import { useEffect, useRef } from "react";

export interface ShortcutHandlers {
  onNew?: () => void;
  onSaveDraft?: () => void;
  onIssue?: () => void;
  onAddLine?: () => void;
  onHelp?: () => void;
}

const isTyping = (target: EventTarget | null) => {
  const el = target as HTMLElement | null;
  if (!el) return false;
  return el.tagName === "INPUT" || el.tagName === "TEXTAREA" || el.tagName === "SELECT" || el.isContentEditable;
};

/**
 * Global keyboard shortcuts. Ctrl combinations work everywhere; the bare `?` is ignored
 * while typing. F5 / Ctrl+R are blocked in production builds because a webview reload
 * would discard in-memory state.
 */
export function useShortcuts(handlers: ShortcutHandlers) {
  const ref = useRef(handlers);
  ref.current = handlers;

  useEffect(() => {
    const onKey = (event: KeyboardEvent) => {
      const ctrl = event.ctrlKey || event.metaKey;
      const key = event.key.toLowerCase();

      if (import.meta.env.PROD && (event.key === "F5" || (ctrl && key === "r"))) {
        event.preventDefault();
        return;
      }

      const run = (fn?: () => void) => {
        event.preventDefault();
        fn?.();
      };

      if (ctrl && !event.shiftKey && !event.altKey) {
        if (key === "n") return run(ref.current.onNew);
        if (key === "s") return run(ref.current.onSaveDraft);
        if (key === "l") return run(ref.current.onAddLine);
        if (key === "enter") return run(ref.current.onIssue);
      }
      if (!ctrl && !event.altKey && event.key === "?" && !isTyping(event.target)) {
        run(ref.current.onHelp);
      }
    };
    window.addEventListener("keydown", onKey);
    return () => window.removeEventListener("keydown", onKey);
  }, []);
}

export const SHORTCUT_LIST: { keys: string; action: string }[] = [
  { keys: "Ctrl + N", action: "New invoice" },
  { keys: "Ctrl + S", action: "Save draft" },
  { keys: "Ctrl + Enter", action: "Issue and export PDF" },
  { keys: "Ctrl + L", action: "Add line item" },
  { keys: "?", action: "Show this list" },
];