import Foundation
import RemoteCore

/// Prototype wire format to verify against physical TV models. No network or TLS
/// policy is implemented here. In particular, callers must never disable trust checks.
public enum SamsungRemoteEncoder {
    public static let clientName = "Wristivo"

    public static func key(for command: RemoteCommand) -> String {
        switch command {
        case .up: "KEY_UP"
        case .down: "KEY_DOWN"
        case .left: "KEY_LEFT"
        case .right: "KEY_RIGHT"
        case .select: "KEY_ENTER"
        case .back: "KEY_RETURN"
        case .home: "KEY_HOME"
        case .playPause: "KEY_PLAYPAUSE"
        case .volumeUp: "KEY_VOLUP"
        case .volumeDown: "KEY_VOLDOWN"
        case .mute: "KEY_MUTE"
        }
    }

    public static func clickFrame(for command: RemoteCommand) throws -> Data {
        try JSONEncoder().encode(Frame(params: Parameters(DataOfCmd: key(for: command))))
    }

    public enum EndpointError: Error, Sendable { case invalidHost }

    /// Accepts a bare hostname or IPv4 address, or a bracketed IPv6 literal.
    /// Treat token as a secret: do not log the returned URL or persist it in telemetry.
    public static func endpoint(host: String, token: String? = nil) throws -> URL {
        guard !host.isEmpty, !host.contains(where: { $0.isWhitespace }),
              !host.contains("/"), !host.contains("@"),
              !host.contains("?"), !host.contains("#"),
              !host.contains("%"), !host.contains("\\"),
              (!host.contains(":") || (host.hasPrefix("[") && host.hasSuffix("]"))) else {
            throw EndpointError.invalidHost
        }
        var parts = URLComponents()
        parts.scheme = "wss"
        parts.host = host
        parts.port = 8002
        parts.path = "/api/v2/channels/samsung.remote.control"
        var items = [URLQueryItem(name: "name", value: Data(clientName.utf8).base64EncodedString())]
        if let token { items.append(URLQueryItem(name: "token", value: token)) }
        parts.queryItems = items
        // '+' is legal in an RFC 3986 query, but some embedded servers treat it as
        // a form-space. Encode it explicitly while retaining URLComponents escaping.
        parts.percentEncodedQuery = parts.percentEncodedQuery?.replacingOccurrences(of: "+", with: "%2B")
        guard let url = parts.url, url.host != nil else { throw EndpointError.invalidHost }
        return url
    }

    private struct Frame: Encodable {
        let method = "ms.remote.control"
        let params: Parameters
    }
    private struct Parameters: Encodable {
        let Cmd = "Click"
        let DataOfCmd: String
        let Option = "false"
        let TypeOfRemote = "SendRemoteKey"
    }
}