commit e4634fedf292b6abc38dc0ade302da27ec54d1fe
Author: Râu Cao <raucao@kosmos.org>
Date:   Fri May 2 14:40:06 2025 +0400

    Export daily stats per user to CSV

diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..9596a7c
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,8 @@
+DB_USER=lndhub
+DB_PASSWORD=12345678
+DB_NAME=lndhub
+DB_HOST=10.1.1.1
+# DB_PORT=5432
+# BATCH_SIZE=10
+# MAX_INVOICES=21000 # per user
+# ANONYMIZATION_KEY=12345678
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3f69639
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+.env
+csv/
+*.csv
+sql/
diff --git a/export-stats.ts b/export-stats.ts
new file mode 100644
index 0000000..1b51639
--- /dev/null
+++ b/export-stats.ts
@@ -0,0 +1,210 @@
+// Import required modules
+import { Client } from "jsr:@db/postgres";
+import { load } from "jsr:@std/dotenv";
+import { crypto } from "jsr:@std/crypto";
+
+// Load environment variables from .env file or system environment
+const env = await load();
+
+// Validate required environment variables
+for (const key of ["DB_USER", "DB_PASSWORD", "DB_NAME", "ANONYMIZATION_KEY"]) {
+  if (!env[key]) {
+    console.error(`Missing ${key} in .env or environment variables`);
+    Deno.exit(1);
+  }
+}
+
+// Adjust based on database capacity
+const BATCH_SIZE = parseInt(env.BATCH_SIZE) || 10;
+// Maximum number of invoices to process per user
+// Skip user if exceeded (likely the case for streaming payments e.g.)
+const MAX_INVOICES = parseInt(env.MAX_INVOICES) || 21000;
+
+// Database connection configuration from .env or environment variables
+const dbConfig = {
+  user: env.DB_USER,
+  password: env.DB_PASSWORD,
+  database: env.DB_NAME,
+  hostname: env.DB_HOST || "localhost",
+  port: parseInt(env.DB_PORT || "5432", 10),
+};
+
+const client = new Client(dbConfig);
+
+// Connect to the database
+try {
+  await client.connect();
+  console.log(`Connected to database`);
+} catch {
+  console.log(`Failed to connect to database`);
+  Deno.exit(1);
+}
+
+// Fetch all user IDs
+const userIdsResult = await client.queryObject("SELECT id FROM users");
+const userIds = userIdsResult.rows.map((row) => row.id);
+
+// CSV file path
+const csvFilePath = "./daily-stats.csv";
+
+// CSV headers
+const csvHeaders = [
+  "User ID", // HMAC-SHA256 hash (truncated to 12 hex chars)
+  "Date",
+  "Balance Start of Day",
+  "Balance End of Day",
+  "Balance Max Day",
+  "Balance Min Day",
+  "Total Flow Out",
+  "Total Flow In",
+];
+
+// Write headers to CSV (create file or overwrite if it exists)
+await Deno.writeTextFile(csvFilePath, csvHeaders.join(",") + "\n");
+
+// Function to compute HMAC-SHA256 hash of user_id, truncated to 48 bits (12 hex chars)
+async function anonymizeUserId(userId) {
+  const keyData = new TextEncoder().encode(env.ANONYMIZATION_KEY);
+  const data = new TextEncoder().encode(userId.toString());
+  const key = await crypto.subtle.importKey(
+    "raw",
+    keyData,
+    { name: "HMAC", hash: "SHA-256" },
+    false,
+    ["sign"]
+  );
+  const signature = await crypto.subtle.sign("HMAC", key, data);
+  const hashArray = Array.from(new Uint8Array(signature).slice(0, 6)); // Take first 6 bytes (48 bits)
+  return hashArray.map((b) => b.toString(16).padStart(2, "0")).join("");
+}
+
+// Function to process a single user and return CSV rows
+async function processUser(userId, client) {
+  // Check the number of settled invoices for the user
+  const countResult = await client.queryObject(
+    `SELECT COUNT(*) AS count
+     FROM invoices
+     WHERE user_id = $1 AND settled_at IS NOT NULL`,
+    [userId]
+  );
+  const invoiceCount = Number(countResult.rows[0].count);
+
+  if (invoiceCount > MAX_INVOICES) {
+    const anonymizedUserId = await anonymizeUserId(userId);
+    console.warn(`Skipping user ${anonymizedUserId}: ${invoiceCount} invoices exceed limit of ${MAX_INVOICES}`);
+    return [];
+  }
+
