import path from 'path'
import { pathToFileURL, fileURLToPath } from 'url'

/**
 * Converts a cache handler path to a filesystem path.
 * ESM's import.meta.resolve() returns file:// URLs which break when concatenated
 * with .next/ or used with path.join/path.relative.
 * @param filePath - Absolute path, relative path, or file:// URL (e.g. from import.meta.resolve)
 * @returns A filesystem path suitable for path operations
 */
export function resolveCacheHandlerPathToFilesystem(filePath: string): string {
  if (filePath.startsWith('file://')) {
    return fileURLToPath(filePath)
  }
  return filePath
}

/**
 * The path for a dynamic route must be URLs with a valid scheme.
 *
 * When an absolute Windows path is passed to it, it interprets the beginning of the path as a protocol (`C:`).
 * Therefore, it is important to always construct a complete path.
 * @param dir File directory
 * @param filePath Absolute or relative path, or file:// URL (e.g. from import.meta.resolve)
 */
export const formatDynamicImportPath = (dir: string, filePath: string) => {
  const resolvedFilePath = resolveCacheHandlerPathToFilesystem(filePath)

  const absoluteFilePath = path.isAbsolute(resolvedFilePath)
    ? resolvedFilePath
    : path.join(dir, resolvedFilePath)
  const formattedFilePath = pathToFileURL(absoluteFilePath).toString()

  return formattedFilePath
}