feat: FEAT-05 — DTC history sync to remote server

- Server: dtc_events table (migrate_phase27_dtc.sql), db.py helpers
  (upsert_dtc_snapshot, list_dtc_events, delete_dtc_event)
- Server API: POST /api/v1/dtc/batch (device auth), GET/DELETE /api/v1/portal/dtc
- Server portal: /dtc page with code, description, MIL, status, timestamps, delete
- Server nav: DTC history in sidebar + mobile bottom nav
- Pi: _upload_dtc_snapshot() in app_upload.py — uploads when snapshot changes,
  skips when OBD disconnected or unchanged

android/app/src/main/java/com/yarisobd/app/DashcamViewModel.kt

@@ -34,12 +34,12 @@ data class DownloadProgress(
 
 class DashcamViewModel(application: Application) : AndroidViewModel(application) {
 
-    private val baseUrl = "http://10.42.0.1/"
+    private val baseUrl = "http://10.42.0.1"  // no trailing slash
     private val okHttp = OkHttpClient.Builder().build()
     private val json = Json { ignoreUnknownKeys = true; coerceInputValues = true }
 
     private val api: PiApi = Retrofit.Builder()
-        .baseUrl(baseUrl)
+        .baseUrl("$baseUrl/")  // Retrofit requires trailing slash
         .client(okHttp)
         .addConverterFactory(json.asConverterFactory("application/json".toMediaType()))
         .build()
@@ -93,14 +93,14 @@ class DashcamViewModel(application: Application) : AndroidViewModel(application)
             val dir = app.getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS) ?: return@launch
             val localFile = File(dir, video.path.substringAfterLast("/"))
 
-            // Skip if already downloaded
+            // Skip if already downloaded and size matches
             if (localFile.exists() && localFile.length() == video.size) {
-                _downloadEvents.emit("Already downloaded: ${localFile.name}")
+                _downloadEvents.emit("✓ Already downloaded: ${localFile.name}")
                 return@launch
             }
 
             try {
-                withContext(Dispatchers.IO) {
+                val result = withContext(Dispatchers.IO) {
                     val request = Request.Builder()
                         .url("$baseUrl/api/local-video/file?path=${video.path}")
                         .get()
@@ -108,10 +108,10 @@ class DashcamViewModel(application: Application) : AndroidViewModel(application)
 
                     val response = okHttp.newCall(request).execute()
                     if (!response.isSuccessful) {
-                        throw Exception("HTTP ${response.code}")
+                        return@withContext "Download failed: HTTP ${response.code}"
                     }
 
-                    val body = response.body ?: throw Exception("Empty body")
+                    val body = response.body ?: return@withContext "Download failed: Empty body"
                     val total = body.contentLength()
                     localFile.parentFile?.mkdirs()
 
@@ -124,19 +124,19 @@ class DashcamViewModel(application: Application) : AndroidViewModel(application)
                                 if (read == -1L) break
                                 sink.write(buffer, read)
                                 downloaded += read
-                                _downloadProgress.value = _downloadProgress.value + (
+                                val progress = DownloadProgress(video.path, downloaded, total)
-                                    video.path to DownloadProgress(video.path, downloaded, total)
+                                _downloadProgress.value = _downloadProgress.value + (video.path to progress)
-                                )
                             }
                         }
                     }
 
                     _downloadProgress.value = _downloadProgress.value - video.path
-                    _downloadEvents.emit("Downloaded: ${localFile.name}")
+                    "✓ Downloaded: ${localFile.name} (${downloaded} bytes)"
                 }
+                _downloadEvents.emit(result)
             } catch (e: Exception) {
                 _downloadProgress.value = _downloadProgress.value - video.path
-                _downloadEvents.emit("Download failed: ${e.message}")
+                _downloadEvents.emit("✗ Download failed: ${e.message}")
             }
         }
     }

android/app/src/main/java/com/yarisobd/app/data/remote/PiApi.kt

@@ -4,8 +4,8 @@ import com.yarisobd.app.data.remote.dto.GpsStatus
 import com.yarisobd.app.data.remote.dto.VideoListResponse
 import okhttp3.ResponseBody
 import retrofit2.http.Body
-import retrofit2.http.DELETE
 import retrofit2.http.GET
+import retrofit2.http.HTTP
 import retrofit2.http.Query
 import retrofit2.http.Streaming
 
@@ -32,6 +32,6 @@ interface PiApi {
     suspend fun getThumbnail(@Query("path") path: String): ResponseBody
 