+  // Fetch settled invoices for the user
+  const invoicesResult = await client.queryObject(
+    `SELECT settled_at, amount, type, service_fee, routing_fee
+     FROM invoices
+     WHERE user_id = $1 AND settled_at IS NOT NULL
+     ORDER BY settled_at ASC`,
+    [userId]
+  );
+  const invoices = invoicesResult.rows;
+
+  if (invoices.length === 0) return [];
+
+  // Aggregate daily statistics using BigInt
+  const dailyData = {};
+  let runningBalance = BigInt(0); // Initialize as BigInt
+
+  for (const invoice of invoices) {
+    const day = invoice.settled_at.toISOString().split("T")[0]; // YYYY-MM-DD
+    // Convert amounts to BigInt, handling NULL fees
+    const amount = BigInt(invoice.amount);
+    const serviceFee = invoice.service_fee ? BigInt(invoice.service_fee) : BigInt(0);
+    const routingFee = invoice.routing_fee ? BigInt(invoice.routing_fee) : BigInt(0);
+
+    // Calculate effective amount: include fees for outgoing, not for incoming
+    const effectiveAmount = invoice.type === "incoming"
+      ? amount
+      : amount + serviceFee + routingFee; // Add fees for outgoing
+    const signedAmount = invoice.type === "incoming" ? effectiveAmount : -effectiveAmount;
+
+    if (!dailyData[day]) {
+      dailyData[day] = {
+        balance_start_of_day: runningBalance,
+        balance_end_of_day: runningBalance,
+        balance_max_day: runningBalance,
+        balance_min_day: runningBalance,
+        total_flow_in: BigInt(0),
+        total_flow_out: BigInt(0),
+      };
+    }
+
+    // Update running balance
+    runningBalance += signedAmount;
+    dailyData[day].balance_end_of_day = runningBalance;
+
+    // Update min/max balance
+    dailyData[day].balance_max_day = runningBalance > dailyData[day].balance_max_day
+      ? runningBalance
+      : dailyData[day].balance_max_day;
+    dailyData[day].balance_min_day = runningBalance < dailyData[day].balance_min_day
+      ? runningBalance
+      : dailyData[day].balance_min_day;
+
+    // Update flows
+    if (signedAmount > 0) {
+      dailyData[day].total_flow_in += signedAmount;
+    } else {
+      dailyData[day].total_flow_out += -signedAmount; // Positive outflow value
+    }
+  }
+
+  // Generate CSV rows for this user with anonymized user_id
+  const anonymizedUserId = await anonymizeUserId(userId);
+  const rows = [];
+  for (const [day, stats] of Object.entries(dailyData)) {
+    rows.push([
+      anonymizedUserId,
+      day,
+      stats.balance_start_of_day.toString(),
+      stats.balance_end_of_day.toString(),
+      stats.balance_max_day.toString(),
+      stats.balance_min_day.toString(),
+      stats.total_flow_out.toString(),
+      stats.total_flow_in.toString(),
+    ].join(","));
+  }
+
+  return rows;
+}
+
+// Process users in parallel with batching
+async function processUsersInParallel(userIds) {
+  for (let i = 0; i < userIds.length; i += BATCH_SIZE) {
+    const batch = userIds.slice(i, i + BATCH_SIZE);
+    console.log(`Processing batch ${i / BATCH_SIZE + 1} of ${Math.ceil(userIds.length / BATCH_SIZE)}`);
+
+    // Process users in parallel and collect rows
+    const promises = batch.map(async (userId) => {
+      const batchClient = new Client(dbConfig); // Use shared dbConfig
+      await batchClient.connect();
+      try {
+        return await processUser(userId, batchClient);
+      } finally {
+        await batchClient.end();
+      }
+    });
+
+    // Wait for all users in the batch to complete
+    const batchRows = (await Promise.all(promises)).flat();
+
+    // Write all rows for the batch to CSV in one operation
+    if (batchRows.length > 0) {
+      await Deno.writeTextFile(csvFilePath, batchRows.join("\n") + "\n", { append: true });
+    }
+  }
+}
+
+// Run parallel processing
+await processUsersInParallel(userIds);
+
+// Close the main database connection
+await client.end();
+
+console.log("Daily statistics written to", csvFilePath);