import AVFoundation
import Foundation
import Siesta

protocol VideosAPI {
    var account: Account! { get }
    var signedIn: Bool { get }

    static func withAnonymousAccountForInstanceURL(_ url: URL) -> Self

    func channel(_ id: String, contentType: Channel.ContentType, data: String?, page: String?) -> Resource
    func channelByName(_ name: String) -> Resource?
    func channelByUsername(_ username: String) -> Resource?
    func channelVideos(_ id: String) -> Resource
    func trending(country: Country, category: TrendingCategory?) -> Resource
    func search(_ query: SearchQuery, page: String?) -> Resource
    func searchSuggestions(query: String) -> Resource

    func video(_ id: Video.ID) -> Resource

    func feed(_ page: Int?) -> Resource?
    var subscriptions: Resource? { get }
    var home: Resource? { get }
    var popular: Resource? { get }
    var playlists: Resource? { get }

    func subscribe(_ channelID: String, onCompletion: @escaping () -> Void)
    func unsubscribe(_ channelID: String, onCompletion: @escaping () -> Void)

    func playlist(_ id: String) -> Resource?
    func playlistVideo(_ playlistID: String, _ videoID: String) -> Resource?
    func playlistVideos(_ id: String) -> Resource?

    func addVideoToPlaylist(
        _ videoID: String,
        _ playlistID: String,
        onFailure: @escaping (RequestError) -> Void,
        onSuccess: @escaping () -> Void
    )

    func removeVideoFromPlaylist(
        _ index: String,
        _ playlistID: String,
        onFailure: @escaping (RequestError) -> Void,
        onSuccess: @escaping () -> Void
    )

    func playlistForm(
        _ name: String,
        _ visibility: String,
        playlist: Playlist?,
        onFailure: @escaping (RequestError) -> Void,
        onSuccess: @escaping (Playlist?) -> Void
    )

    func deletePlaylist(
        _ playlist: Playlist,
        onFailure: @escaping (RequestError) -> Void,
        onSuccess: @escaping () -> Void
    )

    func channelPlaylist(_ id: String) -> Resource?

    func loadDetails(
        _ item: PlayerQueueItem,
        failureHandler: ((RequestError) -> Void)?,
        completionHandler: @escaping (PlayerQueueItem) -> Void
    )
    func shareURL(_ item: ContentItem, frontendURLString: String?, time: CMTime?) -> URL?

    func comments(_ id: Video.ID, page: String?) -> Resource?
}

extension VideosAPI {
    func channel(_ id: String, contentType: Channel.ContentType, data: String? = nil, page: String? = nil) -> Resource {
        channel(id, contentType: contentType, data: data, page: page)
    }

    func loadDetails(
        _ item: PlayerQueueItem,
        failureHandler: ((RequestError) -> Void)? = nil,
        completionHandler: @escaping (PlayerQueueItem) -> Void = { _ in }
    ) {
        guard (item.video?.streams ?? []).isEmpty else {
            completionHandler(item)
            return
        }

        if let video = item.video, video.isLocal {
            completionHandler(item)
            return
        }

        video(item.videoID).load()
            .onSuccess { response in
                guard let video: Video = response.typedContent() else {
                    return
                }

                VideosCacheModel.shared.storeVideo(video)

                var newItem = item
                newItem.id = UUID()
                newItem.video = video

                completionHandler(newItem)
            }
            .onFailure { failureHandler?($0) }
    }

    func shareURL(_ item: ContentItem, frontendURLString: String? = nil, time: CMTime? = nil) -> URL? {
        var urlComponents: URLComponents?
        if let frontendURLString,
           let frontendURL = URL(string: frontendURLString)
        {
            urlComponents = URLComponents(url: frontendURL, resolvingAgainstBaseURL: false)
        } else if let instanceComponents = account?.instance?.urlComponents {
            urlComponents = instanceComponents
        }

        guard var urlComponents else {
            return nil
        }

        var queryItems = [URLQueryItem]()

        switch item.contentType {
        case .video:
            urlComponents.path = "/watch"
            queryItems.append(.init(name: "v", value: item.video.videoID))
        case .channel:
            urlComponents.path = "/channel/\(item.channel.id)"
        case .playlist:
            urlComponents.path = "/playlist"
            queryItems.append(.init(name: "list", value: item.playlist.id))
        default:
            return nil
        }

        if !time.isNil, time!.seconds.isFinite {
            queryItems.append(.init(name: "t", value: "\(Int(time!.seconds))s"))
        }

        if !queryItems.isEmpty {
            urlComponents.queryItems = queryItems
        }

        return urlComponents.url
    }

    func extractChapters(from description: String) -> [Chapter] {
        /*
         The following chapter patterns are covered:

         start - end - title / start - end: Title / start - end title
         start - title / start: title / start title / [start] - title / [start]: title / [start] title
         index. title - start / index. title start
         title: (start)

         The order is important!
         */
        let patterns = [
            "(?<=\\n|^)\\s*(?:►\\s*)?\\[?(?<start>(?:[0-9]+:){1,2}[0-9]+)\\]?(?:\\s*-\\s*)?(?<end>(?:[0-9]+:){1,2}[0-9]+)?(?:\\s*-\\s*|\\s*[:]\\s*)?(?<title>.*)(?=\\n|$)",
            "(?<=\\n|^)\\s*(?:►\\s*)?\\[?(?<start>(?:[0-9]+:){1,2}[0-9]+)\\]?\\s*[-:]?\\s*(?<title>.+)(?=\\n|$)",
            "(?<=\\n|^)(?<index>[0-9]+\\.\\s)(?<title>.+?)(?:\\s*-\\s*)?(?<start>(?:[0-9]+:){1,2}[0-9]+)(?=\\n|$)",
            "(?<=\\n|^)(?<title>.+?):\\s*\\((?<start>(?:[0-9]+:){1,2}[0-9]+)\\)(?=\\n|$)"
        ]

        for pattern in patterns {
            guard let chaptersRegularExpression = try? NSRegularExpression(pattern: pattern, options: .caseInsensitive) else { continue }
            let chapterLines = chaptersRegularExpression.matches(in: description, range: NSRange(description.startIndex..., in: description))

            if !chapterLines.isEmpty {
                return chapterLines.compactMap { line in
                    let titleRange = line.range(withName: "title")
                    let startRange = line.range(withName: "start")
                    guard let titleSubstringRange = Range(titleRange, in: description),
                          let startSubstringRange = Range(startRange, in: description)
                    else {
                        return nil
                    }
                    let titleCapture = String(description[titleSubstringRange]).trimmingCharacters(in: .whitespaces)
                    let startCapture = String(description[startSubstringRange])
                    let startComponents = startCapture.components(separatedBy: ":")
                    guard startComponents.count <= 3 else { return nil }

                    var hours: Double?
                    var minutes: Double?
                    var seconds: Double?

                    if startComponents.count == 3 {
                        hours = Double(startComponents[0])
                        minutes = Double(startComponents[1])
                        seconds = Double(startComponents[2])
                    } else if startComponents.count == 2 {
                        minutes = Double(startComponents[0])
                        seconds = Double(startComponents[1])
                    }

                    guard var startSeconds = seconds else { return nil }

                    startSeconds += (minutes ?? 0) * 60
                    startSeconds += (hours ?? 0) * 60 * 60

                    return .init(title: titleCapture, start: startSeconds)
                }
            }
        }
        return []
    }
}