     /** Delete local copy only */
-    @DELETE("/api/local-video")
+    @HTTP(method = "DELETE", path = "/api/local-video", hasBody = true)
     suspend fun deleteVideo(@Body body: Map<String, String>): Map<String, Any?>
 }

modules/app_upload.py

@@ -310,6 +310,50 @@ def _upload_dashcam_files():
     return uploaded_count
 
 
+_last_dtc_hash = None  # tracks last-uploaded DTC snapshot to avoid redundant pushes
+
+
+def _upload_dtc_snapshot():
+    """Upload current DTC snapshot to server if it differs from last upload.
+    Skips when OBD is disconnected (no point sending empty snapshots that
+    would clear all server-side DTC events)."""
+    global _last_dtc_hash
+    import hashlib as _hl
+    from . import app_obd, app_sql
+
+    # Only upload when OBD is actually connected — don't clear server DTCs
+    # just because the Pi rebooted or the adapter is unplugged.
+    if app_obd.connection is None:
+        return
+
+    mil_on = app_obd.mil_on
+    codes = app_obd.dtc_codes or []
+    if not codes and mil_on is None:
+        return  # No data yet
+
+    # Hash the current snapshot to detect changes
+    payload = {"mil_on": bool(mil_on), "codes": codes}
+    h = _hl.sha256(repr(payload).encode()).hexdigest()
+    if h == _last_dtc_hash:
+        return
+    _last_dtc_hash = h
+
+    try:
+        creds = _credentials()
+        if not creds["server_url"] or not creds["device_name"] or not creds["api_key"]:
+            return
+        resp = requests.post(
+            f"{creds['server_url']}/api/v1/dtc/batch",
+            json=payload,
+            headers=_headers(creds),
+            timeout=5,
+        )
+        resp.raise_for_status()
+    except requests.RequestException:
+        _last_dtc_hash = None  # retry next cycle
+        raise
+
+
 def _upload_loop():
     global _last_error, _last_success_at
     import datetime as _dt
@@ -323,6 +367,7 @@ def _upload_loop():
             sent = _upload_tracking_batch()
             uploaded = _upload_dashcam_files()
             cleanup = app_video.cleanup_uploaded_videos()
+            _upload_dtc_snapshot()  # silently skips when unchanged or OBD offline
             if sent or uploaded:
                 print(f"Upload: sent {sent} tracking rows, {uploaded} dashcam files")
             if cleanup["deleted"]:

server/app.py

@@ -423,6 +423,12 @@ def portal_device_settings_page():
     )
 
 
+@app.get("/dtc")
+@require_login
+def portal_dtc_page():
+    return render_template("dtc.html")
+
+
 # ── Portal JSON API ────────────────────────────────────────────────────────
 
 @app.get("/api/v1/portal/stats")
@@ -850,6 +856,45 @@ def api_device_config_update():
     return jsonify(config)
 
 
+# ── DTC sync (FEAT-05) ────────────────────────────────────────────────────────
+
+@app.post("/api/v1/dtc/batch")
+@require_device_auth
+def upload_dtc_batch():
+    """Receive a DTC snapshot from the Pi. Body: {mil_on: bool, codes: [{code, description}, ...]}."""
+    body = request.get_json(silent=True) or {}
+    mil_on = bool(body.get("mil_on", False))
+    codes = body.get("codes")
+    if not isinstance(codes, list):
+        return jsonify(error="expected 'codes' as a list"), 400
+    for c in codes:
+        if not isinstance(c.get("code"), str) or not c["code"].strip():
+            return jsonify(error="each code must have a non-empty 'code' string"), 400
+    result = db.upsert_dtc_snapshot(g.device_id, mil_on, codes)
+    return jsonify(result), 200
+
+
+@app.get("/api/v1/portal/dtc")
+@require_login
+def portal_dtc():
+    device_id = _portal_device_id()
+    if device_id is None:
+        return jsonify(error="device not configured"), 404
+    return jsonify(db.list_dtc_events(device_id))
+
+
+@app.delete("/api/v1/portal/dtc/<int:dtc_id>")
+@require_login
+def portal_dtc_delete(dtc_id):
+    device_id = _portal_device_id()
+    if device_id is None:
+        return jsonify(error="device not configured"), 404
+    deleted = db.delete_dtc_event(device_id, dtc_id)
+    if not deleted:
+        return jsonify(error="DTC event not found"), 404
+    return jsonify(status="ok")
+
+
 def main():
     app.run(host="0.0.0.0", port=8098)
 

server/modules/db.py

@@ -249,6 +249,83 @@ def insert_dashcam_file(device_id, relative_path, size_bytes, sha256, storage_pa
         )
 
