feat: add structures for MTR arrival and station information handling

main/external/mtr/station_info.h

@@ -0,0 +1,26 @@
+#pragma once
+#include "esp_log.h"
+#include "external/mtr/line_info.h"
+
+static const char* STATION_INFO_TAG = "StationInfo";
+
+// Forward declaration
+struct LineInfo;
+
+struct StationInfo {
+public:
+  StationInfo(cJSON* station_json);
+
+  const char* name() const { return _name.c_str(); }
+  const char* code() const { return _code.c_str(); }
+
+  friend class LineInfo;
+
+private:
+  // Caller transfers ownership of station_name and station_code to StationInfo
+  StationInfo(std::string& station_name, std::string& station_code)
+    : _name(station_name), _code(station_code) { }
+
+  std::string _name;
+  std::string _code;
+};