// The owner's collector (stream-audit §12), as a player reaches it: a session's bundle to
// `v1/sessions` when it ends, and its Event-mode CMCD batches to `v1/cmcd` while it plays.
import Foundation

public final class WaiCollector: @unchecked Sendable {
    public let base: URL
    private let session: URLSession

    public init(base: URL, session: URLSession = URLSession(configuration: .ephemeral)) {
        self.base = base
        self.session = session
    }

    /// Post a bundle; the collector's status and answer.
    public func postSession(_ bundle: Data, completion: @escaping @Sendable (Int, Data?) -> Void = { _, _ in }) {
        post("v1/sessions", type: "text/plain;charset=UTF-8", body: bundle, completion: completion)
    }

    /// Post an `application/cmcd` batch. Telemetry is advisory: a failure is dropped
    /// (stream-audit §7.2).
    public func postCMCD(_ batch: String) {
        guard !batch.isEmpty else { return }
        post("v1/cmcd", type: "application/cmcd", body: Data(batch.utf8)) { _, _ in }
    }

    private func post(_ path: String, type: String, body: Data, completion: @escaping @Sendable (Int, Data?) -> Void) {
        var r = URLRequest(url: base.appendingPathComponent(path))
        r.httpMethod = "POST"
        r.setValue(type, forHTTPHeaderField: "Content-Type")
        r.httpBody = body
        session.dataTask(with: r) { d, resp, _ in completion((resp as? HTTPURLResponse)?.statusCode ?? 0, d) }.resume()
    }
}