import UIKit
import UniformTypeIdentifiers

final class ShareViewController: UIViewController {

    // MARK: – View state

    private enum ViewState {
        case loading
        case success(GetInfoResponse)
        case error(String)
    }

    // MARK: – Header

    private let headerView    = UIView()
    private let headerLabel   = UILabel()
    private let closeButton   = UIButton(type: .system)

    // MARK: – Loading / error

    private let spinner       = UIActivityIndicatorView(style: .large)
    private let messageLabel  = UILabel()

    // MARK: – Metadata card (genişletilebilir — buraya puan/yorum ekleyebilirsin)

    private let scrollView    = UIScrollView()
    /// Bu stack'e ileride yıldız seçici, yorum alanı vb. ekleyebilirsin.
    let contentStack          = UIStackView()

    private let providerLabel = UILabel()
    private let titleLabel    = UILabel()
    private let metaLabel     = UILabel()
    private let genresLabel   = UILabel()
    private let plotLabel     = UILabel()

    // MARK: – Lifecycle

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemBackground
        setupHeader()
        setupLoadingViews()
        setupScrollView()
        Task { await handleIncomingShare() }
    }

    // MARK: – Setup

    private func setupHeader() {
        headerView.backgroundColor = .systemBackground
        headerView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(headerView)

        headerLabel.text = "Ratebubble"
        headerLabel.font = .systemFont(ofSize: 17, weight: .semibold)
        headerLabel.translatesAutoresizingMaskIntoConstraints = false
        headerView.addSubview(headerLabel)

        closeButton.setTitle("Kapat", for: .normal)
        closeButton.addTarget(self, action: #selector(closeTapped), for: .touchUpInside)
        closeButton.translatesAutoresizingMaskIntoConstraints = false
        headerView.addSubview(closeButton)

        let separator = UIView()
        separator.backgroundColor = .separator
        separator.translatesAutoresizingMaskIntoConstraints = false
        headerView.addSubview(separator)

        NSLayoutConstraint.activate([
            headerView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            headerView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            headerView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            headerView.heightAnchor.constraint(equalToConstant: 44),

            headerLabel.centerXAnchor.constraint(equalTo: headerView.centerXAnchor),
            headerLabel.centerYAnchor.constraint(equalTo: headerView.centerYAnchor),

            closeButton.trailingAnchor.constraint(equalTo: headerView.trailingAnchor, constant: -16),
            closeButton.centerYAnchor.constraint(equalTo: headerView.centerYAnchor),

            separator.leadingAnchor.constraint(equalTo: headerView.leadingAnchor),
            separator.trailingAnchor.constraint(equalTo: headerView.trailingAnchor),
            separator.bottomAnchor.constraint(equalTo: headerView.bottomAnchor),
            separator.heightAnchor.constraint(equalToConstant: 0.5),
        ])
    }

    private func setupLoadingViews() {
        spinner.translatesAutoresizingMaskIntoConstraints = false
        spinner.hidesWhenStopped = true
        view.addSubview(spinner)

        messageLabel.text = "Analiz ediliyor..."
        messageLabel.textColor = .secondaryLabel
        messageLabel.textAlignment = .center
        messageLabel.numberOfLines = 0
        messageLabel.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(messageLabel)

        NSLayoutConstraint.activate([
            spinner.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            spinner.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -16),
            messageLabel.topAnchor.constraint(equalTo: spinner.bottomAnchor, constant: 12),
            messageLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 24),
            messageLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -24),
        ])

        spinner.startAnimating()
    }

    private func setupScrollView() {
        scrollView.translatesAutoresizingMaskIntoConstraints = false
        scrollView.alwaysBounceVertical = true
        scrollView.isHidden = true
        view.addSubview(scrollView)

        contentStack.axis = .vertical
        contentStack.spacing = 8
        contentStack.translatesAutoresizingMaskIntoConstraints = false
        scrollView.addSubview(contentStack)

        // Provider (NETFLIX / PRIME VIDEO)
        providerLabel.font = .systemFont(ofSize: 11, weight: .bold)

        // Title
        titleLabel.font = .systemFont(ofSize: 26, weight: .bold)
        titleLabel.numberOfLines = 3

        // Year · Type · Season
        metaLabel.font = .systemFont(ofSize: 14)
        metaLabel.textColor = .secondaryLabel

        // Genres
        genresLabel.font = .systemFont(ofSize: 13)
        genresLabel.textColor = .secondaryLabel
        genresLabel.numberOfLines = 2

        // Plot
        plotLabel.font = .systemFont(ofSize: 14)
        plotLabel.numberOfLines = 5
        plotLabel.textColor = .label

        contentStack.addArrangedSubview(providerLabel)
        contentStack.addArrangedSubview(titleLabel)
        contentStack.setCustomSpacing(4, after: providerLabel)
        contentStack.addArrangedSubview(metaLabel)
        contentStack.addArrangedSubview(genresLabel)
        contentStack.setCustomSpacing(12, after: genresLabel)
        contentStack.addArrangedSubview(plotLabel)

