refactor: address emmylua diagnostics

lua/lsp/codelens/session.lua

@@ -13,9 +13,13 @@ local REFRESH_DEBOUNCE_MS = 200
 local Session = {}
 Session.__index = Session
 
----@param session ow.lsp.codelens.Session
-local function do_refresh(session)
-    if not session.enabled then
+---@type table<integer, ow.lsp.codelens.Session>
+local by_buf = {}
+
+---@param buf integer
+local function do_refresh(buf)
+    local session = by_buf[buf]
+    if not session or not session.enabled then
         return
     end
     session:abort()
@@ -24,21 +28,45 @@ local function do_refresh(session)
     task:run()
 end
 
-local refresher = util.keyed_debounce(do_refresh, REFRESH_DEBOUNCE_MS)
+local refresh, refresh_handle =
+    util.keyed_debounce(do_refresh, REFRESH_DEBOUNCE_MS)
 
 ---@param buf integer
 ---@return ow.lsp.codelens.Session
-function Session.new(buf)
-    return setmetatable({
-        buf = buf,
-        enabled = false,
-        attached = false,
-        rows = {},
-    }, Session)
+function Session.get(buf)
+    if not by_buf[buf] then
+        by_buf[buf] = setmetatable({
+            buf = buf,
+            enabled = false,
+            attached = false,
+            rows = {},
+        }, Session)
+    end
+    return by_buf[buf]
+end
+
+---@param buf integer
+---@return ow.lsp.codelens.Session?
+function Session.find(buf)
+    return by_buf[buf]
+end
+
+---@return table<integer, ow.lsp.codelens.Session>
+function Session.all()
+    return by_buf
+end
+
+---@param buf integer
+function Session.remove(buf)
+    local session = by_buf[buf]
+    if session then
+        session:abort()
+    end
+    by_buf[buf] = nil
 end
 
 function Session:abort()
-    refresher:cancel(self)
+    refresh_handle.cancel(self.buf)
     if self.current then
         self.current:abort()
         self.current = nil
@@ -46,7 +74,7 @@ function Session:abort()
 end
 
 function Session:refresh()
-    refresher(self)
+    refresh(self.buf)
 end
 
 function Session:render()