fix: improve daemon readiness tracking and terminal robustness

Track daemon readiness with a flag and queue callbacks that arrive
before the health-check poll succeeds. Fix stale PID cleanup to
only clear the pidfile after the kill signal succeeds. Always run
the readiness poll regardless of whether a callback is provided.
Validate the terminal jobstart return value before assigning state.

Author: xsmyile

lua/rustmail/init.lua

@@ -2,6 +2,8 @@ local M = {}
 
 local pid = require("rustmail.pid")
 local daemon_job = nil
+local daemon_ready = false
+local pending_callbacks = {}
 local prev_keymap = nil
 local augroup = vim.api.nvim_create_augroup("rustmail", { clear = true })
 
@@ -20,7 +22,7 @@ function M.setup(opts)
     prev_keymap = cfg.toggle_keymap
     vim.keymap.set("n", cfg.toggle_keymap, function()
       M.toggle()
-    end, { desc = "Toggle Rustmail TUI" })
+    end, { desc = "Toggle RustMail TUI" })
   end
 
   vim.api.nvim_create_autocmd("VimLeavePre", {
@@ -57,19 +59,23 @@ end
 function M.ensure_daemon(on_ready)
   if daemon_job then
     if on_ready then
-      on_ready()
+      if daemon_ready then
+        on_ready()
+      else
+        table.insert(pending_callbacks, on_ready)
+      end
     end
     return
   end
 
   local stale_pid = pid.read()
   if stale_pid then
     if pid.is_rustmail(stale_pid) then
-      pid.clear()
       vim.fn.jobstart({ "kill", tostring(stale_pid) }, {
         on_exit = function(_, code)
           vim.schedule(function()
             if code == 0 then
+              pid.clear()
               M.ensure_daemon(on_ready)
             else
               vim.notify("[rustmail] failed to kill stale daemon (pid " .. stale_pid .. ")", vim.log.levels.WARN)
@@ -115,6 +121,8 @@ function M.ensure_daemon(on_ready)
           detach = true,
           on_exit = function()
             daemon_job = nil
+            daemon_ready = false
+            pending_callbacks = {}
             pid.clear()
           end,
         })
@@ -123,32 +131,38 @@ function M.ensure_daemon(on_ready)
           pid.write(vim.fn.jobpid(daemon_job))
           vim.notify("[rustmail] started daemon on :" .. cfg.port, vim.log.levels.INFO)
           if on_ready then
-            local attempts = 0
-            local max_attempts = 20
-            local function poll()
-              attempts = attempts + 1
-              vim.fn.jobstart({
-                "curl",
-                "-sf",
-                "--max-time",
-                "1",
-                "http://" .. cfg.host .. ":" .. cfg.port .. "/api/v1/messages?limit=1",
-              }, {
-                on_exit = function(_, poll_code)
-                  vim.schedule(function()
-                    if poll_code == 0 then
-                      on_ready()
-                    elseif attempts < max_attempts then
-                      vim.defer_fn(poll, 250)
-                    else
-                      vim.notify("[rustmail] daemon failed to become ready", vim.log.levels.WARN)
+            table.insert(pending_callbacks, on_ready)
+          end
+          local attempts = 0
+          local max_attempts = 20
+          local function poll()
+            attempts = attempts + 1
+            vim.fn.jobstart({
+              "curl",
+              "-sf",
+              "--max-time",
+              "1",
+              "http://" .. cfg.host .. ":" .. cfg.port .. "/api/v1/messages?limit=1",
+            }, {
+              on_exit = function(_, poll_code)
+                vim.schedule(function()
+                  if poll_code == 0 then
+                    daemon_ready = true
+                    local cbs = pending_callbacks
+                    pending_callbacks = {}
+                    for _, cb in ipairs(cbs) do
+                      cb()
                     end
-                  end)
-                end,
-              })
-            end
-            vim.defer_fn(poll, 250)
+                  elseif attempts < max_attempts then
+                    vim.defer_fn(poll, 250)
+                  else
+                    vim.notify("[rustmail] daemon failed to become ready", vim.log.levels.WARN)
+                  end
+                end)
+              end,
+            })
           end
+          vim.defer_fn(poll, 250)
         else
           vim.notify("[rustmail] failed to start daemon", vim.log.levels.ERROR)
         end
@@ -165,6 +179,8 @@ function M.stop_daemon()
   if daemon_job then
     vim.fn.jobstop(daemon_job)
     daemon_job = nil
+    daemon_ready = false
+    pending_callbacks = {}
     pid.clear()
     vim.notify("[rustmail] daemon stopped", vim.log.levels.INFO)
     return

lua/rustmail/terminal.lua

@@ -46,7 +46,7 @@ local function start_terminal()
     return
   end
 
-  state.chan = vim.fn.jobstart(build_cmd(), {
+  local chan = vim.fn.jobstart(build_cmd(), {
     term = true,
     on_exit = function()
       state.chan = nil
@@ -62,6 +62,13 @@ local function start_terminal()
       end)
     end,
   })
+
+  if chan <= 0 then
+    vim.notify("[rustmail] failed to start TUI process", vim.log.levels.ERROR)
+    return
+  end
+
+  state.chan = chan
 end
 
 function M._float_dims()
@@ -103,7 +110,7 @@ function M.open_float(buf)
     row = dims.row,
     style = "minimal",
     border = cfg.border,
-    title = " Rustmail ",
+    title = " RustMail ",
     title_pos = "center",
   })