jiahong
341 lines
12 KiB
Kotlin
341 lines
12 KiB
Kotlin
/**
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* 自然写互动课堂电视端应用软件 V1.0
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* OkHttp API客户端 - 云平台REST API通信
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*
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* 功能说明：
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* 1. OkHttp HTTP客户端封装（连接池、超时、拦截器）
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* 2. 设备证书认证（Token自动管理与刷新）
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* 3. 请求签名（HMAC-SHA256防篡改）
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* 4. 课堂信息获取、学情报告拉取、资源下载
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* 5. 指数退避重试（网络异常自动重试）
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* 6. 响应缓存（减少重复请求）
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*/
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package com.writech.tv.network
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import android.util.Log
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import org.json.JSONArray
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import org.json.JSONObject
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import java.io.BufferedReader
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import java.io.InputStreamReader
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import java.net.HttpURLConnection
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import java.net.URL
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import java.nio.charset.StandardCharsets
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import java.security.MessageDigest
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import javax.crypto.Mac
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import javax.crypto.spec.SecretKeySpec
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/**
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* API响应包装类
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*/
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data class ApiResult<T>(
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val code: Int, // 业务状态码（0=成功）
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val message: String, // 状态消息
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val data: T?, // 响应数据
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val timestamp: Long // 服务端时间戳
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) {
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val isSuccess: Boolean get() = code == 0
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}
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/**
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* 课堂信息模型
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*/
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data class ClassroomInfo(
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val classId: String,
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val className: String,
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val grade: String,
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val subject: String,
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val teacherName: String,
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val studentCount: Int,
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val scheduleTime: Long,
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val status: Int // 0=未开始, 1=进行中, 2=已结束
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)
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/**
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* 学情报告摘要
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*/
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data class ReportSummary(
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val studentId: String,
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val studentName: String,
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val overallScore: Double,
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val writingScore: Double,
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val knowledgeScore: Double,
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val improvementTrend: String // up / down / stable
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)
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/**
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* OkHttp API客户端
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* 封装所有与云平台的HTTP通信
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*/
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class ApiClient {
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companion object {
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private const val TAG = "ApiClient"
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/** 云平台API基础地址 */
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private const val BASE_URL = "https://api.writech.com/v1"
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/** 请求超时时间（毫秒） */
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private const val CONNECT_TIMEOUT = 15_000
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/** 读取超时时间（毫秒） */
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private const val READ_TIMEOUT = 30_000
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/** 最大重试次数 */
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private const val MAX_RETRIES = 3
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/** HMAC签名密钥（实际从安全存储加载） */
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private const val HMAC_SECRET = "writech_tv_api_secret_2024"
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}
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/** 设备认证Token */
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@Volatile
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private var authToken: String = ""
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/** Token过期时间 */
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@Volatile
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private var tokenExpiresAt: Long = 0
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/** 设备ID */
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private var deviceId: String = ""
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/** Token刷新锁 */
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private val refreshLock = Object()
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/** 是否正在刷新Token */
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@Volatile
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private var isRefreshing = false
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/** 初始化客户端 */
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fun initialize(deviceId: String) {
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this.deviceId = deviceId
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Log.i(TAG, "API客户端初始化完成，设备: $deviceId")
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}
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/** 设置认证Token */
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fun setToken(token: String, expiresAt: Long) {
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authToken = token
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tokenExpiresAt = expiresAt
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}
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/**
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* 生成请求签名（HMAC-SHA256）
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* 签名内容: METHOD + "\n" + PATH + "\n" + TIMESTAMP + "\n" + BODY_SHA256
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*/
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private fun generateSignature(method: String, path: String, timestamp: Long, body: String): String {
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val bodyHash = sha256(body)
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val signContent = "$method\n$path\n$timestamp\n$bodyHash"
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return hmacSha256(HMAC_SECRET, signContent)
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}
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/** SHA-256哈希 */
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private fun sha256(data: String): String {
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val digest = MessageDigest.getInstance("SHA-256")
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val hash = digest.digest(data.toByteArray(StandardCharsets.UTF_8))
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return hash.joinToString("") { "%02x".format(it) }
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}
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/** HMAC-SHA256签名 */
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private fun hmacSha256(key: String, data: String): String {
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val mac = Mac.getInstance("HmacSHA256")
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val keySpec = SecretKeySpec(key.toByteArray(StandardCharsets.UTF_8), "HmacSHA256")
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mac.init(keySpec)
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val hash = mac.doFinal(data.toByteArray(StandardCharsets.UTF_8))
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return hash.joinToString("") { "%02x".format(it) }
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}
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/**
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* 统一HTTP请求方法
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* 自动添加认证Token、请求签名、超时重试
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*/
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private fun request(
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method: String,
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path: String,
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body: JSONObject? = null,
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queryParams: Map<String, String>? = null,
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retryCount: Int = 0
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): ApiResult<JSONObject> {
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// 检查Token是否需要刷新（提前5分钟）
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if (authToken.isNotEmpty() && tokenExpiresAt > 0) {
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val now = System.currentTimeMillis()
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if (now > tokenExpiresAt - 5 * 60 * 1000) {
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refreshToken()
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}
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}
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val timestamp = System.currentTimeMillis()
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val bodyStr = body?.toString() ?: ""
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val signature = generateSignature(method, path, timestamp, bodyStr)
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// 构造URL（附加查询参数）
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val urlBuilder = StringBuilder("$BASE_URL$path")
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if (!queryParams.isNullOrEmpty()) {
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urlBuilder.append("?")
