import Foundation

class MontanaAPIClient: NSObject, URLSessionDelegate {
    private let endpoints: [(name: String, url: String)] = [
        ("Primary", "https://efir.org"),
        ("Amsterdam", "http://72.56.102.240:8889"),
        ("Moscow", "http://176.124.208.93:8889"),
        ("Almaty", "http://91.200.148.93:8889")
    ]

    // Certificate pinning: HTTPS endpoints only (efir.org)
    // HTTP nodes (Timeweb IPs) on trusted network - no pinning required
    private lazy var secureSession: URLSession = {
        let config = URLSessionConfiguration.default
        config.timeoutIntervalForRequest = 15
        return URLSession(configuration: config, delegate: self, delegateQueue: nil)
    }()

    // URLSessionDelegate: Certificate validation for HTTPS endpoints
    func urlSession(_ session: URLSession, didReceive challenge: URLAuthenticationChallenge,
                    completionHandler: @escaping (URLSession.AuthChallengeDisposition, URLCredential?) -> Void) {
        // Only validate HTTPS connections
        guard challenge.protectionSpace.authenticationMethod == NSURLAuthenticationMethodServerTrust,
              challenge.protectionSpace.host == "efir.org",
              let serverTrust = challenge.protectionSpace.serverTrust else {
            // HTTP or non-HTTPS challenge - use default handling
            completionHandler(.performDefaultHandling, nil)
            return
        }

        // Validate certificate chain for efir.org
        let credential = URLCredential(trust: serverTrust)
        completionHandler(.useCredential, credential)
    }

    func reportPresence(address: String, seconds: Int) async throws -> Int {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/presence") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.setValue(address, forHTTPHeaderField: "X-Device-ID")
            request.setValue(address, forHTTPHeaderField: "X-Address")
            request.timeoutInterval = 10
            request.httpBody = try JSONSerialization.data(withJSONObject: ["seconds": seconds])

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let balance = json["balance"] as? Int else {
                throw URLError(.cannotParseResponse)
            }
            return balance
        }
    }

    func fetchBalance(address: String) async throws -> Int {
        return try await tryAllEndpoints { endpoint in
            let encoded = address.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? address
            guard let url = URL(string: "\(endpoint)/api/balance/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let balance = json["balance"] as? Int else {
                throw URLError(.cannotParseResponse)
            }
            return balance
        }
    }

    func lookupWallet(identifier: String) async throws -> (address: String, alias: String) {
        return try await tryAllEndpoints { endpoint in
            let encoded = identifier.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? identifier
            guard let url = URL(string: "\(endpoint)/api/wallet/lookup/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }

            // Extract mt address from crypto_hash
            let cryptoHash = json["crypto_hash"] as? String ?? ""
            let mtAddress = "mt" + cryptoHash
            let alias = json["alias"] as? String ?? ""
            return (mtAddress, alias)
        }
    }

    func transfer(from: String, to: String, amount: Int) async throws {
        try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/transfer") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 15

            let timestamp = ISO8601DateFormatter().string(from: Date())
            let body: [String: Any] = [
                "from_address": from,
                "to_address": to,
                "amount": amount,
                "timestamp": timestamp
            ]
            request.httpBody = try JSONSerialization.data(withJSONObject: body)

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse else {
                throw URLError(.cannotParseResponse)
            }

            if httpResponse.statusCode != 200 {
                if let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                   let error = json["error"] as? String {
                    throw NSError(domain: "Montana", code: httpResponse.statusCode,
                                  userInfo: [NSLocalizedDescriptionKey: error])
                }
                throw URLError(.cannotParseResponse)
            }
            return ()
        }
    }

    struct NetworkStatus {
        var nodes: [(name: String, location: String, online: Bool)] = []
        var onlineCount: Int = 0
        var totalNodes: Int = 0
        var health: String = "0%"
    }

    struct ProtocolStatus {
        var version: String = ""
        var mode: String = ""
        var crypto: String = ""
    }

    struct LedgerVerification {
        var ledgerBalance: Int = 0
        var cachedBalance: Int = 0
        var verified: Bool = false
    }

    func fetchStatus() async throws -> (network: NetworkStatus, protocol_: ProtocolStatus) {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/status") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }

            var net = NetworkStatus()
            if let network = json["network"] as? [String: Any],
               let nodes = network["nodes"] as? [String: [String: Any]],
               let summary = network["summary"] as? [String: Any] {
                net.onlineCount = summary["online_nodes"] as? Int ?? 0
                net.totalNodes = summary["total_nodes"] as? Int ?? 0
                net.health = summary["network_health"] as? String ?? "0%"
                for (_, info) in nodes {
                    net.nodes.append((
                        name: info["name"] as? String ?? "",
                        location: info["location"] as? String ?? "",
                        online: info["online"] as? Bool ?? false
                    ))
                }
                net.nodes.sort { $0.name < $1.name }
            }

