import Dependencies
import DependenciesMacros
import Foundation

public extension DependencyValues {
  var fileClient: FileClient {
    get { self[FileClient.self] }
    set { self[FileClient.self] = newValue }
  }
}

@DependencyClient
public struct FileClient: Sendable {
  public var copy: @Sendable (URL, URL) async throws -> Void
  public var fileExists: @Sendable (URL) -> Bool = { _ in true }
  public var homeDirectory: @Sendable () -> URL = { URL(filePath: "~/") }
  public var load: @Sendable (URL) async throws -> Data
  public var write: @Sendable (Data, URL) async throws -> Void
}

extension FileClient: DependencyKey {
  public static let testValue: FileClient = Self()

  public static var liveValue: Self {
    let manager = LiveFileClient()
    return .init {
      try await manager.copy($0, to: $1)
    } fileExists: { url in
      manager.fileExists(at: url)
    } homeDirectory: {
      manager.homeDirectory()
    } load: { url in
      try await manager.load(from: url)
    } write: { data, url in
      try await manager.write(data, to: url)
    }
  }
}

struct LiveFileClient: Sendable {

  private var manager: FileManager { FileManager.default }

  func copy(_ url: URL, to toUrl: URL) async throws {
    try manager.copyItem(at: url, to: toUrl)
  }

  func fileExists(at url: URL) -> Bool {
    manager.fileExists(atPath: url.absoluteString.replacing("file://", with: ""))
  }

  func homeDirectory() -> URL {
    manager.homeDirectoryForCurrentUser
  }

  func load(from url: URL) async throws -> Data {
    try Data(contentsOf: url)
  }

  func write(_ data: Data, to url: URL) async throws {
    try data.write(to: url)
  }
}