feat: Lightning Network integration for tool usage (#610)

Co-authored-by: Kimi Agent <kimi@timmy.local>
Co-committed-by: Kimi Agent <kimi@timmy.local>

src/dashboard/routes/system.py

@@ -16,52 +16,11 @@ router = APIRouter(tags=["system"])
 
 @router.get("/lightning/ledger", response_class=HTMLResponse)
 async def lightning_ledger(request: Request):
-    """Ledger and balance page."""
-    # Mock data for now, as this seems to be a UI-first feature
-    balance = {
-        "available_sats": 1337,
-        "incoming_total_sats": 2000,
-        "outgoing_total_sats": 663,
-        "fees_paid_sats": 5,
-        "net_sats": 1337,
-        "pending_incoming_sats": 0,
-        "pending_outgoing_sats": 0,
-    }
+    """Ledger and balance page backed by the in-memory Lightning ledger."""
+    from lightning.ledger import get_balance, get_transactions
 
-    # Mock transactions
-    from collections import namedtuple
-    from enum import Enum
-
-    class TxType(Enum):
-        incoming = "incoming"
-        outgoing = "outgoing"
-
-    class TxStatus(Enum):
-        completed = "completed"
-        pending = "pending"
-
-    Tx = namedtuple(
-        "Tx", ["tx_type", "status", "amount_sats", "payment_hash", "memo", "created_at"]
-    )
-
-    transactions = [
-        Tx(
-            TxType.outgoing,
-            TxStatus.completed,
-            50,
-            "hash1",
-            "Model inference",
-            "2026-03-04 10:00:00",
-        ),
-        Tx(
-            TxType.incoming,
-            TxStatus.completed,
-            1000,
-            "hash2",
-            "Manual deposit",
-            "2026-03-03 15:00:00",
-        ),
-    ]
+    balance = get_balance()
+    transactions = get_transactions()
 
     return templates.TemplateResponse(
         request,
@@ -70,7 +29,7 @@ async def lightning_ledger(request: Request):
             "balance": balance,
             "transactions": transactions,
             "tx_types": ["incoming", "outgoing"],
-            "tx_statuses": ["completed", "pending"],
+            "tx_statuses": ["pending", "settled", "failed", "expired"],
             "filter_type": None,
             "filter_status": None,
             "stats": {},

src/lightning/__init__.py

@@ -0,0 +1 @@
+"""Lightning Network integration for tool-usage micro-payments."""

src/lightning/factory.py

@@ -0,0 +1,69 @@
+"""Lightning backend factory.
+
+Returns a mock or real LND backend based on ``settings.lightning_backend``.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import logging
+import secrets
+from dataclasses import dataclass
+
+from config import settings
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class Invoice:
+    """Minimal Lightning invoice representation."""
+
+    payment_hash: str
+    payment_request: str
+    amount_sats: int
+    memo: str
+
+
+class MockBackend:
+    """In-memory mock Lightning backend for development and testing."""
+
+    def create_invoice(self, amount_sats: int, memo: str = "") -> Invoice:
+        """Create a fake invoice with a random payment hash."""
+        raw = secrets.token_bytes(32)
+        payment_hash = hashlib.sha256(raw).hexdigest()
+        payment_request = f"lnbc{amount_sats}mock{payment_hash[:20]}"
+        logger.debug("Mock invoice: %s sats — %s", amount_sats, payment_hash[:12])
+        return Invoice(
+            payment_hash=payment_hash,
+            payment_request=payment_request,
+            amount_sats=amount_sats,
+            memo=memo,
+        )
+
+
+# Singleton — lazily created
+_backend: MockBackend | None = None
+
+
+def get_backend() -> MockBackend:
+    """Return the configured Lightning backend (currently mock-only).
+
+    Raises ``ValueError`` if an unsupported backend is requested.
+    """
+    global _backend  # noqa: PLW0603
+    if _backend is not None:
+        return _backend
+
+    kind = settings.lightning_backend
+    if kind == "mock":
+        _backend = MockBackend()
+    elif kind == "lnd":
+        # LND gRPC integration is on the roadmap — for now fall back to mock.
+        logger.warning("LND backend not yet implemented — using mock")
+        _backend = MockBackend()
+    else:
+        raise ValueError(f"Unknown lightning_backend: {kind!r}")
+
+    logger.info("Lightning backend: %s", kind)
+    return _backend