 
+# ── DTC events (FEAT-05) ────────────────────────────────────────────────────
+
+def upsert_dtc_snapshot(device_id, mil_on, codes):
+    """Receive a DTC snapshot from the Pi. Inserts new codes, updates existing,
+    marks codes absent from this snapshot as cleared. Returns stats dict."""
+    with get_cursor(commit=True) as cur:
+        cur.execute(
+            "SELECT code FROM dtc_events WHERE device_id = %s AND is_active = TRUE",
+            (device_id,),
+        )
+        previously_active = {row[0] for row in cur.fetchall()}
+    current_codes = {c["code"] for c in codes}
+
+    new_codes = current_codes - previously_active
+    cleared_codes = previously_active - current_codes
+    unchanged = previously_active & current_codes
+
+    with get_cursor(commit=True) as cur:
+        for c in codes:
+            if c["code"] in new_codes:
+                cur.execute(
+                    """INSERT INTO dtc_events (device_id, code, description, mil_on, is_active)
+                       VALUES (%s, %s, %s, %s, TRUE)
+                       ON CONFLICT (device_id, code) DO UPDATE SET
+                           description = EXCLUDED.description,
+                           mil_on = EXCLUDED.mil_on,
+                           is_active = TRUE,
+                           last_seen_at = now()""",
+                    (device_id, c["code"], c.get("description", ""), mil_on),
+                )
+            elif c["code"] in unchanged:
+                cur.execute(
+                    """UPDATE dtc_events SET mil_on = %s, last_seen_at = now(), is_active = TRUE
+                       WHERE device_id = %s AND code = %s""",
+                    (mil_on, device_id, c["code"]),
+                )
+        for code in cleared_codes:
+            cur.execute(
+                """UPDATE dtc_events SET is_active = FALSE, cleared_at = now()
+                   WHERE device_id = %s AND code = %s""",
+                (device_id, code),
+            )
+    return {"received": len(codes), "cleared": len(cleared_codes), "unchanged": len(unchanged)}
+
+
+def list_dtc_events(device_id):
+    with get_cursor() as cur:
+        cur.execute(
+            """SELECT id, code, description, mil_on, is_active, first_seen_at, last_seen_at, cleared_at
+               FROM dtc_events WHERE device_id = %s ORDER BY last_seen_at DESC""",
+            (device_id,),
+        )
+        rows = cur.fetchall()
+    return [
+        {
+            "id": r[0],
+            "code": r[1],
+            "description": r[2],
+            "mil_on": r[3],
+            "is_active": r[4],
+            "first_seen_at": r[5].isoformat() if r[5] else None,
+            "last_seen_at": r[6].isoformat() if r[6] else None,
+            "cleared_at": r[7].isoformat() if r[7] else None,
+        }
+        for r in rows
+    ]
+
+
+def delete_dtc_event(device_id, dtc_id):
+    with get_cursor(commit=True) as cur:
+        cur.execute(
+            "DELETE FROM dtc_events WHERE id = %s AND device_id = %s RETURNING id",
+            (dtc_id, device_id),
+        )
+        return cur.fetchone() is not None
+
+
 # ── User auth ──────────────────────────────────────────────────────────────
 
 def get_user_by_id(user_id):

server/sql/migrate_phase27_dtc.sql

@@ -0,0 +1,18 @@
+-- Phase 27 / FEAT-05: DTC history synced to remote server.
+-- Pi pushes current DTC snapshot; server diffs against stored state.
+
+CREATE TABLE IF NOT EXISTS dtc_events (
+    id SERIAL PRIMARY KEY,
+    device_id INTEGER NOT NULL REFERENCES devices(id) ON DELETE CASCADE,
+    code VARCHAR(10) NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    mil_on BOOLEAN NOT NULL DEFAULT FALSE,
+    is_active BOOLEAN NOT NULL DEFAULT TRUE,
+    first_seen_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    last_seen_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+    cleared_at TIMESTAMPTZ,
+    UNIQUE (device_id, code)
+);
+
+CREATE INDEX IF NOT EXISTS idx_dtc_events_device_active
+    ON dtc_events (device_id, is_active);