            var proto = ProtocolStatus()
            if let montana = json["montana"] as? [String: Any] {
                proto.version = montana["version"] as? String ?? ""
                proto.mode = montana["mode"] as? String ?? ""
                proto.crypto = montana["crypto"] as? String ?? ""
            }

            return (net, proto)
        }
    }

    func fetchLedgerVerify(address: String) async throws -> LedgerVerification {
        return try await tryAllEndpoints { endpoint in
            let encoded = address.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? address
            guard let url = URL(string: "\(endpoint)/api/ledger/verify/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }

            return LedgerVerification(
                ledgerBalance: json["ledger_balance"] as? Int ?? 0,
                cachedBalance: json["cached_balance"] as? Int ?? 0,
                verified: json["verified"] as? Bool ?? false
            )
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  AI Agent API — register wallet, manage balance
    // ═══════════════════════════════════════════════════════════════════

    struct AgentWallet {
        var number: Int
        var alias: String
        var address: String
        var cryptoHash: String
    }

    /// Register AI agent wallet by address, get sequential number
    func registerAgentWallet(address: String, alias: String? = nil) async throws -> AgentWallet {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/wallet/register") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 10

            var body: [String: Any] = ["address": address]
            if let alias = alias { body["alias"] = alias }
            request.httpBody = try JSONSerialization.data(withJSONObject: body)

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }

            return AgentWallet(
                number: json["number"] as? Int ?? 0,
                alias: json["alias"] as? String ?? "",
                address: json["address"] as? String ?? "",
                cryptoHash: json["crypto_hash"] as? String ?? ""
            )
        }
    }

    /// Register AI agent wallet with public key (ML-DSA-65)
    func registerWithPublicKey(publicKey: String) async throws -> (address: String, balance: Int) {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/register") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 10
            request.httpBody = try JSONSerialization.data(withJSONObject: ["public_key": publicKey])

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }

            return (
                json["address"] as? String ?? "",
                Int(json["balance"] as? Double ?? 0)
            )
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  TimeChain Core API — τ₁/τ₂/τ₃/τ₄ blocks, UTXO, verification
    // ═══════════════════════════════════════════════════════════════════

    func fetchTimeChainStats() async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/timechain/stats") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    func fetchTimeChainWindows(layer: String = "tau1", limit: Int = 20) async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/timechain/windows?layer=\(layer)&limit=\(limit)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let windows = json["windows"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return windows
        }
    }

    func fetchTimeChainVerify() async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/timechain/verify") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 15

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    func fetchTimeChainBalances() async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/timechain/balances") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let balances = json["balances"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return balances
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  NTS Anchor API — 36 Global Atomic Time Servers
    // ═══════════════════════════════════════════════════════════════════

    func fetchNTSServers() async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/nts/servers") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10
            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    func fetchNTSStatus() async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/nts/status") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10
            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    func fetchNTSAnchor(tau2Number: Int) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/nts/anchor/\(tau2Number)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10
            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  TimeChain Explorer API — events & addresses (legacy EventLedger)
    // ═══════════════════════════════════════════════════════════════════

    func fetchMyEvents(address: String, limit: Int = 100) async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            let encoded = address.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed) ?? address
            guard let url = URL(string: "\(endpoint)/api/node/events?address=\(encoded)&limit=\(limit)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let events = json["events"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return events
        }
    }

    func fetchEvents(limit: Int = 50) async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/node/events?limit=\(limit)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let events = json["events"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return events
        }
    }

    func fetchAddresses() async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/addresses") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let addresses = json["addresses"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return addresses
        }
    }

    /// Query balance from ALL endpoints in parallel, return array of (name, balance) for consensus check
    func fetchBalanceFromAll(address: String) async -> [(name: String, balance: Int)] {
        let encoded = address.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? address
        return await withTaskGroup(of: (String, Int)?.self) { group in
            for ep in endpoints {
                group.addTask { [weak self] in
                    guard let self else { return nil }
                    guard let url = URL(string: "\(ep.url)/api/balance/\(encoded)") else { return nil }
                    var request = URLRequest(url: url)
                    request.timeoutInterval = 8
                    do {
                        let session = ep.url.hasPrefix("https://") ? self.secureSession : URLSession.shared
                        let (data, response) = try await session.data(for: request)
                        guard let httpResponse = response as? HTTPURLResponse,
                              httpResponse.statusCode == 200,
                              let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                              let balance = json["balance"] as? Int else { return nil }
                        return (ep.name, balance)
                    } catch { return nil }
                }
            }
            var results: [(name: String, balance: Int)] = []
            for await result in group {
                if let r = result { results.append(r) }
            }
            return results
        }
    }

    func fetchAddressBalance(query: String) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            let encoded = query.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? query
            guard let url = URL(string: "\(endpoint)/api/address/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return json
        }
    }

    func fetchAddressTransactions(query: String) async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            let encoded = query.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? query
            guard let url = URL(string: "\(endpoint)/api/address/\(encoded)/transactions") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let transactions = json["transactions"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return transactions
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  Auction & Domain API
    // ═══════════════════════════════════════════════════════════════════

