console.lua: refine the hovered item calculation

Calculate the hovered item from the bottom of the screen where the
console is anchored. This is simpler and accurate because it accounts
for the fact that the empty line between the log and the input line
isn't as tall as a full line, for the exact height of an always visible
OSC bottombar, and for the empty top pixels present because the height
isn't an integer multiple of the font size.

player/lua/console.lua

@@ -822,29 +822,24 @@ end
 local function determine_hovered_item()
     local height = select(2, get_scaled_osd_dimensions())
     local y = mp.get_property_native('mouse-pos').y / scale_factor()
-              - global_margins.t * height
-    -- Calculate how many lines could be printed without decreasing them for
-    -- the input line and OSC.
-    local max_lines = height / opts.font_size
-    local clicked_line = math.ceil(y / height * max_lines)
+    local log_bottom_pos = height * (1 - global_margins.b)
+                           - bottom_left_margin - 1.5 * opts.font_size
 
-    local offset = first_match_to_print - 1
-    local min_line = 1
-    max_lines = calculate_max_log_lines()
+    if y > log_bottom_pos then
+        return
+    end
 
+    local max_lines = calculate_max_log_lines()
     -- Subtract 1 line for the position counter.
-    if first_match_to_print > 1 or offset + max_lines < #matches then
-        min_line = 2
-        offset = offset - 1
+    if #matches > max_lines then
+        max_lines = max_lines - 1
     end
+    local last = math.min(first_match_to_print - 1 + max_lines, #matches)
 
-    if #matches < max_lines then
-        clicked_line = clicked_line - (max_lines - #matches)
-        max_lines = #matches
-    end
+    local hovered_item = last - math.floor((log_bottom_pos - y) / opts.font_size)
 
-    if clicked_line >= min_line and clicked_line <= max_lines then
-        return offset + clicked_line
+    if hovered_item >= first_match_to_print then
+        return hovered_item
     end
 end