server/templates/base.html

@@ -49,6 +49,11 @@
                     <i class="fas fa-video fa-fw"></i><span>Dashcam archive</span>
                 </a>
             </li>
+            <li class="nav-item">
+                <a class="nav-link{% if request.endpoint == 'portal_dtc_page' %} active{% endif %}" href="{{ url_for('portal_dtc_page') }}">
+                    <i class="fas fa-exclamation-triangle fa-fw"></i><span>DTC history</span>
+                </a>
+            </li>
             <li class="nav-item">
                 <a class="nav-link{% if request.endpoint == 'portal_device_settings_page' %} active{% endif %}" href="{{ url_for('portal_device_settings_page') }}">
                     <i class="fas fa-sliders-h fa-fw"></i><span>Device settings</span>
@@ -117,6 +122,10 @@
             <i class="fas fa-sliders-h"></i>
             <span>Device</span>
         </a>
+        <a class="mobile-nav-item{% if request.endpoint == 'portal_dtc_page' %} active{% endif %}" href="{{ url_for('portal_dtc_page') }}">
+            <i class="fas fa-exclamation-triangle"></i>
+            <span>DTC</span>
+        </a>
         <a class="mobile-nav-item" href="{{ url_for('logout') }}">
             <i class="fas fa-sign-out-alt"></i>
             <span>Logout</span>

server/templates/dtc.html

@@ -0,0 +1,94 @@
+{% extends "base.html" %}
+
+{% block title %}DTC history – Yaris OBD Remote{% endblock %}
+
+{% block content %}
+<h3 class="text-dark mb-3 fw-bold">DTC history</h3>
+
+<div class="row g-3">
+    <div class="col-12">
+        <div class="card shadow-sm">
+            <div class="card-header py-2 d-flex justify-content-between align-items-center">
+                <h6 class="text-primary fw-bold m-0">Diagnostic trouble codes</h6>
+                <span id="dtc-count" class="badge bg-secondary">0</span>
+            </div>
+            <div class="card-body p-0">
+                <div id="dtc-loading" class="text-center text-muted py-4">
+                    <span class="spinner-border spinner-border-sm me-2" aria-hidden="true"></span>
+                    Loading…
+                </div>
+                <div id="dtc-error" class="alert alert-danger m-3" role="alert" hidden></div>
+                <div class="table-responsive">
+                    <table class="table table-sm table-hover mb-0" id="dtc-table" hidden>
+                        <thead class="table-light">
+                            <tr>
+                                <th class="ps-3">Code</th>
+                                <th>Description</th>
+                                <th>MIL</th>
+                                <th>Status</th>
+                                <th>First seen</th>
+                                <th>Last seen</th>
+                                <th class="pe-3">Actions</th>
+                            </tr>
+                        </thead>
+                        <tbody id="dtc-body"></tbody>
+                    </table>
+                </div>
+                <div id="dtc-empty" class="text-muted text-center py-4 small" hidden>No DTC events recorded yet.</div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+<script>
+(function () {
+    const loading = document.getElementById("dtc-loading");
+    const error = document.getElementById("dtc-error");
+    const table = document.getElementById("dtc-table");
+    const tbody = document.getElementById("dtc-body");
+    const empty = document.getElementById("dtc-empty");
+    const count = document.getElementById("dtc-count");
+
+    function fmt(iso) { return iso ? new Date(iso).toLocaleString() : "—"; }
+
+    async function load() {
+        try {
+            const r = await fetch("/api/v1/portal/dtc");
+            if (!r.ok) throw new Error("Cannot load DTC events.");
+            const events = await r.json();
+            loading.hidden = true;
+            count.textContent = events.length;
+            if (!events.length) { empty.hidden = false; return; }
+            tbody.innerHTML = events.map(e => `
+                <tr>
+                    <td class="ps-3 fw-bold font-monospace ${e.is_active ? 'text-danger' : 'text-muted'}">${e.code}</td>
+                    <td>${e.description || "—"}</td>
+                    <td>${e.mil_on ? '<span class="badge text-bg-warning">ON</span>' : '<span class="badge text-bg-secondary">OFF</span>'}</td>
+                    <td>${e.is_active ? '<span class="badge text-bg-danger">Active</span>' : '<span class="badge text-bg-success">Cleared</span>'}</td>
+                    <td class="small text-muted">${fmt(e.first_seen_at)}</td>
+                    <td class="small text-muted">${fmt(e.last_seen_at)}</td>
+                    <td class="pe-3"><button class="btn btn-sm btn-outline-danger" data-dtc-id="${e.id}" title="Delete">🗑</button></td>
+                </tr>
+            `).join("");
+            table.hidden = false;
+
+            tbody.querySelectorAll("[data-dtc-id]").forEach(btn => {
+                btn.addEventListener("click", async () => {
+                    if (!confirm("Delete this DTC event?")) return;
+                    const r = await fetch("/api/v1/portal/dtc/" + btn.dataset.dtcId, {method: "DELETE"});
+                    if (!r.ok) { error.textContent = "Could not delete."; error.hidden = false; return; }
+                    load();
+                });
+            });
+        } catch (e) {
+            loading.hidden = true;
+            error.textContent = e.message;
+            error.hidden = false;
+        }
+    }
+    load();
+})();
+</script>
+{% endblock %}