Added functionality to fetch account statement as MT940 from LNBits wallet transactions

src/main/java/lnbits/LnbitsHelper.java

@@ -0,0 +1,150 @@
+package lnbits;
+
+import com.prowidesoftware.swift.model.field.*;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpHeaders;
+import org.apache.http.client.ClientProtocolException;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.util.EntityUtils;
+import org.codehaus.jackson.map.ObjectMapper;
+import org.codehaus.jackson.type.TypeReference;
+
+import java.io.BufferedInputStream;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.text.SimpleDateFormat;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Properties;
+import java.util.stream.Collectors;
+
+public class LnbitsHelper {
+    private static String lnbitsUrl;
+
+    private static String uriWallet;
+    private static String uriPayments;
+
+    private static String xApiKey;
+
+    private static void loadConfiguration() {
+        Properties properties = new Properties();
+        try {
+            BufferedInputStream stream = new BufferedInputStream(new FileInputStream("config/lnbits.properties"));
+            properties.load(stream);
+            stream.close();
+
+            lnbitsUrl = properties.getProperty("lnbitsUrl");
+            uriWallet = properties.getProperty("uriWallet");
+            uriPayments = properties.getProperty("uriPayments");
+            xApiKey = properties.getProperty("xApiKey");
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+    public static Collection<Field> getMt940Fields(java.util.Date from, java.util.Date to) throws IOException {
+        loadConfiguration();
+
+        Collection<Field> mt940Fields = new ArrayList<>();
+        Long currentBalance = getCurrentBalance();
+        Collection<LnTransaction> afterFromSettledPayments = getPayments()
+                .stream()
+                .filter(tx -> tx.getTime().after(from) && !tx.getPending())
+                .collect(Collectors.toList());
+        Long fromBalance = currentBalance - afterFromSettledPayments
+                .stream()
+                .map(tx -> tx.getAmount() + tx.getFee())
+                .reduce(0L, Long::sum);
+        Collection<LnTransaction> fromToPayments = afterFromSettledPayments
+                .stream()
+                .filter(tx -> tx.getTime().before(to))
+                .collect(Collectors.toList());
+        Long toBalance = fromBalance + fromToPayments
+                .stream()
+                .map(tx -> tx.getAmount() + tx.getFee())
+                .reduce(0L, Long::sum);
+        // initialBalance
+        String simpleFrom = new SimpleDateFormat("yyMMdd").format(from);
+        mt940Fields.add(new Field60F()
+                .setDCMark("C")
+                .setDate(simpleFrom)
+                .setCurrency("EUR")
+                .setAmount(fromBalance/1000L)
+        );
+
+        for (LnTransaction tx : fromToPayments) {
+            mt940Fields.add(tx.toField61());
+            mt940Fields.add(tx.toField86());
+        }
+
+        // finalBalance
+        String simpleTo = new SimpleDateFormat("yyMMdd").format(from);
+        mt940Fields.add(new Field62F()
+                .setDCMark("C")
+                .setDate(simpleTo)
+                .setCurrency("EUR")
+                .setAmount(toBalance/1000L)
+        );
+
+        return mt940Fields;
+    }
+
+    private static Collection<LnTransaction> getPayments() throws IOException {
+        CloseableHttpClient httpClient = HttpClients.createDefault();
+        try {
+            HttpGet request = new HttpGet(lnbitsUrl + uriPayments);
+            request.addHeader("X-API-KEY", xApiKey);
+            request.addHeader(HttpHeaders.ACCEPT, "application/json");
+
+            CloseableHttpResponse response = httpClient.execute(request);
+            try {
+                HttpEntity entity = response.getEntity();
+                if (entity != null && response.getStatusLine().getStatusCode() == 200) {
+                    String result = EntityUtils.toString(entity);
+                    return new ObjectMapper().readValue(result, new TypeReference<List<LnTransaction>>(){});
+                } else {
+                    throw new RuntimeException("Request failed");
+                }
+            } finally {
+                response.close();
+            }
+        } catch (ClientProtocolException e) {
+            throw new RuntimeException(e);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        } finally {
+            httpClient.close();
+        }
+    }
+    private static Long getCurrentBalance() throws IOException {
+        CloseableHttpClient httpClient = HttpClients.createDefault();
+        try {
+            HttpGet request = new HttpGet(lnbitsUrl + uriWallet);
+            request.addHeader("X-API-KEY", xApiKey);
+            request.addHeader(HttpHeaders.ACCEPT, "application/json");
+
+            CloseableHttpResponse response = httpClient.execute(request);
+            try {
+                HttpEntity entity = response.getEntity();
+                if (entity != null && response.getStatusLine().getStatusCode() == 200) {
+                    String result = EntityUtils.toString(entity);
+                    WalletDetails walletDetails = new ObjectMapper().readValue(result, WalletDetails.class);
+                    return walletDetails.getBalance();
+                } else {
+                    throw new RuntimeException("Request failed");
+                }
+            } finally {
+                response.close();
+            }
+        } catch (ClientProtocolException e) {
+            throw new RuntimeException(e);
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        } finally {
+            httpClient.close();
+        }
+    }
+}