Add sparklines for Bitcoin, Gold, and Silver with 30-day history

src/main.cpp

@@ -153,6 +153,16 @@ const char* getIndexFriendlyName(const char* ticker) {
 
 unsigned long lastRefresh = 0;
 const unsigned long REFRESH_INTERVAL = 180000;
+const unsigned long HISTORY_REFRESH_INTERVAL = 3600000;
+
+#define HISTORY_DAYS 30
+double btcHistory[HISTORY_DAYS] = {0};
+double goldHistory[HISTORY_DAYS] = {0};
+double silverHistory[HISTORY_DAYS] = {0};
+bool btcHistoryLoaded = false;
+bool goldHistoryLoaded = false;
+bool silverHistoryLoaded = false;
+unsigned long lastHistoryRefresh = 0;
 
 enum ScreenState {
   SCREEN_DASHBOARD,
@@ -264,6 +274,108 @@ bool fetchPriceFinnhub(const char* symbol, double* result) {
   return true;
 }
 
+bool fetchHistory(const char* symbol, double* history, bool* loaded) {
+  WiFiClientSecure client;
+  client.setInsecure();
+
+  HTTPClient http;
+  String url = "https://query1.finance.yahoo.com/v8/finance/chart/" + String(symbol) + "?interval=1d&range=1mo";
+
+  if (!http.begin(client, url)) return false;
+
+  http.setUserAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36");
+  http.setTimeout(15000);
+
+  int httpCode = http.GET();
+  if (httpCode != HTTP_CODE_OK) {
+    http.end();
+    return false;
+  }
+
+  String payload = http.getString();
+  http.end();
+
+  String arraySearch = "\"close\":[";
+  int arrayIdx = payload.indexOf(arraySearch);
+  if (arrayIdx == -1) return false;
+
+  int arrayStart = arrayIdx + arraySearch.length();
+  int arrayEnd = payload.indexOf("]", arrayStart);
+  if (arrayEnd == -1) return false;
+
+  String closeArray = payload.substring(arrayStart, arrayEnd);
+
+  int dayIndex = 0;
+  int pos = 0;
+
+  while (pos < closeArray.length() && dayIndex < HISTORY_DAYS) {
+    while (pos < closeArray.length() && (closeArray[pos] == ' ' || closeArray[pos] == ',')) pos++;
+    if (pos >= closeArray.length()) break;
+
+    int valueStart = pos;
+    while (pos < closeArray.length() && closeArray[pos] != ',' && closeArray[pos] != ' ') pos++;
+
+    String valueStr = closeArray.substring(valueStart, pos);
+
+    if (valueStr.equals("null") || valueStr.length() == 0) {
+      pos++;
+      continue;
+    }
+
+    double value = valueStr.toDouble();
+    if (value > 0) {
+      history[dayIndex++] = value;
+    }
+    pos++;
+  }
+
+  if (dayIndex > 0) {
+    *loaded = true;
+    return true;
+  }
+  return false;
+}
+
+void fetchAllHistory() {
+  fetchHistory("BTC-USD", btcHistory, &btcHistoryLoaded);
+  fetchHistory("GC=F", goldHistory, &goldHistoryLoaded);
+  fetchHistory("SI=F", silverHistory, &silverHistoryLoaded);
+}
+
+void drawSparkline(int x, int y, int width, int height, double* history, bool loaded, uint16_t color) {
+  if (!loaded) return;
+
+  double minVal = history[0];
+  double maxVal = history[0];
+  int validDays = 0;
+
+  for (int i = 0; i < HISTORY_DAYS; i++) {
+    if (history[i] > 0) {
+      if (history[i] < minVal) minVal = history[i];
+      if (history[i] > maxVal) maxVal = history[i];
+      validDays++;
+    }
+  }
+
+  if (validDays < 2 || maxVal <= minVal) return;
+
+  double range = maxVal - minVal;
+  if (range < 1) range = 1;
+
+  for (int i = 0; i < validDays - 1; i++) {
+    int x1 = x + (i * width) / (validDays - 1);
+    int x2 = x + ((i + 1) * width) / (validDays - 1);
+    int y1 = y + height - (int)((history[i] - minVal) * height / range);
+    int y2 = y + height - (int)((history[i + 1] - minVal) * height / range);
+
+    lcd.drawLine(x1, y1, x2, y2, color);
+  }
+
+  int lastX = x + ((validDays - 1) * width) / (validDays - 1);
+  int lastY = y + height - (int)((history[validDays - 1] - minVal) * height / range);
+  lcd.drawPixel(lastX, lastY, TFT_WHITE);
+}
+
 void loadConfig() {
   preferences.begin("dashboard", true);
   
@@ -499,13 +611,19 @@ void drawDashboard() {
   lcd.drawString("Bitcoin:", col1X, labelY);
   lcd.drawString(formatPriceUS(btcPrice, 0), col1X, priceY);
 
+  drawSparkline(col1X, labelY + 53, 240, 35, btcHistory, btcHistoryLoaded, TFT_ORANGE);
+
   lcd.setTextColor(TFT_GOLD, TFT_BLACK);
-  lcd.drawString("Gold:", col1X, labelY + 65);
+  lcd.drawString("Gold:", col1X, labelY + 113);
-  lcd.drawString(formatPriceUS(goldPrice, 2), col1X, priceY + 65);
+  lcd.drawString(formatPriceUS(goldPrice, 2), col1X, priceY + 113);
+
+  drawSparkline(col1X, labelY + 178, 240, 35, goldHistory, goldHistoryLoaded, TFT_GOLD);
 
   lcd.setTextColor(TFT_SILVER, TFT_BLACK);
-  lcd.drawString("Silver:", col1X, labelY + 130);
+  lcd.drawString("Silver:", col1X, labelY + 233);
-  lcd.drawString(formatPriceUS(silverPrice, 2), col1X, priceY + 130);
+  lcd.drawString(formatPriceUS(silverPrice, 2), col1X, priceY + 233);
+
+  drawSparkline(col1X, labelY + 298, 240, 35, silverHistory, silverHistoryLoaded, TFT_SILVER);
 
   lcd.setTextColor(TFT_GREEN, TFT_BLACK);
   int stockY = labelY;
@@ -808,7 +926,9 @@ void setup() {
 
       delay(1000);
       updatePrices();
+      fetchAllHistory();
       lastRefresh = millis();
+      lastHistoryRefresh = millis();
       drawDashboard();
       return;
     }
@@ -881,6 +1001,11 @@ void loop() {
     drawFooterCountdown();
   }
 
+  if (currentScreen == SCREEN_DASHBOARD && millis() - lastHistoryRefresh > HISTORY_REFRESH_INTERVAL) {
+    fetchAllHistory();
+    lastHistoryRefresh = millis();
+  }
+
   if (currentScreen == SCREEN_DASHBOARD && millis() - lastRefresh > REFRESH_INTERVAL) {
     showRefreshingMessage();
     updatePrices();