initial commit

docs/SYSTEM.md

@@ -0,0 +1,41 @@
+## System
+
+The customer and the merchant must have a supporting infrastructure to make and accept payments using a bolt card.
+
+### Interaction
+```mermaid
+flowchart TB
+    BoltCard(bolt card)-. NFC .-PointOfSale(point of sale)
+    MerchantServer(merchant server)-. LNURLw .-BoltCardServer(bolt card server)
+    LightningNodeA(lightning node)-. lightning network .-LightningNodeB(lightning node)
+    
+    subgraph merchant
+    PointOfSale<-->MerchantServer
+    LightningNodeB-->MerchantServer
+    end
+    
+    subgraph customer
+    BoltCardServer-->LightningNodeA
+    end
+```
+
+### Sequencing
+```mermaid
+sequenceDiagram
+    participant p1 as customer bolt card
+    participant p2 as merchant point of sale
+    participant p3 as merchant server
+    participant p4 as customer bolt card server
+    participant p5 as customer lightining node
+    participant p6 as merchant lightning node
+    p1->>p2: NFC read
+    p2->>p3: API call
+    p3->>p4: LNURLw request
+    p4->>p3: LNURLw response
+    p3->>p4: LNURLw callback
+    p4->>p3: LNURLw response
+    p4->>p5: API call
+    p5-->>p6: lightning network payment
+    p6->>p3: payment notification
+    p3->>p2: user notification
+```