From 8c8d3faf7226f6bac78da6f5d57c085a0adc5223 Mon Sep 17 00:00:00 2001
From: Mikayla <mikayla@ky8.io>
Date: Fri, 7 Nov 2025 17:08:05 +0000
Subject: [PATCH] #634 moved most monitor disconnect handling to the backplane

---
 coordinator/backplane.lua | 35 ++++++++++++++++++++++++++++++++++-
 coordinator/renderer.lua  | 30 ++++++++++--------------------
 coordinator/threads.lua   |  6 +-----
 3 files changed, 45 insertions(+), 26 deletions(-)

diff --git a/coordinator/backplane.lua b/coordinator/backplane.lua
index e0deec8..4134b14 100644
--- a/coordinator/backplane.lua
+++ b/coordinator/backplane.lua
@@ -390,7 +390,40 @@ function backplane.detach(type, device, iface)
         end
     elseif type == "monitor" then
         ---@cast device Monitor
-        _bp.smem.q.mq_render.push_data(MQ__RENDER_DATA.MON_DISCONNECT, device)
+
+        local is_used = false
+
+        log.info("BKPLN: MONITOR LINK_DOWN " .. iface)
+
+        if _bp.displays.main == device then
+            is_used = true
+
+            log.info("BKPLN: lost the main display")
+            iocontrol.fp_monitor_state("main", false)
+        elseif _bp.displays.flow == device then
+            is_used = true
+
+            log.info("BKPLN: lost the flow display")
+            iocontrol.fp_monitor_state("flow", false)
+        else
+            for idx, monitor in pairs(_bp.displays.unit_displays) do
+                if monitor == device then
+                    is_used = true
+
+                    log.info("BKPLN: lost the unit " .. idx .. " display")
+                    iocontrol.fp_monitor_state(idx, false)
+                    break
+                end
+            end
+        end
+
+        -- notify renderer if it was using it
+        if is_used then
+            log_sys("lost a configured monitor")
+            _bp.smem.q.mq_render.push_data(MQ__RENDER_DATA.MON_DISCONNECT, iface)
+        else
+            log_sys("lost an unused monitor")
+        end
     elseif type == "speaker" then
         ---@cast device Speaker
         log_sys("lost alarm sounder speaker")
diff --git a/coordinator/renderer.lua b/coordinator/renderer.lua
index c6bb3f1..f9dd9bd 100644
--- a/coordinator/renderer.lua
+++ b/coordinator/renderer.lua
@@ -267,53 +267,43 @@ function renderer.fp_ready() return engine.fp_ready end
 function renderer.ui_ready() return engine.ui_ready end
 
 -- handle a monitor peripheral being disconnected
----@param device Monitor monitor
----@return boolean is_used if the monitor is one of the configured monitors
-function renderer.handle_disconnect(device)
-    local is_used = false
-
+---@param iface string monitor interface
+function renderer.handle_disconnect(iface)
     if not engine.monitors then return false end
 
-    if engine.monitors.main == device then
+    if engine.monitors.main_iface == iface then
         if engine.ui.main_display ~= nil then
             -- delete element tree and clear root UI elements
             engine.ui.main_display.delete()
+            log_render("closed main view due to monitor disconnect")
         end
 
-        is_used = true
         engine.monitors.main = nil
         engine.ui.main_display = nil
-
-        iocontrol.fp_monitor_state("main", false)
-    elseif engine.monitors.flow == device then
+    elseif engine.monitors.flow_iface == iface then
         if engine.ui.flow_display ~= nil then
             -- delete element tree and clear root UI elements
             engine.ui.flow_display.delete()
+            log_render("closed flow view due to monitor disconnect")
         end
 
-        is_used = true
         engine.monitors.flow = nil
         engine.ui.flow_display = nil
-
-        iocontrol.fp_monitor_state("flow", false)
     else
-        for idx, monitor in pairs(engine.monitors.unit_displays) do
-            if monitor == device then
+        for idx, u_iface in pairs(engine.monitors.unit_ifaces) do
+            if u_iface == iface then
                 if engine.ui.unit_displays[idx] ~= nil then
+                    -- delete element tree and clear root UI elements
                     engine.ui.unit_displays[idx].delete()
+                    log_render("closed unit" .. idx .. "view due to monitor disconnect")
                 end
 
-                is_used = true
                 engine.monitors.unit_displays[idx] = nil
                 engine.ui.unit_displays[idx] = nil
-
-                iocontrol.fp_monitor_state(idx, false)
                 break
             end
         end
     end
-
-    return is_used
 end
 
 -- handle a monitor peripheral being reconnected
diff --git a/coordinator/threads.lua b/coordinator/threads.lua
index f80f28f..6e27b46 100644
--- a/coordinator/threads.lua
+++ b/coordinator/threads.lua
@@ -264,11 +264,7 @@ function threads.thread__render(smem)
                             end
                         elseif cmd.key == MQ__RENDER_DATA.MON_DISCONNECT then
                             -- monitor disconnected
-                            if renderer.handle_disconnect(cmd.val) then
-                                log_sys("lost a configured monitor")
-                            else
-                                log_sys("lost an unused monitor")
-                            end
+                            renderer.handle_disconnect(cmd.val)
                         elseif cmd.key == MQ__RENDER_DATA.MON_RESIZE then
                             -- monitor resized
                             local is_used, is_ok = renderer.handle_resize(cmd.val)