//
//  SaleUserQrParser.swift
//  suixinkan
//
//  Created by Codex on 2026/6/29.
//

import Foundation

/// 获客员绑定二维码解析器，从扫码内容提取 sale_user_id。
enum SaleUserQrParser {
    /// 标准获客员绑定二维码 method，与后端约定一致。
    static let methodSaleUserBind = "sale_user_bind"

    /// 从获客员二维码内容解析 sale_user_id。
    /// 标准格式：`{"method":"sale_user_bind","sale_user_id":2}`
    /// 兼容：纯数字、URL query、无 method 的历史 JSON。
    static func parseSaleUserId(_ content: String) -> Int? {
        let trimmed = content.trimmingCharacters(in: .whitespacesAndNewlines)
        if trimmed.isEmpty { return nil }

        if trimmed.hasPrefix("{") {
            if let value = parseFromJSON(trimmed) {
                return value
            }
        }

        if let value = Int(trimmed), value > 0 {
            return value
        }

        if trimmed.contains("://") || trimmed.contains("?") {
            return parseFromURL(trimmed)
        }

        return nil
    }

    /// 判断扫码内容是否为获客员绑定专用二维码。
    static func isSaleUserBindQR(_ content: String) -> Bool {
        guard let object = jsonObject(from: content) else { return false }
        let method = (object["method"] as? String)?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        return method == methodSaleUserBind
    }

    private static func parseFromJSON(_ json: String) -> Int? {
        guard let object = jsonObject(from: json) else { return nil }
        return parseFromJSONObject(object)
    }

    private static func jsonObject(from json: String) -> [String: Any]? {
        guard let data = json.data(using: .utf8),
              let object = try? JSONSerialization.jsonObject(with: data) as? [String: Any]
        else { return nil }
        return object
    }

    private static func parseFromJSONObject(_ object: [String: Any]) -> Int? {
        let method = (object["method"] as? String)?
            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        if method == methodSaleUserBind {
            return readIntValue(object["sale_user_id"])
        }
        return readSaleUserId(object)
    }

    private static func readSaleUserId(_ object: [String: Any]) -> Int? {
        let keys = ["sale_user_id", "saleUserId", "user_id", "id"]
        for key in keys {
            if let value = readIntValue(object[key]) {
                return value
            }
        }
        return nil
    }

    private static func readIntValue(_ value: Any?) -> Int? {
        switch value {
        case let intValue as Int where intValue > 0:
            return intValue
        case let number as NSNumber where number.intValue > 0:
            return number.intValue
        case let stringValue as String:
            let trimmed = stringValue.trimmingCharacters(in: .whitespacesAndNewlines)
            if let intValue = Int(trimmed), intValue > 0 {
                return intValue
            }
            return nil
        default:
            return nil
        }
    }

    private static func parseFromURL(_ urlString: String) -> Int? {
        guard let components = URLComponents(string: urlString) else { return nil }
        let keys = ["sale_user_id", "saleUserId", "user_id", "id"]
        for key in keys {
            if let value = components.queryItems?.first(where: { $0.name == key })?.value,
               let intValue = Int(value.trimmingCharacters(in: .whitespacesAndNewlines)),
               intValue > 0 {
                return intValue
            }
        }
        return nil
    }
}