import Dependencies
import Foundation
import ShellClient

@_spi(Internal)
public func findConfigurationFiles(
  env: [String: String] = ProcessInfo.processInfo.environment
) throws -> [URL] {
  @Dependency(\.logger) var logger
  @Dependency(\.fileClient) var fileClient

  logger.debug("Begin find configuration files.")
  logger.trace("Env: \(env)")

  let homeDir = fileClient.homeDir()
  var url = homeDir.appending(path: ".hparc")

  if fileClient.isReadable(url) {
    logger.debug("Found configuration in home directory")
    return [url]
  }

  if let configHome = env["HPA_CONFIG_HOME"] {
    url = .init(filePath: configHome)

    if fileClient.isDirectory(url) {
      logger.debug("Found configuration directory from hpa config home env var.")
      return try fileClient.contentsOfDirectory(url)
    }
    if fileClient.isReadable(url) {
      logger.debug("Found configuration from hpa config home env var.")
      return [url]
    }
  }

  if let pwd = env["PWD"] {
    url = .init(filePath: "\(pwd)").appending(path: ".hparc")
    if fileClient.isReadable(url) {
      logger.debug("Found configuration in current working directory.")
      return [url]
    }
  }

  if let xdgConfigHome = env["XDG_CONFIG_HOME"] {
    logger.debug("XDG Config Home: \(xdgConfigHome)")

    url = .init(filePath: "\(xdgConfigHome)")
      .appending(path: "hpa-playbook")

    logger.debug("XDG Config url: \(url.absoluteString)")

    if fileClient.isDirectory(url) {
      logger.debug("Found configuration in xdg config home.")
      return try fileClient.contentsOfDirectory(url)
    }

    if fileClient.isReadable(url) {
      logger.debug("Not directory, but readable.")
      return [url]
    }
  }

  // We could not find configuration in any usual places.
  throw ConfigurationError.configurationNotFound
}

func path(for url: URL) -> String {
  url.absoluteString.replacing("file://", with: "")
}

enum ConfigurationError: Error {
  case configurationNotFound
}