import Foundation

/// Cross-process (main app ⇆ share extension) queue of podcast-generation
/// requests, plus the user's "auto-generate for these tags" rule. Lives in the
/// shared App Group so the share extension can enqueue work the main app runs —
/// the extension itself is too short-lived to generate audio.
enum PodcastRequests {
    private static let appGroupId = "group.com.magicive.marks"
    private static let pendingKey = "pendingPodcastRequests"
    private static let autoTagsKey = "podcastAutoTags"

    private static var defaults: UserDefaults? { UserDefaults(suiteName: appGroupId) }

    struct Request: Codable {
        let url: String
        let title: String
    }

    // MARK: - Pending queue

    /// Enqueue a request. De-duplicates on URL so repeated saves don't pile up.
    static func enqueue(url: String, title: String) {
        var list = pending()
        guard !list.contains(where: { $0.url == url }) else { return }
        list.append(Request(url: url, title: title))
        save(list)
    }

    static func pending() -> [Request] {
        guard let data = defaults?.data(forKey: pendingKey),
              let list = try? JSONDecoder().decode([Request].self, from: data) else { return [] }
        return list
    }

    /// Return everything pending and clear the queue.
    static func drain() -> [Request] {
        let list = pending()
        defaults?.removeObject(forKey: pendingKey)
        return list
    }

    private static func save(_ list: [Request]) {
        guard let data = try? JSONEncoder().encode(list) else { return }
        defaults?.set(data, forKey: pendingKey)
    }

    // MARK: - Auto-tag rule

    /// Tags that auto-trigger podcast generation when a bookmark is saved.
    static var autoTags: [String] {
        get { defaults?.stringArray(forKey: autoTagsKey) ?? [] }
        set { defaults?.set(newValue, forKey: autoTagsKey) }
    }

    /// Whether saving a bookmark with `tags` should auto-generate a podcast.
    static func matchesAutoTag(_ tags: [String]) -> Bool {
        let auto = Set(autoTags.map { $0.lowercased() })
        guard !auto.isEmpty else { return false }
        return tags.contains { auto.contains($0.lowercased()) }
    }
}