From a5b9d70f04262a67538e8095062f6f7deac38a28 Mon Sep 17 00:00:00 2001
From: KoalaTrapLord <rgriffith.crc@outlook.com>
Date: Wed, 18 Mar 2026 00:55:40 -0400
Subject: [PATCH] Unity U2: Add ApiClient.cs singleton HTTP client for FastAPI
 backend (Epic #45)

---
 .../Assets/Scripts/Services/ApiClient.cs      | 133 ++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 unity-client/Assets/Scripts/Services/ApiClient.cs

diff --git a/unity-client/Assets/Scripts/Services/ApiClient.cs b/unity-client/Assets/Scripts/Services/ApiClient.cs
new file mode 100644
index 0000000..9ba8e1f
--- /dev/null
+++ b/unity-client/Assets/Scripts/Services/ApiClient.cs
@@ -0,0 +1,133 @@
+using System;
+using System.Collections;
+using System.Text;
+using UnityEngine;
+using UnityEngine.Networking;
+
+namespace CommanderAILab.Services
+{
+    /// <summary>
+    /// Singleton HTTP client for Commander AI Lab FastAPI backend.
+    /// All REST calls go through this service.
+    /// </summary>
+    public class ApiClient : MonoBehaviour
+    {
+        public static ApiClient Instance { get; private set; }
+
+        [SerializeField] private string baseUrl = "http://localhost:8080";
+        [SerializeField] private float timeoutSeconds = 30f;
+
+        public string BaseUrl
+        {
+            get => baseUrl;
+            set
+            {
+                baseUrl = value.TrimEnd('/');
+                PlayerPrefs.SetString("ApiBaseUrl", baseUrl);
+            }
+        }
+
+        private void Awake()
+        {
+            if (Instance != null && Instance != this) { Destroy(gameObject); return; }
+            Instance = this;
+            DontDestroyOnLoad(gameObject);
+            baseUrl = PlayerPrefs.GetString("ApiBaseUrl", baseUrl);
+        }
+
+        // ── Generic Helpers ──────────────────────────────────────
+
+        public Coroutine Get<T>(string path, Action<T> onSuccess, Action<string> onError = null)
+        {
+            return StartCoroutine(GetCoroutine(path, onSuccess, onError));
+        }
+
+        public Coroutine Post<TReq, TRes>(string path, TReq body, Action<TRes> onSuccess, Action<string> onError = null)
+        {
+            return StartCoroutine(PostCoroutine(path, body, onSuccess, onError));
+        }
+
+        private IEnumerator GetCoroutine<T>(string path, Action<T> onSuccess, Action<string> onError)
+        {
+            var url = $"{baseUrl}{path}";
+            using var request = UnityWebRequest.Get(url);
+            request.timeout = (int)timeoutSeconds;
+            yield return request.SendWebRequest();
+
+            if (request.result != UnityWebRequest.Result.Success)
+            {
+                Debug.LogWarning($"[ApiClient] GET {path} failed: {request.error}");
+                onError?.Invoke(request.error);
+                yield break;
+            }
+            var obj = JsonUtility.FromJson<T>(request.downloadHandler.text);
+            onSuccess?.Invoke(obj);
+        }
+
+        private IEnumerator PostCoroutine<TReq, TRes>(string path, TReq body, Action<TRes> onSuccess, Action<string> onError)
+        {
+            var url = $"{baseUrl}{path}";
+            var json = JsonUtility.ToJson(body);
+            using var request = new UnityWebRequest(url, "POST");
+            request.uploadHandler = new UploadHandlerRaw(Encoding.UTF8.GetBytes(json));
+            request.downloadHandler = new DownloadHandlerBuffer();
+            request.SetRequestHeader("Content-Type", "application/json");
+            request.timeout = (int)timeoutSeconds;
+            yield return request.SendWebRequest();
+
+            if (request.result != UnityWebRequest.Result.Success)
+            {
+                Debug.LogWarning($"[ApiClient] POST {path} failed: {request.error}");
+                onError?.Invoke(request.error);
+                yield break;
+            }
+            var obj = JsonUtility.FromJson<TRes>(request.downloadHandler.text);
+            onSuccess?.Invoke(obj);
+        }
+
+        // ── Health Check ─────────────────────────────────────────
+
+        public Coroutine HealthCheck(Action<bool> callback)
+        {
+            return StartCoroutine(HealthCheckCoroutine(callback));
+        }
+
+        private IEnumerator HealthCheckCoroutine(Action<bool> callback)
+        {
+            using var request = UnityWebRequest.Get($"{baseUrl}/docs");
+            request.timeout = 5;
+            yield return request.SendWebRequest();
+            callback?.Invoke(request.result == UnityWebRequest.Result.Success);
+        }
+
+        // ── Collection ───────────────────────────────────────────
+        // GET /api/collection
+        // GET /api/collection?search=...
+
+        // ── Decks ────────────────────────────────────────────────
+        // GET  /api/decks
+        // POST /api/decks
+        // GET  /api/decks/{id}
+        // PATCH /api/decks/{id}
+        // DELETE /api/decks/{id}
+
+        // ── Simulator ────────────────────────────────────────────
+        // POST /api/lab/start
+        // GET  /api/lab/status/{id}
+        // GET  /api/lab/results/{id}
+
+        // ── Coach ────────────────────────────────────────────────
+        // POST /api/coach/chat
+
+        // ── Deck Generator ───────────────────────────────────────
+        // POST /api/deckgen/v3
+
+        // ── Scanner ──────────────────────────────────────────────
+        // POST /api/scanner/scan
+
+        // ── Meta ─────────────────────────────────────────────────
+        // GET /api/lab/meta/commanders
+        // GET /api/lab/meta/search?q=...
+        // GET /api/lab/precons
+    }
+}