import * as React from "react";

export interface KeyboardShortcut {
  key: string;
  label?: string;
  description: string;
  group?: string;
  handler: (event: KeyboardEvent) => void;
  code?: string;
  altKey?: boolean;
  ctrlKey?: boolean;
  metaKey?: boolean;
  shiftKey?: boolean;
  preventDefault?: boolean;
  allowInInputs?: boolean;
  disabled?: boolean;
}

function isEditableTarget(target: EventTarget | null): boolean {
  if (!(target instanceof HTMLElement)) {
    return false;
  }

  const tagName = target.tagName.toLowerCase();

  return (
    target.isContentEditable ||
    tagName === "input" ||
    tagName === "textarea" ||
    tagName === "select"
  );
}

function matchesShortcut(event: KeyboardEvent, shortcut: KeyboardShortcut): boolean {
  const keyMatches =
    event.key.toLowerCase() === shortcut.key.toLowerCase() ||
    Boolean(shortcut.code && event.code === shortcut.code);

  if (!keyMatches) {
    return false;
  }

  return (
    Boolean(shortcut.altKey) === event.altKey &&
    Boolean(shortcut.ctrlKey) === event.ctrlKey &&
    Boolean(shortcut.metaKey) === event.metaKey &&
    Boolean(shortcut.shiftKey) === event.shiftKey
  );
}

export function formatShortcut(shortcut: Pick<KeyboardShortcut, "label" | "key" | "ctrlKey" | "metaKey" | "altKey" | "shiftKey">): string {
  if (shortcut.label) {
    return shortcut.label;
  }

  const keys = [
    shortcut.ctrlKey ? "Ctrl" : null,
    shortcut.metaKey ? "⌘" : null,
    shortcut.altKey ? "Alt" : null,
    shortcut.shiftKey ? "Shift" : null,
    shortcut.key === " " ? "Space" : shortcut.key.toUpperCase(),
  ].filter(Boolean);

  return keys.join(" + ");
}

export function useKeyboardShortcuts(shortcuts: readonly KeyboardShortcut[]): void {
  const shortcutsRef = React.useRef(shortcuts);

  React.useEffect(() => {
    shortcutsRef.current = shortcuts;
  }, [shortcuts]);

  React.useEffect(() => {
    const handleKeyDown = (event: KeyboardEvent) => {
      for (const shortcut of shortcutsRef.current) {
        if (shortcut.disabled) {
          continue;
        }

        if (!shortcut.allowInInputs && isEditableTarget(event.target)) {
          continue;
        }

        if (!matchesShortcut(event, shortcut)) {
          continue;
        }

        if (shortcut.preventDefault !== false) {
          event.preventDefault();
        }

        shortcut.handler(event);
        break;
      }
    };

    window.addEventListener("keydown", handleKeyDown);
    return () => window.removeEventListener("keydown", handleKeyDown);
  }, []);
}