fix BML POS QRs

2026-09-21 15:26:18 +05:00
parent 0357d7e0bc
commit 80fd238195
15 changed files with 226 additions and 58 deletions
@@ -9,22 +9,58 @@ data class PaymvQrData(

 object PaymvQrParser {

+    private const val BML_GATEWAY_PREFIX = "https://pay.bml.com.mv/app/"
+    private const val BML_EBANKING_PREFIX = "https://ebanking.bankofmaldives.com.mv/qrpay/"
+    private const val BML_POS_DOMAIN = "mv.com.bml.qtr"
+
    /**
-     * Returns the BML gateway URL if [raw] is or contains one, otherwise null.
-     * Handles both plain URL QRs and combined EMV QRs (e.g. Fahipay+BML card QR).
-     * For combined EMV QRs the URL is parsed from TLV (root tag 35 → sub-tag 20 → sub-sub-tag 01)
-     * rather than via regex, to avoid greedily consuming subsequent EMV tag bytes.
+     * Returns the value to hand to the BML QR payment flow, or null when [raw] is not a BML QR.
+     *
+     * Three shapes exist:
+     *  - plain URL QRs — the QR text is the gateway short link or an ebanking `qrpay` link;
+     *  - combined EMV QRs (e.g. Fahipay+BML card QRs), which carry the full gateway URL in TLV at
+     *    `35` → `20` → `01`;
+     *  - BML POS QRs (supplementary data domain `mv.com.bml.qtr`), where the same TLV path holds a
+     *    bare reference such as `02:<32 hex>` rather than a URL. Those return the whole EMV payload,
+     *    which [bmlPayRequestKey] then reduces back to the reference the lookup wants.
+     *
+     * The TLV is walked rather than regex-matched so a URL cannot greedily swallow the EMV tags
+     * that follow it.
     */
-    fun extractBmlGatewayUrl(raw: String): String? {
-        if (raw.startsWith("https://pay.bml.com.mv/app/")) return raw
-        return try {
-            val root = parseTlv(raw)
-            val bmlMerchantInfo = root["35"]?.let { parseTlv(it) } ?: return null
-            val inner = bmlMerchantInfo["20"]?.let { parseTlv(it) } ?: return null
-            inner["01"]?.takeIf { it.startsWith("https://pay.bml.com.mv/app/") }
-        } catch (_: Exception) {
-            null
-        }
+    fun bmlQrPayTarget(raw: String): String? {
+        if (raw.startsWith(BML_GATEWAY_PREFIX) || raw.startsWith(BML_EBANKING_PREFIX)) return raw
+        val ref = bmlQrReference(raw) ?: return null
+        if (ref.startsWith("https://")) return ref.takeIf { it.startsWith(BML_GATEWAY_PREFIX) }
+        // A bare reference only means a BML POS QR when the supplementary domain says so; anything
+        // else keeps falling through to the PayMV parse, as it did before POS QRs existed.
+        return raw.takeIf { supplementaryDomain(it)?.startsWith(BML_POS_DOMAIN) == true }
+    }
+
+    /** TLV `80` → `00` — the supplementary data domain (`mv.favara.mpqr`, `mv.com.bml.qtr`, …). */
+    private fun supplementaryDomain(raw: String): String? = try {
+        parseTlv(raw)["80"]?.let { parseTlv(it) }?.get("00")
+    } catch (_: Exception) {
+        null
+    }
+
+    /** TLV `35` → `20` → `01` — the BML payment reference carried inside an EMV QR. */
+    private fun bmlQrReference(raw: String): String? = try {
+        val merchantInfo = parseTlv(raw)["35"]?.let { parseTlv(it) }
+        val inner = merchantInfo?.get("20")?.let { parseTlv(it) }
+        inner?.get("01")?.takeIf { it.isNotBlank() }
+    } catch (_: Exception) {
+        null
+    }
+
+    /**
+     * The `payrequest` lookup key for [target] (a value returned by [bmlQrPayTarget]), to be
+     * Base64-encoded into the URL. URL QRs resolve under the URL itself; POS QRs resolve under the
+     * bare `35` → `20` → `01` reference (the whole EMV payload is rejected with code 112,
+     * "Unsupported payment link").
+     */
+    fun bmlPayRequestKey(target: String): String {
+        if (target.startsWith("https://")) return target
+        return bmlQrReference(target) ?: target
    }

    fun parse(raw: String): PaymvQrData? {