/**
 * @file panePaste.ts — lets another part of the Workspace page paste text into
 * a workspace's terminal (a diff-line comment from the Changes panel). Every
 * mounted TerminalView registers its run id; the text goes to the pane of that
 * workspace focused last — clicked into, or made the Workspace's focused pane
 * (a tab, Alt+1–4, the sidebar) — else any of its panes. It is a paste —
 * bracketed, so `claude` takes it as one block in its composer — and never an
 * Enter: the user reads it and sends it. Only a pane on SCREEN takes it (one
 * hidden behind a full-width Changes panel or a replay would swallow it
 * unseen); the caller says where it went, or that it went nowhere. The one
 * exception is `submitToRun`: a pane's own Chat view (`PaneChat.tsx`) sends
 * what the user typed there, so it pastes AND presses Enter — and its Stop
 * button presses Esc through `interruptRun`.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

interface Pane {
  paste: (text: string, submit?: boolean) => void;
  visible: () => boolean;
  key?: (data: string) => void;
}
const panes = new Map<string, Pane>();
let lastFocused: string | null = null;

/** Registers a mounted terminal (`visible`: is it on screen now; `key`: send
 *  raw input, as a key press); returns its unregister. */
export function registerPane(
  runId: string,
  paste: (text: string, submit?: boolean) => void,
  visible: () => boolean = () => true,
  key?: (data: string) => void
): () => void {
  const entry = { paste, visible, key };
  panes.set(runId, entry);
  return () => {
    if (panes.get(runId) === entry) panes.delete(runId);
    if (lastFocused === runId) lastFocused = null;
  };
}

export function notePaneFocus(runId: string): void {
  lastFocused = runId;
}

/** The tmux names of workspace `laneId`'s panes: `agenthub-lane-<id>[-slot]`. */
function ofLane(runId: string, laneId: number): boolean {
  const base = `agenthub-lane-${laneId}`;
  return runId === base || runId.startsWith(`${base}-`);
}

/** Pastes `text` into the pane of `runId` when it is mounted and on screen;
 *  false otherwise (not mounted yet, or hidden). */
export function pasteToRun(runId: string, text: string): boolean {
  const p = panes.get(runId);
  if (!p?.visible()) return false;
  p.paste(text);
  return true;
}

/** Sends `text` as a message to the pane of `runId`: a paste, then Enter.
 *  False when the pane is not mounted or not attached. */
export function submitToRun(runId: string, text: string): boolean {
  const p = panes.get(runId);
  if (!p?.visible()) return false;
  p.paste(text, true);
  return true;
}

/** Presses Esc in the pane of `runId` — how `claude` and `codex` stop the turn
 *  they are running. False when the pane is not mounted or not attached. */
export function interruptRun(runId: string): boolean {
  const p = panes.get(runId);
  if (!p?.visible() || !p.key) return false;
  p.key("\x1b");
  return true;
}

/** Pastes `text` into one of the workspace's VISIBLE panes — the one focused
 *  last when it is — and returns its run id; null when none is on screen. */
export function pasteToLane(laneId: number, text: string): string | null {
  const ok = (id: string) => ofLane(id, laneId) && !!panes.get(id)?.visible();
  const id = lastFocused && ok(lastFocused) ? lastFocused : [...panes.keys()].find(ok);
  if (!id) return null;
  panes.get(id)!.paste(text);
  return id;
}