import Combine
import Models
import Services
import SwiftUI
import WebKit

struct SafariWebLink: Identifiable {
  let id: UUID
  let url: URL
}

func encodeHighlightResult(_ highlight: Highlight) -> [String: Any]? {
  let data = try? JSONEncoder().encode(highlight)
  if let data = data, let dictionary = try? JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String: Any] {
    return dictionary
  }
  return nil
}

final class WebReaderViewModel: ObservableObject {
  @Published var isLoading = false
  @Published var articleContent: ArticleContent?

  var subscriptions = Set<AnyCancellable>()

  func loadContent(dataService: DataService, slug: String) {
    isLoading = true

    guard let viewer = dataService.currentViewer else { return }

    dataService.articleContentPublisher(username: viewer.username, slug: slug).sink(
      receiveCompletion: { [weak self] completion in
        guard case .failure = completion else { return }
        self?.isLoading = false
      },
      receiveValue: { [weak self] articleContent in
        self?.articleContent = articleContent
      }
    )
    .store(in: &subscriptions)
  }

  func createHighlight(
    messageBody: [String: Any],
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    dataService.createHighlightPublisher(
      shortId: messageBody["shortId"] as? String ?? "",
      highlightID: messageBody["id"] as? String ?? "",
      quote: messageBody["quote"] as? String ?? "",
      patch: messageBody["patch"] as? String ?? "",
      articleId: messageBody["articleId"] as? String ?? "",
      annotation: messageBody["annotation"] as? String ?? ""
    )
    .sink { completion in
      guard case .failure = completion else { return }
      replyHandler([], "createHighlight: Error encoding response")
    } receiveValue: { highlight in
      if let highlight = encodeHighlightResult(highlight) {
        replyHandler(["result": highlight], nil)
      } else {
        replyHandler([], "createHighlight: Error encoding response")
      }
    }
    .store(in: &subscriptions)
  }

  func deleteHighlight(
    messageBody: [String: Any],
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    dataService.deleteHighlightPublisher(
      highlightId: messageBody["highlightId"] as? String ?? ""
    )
    .sink { completion in
      guard case .failure = completion else { return }
      replyHandler(["result": false], nil)
    } receiveValue: { _ in
      replyHandler(["result": true], nil)
    }
    .store(in: &subscriptions)
  }

  func mergeHighlight(
    messageBody: [String: Any],
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    dataService.mergeHighlightPublisher(
      shortId: messageBody["shortId"] as? String ?? "",
      highlightID: messageBody["id"] as? String ?? "",
      quote: messageBody["quote"] as? String ?? "",
      patch: messageBody["patch"] as? String ?? "",
      articleId: messageBody["articleId"] as? String ?? "",
      overlapHighlightIdList: messageBody["overlapHighlightIdList"] as? [String] ?? []
    )
    .sink { completion in
      guard case .failure = completion else { return }
      replyHandler([], "mergeHighlight: Error encoding response")
    } receiveValue: { highlight in
      if let highlight = encodeHighlightResult(highlight) {
        replyHandler(["result": highlight], nil)
      } else {
        replyHandler([], "mergeHighlight: Error encoding response")
      }
    }
    .store(in: &subscriptions)
  }

  func updateHighlight(
    messageBody: [String: Any],
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    dataService.updateHighlightAttributesPublisher(
      highlightID: messageBody["highlightId"] as? String ?? "",
      annotation: messageBody["annotation"] as? String ?? "",
      sharedAt: nil
    )
    .sink { completion in
      guard case .failure = completion else { return }
      replyHandler([], "updateHighlight: Error encoding response")
    } receiveValue: { highlight in
      // Update highlight JS code just expects the highlight ID back
      replyHandler(["result": highlight.id], nil)
    }
    .store(in: &subscriptions)
  }

  func updateReadingProgress(
    messageBody: [String: Any],
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    let itemID = messageBody["id"] as? String
    let readingProgress = messageBody["readingProgressPercent"] as? Double
    let anchorIndex = messageBody["readingProgressAnchorIndex"] as? Int

    guard let itemID = itemID, let readingProgress = readingProgress, let anchorIndex = anchorIndex else {
      replyHandler(["result": false], nil)
      return
    }

    dataService.updateArticleReadingProgressPublisher(
      itemID: itemID,
      readingProgress: readingProgress,
      anchorIndex: anchorIndex
    )
    .sink { completion in
      guard case .failure = completion else { return }
      replyHandler(["result": false], nil)
    } receiveValue: { _ in
      replyHandler(["result": true], nil)
    }
    .store(in: &subscriptions)
  }

  func webViewActionWithReplyHandler(
    message: WKScriptMessage,
    replyHandler: @escaping WKScriptMessageReplyHandler,
    dataService: DataService
  ) {
    guard let messageBody = message.body as? [String: Any] else { return }
    guard let actionID = messageBody["actionID"] as? String else { return }

    switch actionID {
    case "deleteHighlight":
      deleteHighlight(messageBody: messageBody, replyHandler: replyHandler, dataService: dataService)
    case "createHighlight":
      createHighlight(messageBody: messageBody, replyHandler: replyHandler, dataService: dataService)
    case "mergeHighlight":
      mergeHighlight(messageBody: messageBody, replyHandler: replyHandler, dataService: dataService)
    case "updateHighlight":
      updateHighlight(messageBody: messageBody, replyHandler: replyHandler, dataService: dataService)
    case "articleReadingProgress":
      updateReadingProgress(messageBody: messageBody, replyHandler: replyHandler, dataService: dataService)
    default:
      replyHandler(nil, "Unknown actionID: \(actionID)")
    }
  }
}