src/lightning/ledger.py

@@ -0,0 +1,146 @@
+"""In-memory Lightning transaction ledger.
+
+Tracks invoices, settlements, and balances per the schema in
+``docs/adr/018-lightning-ledger.md``.  Uses a simple in-memory list so the
+dashboard can display real (ephemeral) data without requiring SQLite yet.
+"""
+
+from __future__ import annotations
+
+import logging
+import uuid
+from dataclasses import dataclass
+from datetime import UTC, datetime
+from enum import StrEnum
+
+logger = logging.getLogger(__name__)
+
+
+class TxType(StrEnum):
+    incoming = "incoming"
+    outgoing = "outgoing"
+
+
+class TxStatus(StrEnum):
+    pending = "pending"
+    settled = "settled"
+    failed = "failed"
+    expired = "expired"
+
+
+@dataclass
+class LedgerEntry:
+    """Single ledger row matching the ADR-018 schema."""
+
+    id: str
+    tx_type: TxType
+    status: TxStatus
+    payment_hash: str
+    amount_sats: int
+    memo: str
+    source: str
+    created_at: str
+    invoice: str = ""
+    preimage: str = ""
+    task_id: str = ""
+    agent_id: str = ""
+    settled_at: str = ""
+    fee_sats: int = 0
+
+
+# ── In-memory store ──────────────────────────────────────────────────
+_entries: list[LedgerEntry] = []
+
+
+def create_invoice_entry(
+    payment_hash: str,
+    amount_sats: int,
+    memo: str = "",
+    source: str = "tool_usage",
+    task_id: str = "",
+    agent_id: str = "",
+    invoice: str = "",
+) -> LedgerEntry:
+    """Record a new incoming invoice in the ledger."""
+    entry = LedgerEntry(
+        id=uuid.uuid4().hex[:16],
+        tx_type=TxType.incoming,
+        status=TxStatus.pending,
+        payment_hash=payment_hash,
+        amount_sats=amount_sats,
+        memo=memo,
+        source=source,
+        task_id=task_id,
+        agent_id=agent_id,
+        invoice=invoice,
+        created_at=datetime.now(UTC).isoformat(),
+    )
+    _entries.append(entry)
+    logger.debug("Ledger entry created: %s (%s sats)", entry.id, amount_sats)
+    return entry
+
+
+def mark_settled(payment_hash: str, preimage: str = "") -> LedgerEntry | None:
+    """Mark a pending entry as settled by payment hash."""
+    for entry in _entries:
+        if entry.payment_hash == payment_hash and entry.status == TxStatus.pending:
+            entry.status = TxStatus.settled
+            entry.preimage = preimage
+            entry.settled_at = datetime.now(UTC).isoformat()
+            logger.debug("Ledger settled: %s", payment_hash[:12])
+            return entry
+    return None
+
+
+def get_balance() -> dict:
+    """Compute the current balance from settled and pending entries."""
+    incoming_total = sum(
+        e.amount_sats
+        for e in _entries
+        if e.tx_type == TxType.incoming and e.status == TxStatus.settled
+    )
+    outgoing_total = sum(
+        e.amount_sats
+        for e in _entries
+        if e.tx_type == TxType.outgoing and e.status == TxStatus.settled
+    )
+    fees = sum(e.fee_sats for e in _entries if e.status == TxStatus.settled)
+    pending_in = sum(
+        e.amount_sats
+        for e in _entries
+        if e.tx_type == TxType.incoming and e.status == TxStatus.pending
+    )
+    pending_out = sum(
+        e.amount_sats
+        for e in _entries
+        if e.tx_type == TxType.outgoing and e.status == TxStatus.pending
+    )
+    net = incoming_total - outgoing_total - fees
+    return {
+        "incoming_total_sats": incoming_total,
+        "outgoing_total_sats": outgoing_total,
+        "fees_paid_sats": fees,
+        "net_sats": net,
+        "pending_incoming_sats": pending_in,
+        "pending_outgoing_sats": pending_out,
+        "available_sats": net - pending_out,
+    }
+
+
+def get_transactions(
+    tx_type: str | None = None,
+    status: str | None = None,
+    limit: int = 50,
+) -> list[LedgerEntry]:
+    """Return ledger entries, optionally filtered."""
+    result = _entries
+    if tx_type:
+        result = [e for e in result if e.tx_type.value == tx_type]
+    if status:
+        result = [e for e in result if e.status.value == status]
+    return list(reversed(result))[:limit]
+
+
+def clear() -> None:
+    """Reset the ledger (for testing)."""
+    _entries.clear()