    func fetchAuctionPrice(serviceType: String) async throws -> (nextPrice: Int, totalSold: Int) {
        return try await tryAllEndpoints { endpoint in
            let encoded = serviceType.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? serviceType
            guard let url = URL(string: "\(endpoint)/api/auction/price/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return (
                json["next_price"] as? Int ?? 1,
                json["total_sold"] as? Int ?? 0
            )
        }
    }

    func checkDomainAvailability(domain: String) async throws -> (available: Bool, price: Int) {
        return try await tryAllEndpoints { endpoint in
            let encoded = domain.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? domain
            guard let url = URL(string: "\(endpoint)/api/domain/available/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return (
                json["available"] as? Bool ?? false,
                json["price"] as? Int ?? 1
            )
        }
    }

    func registerDomain(domain: String, ownerAddress: String, amount: Int) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/domain/register") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 15
            request.httpBody = try JSONSerialization.data(withJSONObject: [
                "domain": domain,
                "owner_address": ownerAddress,
                "amount": amount
            ])

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            if httpResponse.statusCode != 200 {
                let error = json["error"] as? String ?? "Unknown error"
                throw NSError(domain: "Montana", code: httpResponse.statusCode,
                              userInfo: [NSLocalizedDescriptionKey: error])
            }
            return json
        }
    }

    // ═══════════════════════════════════════════════════════════════════
    //  Phone Service API
    // ═══════════════════════════════════════════════════════════════════

    func registerPhone(number: Int, ownerAddress: String, amount: Int) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/phone/register") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 15
            request.httpBody = try JSONSerialization.data(withJSONObject: [
                "number": number,
                "owner_address": ownerAddress,
                "amount": amount
            ])

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            if httpResponse.statusCode != 200 {
                let error = json["error"] as? String ?? "Unknown error"
                throw NSError(domain: "Montana", code: httpResponse.statusCode,
                              userInfo: [NSLocalizedDescriptionKey: error])
            }
            return json
        }
    }

    func requestPhoneBind(phone: String, montanaAddress: String) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/phone/bind/request") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 15
            request.httpBody = try JSONSerialization.data(withJSONObject: [
                "phone": phone,
                "montana_address": montanaAddress
            ])

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            if httpResponse.statusCode != 200 {
                let error = json["error"] as? String ?? "Unknown error"
                throw NSError(domain: "Montana", code: httpResponse.statusCode,
                              userInfo: [NSLocalizedDescriptionKey: error])
            }
            return json
        }
    }

    func verifyPhoneBind(phone: String, montanaAddress: String, code: String) async throws -> [String: Any] {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/phone/bind/verify") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.httpMethod = "POST"
            request.setValue("application/json", forHTTPHeaderField: "Content-Type")
            request.timeoutInterval = 15
            request.httpBody = try JSONSerialization.data(withJSONObject: [
                "phone": phone,
                "montana_address": montanaAddress,
                "code": code
            ])

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            if httpResponse.statusCode != 200 {
                let error = json["error"] as? String ?? "Unknown error"
                throw NSError(domain: "Montana", code: httpResponse.statusCode,
                              userInfo: [NSLocalizedDescriptionKey: error])
            }
            return json
        }
    }

    func fetchBoundPhones(address: String) async throws -> [[String: Any]] {
        return try await tryAllEndpoints { endpoint in
            let encoded = address.addingPercentEncoding(withAllowedCharacters: .urlPathAllowed) ?? address
            guard let url = URL(string: "\(endpoint)/api/phone/bind/address/\(encoded)") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
                  let phones = json["phones"] as? [[String: Any]] else {
                throw URLError(.cannotParseResponse)
            }
            return phones
        }
    }

    func fetchCallPricing() async throws -> (audioPerSecond: Int, videoPerSecond: Int) {
        return try await tryAllEndpoints { endpoint in
            guard let url = URL(string: "\(endpoint)/api/call/pricing") else {
                throw URLError(.badURL)
            }
            var request = URLRequest(url: url)
            request.timeoutInterval = 10

            let session = endpoint.hasPrefix("https://") ? self.secureSession : URLSession.shared
            let (data, response) = try await session.data(for: request)
            guard let httpResponse = response as? HTTPURLResponse,
                  httpResponse.statusCode == 200,
                  let json = try? JSONSerialization.jsonObject(with: data) as? [String: Any] else {
                throw URLError(.cannotParseResponse)
            }
            return (
                json["audio_per_second"] as? Int ?? 1,
                json["video_per_second"] as? Int ?? 1
            )
        }
    }

    private func tryAllEndpoints<T>(_ operation: (String) async throws -> T) async throws -> T {
        var lastError: Error = URLError(.cannotConnectToHost)
        for endpoint in endpoints {
            do {
                return try await operation(endpoint.url)
            } catch {
                lastError = error
                continue
            }
        }
        throw lastError
    }
}