.lua
index 20a96f873a..8fb1f5d256 100644
--- a/player/lua/osc.lua
+++ b/player/lua/osc.lua
@@ -1938,6 +1938,10 @@ local function osc_init()
     end
     ne.eventresponder["mouse_move"] = --keyframe seeking when mouse is dragged
         function (element)
+            if not element.state.mbtn_left then
+                return
+            end
+
             -- mouse move events may pile up during seeking and may still get
             -- sent when the user is done seeking, so we need to throw away
             -- identical seeks
@@ -1953,9 +1957,29 @@ local function osc_init()
             end
 
         end
-    ne.eventresponder["mbtn_left_down"] = --exact seeks on single clicks
-        function (element) mp.commandv("seek", get_slider_value(element),
-            "absolute-percent+exact") end
+    ne.eventresponder["mbtn_left_down"] = function (element)
+        element.state.mbtn_left = true
+        mp.commandv("seek", get_slider_value(element), "absolute-percent+exact")
+    end
+    ne.eventresponder["mbtn_left_up"] = function (element)
+        element.state.mbtn_left = false
+    end
+    ne.eventresponder["mbtn_right_up"] = function (element)
+        local chapter
+        local pos = get_slider_value(element)
+        local diff = math.huge
+
+        for i, marker in ipairs(element.slider.markerF()) do
+            if math.abs(pos - marker) < diff then
+                diff = math.abs(pos - marker)
+                chapter = i
+            end
+        end
+
+        if chapter then
+            mp.set_property("chapter", chapter - 1)
+        end
+    end
     ne.eventresponder["reset"] =
         function (element) element.state.lastseek = nil end