import Foundation public enum T3ChatUsageError: LocalizedError, Sendable {    case noSessionCookie    case invalidCredentials    case vercelChallenge    case apiError(String)    case parseFailed(String)     public var errorDescription: String? {        switch self {        case .noSessionCookie:            "No T3 Chat cookies found. Please log in to t3.chat in your browser."        case .invalidCredentials:            "T3 Chat session cookie is invalid or expired."        case .vercelChallenge:            "T3 Chat returned a Vercel security challenge. Paste the full browser cURL request, " +                "not just the Cookie header."        case let .apiError(message):            "T3 Chat API error: \(message)"        case let .parseFailed(message):            "Could not parse T3 Chat usage: \(message)"        }    }} public struct T3ChatSubscription: Decodable, Sendable {    public let productId: String?    public let productName: String?    public let status: String?    public let currentPeriodStart: TimeInterval?    public let currentPeriodEnd: TimeInterval?    public let canceledAt: TimeInterval?    public let trialEndsAt: TimeInterval?} public struct T3ChatCustomerData: Decodable, Sendable {    public let subTier: String?    public let subscription: T3ChatSubscription?    public let lifetimeBalance: Double?    public let usageBand: String?    public let billingNextResetAt: TimeInterval?    public let usageFourHourPercentage: Double?    public let usageMonthPercentage: Double?    public let usageFourHourNextResetAt: TimeInterval?    public let usagePeriodPercentage: Double?    public let usageWindowNextResetAt: TimeInterval?     public var planName: String? {        let raw = self.subscription?.productName ?? self.subTier        guard let raw = raw?.trimmingCharacters(in: .whitespacesAndNewlines), !raw.isEmpty else {            return nil        }        return raw.split(separator: "-").map { part in            part.prefix(1).uppercased() + String(part.dropFirst())        }.joined(separator: " ")    }} public struct T3ChatUsageSnapshot: Sendable {    public let customerData: T3ChatCustomerData    public let updatedAt: Date     public init(customerData: T3ChatCustomerData, updatedAt: Date) {        self.customerData = customerData        self.updatedAt = updatedAt    }     public func toUsageSnapshot() -> UsageSnapshot {        let baseReset = Self.date(fromMilliseconds: self.customerData.usageFourHourNextResetAt)            ?? Self.date(fromMilliseconds: self.customerData.usageWindowNextResetAt)        // billingNextResetAt tracks the usage window reset, not the overage billing period.        // If subscription metadata is absent, leave the overage reset unknown instead of showing the base reset.        let overageReset = Self.date(fromMilliseconds: self.customerData.subscription?.currentPeriodEnd)         let primary = RateWindow(            usedPercent: Self.percent(self.customerData.usageFourHourPercentage),            windowMinutes: 4 * 60,            resetsAt: baseReset,            resetDescription: Self.description(label: "Base", usageBand: self.customerData.usageBand))         let secondaryPercent = self.customerData.usageMonthPercentage            ?? self.customerData.usagePeriodPercentage        let secondary = RateWindow(            usedPercent: Self.percent(secondaryPercent),            windowMinutes: nil,            resetsAt: overageReset,            resetDescription: "Overage")         let identity = ProviderIdentitySnapshot(            providerID: .t3chat,            accountEmail: nil,            accountOrganization: nil,            loginMethod: self.customerData.planName)         return UsageSnapshot(            primary: primary,            secondary: secondary,            updatedAt: self.updatedAt,            identity: identity)    }     private static func percent(_ raw: Double?) -> Double {        min(100, max(0, raw ?? 0))    }     private static func date(fromMilliseconds raw: TimeInterval?) -> Date? {        guard let raw, raw > 0 else { return nil }        // T3 Chat currently returns JavaScript epoch milliseconds, while some subscription fields may be seconds.        let seconds = raw > 10_000_000_000 ? raw / 1000 : raw        return Date(timeIntervalSince1970: seconds)    }     private static func description(label: String, usageBand: String?) -> String {        guard let usageBand = usageBand?.trimmingCharacters(in: .whitespacesAndNewlines),              !usageBand.isEmpty        else {            return label        }        return "\(label) - \(usageBand)"    }} public enum T3ChatUsageParser {    public static func parseJSONLines(_ data: Data, now: Date = Date()) throws -> T3ChatUsageSnapshot {        guard let text = String(data: data, encoding: .utf8) else {            throw T3ChatUsageError.parseFailed("Response is not UTF-8.")        }        return try self.parseJSONLines(text, now: now)    }     public static func parseJSONLines(_ text: String, now: Date = Date()) throws -> T3ChatUsageSnapshot {        let lines = text.split(whereSeparator: \.isNewline)        for line in lines {            guard let data = String(line).data(using: .utf8) else { continue }            guard let object = try? JSONSerialization.jsonObject(with: data) else { continue }            guard let customerObject = self.findCustomerData(in: object) else { continue }            let customerData = try self.decodeCustomerData(customerObject)            return T3ChatUsageSnapshot(customerData: customerData, updatedAt: now)        }         throw T3ChatUsageError.parseFailed("Missing customer data object.")    }     private static func findCustomerData(in object: Any) -> [String: Any]? {        if let dictionary = object as? [String: Any] {            if dictionary["usageFourHourPercentage"] != nil ||                dictionary["usageMonthPercentage"] != nil ||                dictionary["subscription"] != nil && dictionary["usageBand"] != nil            {                return dictionary            }             for value in dictionary.values {                if let found = self.findCustomerData(in: value) {                    return found                }            }        }         if let array = object as? [Any] {            for value in array {                if let found = self.findCustomerData(in: value) {                    return found                }            }        }         return nil    }     private static func decodeCustomerData(_ object: [String: Any]) throws -> T3ChatCustomerData {        do {            let data = try JSONSerialization.data(withJSONObject: object, options: [])            return try JSONDecoder().decode(T3ChatCustomerData.self, from: data)        } catch {            throw T3ChatUsageError.parseFailed(error.localizedDescription)        }    }}