added ios module

ios/OralTrainer/Services/HTTPClient.swift

@@ -0,0 +1,133 @@
+import Foundation
+
+enum HTTPClientError: LocalizedError {
+    case invalidURL
+    case badStatus(Int, String)
+
+    var errorDescription: String? {
+        switch self {
+        case .invalidURL:
+            return "无效的服务地址"
+        case .badStatus(let code, let body):
+            return "HTTP \(code): \(body)"
+        }
+    }
+}
+
+struct HTTPResult {
+    let statusCode: Int
+    let body: Data
+    let effectiveBaseURL: String
+}
+
+enum HTTPClient {
+    static func getJSON<T: Decodable>(
+        _ type: T.Type,
+        baseURL: String,
+        path: String,
+        timeout: TimeInterval
+    ) async throws -> (value: T, effectiveBaseURL: String) {
+        let result = try await execute(
+            baseURL: baseURL,
+            path: path,
+            method: "GET",
+            timeout: timeout,
+            headers: ["Accept": "application/json"]
+        )
+        guard (200...299).contains(result.statusCode) else {
+            let body = String(data: result.body, encoding: .utf8) ?? ""
+            throw HTTPClientError.badStatus(result.statusCode, body)
+        }
+        let value = try JSONDecoder().decode(T.self, from: result.body)
+        return (value, result.effectiveBaseURL)
+    }
+
+    static func execute(
+        baseURL: String,
+        path: String,
+        method: String,
+        timeout: TimeInterval,
+        headers: [String: String] = [:],
+        body: Data? = nil
+    ) async throws -> HTTPResult {
+        let trimmedBase = baseURL.trimmingCharacters(in: CharacterSet(charactersIn: "/"))
+        guard let base = URL(string: trimmedBase), base.scheme != nil, base.host != nil else {
+            throw HTTPClientError.invalidURL
+        }
+        let endpoint = URL(string: path, relativeTo: base) ?? base
+        do {
+            return try await perform(
+                url: endpoint,
+                method: method,
+                timeout: timeout,
+                headers: headers,
+                body: body,
+                effectiveBaseURL: trimmedBase
+            )
+        } catch {
+            // 与安卓端一致：HTTPS 因 TLS 问题失败时，降级用同一请求重试 HTTP。
+            guard AppConfig.allowHTTPFallback,
+                  endpoint.scheme == "https",
+                  isTLSError(error) else {
+                throw error
+            }
+            var baseComponents = URLComponents(string: trimmedBase)
+            baseComponents?.scheme = "http"
+            guard let httpBase = baseComponents?.string,
+                  let httpURL = URL(string: path, relativeTo: URL(string: httpBase)) else {
+                throw error
+            }
+            return try await perform(
+                url: httpURL,
+                method: method,
+                timeout: timeout,
+                headers: headers,
+                body: body,
+                effectiveBaseURL: httpBase
+            )
+        }
+    }
+
+    private static func perform(
+        url: URL,
+        method: String,
+        timeout: TimeInterval,
+        headers: [String: String],
+        body: Data?,
+        effectiveBaseURL: String
+    ) async throws -> HTTPResult {
+        var request = URLRequest(url: url)
+        request.httpMethod = method
+        request.timeoutInterval = timeout
+        request.setValue(AppConfig.userAgent, forHTTPHeaderField: "User-Agent")
+        for (key, value) in headers {
+            request.setValue(value, forHTTPHeaderField: key)
+        }
+        request.httpBody = body
+        let (data, response) = try await URLSession.shared.data(for: request)
+        guard let http = response as? HTTPURLResponse else {
+            throw HTTPClientError.invalidURL
+        }
+        return HTTPResult(statusCode: http.statusCode, body: data, effectiveBaseURL: effectiveBaseURL)
+    }
+
+    private static func isTLSError(_ error: Error) -> Bool {
+        let nsError = error as NSError
+        let tlsCodes: [Int] = [
+            NSURLErrorSecureConnectionFailed,
+            NSURLErrorServerCertificateHasBadDate,
+            NSURLErrorServerCertificateUntrusted,
+            NSURLErrorServerCertificateHasUnknownRoot,
+            NSURLErrorServerCertificateNotYetValid,
+            NSURLErrorClientCertificateRejected,
+            NSURLErrorClientCertificateRequired,
+            NSURLErrorCannotLoadFromNetwork,
+        ]
+        if tlsCodes.contains(nsError.code) {
+            return true
+        }
+        let message = (nsError.localizedDescription + " " + (nsError.localizedFailureReason ?? ""))
+            .lowercased()
+        return message.contains("ssl") || message.contains("tls") || message.contains("certificate")
+    }
+}