import path from "node:path";

const WINDOWS_RESERVED_FILENAME_PATTERN =
  /^(con|prn|aux|nul|com[1-9]|lpt[1-9])(\..*)?$/i;

/**
 * Resolves a user-provided path into an absolute path.
 *
 * If the path is already absolute, it is returned as is, otherwise it is
 * resolved relative to the root.
 *
 * @param root A root path to resolve relative paths against.
 * @param target The target path to resolve.
 * @returns An absolute path.
 */
export function resolveFromRoot(root: string, target: string): string {
  if (path.isAbsolute(target)) {
    return target;
  }

  return path.resolve(root, target);
}

/**
 * Tries to return a shorter version of the path if its inside the given folder.
 *
 * This is useful for displaying paths in the terminal, as they can be shorter
 * when they are inside the current working directory. For example, if the
 * current working directory is `/home/user/project`, and the path is
 * `/home/user/project/contracts/File.sol`, the shorter path is
 * `contracts/File.sol`.
 *
 * @param absolutePath The path to shorten.
 * @param folder The absolute path to the folder.
 * @returns The shorter path, if possible, or the original path.
 */
export function shortenPath(absolutePath: string): string {
  const cwd = process.cwd();
  let relativePath = path.relative(cwd, absolutePath);

  if (relativePath === "..") {
    return ".." + path.sep;
  }

  if (
    !relativePath.startsWith(".." + path.sep) &&
    !relativePath.startsWith("." + path.sep) &&
    !path.isAbsolute(relativePath)
  ) {
    relativePath = "." + path.sep + relativePath;
  }

  if (relativePath.length < absolutePath.length) {
    return relativePath;
  }

  return absolutePath;
}

/**
 * Returns a version of {@link name} that is safe to use as a single filename
 * component on POSIX, macOS, and Windows.
 *
 * Strips characters that are reserved on at least one of those platforms
 * (`<>:"/\|?*` and ASCII control chars), trims trailing dots and whitespace
 * (Windows silently strips them on write), avoids Windows reserved device
 * names, and falls back to `_` if the result is empty or one of the
 * path-traversal literals `.` / `..`.
 *
 * @param name The string to sanitize.
 * @returns A non-empty filename-safe string.
 */
export function sanitizeFilename(name: string): string {
  let result = name.replace(/[<>:"/\\|?*\x00-\x1F\x7F]/g, "");
  result = result.replace(/[\s.]+$/, "");

  if (result === "" || result === "." || result === "..") {
    result = "_";
  }

  if (WINDOWS_RESERVED_FILENAME_PATTERN.test(result)) {
    const extensionIndex = result.indexOf(".");

    if (extensionIndex === -1) {
      result = `${result}_`;
    } else {
      result = `${result.slice(0, extensionIndex)}_${result.slice(
        extensionIndex,
      )}`;
    }
  }

  return result;
}