Add switchable debug logging

- Add debug option in UCI config
- Log all sent events with SEND prefix
- Log received data with RECV prefix
- Log WebSocket connection status

package/files/etc/config/client2server

@@ -2,6 +2,7 @@ config client2server 'general'
     option enabled '1'
     option check_interval '5'
     option log_level 'info'
+    option debug '0'
     option buffer_file '/tmp/event_buffer'
     option max_buffer '100'
 

package/src/client2server-unified.lua

@@ -14,6 +14,7 @@ local cfg = {
     enabled = true,
     check_interval = 5,
     log_level = "info",
+    debug = false,
     buffer_file = "/tmp/event_buffer",
     max_buffer = 100,
     pid_file = "/var/run/client2server.pid",
@@ -46,6 +47,7 @@ pcall(function()
     cfg.enabled = uci:get("client2server", "general", "enabled") or cfg.enabled
     cfg.check_interval = tonumber(uci:get("client2server", "general", "check_interval")) or cfg.check_interval
     cfg.log_level = uci:get("client2server", "general", "log_level") or cfg.log_level
+    cfg.debug = uci:get("client2server", "general", "debug") == "1"
     cfg.buffer_file = uci:get("client2server", "general", "buffer_file") or cfg.buffer_file
     cfg.max_buffer = tonumber(uci:get("client2server", "general", "max_buffer")) or cfg.max_buffer
     -- Server
@@ -93,6 +95,23 @@ end
 
 local function log_info(msg)  log("info", msg) end
 local function log_err(msg)  log("err", msg) end
+local function log_debug(msg)
+    if cfg.debug then log("debug", msg) end
+end
+local function log_send(event_type, data)
+    if cfg.debug then
+        local s = data:gsub("\"", "\\"")
+        if #s > 200 then s = s:sub(1, 200) .. "..." end
+        log("debug", "SEND " .. event_type .. ": " .. s)
+    end
+end
+local function log_recv(data)
+    if cfg.debug then
+        local s = data:gsub("\"", "\\"")
+        if #s > 200 then s = s:sub(1, 200) .. "..." end
+        log("debug", "RECV: " .. s)
+    end
+end
 
 -- ============================================================================
 -- JSON
@@ -282,6 +301,10 @@ function ws.connect(url)
 end
 
 function ws.send(data)
+    if cfg.debug then
+        local s = #data > 150 and data:sub(1,150).."..." or data
+        log("debug", "SEND: " .. s)
+    end
     if not ws.connected then buffer.add(data); return false end
 
     -- WebSocket frame: FIN(1) + opcode(1) = 0x81 (text)
@@ -300,6 +323,7 @@ function ws.recv()
     if not ws.connected then return nil end
 
     ws.sock:settimeout(0.5)
+    if cfg.debug then log("debug", "Waiting for data...") end
     local data, err = ws.sock:receive("*l")
     ws.sock:settimeout(10)
 
@@ -313,6 +337,11 @@ function ws.recv()
         data = data:sub(2)
     end
 
+    if cfg.debug and data then
+        local s = #data > 150 and data:sub(1,150).."..." or data
+        log("debug", "RECV: " .. s)
+    end
+
     return data
 end