Harden pincode lookups and retry postal http

src/main/kotlin/com/android/trisolarisserver/component/PostalPincodeClient.kt

@@ -19,21 +19,33 @@ class PostalPincodeClient(
 
     fun resolve(pinCode: String): PincodeLookupResult {
         return try {
-            val url = UriComponentsBuilder.fromUriString(baseUrl)
-                .path("/pincode/{pin}")
-                .buildAndExpand(pinCode)
-                .toUriString()
-            val response = restTemplate.getForEntity(url, String::class.java)
-            val body = response.body ?: return PincodeLookupResult(null, null, "EMPTY_BODY", "postalpincode.in")
-            val resolved = parseCityState(body)
-            val status = if (resolved == null) "ZERO_RESULTS" else "OK"
-            PincodeLookupResult(resolved, body, status, "postalpincode.in")
+            val first = fetch(baseUrl, pinCode)
+            if (first.resolvedCityState != null) return first
+            if (first.status == "ERROR" && baseUrl.startsWith("https://")) {
+                val httpUrl = baseUrl.replaceFirst("https://", "http://")
+                val second = fetch(httpUrl, pinCode)
+                if (second.resolvedCityState != null) return second
+                return second
+            }
+            first
         } catch (ex: Exception) {
             logger.warn("Postalpincode lookup failed: {}", ex.message)
             PincodeLookupResult(null, null, "ERROR", "postalpincode.in", ex.message)
         }
     }
 
+    private fun fetch(base: String, pinCode: String): PincodeLookupResult {
+        val url = UriComponentsBuilder.fromUriString(base)
+            .path("/pincode/{pin}")
+            .buildAndExpand(pinCode)
+            .toUriString()
+        val response = restTemplate.getForEntity(url, String::class.java)
+        val body = response.body ?: return PincodeLookupResult(null, null, "EMPTY_BODY", "postalpincode.in")
+        val resolved = parseCityState(body)
+        val status = if (resolved == null) "ZERO_RESULTS" else "OK"
+        return PincodeLookupResult(resolved, body, status, "postalpincode.in")
+    }
+
     private fun parseCityState(body: String): String? {
         val root = objectMapper.readTree(body)
         if (!root.isArray || root.isEmpty) return null