        // ── Buraya ileride yorum/puan UI'ı eklenecek ──

        NSLayoutConstraint.activate([
            scrollView.topAnchor.constraint(equalTo: headerView.bottomAnchor),
            scrollView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            scrollView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            scrollView.bottomAnchor.constraint(equalTo: view.bottomAnchor),

            contentStack.topAnchor.constraint(equalTo: scrollView.topAnchor, constant: 20),
            contentStack.leadingAnchor.constraint(equalTo: scrollView.leadingAnchor, constant: 20),
            contentStack.trailingAnchor.constraint(equalTo: scrollView.trailingAnchor, constant: -20),
            contentStack.widthAnchor.constraint(equalTo: scrollView.widthAnchor, constant: -40),
            contentStack.bottomAnchor.constraint(equalTo: scrollView.bottomAnchor, constant: -32),
        ])
    }

    // MARK: – State application

    @MainActor
    private func apply(_ state: ViewState) {
        switch state {

        case .loading:
            spinner.startAnimating()
            messageLabel.text = "Analiz ediliyor..."
            messageLabel.isHidden = false
            scrollView.isHidden = true

        case .success(let info):
            spinner.stopAnimating()
            messageLabel.isHidden = true

            switch info.provider {
            case "netflix":
                providerLabel.text = "NETFLIX"
                providerLabel.textColor = .systemRed
            case "primevideo":
                providerLabel.text = "PRIME VIDEO"
                providerLabel.textColor = .systemCyan
            default:
                providerLabel.text = info.provider.uppercased()
                providerLabel.textColor = .secondaryLabel
            }

            titleLabel.text = info.title

            var parts: [String] = []
            if let year = info.year { parts.append("\(year)") }
            parts.append(info.type == "movie" ? "Film" : "Dizi")
            if let season = info.currentSeason { parts.append("Sezon \(season)") }
            metaLabel.text = parts.joined(separator: " · ")

            if info.genres.isEmpty {
                genresLabel.isHidden = true
            } else {
                genresLabel.text = info.genres.joined(separator: ", ")
                genresLabel.isHidden = false
            }

            if let plot = info.plot, !plot.isEmpty {
                plotLabel.text = plot
                plotLabel.isHidden = false
            } else {
                plotLabel.isHidden = true
            }

            scrollView.isHidden = false

        case .error(let message):
            spinner.stopAnimating()
            messageLabel.text = message
            messageLabel.isHidden = false
            scrollView.isHidden = true
        }
    }

    // MARK: – Share handling

    @MainActor
    private func handleIncomingShare() async {
        let items = extensionContext?.inputItems.compactMap { $0 as? NSExtensionItem } ?? []
        let providers = items.flatMap { $0.attachments ?? [] }

        guard !providers.isEmpty else {
            apply(.error("Paylaşılan içerik okunamadı."))
            return
        }

        for provider in providers {
            if let extracted = await extractURL(from: provider), isSupportedStreamingURL(extracted) {
                // Ana uygulama arka planda açılırsa URL'i görmesi için sakla
                SharedPayloadStore.saveIncomingURL(extracted.absoluteString)

                do {
                    let info = try await APIClient.shared.getInfo(url: extracted.absoluteString)
                    apply(.success(info))
                } catch {
                    apply(.error("Bilgiler alınamadı:\n\(error.localizedDescription)"))
                }
                return
            }
        }

        apply(.error("Geçerli bir Netflix/Prime Video linki bulunamadı."))
    }

    // MARK: – Actions

    @objc private func closeTapped() {
        extensionContext?.completeRequest(returningItems: nil, completionHandler: nil)
    }

    // MARK: – URL helpers

    private func extractURL(from provider: NSItemProvider) async -> URL? {
        if provider.hasItemConformingToTypeIdentifier(UTType.url.identifier) {
            return await withCheckedContinuation { continuation in
                provider.loadItem(forTypeIdentifier: UTType.url.identifier, options: nil) { item, _ in
                    if let url = item as? URL {
                        continuation.resume(returning: url)
                        return
                    }
                    if let raw = item as? String {
                        continuation.resume(returning: Self.firstURL(in: raw))
                        return
                    }
                    continuation.resume(returning: nil)
                }
            }
        }

        if provider.hasItemConformingToTypeIdentifier(UTType.text.identifier) {
            return await withCheckedContinuation { continuation in
                provider.loadItem(forTypeIdentifier: UTType.text.identifier, options: nil) { item, _ in
                    if let raw = item as? String, let url = Self.firstURL(in: raw) {
                        continuation.resume(returning: url)
                        return
                    }
                    continuation.resume(returning: nil)
                }
            }
        }

        return nil
    }

    private func isSupportedStreamingURL(_ url: URL) -> Bool {
        let host = url.host?.lowercased() ?? ""
        let netflixHosts = ["www.netflix.com", "netflix.com", "www.netflix.com.tr", "netflix.com.tr"]
        let primeHosts   = ["www.primevideo.com", "primevideo.com", "www.amazon.com", "amazon.com"]

        guard netflixHosts.contains(host) || primeHosts.contains(host) else { return false }

        let path = url.path.lowercased()
        if path.contains("/title/") || path.contains("/watch/") || path.contains("/detail/") {
            return true
        }
        return !path.isEmpty && path != "/"
    }

    private static func firstURL(in raw: String) -> URL? {
        let text = raw.trimmingCharacters(in: .whitespacesAndNewlines)
        if let url = URL(string: text), url.scheme?.isEmpty == false { return url }
        guard let detector = try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue) else {
            return nil
        }
        let range = NSRange(text.startIndex..<text.endIndex, in: text)
        return detector.firstMatch(in: text, options: [], range: range)?.url
    }
}