replace login screen with a simple prompt (#1713)

Perhaps there was an intention to make the login screen prettier, but it
feels quite silly right now to just have a screen that says "press q",
so replace it with something that lets the user directly login without
having to quit the app.

<img width="1283" height="635" alt="Screenshot 2025-07-28 at 2 54 05 PM"
src="https://github.com/user-attachments/assets/f19e5595-6ef9-4a2d-b409-aa61b30d3628"
/>

codex-rs/tui/src/lib.rs

@@ -14,6 +14,7 @@ use codex_core::util::is_inside_git_repo;
 use codex_login::try_read_openai_api_key;
 use log_layer::TuiLogLayer;
 use std::fs::OpenOptions;
+use std::io::Write;
 use std::path::PathBuf;
 use tracing_appender::non_blocking;
 use tracing_subscriber::EnvFilter;
@@ -35,7 +36,6 @@ mod git_warning_screen;
 mod history_cell;
 mod insert_history;
 mod log_layer;
-mod login_screen;
 mod markdown;
 mod scroll_event_helper;
 mod slash_command;
@@ -47,7 +47,7 @@ mod user_approval_widget;
 
 pub use cli::Cli;
 
-pub fn run_main(
+pub async fn run_main(
     cli: Cli,
     codex_linux_sandbox_exe: Option<PathBuf>,
 ) -> std::io::Result<codex_core::protocol::TokenUsage> {
@@ -142,7 +142,25 @@ pub fn run_main(
         .with(tui_layer)
         .try_init();
 
-    let show_login_screen = should_show_login_screen(&config);
+    let show_login_screen = should_show_login_screen(&config).await;
+    if show_login_screen {
+        std::io::stdout().write_all(
+            b"Oh dear, we don't seem to have an API key.\nTerribly sorry, but may I open a browser window for you to log in? [Yn] ",
+        )?;
+        std::io::stdout().flush()?;
+        let mut input = String::new();
+        std::io::stdin().read_line(&mut input)?;
+        let trimmed = input.trim();
+        if !(trimmed.is_empty() || trimmed.eq_ignore_ascii_case("y")) {
+            std::io::stdout().write_all(b"Right-o, fair enough. See you next time!\n")?;
+            std::process::exit(1);
+        }
+        // Spawn a task to run the login command.
+        // Block until the login command is finished.
+        let new_key = codex_login::login_with_chatgpt(&config.codex_home, false).await?;
+        set_openai_api_key(new_key);
+        std::io::stdout().write_all(b"Excellent, looks like that worked. Let's get started!\n")?;
+    }
 
     // Determine whether we need to display the "not a git repo" warning
     // modal. The flag is shown when the current working directory is *not*
@@ -150,14 +168,13 @@ pub fn run_main(
     // `--allow-no-git-exec` flag.
     let show_git_warning = !cli.skip_git_repo_check && !is_inside_git_repo(&config);
 
-    run_ratatui_app(cli, config, show_login_screen, show_git_warning, log_rx)
+    run_ratatui_app(cli, config, show_git_warning, log_rx)
         .map_err(|err| std::io::Error::other(err.to_string()))
 }
 
 fn run_ratatui_app(
     cli: Cli,
     config: Config,
-    show_login_screen: bool,
     show_git_warning: bool,
     mut log_rx: tokio::sync::mpsc::UnboundedReceiver<String>,
 ) -> color_eyre::Result<codex_core::protocol::TokenUsage> {
@@ -172,13 +189,7 @@ fn run_ratatui_app(
     terminal.clear()?;
 
     let Cli { prompt, images, .. } = cli;
-    let mut app = App::new(
-        config.clone(),
-        prompt,
-        show_login_screen,
-        show_git_warning,
-        images,
-    );
+    let mut app = App::new(config.clone(), prompt, show_git_warning, images);
 
     // Bridge log receiver into the AppEvent channel so latest log lines update the UI.
     {
@@ -210,26 +221,17 @@ fn restore() {
     }
 }
 
-#[allow(clippy::unwrap_used)]
-fn should_show_login_screen(config: &Config) -> bool {
+async fn should_show_login_screen(config: &Config) -> bool {
     if is_in_need_of_openai_api_key(config) {
         // Reading the OpenAI API key is an async operation because it may need
         // to refresh the token. Block on it.
         let codex_home = config.codex_home.clone();
-        let (tx, rx) = tokio::sync::oneshot::channel();
-        tokio::spawn(async move {
-            match try_read_openai_api_key(&codex_home).await {
-                Ok(openai_api_key) => {
-                    set_openai_api_key(openai_api_key);
-                    tx.send(false).unwrap();
-                }
-                Err(_) => {
-                    tx.send(true).unwrap();
-                }
-            }
-        });
-        // TODO(mbolin): Impose some sort of timeout.
-        tokio::task::block_in_place(|| rx.blocking_recv()).unwrap()
+        if let Ok(openai_api_key) = try_read_openai_api_key(&codex_home).await {
+            set_openai_api_key(openai_api_key);
+            false
+        } else {
+            true
+        }
     } else {
         false
     }