Implemented history writer

Client/streamhub/Protocol.cpp

@@ -253,6 +253,23 @@ std::string BuildZoom(uint32_t reqId, double t0, double t1, int n,
     return out;
 }
 
+std::string BuildHistoryZoom(uint32_t reqId, double t0, double t1, int n,
+                              const std::string& signalsCsv) {
+    char head[256];
+    snprintf(head, sizeof(head),
+             "{\"type\":\"historyZoom\",\"reqId\":%u,"
+             "\"t0\":%.17g,\"t1\":%.17g,\"n\":%d,\"signals\":\"",
+             static_cast<unsigned>(reqId), t0, t1, n);
+    std::string out(head);
+    out += signalsCsv;
+    out += "\"}";
+    return out;
+}
+
+std::string BuildHistoryInfo() {
+    return "{\"type\":\"historyInfo\"}";
+}
+
 std::string BuildSetMaxPoints(uint32_t n) {
     char buf[128];
     snprintf(buf, sizeof(buf), "{\"type\":\"setMaxPoints\",\"maxPoints\":%u}",
@@ -530,4 +547,60 @@ bool ParseMaxPointsUpdated(const std::string& json, uint32_t& maxPoints) {
     return true;
 }
 
+/* ---- historyInfo -------------------------------------------------------- */
+
+bool ParseHistoryInfo(const std::string& json, HistoryInfoMsg& out) {
+    out.signals.clear();
+    out.enabled = false;
+
+    char tmp[16] = "";
+    jsonGetStr(json.c_str(), "enabled", tmp, sizeof(tmp));
+    out.enabled = (strcmp(tmp, "true") == 0);
+
+    double df = 0.0;
+    jsonGetDouble(json.c_str(), "durationHours", df);
+    out.durationHours = df;
+
+    double decF = 0.0;
+    jsonGetDouble(json.c_str(), "decimation", decF);
+    out.decimation = static_cast<uint32_t>(decF);
+
+    /* Parse "signals":{...} block — same key iteration as zoom */
+    const char *sig = strstr(json.c_str(), "\"signals\":{");
+    if (!sig) { return out.enabled; }
+    sig += 11; /* past '{"signals":{' */
+
+    while (*sig) {
+        /* Find next "key":{ */
+        const char *q = strchr(sig, '"');
+        if (!q) { break; }
+        q++;
+        const char *qEnd = strchr(q, '"');
+        if (!qEnd) { break; }
+
+        HistorySignalRange hr;
+        hr.key = std::string(q, qEnd);
+
+        /* Find the nested object */
+        const char *brace = strchr(qEnd, '{');
+        if (!brace) { break; }
+
+        jsonGetDouble(brace, "t0", hr.t0);
+        jsonGetDouble(brace, "t1", hr.t1);
+        double cntF = 0.0, capF = 0.0;
+        jsonGetDouble(brace, "count", cntF);
+        jsonGetDouble(brace, "capacity", capF);
+        hr.count    = static_cast<uint32_t>(cntF);
+        hr.capacity = static_cast<uint32_t>(capF);
+
+        out.signals.push_back(hr);
+
+        /* Advance past the closing brace */
+        const char *end = strchr(brace, '}');
+        if (!end) { break; }
+        sig = end + 1;
+    }
+    return true;
+}
+
 } /* namespace StreamHubClient */