Implement JSON transfer and marquee for long directions

README.md

@@ -8,5 +8,6 @@
 - [x] Create container
 - [x] Write ESP8266 client
 - [ ] Make port configurable
-- [ ] Transfer using JSON
+- [x] Transfer using JSON
 - [x] Correctly implement basic auth
+- [ ] Use unidecode to replace non-ascii stuff in the backend

client/client.ino

@@ -1,4 +1,4 @@
-// Screen libraries etc.
+#include <ArduinoJson.h>
 #include <ESP8266WiFi.h>
 #include <SPI.h>
 #include <Wire.h>
@@ -33,6 +33,7 @@ enum {
 } state = CONNECTING;
 int frame = 0;
 int buttonPushed = false;
+JsonDocument departures;
 
 void ICACHE_RAM_ATTR onButtonFalling() {
   buttonPushed = true;
@@ -54,7 +55,7 @@ void setup() {
   pinMode(BUTTON_PIN, INPUT_PULLUP);
   attachInterrupt(BUTTON_PIN, onButtonFalling, FALLING);
 
-  display.setTextColor(SSD1306_WHITE);
+  display.setTextColor(SSD1306_INVERSE);
   display.setTextSize(1);
   display.setCursor(0, 0);
   display.printf("Connecting to\n%s\n", WIFI_SSID);
@@ -66,11 +67,39 @@ void setup() {
   */
 }
 
-void drawSpinner (int frame) {
+void drawSpinner(int frame) {
   display.fillRect(120, 56, spinny_dims[0], spinny_dims[1], SSD1306_BLACK);
   display.drawBitmap(120, 56, spinny[frame % spinny_dims[2]], spinny_dims[0], spinny_dims[1], SSD1306_WHITE);
 }
 
+// TODO: Error handling
+String fetchDepartures() {
+  std::unique_ptr<BearSSL::WiFiClientSecure> https(new BearSSL::WiFiClientSecure);
+  https->setInsecure();
+  
+  HTTPClient client;
+  if (!client.begin(*https, "vrnp.beany.club", 443, "/departures?stop_id=de:08221:1225&platform=A")) {
+    display.clearDisplay();
+    display.setCursor(0, 0);
+    display.print("begin failed");
+    display.display();
+    for (;;);
+  }
+
+  client.addHeader("Authorization", AUTH_TOKEN);
+  client.addHeader("Accept", "application/json");
+  int statusCode = client.GET();
+  if (statusCode != 200) {
+    display.clearDisplay();
+    display.setCursor(0, 0);
+    display.printf("http non-ok: %d\n", statusCode);
+    display.display();
+    for (;;);
+  }
+
+  return client.getString();
+}
+
 void loop() {
   switch (state) {
     case CONNECTING: {
@@ -82,40 +111,16 @@ void loop() {
       }
       
       display.clearDisplay();
-      display.setCursor(0, 0);
+      display.fillRect(0, 56, 128, 8, SSD1306_INVERSE);
-      display.print("Connected!\nRequesting departures");
+      display.setCursor(0, 56);
+      display.print("requesting departures");
       display.display();
 
-      std::unique_ptr<BearSSL::WiFiClientSecure> https(new BearSSL::WiFiClientSecure);
+      String departuresRaw = fetchDepartures();
-      https->setInsecure();
+      deserializeJson(departures, departuresRaw);
-      HTTPClient client;
-      if (!client.begin(*https, "vrnp.beany.club", 443, "/departures?stop_id=de:08221:1225&platform=A")) {
-        display.clearDisplay();
-        display.setCursor(0, 0);
-        display.print("begin failed");
-        display.display();
-        for (;;);
-        return;
-      }
-
-      client.addHeader("Authorization", AUTH_TOKEN);
-      int statusCode = client.GET();
-      if (statusCode != 200) {
-        display.clearDisplay();
-        display.setCursor(0, 0);
-        display.printf("http non-ok: %d\n", statusCode);
-        display.display();
-        for (;;);
-        return;
-      }
-      
-      display.clearDisplay();
-      display.setCursor(0, 0);
-      display.print(client.getString());
-      display.display();
       
       state = SHOWING_DEPARTURES;
-      delay(FRAME_DELAY);
+      frame = 0;
       return;
     }
       
@@ -125,13 +130,48 @@ void loop() {
         return;
       }
 
+      /*
       if (buttonPushed) {
         buttonPushed = false;
         delay(FRAME_DELAY);
         return;
       }
+      */
+
+      // Marquee effect for direction strings longer than 11 characters
+      // Neither particularly efficient nor legible
+      // (This could use some love)
+
+      int availableWidth = 11;
+
+      display.clearDisplay();
+      display.setCursor(0, 0);
+      for (JsonVariant departure : departures["departures"].as<JsonArray>()) {
+        const char *directionStr = departure["direction"].as<const char *>();
+
+        char buf[128] = {0};
+        const char *dirStart;
+
+        if (strlen(directionStr) <= availableWidth || (strlen(directionStr) + 3 + availableWidth) > 127) {
+          dirStart = directionStr;
+        } else {
+          memcpy(buf, directionStr, strlen(directionStr));
+          memcpy(buf + strlen(directionStr), "   ", 3);
+          memcpy(buf + strlen(directionStr) + 3, directionStr, availableWidth);
+          buf[strlen(directionStr) + 3 + availableWidth] = '\0';
+          dirStart = buf + frame % (strlen(directionStr) + 3);
+        }
+
+        display.printf("%2s %-11.11s %6s\n",
+          departure["symbol"].as<const char*>(),
+          dirStart,
+          departure["leaving"].as<const char*>()
+        );
+      }
+      display.display();
       
-      delay(FRAME_DELAY);
+      frame++;
+      delay(500);
       return;
   }
 }