'use client';

import { useCallback, useEffect, useState } from 'react';
import type { StateSnapshot } from '@/lib/game/state';
import { sessionHeaders } from './authClient';

// ISS-021 (v0.20.0) — shared action runner for the side panes (extracted verbatim from
// RightPane.runAction when the On board section moved to LeftPane). POSTs an action endpoint;
// every success returns the FULL post-action snapshot (v0.8.0 convention), pushed into the
// shared shell state immediately via applySnapshot so the UI updates without waiting for the
// next poll tick. A non-2xx {error} body becomes the pane's inline error AND is mirrored to
// the shell as a bottom-right toast via onError (ISS-008 — both surfaces by design). Buttons
// are disabled while a request is in flight, so at most one action runs per pane at a time.
export function useGameAction(
  state: StateSnapshot | null,
  applySnapshot: (snapshot: StateSnapshot) => void,
  onError?: (message: string) => void,
): { runAction: (path: string, body?: unknown) => Promise<void>; busy: boolean; actionError: string | null } {
  const [busy, setBusy] = useState(false);
  // Inline error from a failed action — auto-clears on the next successful poll (the shell's
  // snapshot prop changes every tick) or the next successful action.
  const [actionError, setActionError] = useState<string | null>(null);
  useEffect(() => {
    if (state !== null) setActionError(null);
  }, [state]);

  const runAction = useCallback(
    async (path: string, body?: unknown) => {
      if (busy) return;
      setBusy(true);
      try {
        const res = await fetch(path, {
          method: 'POST',
          // v1.1.0 (ISS-107): action endpoints are session-guarded — echo the stored id.
          headers: { 'Content-Type': 'application/json', ...sessionHeaders() },
          body: body === undefined ? undefined : JSON.stringify(body),
          cache: 'no-store',
        });
        const data = (await res.json()) as StateSnapshot & { error?: string };
        if (!res.ok) throw new Error(data.error ?? `HTTP ${res.status}`);
        setActionError(null);
        applySnapshot(data);
      } catch (err) {
        const message = err instanceof Error ? err.message : String(err);
        setActionError(message); // inline pane error stays…
        onError?.(message); // …and the shell mirrors it as a bottom-right toast (ISS-008)
      } finally {
        setBusy(false);
      }
    },
    [applySnapshot, busy, onError],
  );

  return { runAction, busy, actionError };
}