//
//  DebridManager.swift
//  Ferrite
//
//  Created by Brian Dashore on 7/20/22.
//

import Foundation
import SwiftUI

@MainActor
public class DebridManager: ObservableObject {
    // UI Variables
    var toastModel: ToastViewModel?
    @Published var showWebView: Bool = false
    @Published var showLoadingProgress: Bool = false

    // Service agnostic variables
    @Published var currentDebridTask: Task<Void, Never>?

    // RealDebrid auth variables
    let realDebrid: RealDebrid = .init()

    @Published var realDebridEnabled: Bool = false {
        didSet {
            UserDefaults.standard.set(realDebridEnabled, forKey: "RealDebrid.Enabled")
        }
    }

    @Published var realDebridAuthProcessing: Bool = false
    @Published var realDebridAuthUrl: String = ""

    // RealDebrid fetch variables
    @Published var realDebridHashes: [RealDebridIA] = []
    @Published var realDebridDownloadUrl: String = ""
    @Published var selectedRealDebridItem: RealDebridIA?
    @Published var selectedRealDebridFile: RealDebridIAFile?

    init() {
        realDebridEnabled = UserDefaults.standard.bool(forKey: "RealDebrid.Enabled")
    }

    public func populateDebridHashes(_ searchResults: [SearchResult]) async {
        var hashes: [String] = []

        for result in searchResults {
            if let hash = result.magnetHash {
                hashes.append(hash)
            }
        }

        do {
            let debridHashes = try await realDebrid.instantAvailability(magnetHashes: hashes)

            realDebridHashes = debridHashes
        } catch {
            let error = error as NSError

            if error.code != -999 {
                toastModel?.updateToastDescription("RealDebrid hash error: \(error)")
            }

            print("RealDebrid hash error: \(error)")
        }
    }

    public func matchSearchResult(result: SearchResult?) -> RealDebridIAStatus {
        guard let result = result else {
            return .none
        }

        guard let debridMatch = realDebridHashes.first(where: { result.magnetHash == $0.hash }) else {
            return .none
        }

        if debridMatch.batches.isEmpty {
            return .full
        } else {
            return .partial
        }
    }

    public func setSelectedRdResult(result: SearchResult) -> Bool {
        guard let magnetHash = result.magnetHash else {
            toastModel?.updateToastDescription("Could not find the torrent magnet hash")
            return false
        }

        if let realDebridItem = realDebridHashes.first(where: { magnetHash == $0.hash }) {
            selectedRealDebridItem = realDebridItem
            return true
        } else {
            toastModel?.updateToastDescription("Could not find the associated RealDebrid entry for magnet hash \(magnetHash)")
            return false
        }
    }

    public func authenticateRd() async {
        do {
            realDebridAuthProcessing = true
            let verificationResponse = try await realDebrid.getVerificationInfo()

            realDebridAuthUrl = verificationResponse.directVerificationURL
            showWebView.toggle()

            try await realDebrid.getDeviceCredentials(deviceCode: verificationResponse.deviceCode)

            realDebridEnabled = true
        } catch {
            toastModel?.updateToastDescription("RealDebrid authentication error: \(error)")
            realDebrid.authTask?.cancel()

            print("RealDebrid authentication error: \(error)")
        }
    }

    public func logoutRd() async {
        do {
            try await realDebrid.deleteTokens()
            realDebridEnabled = false
            realDebridAuthProcessing = false
        } catch {
            toastModel?.updateToastDescription("RealDebrid logout error: \(error)")

            print("RealDebrid logout error: \(error)")
        }
    }

    public func fetchRdDownload(searchResult: SearchResult, iaFile: RealDebridIAFile? = nil) async {
        defer {
            currentDebridTask = nil
            showLoadingProgress = false
        }

        showLoadingProgress = true

        guard let magnetLink = searchResult.magnetLink else {
            toastModel?.updateToastDescription("Could not run your action because the magnet link is invalid.")
            print("RealDebrid error: Invalid magnet link")

            return
        }

        var realDebridId: String?

        do {
            realDebridId = try await realDebrid.addMagnet(magnetLink: magnetLink)

            var fileIds: [Int] = []

            if let iaFile = iaFile {
                guard let iaBatchFromFile = selectedRealDebridItem?.batches[safe: iaFile.batchIndex] else {
                    return
                }

                fileIds = iaBatchFromFile.files.map(\.id)
            }

            if let realDebridId = realDebridId {
                try await realDebrid.selectFiles(debridID: realDebridId, fileIds: fileIds)

                let torrentLink = try await realDebrid.torrentInfo(debridID: realDebridId, selectedIndex: iaFile?.batchFileIndex ?? 0)
                let downloadLink = try await realDebrid.unrestrictLink(debridDownloadLink: torrentLink)

                realDebridDownloadUrl = downloadLink
            } else {
                toastModel?.updateToastDescription("Could not cache this torrent. Aborting.")
            }
        } catch {
            let error = error as NSError

            switch error.code {
            case -999:
                toastModel?.updateToastDescription("Download cancelled", newToastType: .info)
            default:
                toastModel?.updateToastDescription("RealDebrid download error: \(error)")
            }

            // Delete the torrent download if it exists
            if let realDebridId = realDebridId {
                try? await realDebrid.deleteTorrent(debridID: realDebridId)
            }

            showLoadingProgress = false

            print("RealDebrid download error: \(error)")
        }
    }
}