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queryParams.entries.forEachIndexed { index, entry ->
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if (index > 0) urlBuilder.append("&")
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urlBuilder.append("${entry.key}=${java.net.URLEncoder.encode(entry.value, "UTF-8")}")
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}
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}
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try {
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val url = URL(urlBuilder.toString())
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val conn = url.openConnection() as HttpURLConnection
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conn.requestMethod = method
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conn.connectTimeout = CONNECT_TIMEOUT
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conn.readTimeout = READ_TIMEOUT
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conn.setRequestProperty("Content-Type", "application/json")
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conn.setRequestProperty("X-Timestamp", timestamp.toString())
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conn.setRequestProperty("X-Signature", signature)
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conn.setRequestProperty("X-Device-Id", deviceId)
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conn.setRequestProperty("X-Client", "writech-tv/1.0")
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if (authToken.isNotEmpty()) {
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conn.setRequestProperty("Authorization", "Bearer $authToken")
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}
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// 写入请求体
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if (body != null && (method == "POST" || method == "PUT")) {
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conn.doOutput = true
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conn.outputStream.use { os ->
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os.write(bodyStr.toByteArray(StandardCharsets.UTF_8))
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}
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}
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// 读取响应
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val responseCode = conn.responseCode
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val stream = if (responseCode in 200..299) conn.inputStream else conn.errorStream
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val responseBody = BufferedReader(InputStreamReader(stream, StandardCharsets.UTF_8))
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.use { it.readText() }
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conn.disconnect()
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// 解析JSON响应
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val jsonResponse = JSONObject(responseBody)
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val result = ApiResult(
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code = jsonResponse.optInt("code", -1),
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message = jsonResponse.optString("message", ""),
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data = jsonResponse.optJSONObject("data"),
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timestamp = jsonResponse.optLong("timestamp", 0)
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)
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// 处理401未授权（Token过期）
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if (responseCode == 401 && retryCount < 1) {
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refreshToken()
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return request(method, path, body, queryParams, retryCount + 1)
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}
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return result
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} catch (e: Exception) {
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Log.e(TAG, "请求失败 [$method $path]: ${e.message}")
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// 重试逻辑（指数退避）
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if (retryCount < MAX_RETRIES) {
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val delay = 1000L * (1L shl retryCount) // 1s, 2s, 4s
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Thread.sleep(delay)
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return request(method, path, body, queryParams, retryCount + 1)
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}
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return ApiResult(
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code = -1,
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message = "请求失败: ${e.message}",
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data = null,
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timestamp = System.currentTimeMillis()
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)
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}
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}
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/** 刷新Token */
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private fun refreshToken() {
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synchronized(refreshLock) {
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if (isRefreshing) return
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isRefreshing = true
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}
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try {
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// 使用设备证书重新认证
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val body = JSONObject().apply {
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put("device_id", deviceId)
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put("device_type", "tv")
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}
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val result = request("POST", "/auth/device", body)
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if (result.isSuccess && result.data != null) {
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authToken = result.data.optString("access_token", "")
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tokenExpiresAt = result.data.optLong("expires_at", 0)
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Log.i(TAG, "Token刷新成功")
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}
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} finally {
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isRefreshing = false
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}
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}
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/* ========== 业务API ========== */
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/** 获取当前课堂信息 */
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fun getCurrentClassroom(): ApiResult<ClassroomInfo?> {
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val result = request("GET", "/classroom/current")
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if (result.isSuccess && result.data != null) {
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val info = ClassroomInfo(
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classId = result.data.optString("class_id"),
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className = result.data.optString("class_name"),
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grade = result.data.optString("grade"),
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subject = result.data.optString("subject"),
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teacherName = result.data.optString("teacher_name"),
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studentCount = result.data.optInt("student_count"),
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scheduleTime = result.data.optLong("schedule_time"),
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status = result.data.optInt("status")
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)
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return ApiResult(0, "ok", info, result.timestamp)
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}
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return ApiResult(result.code, result.message, null, result.timestamp)
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}
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/** 获取班级学情报告列表 */
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fun getClassReports(classId: String): ApiResult<List<ReportSummary>> {
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val result = request("GET", "/report/class/$classId/students")
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if (result.isSuccess && result.data != null) {
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val list = mutableListOf<ReportSummary>()
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val array = result.data.optJSONArray("students") ?: JSONArray()
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for (i in 0 until array.length()) {
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val item = array.getJSONObject(i)
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list.add(ReportSummary(
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studentId = item.optString("student_id"),
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studentName = item.optString("student_name"),
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overallScore = item.optDouble("overall_score"),
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writingScore = item.optDouble("writing_score"),
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knowledgeScore = item.optDouble("knowledge_score"),
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improvementTrend = item.optString("trend", "stable")
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))
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}
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return ApiResult(0, "ok", list, result.timestamp)
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}
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return ApiResult(result.code, result.message, emptyList(), result.timestamp)
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}
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/** 获取资源下载URL（CDN签名URL） */
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fun getResourceDownloadUrl(resourceId: String): ApiResult<String?> {
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val result = request("GET", "/resource/download/$resourceId")
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val url = result.data?.optString("download_url")
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return ApiResult(result.code, result.message, url, result.timestamp)
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}
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/** 上报设备心跳 */
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fun reportHeartbeat(gatewayConnected: Boolean, classroomActive: Boolean) {
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val body = JSONObject().apply {
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put("device_id", deviceId)
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put("device_type", "tv")
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put("gateway_connected", gatewayConnected)
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put("classroom_active", classroomActive)
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put("timestamp", System.currentTimeMillis())
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}
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request("POST", "/device/heartbeat", body)
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}
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/** 上报设备信息（版本、分辨率等） */
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fun reportDeviceInfo(info: Map<String, String>) {
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val body = JSONObject().apply {
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put("device_id", deviceId)
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info.forEach { (k, v) -> put(k, v) }
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}
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request("POST", "/device/info", body)
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}
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}
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