import Foundation

struct ServerConfig: Equatable {
    let baseURL: URL
    let livekitURL: URL

    enum ConfigError: LocalizedError, Equatable {
        case notHTTPS(String)
        case invalidURL(String)

        var errorDescription: String? {
            switch self {
            case .notHTTPS(let raw):
                return "Server URL must use https: \(raw)"
            case .invalidURL(let raw):
                return "Invalid server URL: \(raw)"
            }
        }
    }

    static func parse(_ raw: String) -> Result<ServerConfig, ConfigError> {
        let trimmed = raw.trimmingCharacters(in: .whitespacesAndNewlines)
        guard !trimmed.isEmpty else { return .failure(.invalidURL(raw)) }
        var candidate = trimmed
        if !candidate.contains("://") { candidate = "https://" + candidate }
        guard let components = URLComponents(string: candidate),
              let scheme = components.scheme?.lowercased(),
              let host = components.host, !host.isEmpty else {
            return .failure(.invalidURL(raw))
        }
        if scheme != "https" { return .failure(.notHTTPS(raw)) }
        var c = components
        c.path = ""
        c.fragment = nil
        guard let base = c.url else { return .failure(.invalidURL(raw)) }
        // LAN deployment: LiveKit is reachable directly on :7880 (plain ws).
        // Real domains use wss via same origin. The SDK derives /rtc from the base.
        let livekit: URL
        if Self.isPrivateIP(host) {
            livekit = URL(string: "ws://\(host):7880")!
        } else {
            let portSuffix = components.port.map { ":\($0)" } ?? ""
            livekit = URL(string: "wss://\(host)\(portSuffix)/livekit")!
        }
        return .success(ServerConfig(baseURL: base, livekitURL: livekit))
    }

    static func isPrivateIP(_ host: String) -> Bool {
        let parts = host.split(separator: ".").compactMap { UInt8($0) }
        guard parts.count == 4 else { return false }
        return parts[0] == 10
            || (parts[0] == 172 && (16...31).contains(parts[1]))
            || (parts[0] == 192 && parts[1] == 168)
    }

    var host: String { baseURL.host ?? "" }
}