import Foundation

/// 推送点击后可到达的业务页面。
enum PushDestination: Sendable, Equatable {
    case payment
    case orders
    case verificationOrders
    case task
    case queue
    case messageCenter

    /// 目标页面是否依赖当前景区上下文。
    var requiresScenicContext: Bool {
        switch self {
        case .payment, .task, .queue:
            true
        case .orders, .verificationOrders, .messageCenter:
            false
        }
    }
}

/// 极光/APNs payload 解析结果，兼容顶层字段及常见 JSON 嵌套格式。
struct PushPayload: Sendable, Equatable {
    private let values: [String: String]

    /// 从系统通知 userInfo 解析路由字段。
    nonisolated init(userInfo: [AnyHashable: Any]) {
        var flattened: [String: String] = [:]
        Self.mergeDictionary(userInfo, into: &flattened)
        values = flattened
    }

    /// 从可发送的字符串字典创建 payload，供跨 Actor 回调及测试使用。
    nonisolated init(values: [String: String]) {
        self.values = values
    }

    /// 可发送的规范化字段快照。
    nonisolated var normalizedValues: [String: String] {
        values
    }

    /// 根据后端约定和历史兼容字段解析目标页面。
    nonisolated var destination: PushDestination {
        let type = value(for: "type")
        let route = value(for: "route")
        let uri = value(for: "uri")
        let action = value(for: "action")
        let merged = [route, uri, action].joined(separator: " ").lowercased()

        if type == "1" || type == "6"
            || merged.contains("payment") || merged.contains("payment_qr")
            || merged.contains("收款") {
            return .payment
        }
        if merged.contains("queue") || merged.contains("scenic-queue")
            || merged.contains("排队") || merged.contains("叫号") {
            return .queue
        }
        if merged.contains("verification") || merged.contains("writeoff")
            || merged.contains("write_off") || merged.contains("核销") {
            return .verificationOrders
        }
        if merged.contains("order") || merged.contains("订单") {
            return .orders
        }
        if merged.contains("task") || merged.contains("任务") {
            return .task
        }
        return .messageCenter
    }

    private nonisolated func value(for key: String) -> String {
        values[key]?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
    }

    private nonisolated static func mergeDictionary(
        _ dictionary: [AnyHashable: Any],
        into result: inout [String: String]
    ) {
        for (rawKey, value) in dictionary {
            guard let key = rawKey as? String else { continue }
            merge(value, key: key, into: &result)
        }
    }

    private nonisolated static func merge(
        _ value: Any,
        key: String,
        into result: inout [String: String]
    ) {
        if let dictionary = value as? [String: Any] {
            result[key] = stringValue(value)
            mergeDictionary(dictionary, into: &result)
            return
        }
        if let dictionary = value as? [AnyHashable: Any] {
            result[key] = stringValue(value)
            mergeDictionary(dictionary, into: &result)
            return
        }

        let text = stringValue(value)
        result[key] = text
        guard Self.nestedJSONKeys.contains(key),
              let data = text.data(using: .utf8),
              let object = try? JSONSerialization.jsonObject(with: data)
        else { return }

        if let dictionary = object as? [String: Any] {
            mergeDictionary(dictionary, into: &result)
        }
    }

    private nonisolated static func stringValue(_ value: Any) -> String {
        switch value {
        case let string as String:
            string
        case let number as NSNumber:
            number.stringValue
        default:
            String(describing: value)
        }
    }

    private nonisolated static let nestedJSONKeys: Set<String> = [
        "extras", "extra", "data", "JMessageExtra", "n_extras",
    ]
}