tests/unit/test_lightning.py

@@ -0,0 +1,109 @@
+"""Unit tests for the lightning package (factory + ledger)."""
+
+from __future__ import annotations
+
+import pytest
+
+from lightning.factory import Invoice, MockBackend, get_backend
+from lightning.ledger import (
+    TxStatus,
+    TxType,
+    clear,
+    create_invoice_entry,
+    get_balance,
+    get_transactions,
+    mark_settled,
+)
+
+
+@pytest.fixture(autouse=True)
+def _clean_ledger():
+    """Reset the in-memory ledger between tests."""
+    clear()
+    yield
+    clear()
+
+
+# ── Factory tests ────────────────────────────────────────────────────
+
+
+class TestMockBackend:
+    def test_create_invoice_returns_invoice(self):
+        backend = MockBackend()
+        inv = backend.create_invoice(100, "test memo")
+        assert isinstance(inv, Invoice)
+        assert inv.amount_sats == 100
+        assert inv.memo == "test memo"
+        assert len(inv.payment_hash) == 64  # SHA-256 hex
+        assert inv.payment_request.startswith("lnbc")
+
+    def test_invoices_have_unique_hashes(self):
+        backend = MockBackend()
+        a = backend.create_invoice(10)
+        b = backend.create_invoice(10)
+        assert a.payment_hash != b.payment_hash
+
+
+class TestGetBackend:
+    def test_returns_mock_backend(self):
+        backend = get_backend()
+        assert isinstance(backend, MockBackend)
+
+
+# ── Ledger tests ─────────────────────────────────────────────────────
+
+
+class TestLedger:
+    def test_create_invoice_entry(self):
+        entry = create_invoice_entry(
+            payment_hash="abc123",
+            amount_sats=500,
+            memo="test",
+            source="unit_test",
+        )
+        assert entry.tx_type == TxType.incoming
+        assert entry.status == TxStatus.pending
+        assert entry.amount_sats == 500
+
+    def test_mark_settled(self):
+        create_invoice_entry(payment_hash="hash1", amount_sats=100)
+        result = mark_settled("hash1", preimage="secret")
+        assert result is not None
+        assert result.status == TxStatus.settled
+        assert result.preimage == "secret"
+        assert result.settled_at != ""
+
+    def test_mark_settled_unknown_hash(self):
+        assert mark_settled("nonexistent") is None
+
+    def test_get_balance_empty(self):
+        bal = get_balance()
+        assert bal["net_sats"] == 0
+        assert bal["available_sats"] == 0
+
+    def test_get_balance_with_settled(self):
+        create_invoice_entry(payment_hash="h1", amount_sats=1000)
+        mark_settled("h1")
+        bal = get_balance()
+        assert bal["incoming_total_sats"] == 1000
+        assert bal["net_sats"] == 1000
+        assert bal["available_sats"] == 1000
+
+    def test_get_balance_pending_not_counted(self):
+        create_invoice_entry(payment_hash="h2", amount_sats=500)
+        bal = get_balance()
+        assert bal["incoming_total_sats"] == 0
+        assert bal["pending_incoming_sats"] == 500
+
+    def test_get_transactions_returns_entries(self):
+        create_invoice_entry(payment_hash="t1", amount_sats=10)
+        create_invoice_entry(payment_hash="t2", amount_sats=20)
+        txs = get_transactions()
+        assert len(txs) == 2
+
+    def test_get_transactions_filter_by_status(self):
+        create_invoice_entry(payment_hash="f1", amount_sats=10)
+        create_invoice_entry(payment_hash="f2", amount_sats=20)
+        mark_settled("f1")
+        assert len(get_transactions(status="settled")) == 1
+        assert len(get_transactions(status="pending")) == 1