Implement withdrawal

db/init.sql

@@ -54,3 +54,11 @@ CREATE TABLE orders(
 );
 ALTER TABLE orders ADD CONSTRAINT order_price CHECK(price > 0 AND price < 100);
 ALTER TABLE orders ADD CONSTRAINT order_quantity CHECK(quantity > 0);
+CREATE TABLE withdrawals(
+    id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
+    created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    deleted_at TIMESTAMP WITH TIME ZONE,
+    pubkey TEXT NOT NULL REFERENCES users(pubkey),
+    bolt11 TEXT NOT NULL UNIQUE,
+    paid_at TIMESTAMP WITH TIME ZONE
+);

db/types.go

@@ -66,4 +66,12 @@ type (
 		Invoice
 		OrderId null.String
 	}
+	Withdrawal struct {
+		Id        UUID
+		CreatedAt time.Time
+		DeletedAt null.Time
+		Pubkey    string
+		Bolt11    string `json:"bolt11"`
+		PaidAt    null.Time
+	}
 )

db/withdrawal.go

@@ -0,0 +1,13 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+)
+
+func (db *DB) CreateWithdrawal(tx *sql.Tx, c context.Context, w *Withdrawal) error {
+	if _, err := tx.ExecContext(c, "INSERT INTO withdrawals(pubkey, bolt11) VALUES ($1, $2)", w.Pubkey, w.Bolt11); err != nil {
+		return err
+	}
+	return nil
+}

lnd/withdrawal.go

@@ -0,0 +1,30 @@
+package lnd
+
+import (
+	"context"
+	"database/sql"
+	"log"
+	"time"
+
+	"github.com/btcsuite/btcd/btcutil"
+)
+
+func (lnd *LNDClient) PayInvoice(tx *sql.Tx, bolt11 string) error {
+	maxFeeSats := btcutil.Amount(10)
+	ctx, cancel := context.WithTimeout(context.TODO(), 10*time.Second)
+	defer cancel()
+	log.Printf("attempting to pay bolt11 %s ...\n", bolt11)
+	payChan := lnd.Client.PayInvoice(ctx, bolt11, maxFeeSats, nil)
+	res := <-payChan
+	if res.Err != nil {
+		log.Printf("error paying bolt11: %s -- %s\n", bolt11, res.Err)
+		tx.Rollback()
+		return res.Err
+	}
+	log.Printf("successfully paid bolt11: %s\n", bolt11)
+	if _, err := tx.ExecContext(ctx, "UPDATE withdrawals SET paid_at = CURRENT_TIMESTAMP WHERE bolt11 = $1", bolt11); err != nil {
+		tx.Rollback()
+		return err
+	}
+	return res.Err
+}

server/error.go

@@ -13,7 +13,7 @@ func httpErrorHandler(err error, c echo.Context) {
 	if httpError, ok := err.(*echo.HTTPError); ok {
 		code = httpError.Code
 	}
-	if strings.Contains(err.Error(), "violates check constraint") {
+	if strings.Contains(err.Error(), "violates check constraint") || strings.Contains(err.Error(), "violates unique constraint") {
 		code = 400
 	}
 	c.JSON(code, map[string]any{"status": code})

server/router/handler/withdrawal.go

@@ -0,0 +1,79 @@
+package handler
+
+import (
+	context_ "context"
+	"database/sql"
+	"net/http"
+	"strings"
+	"time"
+
+	"git.ekzyis.com/ekzyis/delphi.market/db"
+	"git.ekzyis.com/ekzyis/delphi.market/server/router/context"
+	"github.com/labstack/echo/v4"
+	"github.com/lightningnetwork/lnd/zpay32"
+)
+
+func HandleWithdrawal(sc context.ServerContext) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		var (
+			w   db.Withdrawal
+			u   db.User
+			inv *zpay32.Invoice
+			tx  *sql.Tx
+			err error
+		)
+		if err := c.Bind(&w); err != nil {
+			code := http.StatusBadRequest
+			return c.JSON(code, map[string]any{"status": code, "reason": "bolt11 required"})
+		}
+
+		if inv, err = zpay32.Decode(w.Bolt11, sc.Lnd.ChainParams); err != nil {
+			code := http.StatusBadRequest
+			return c.JSON(code, map[string]any{"status": code, "reason": "zpay32 decode error"})
+		}
+
+		// transaction start
+		ctx, cancel := context_.WithTimeout(c.Request().Context(), 5*time.Second)
+		defer cancel()
+		if tx, err = sc.Db.BeginTx(ctx, nil); err != nil {
+			return err
+		}
+		defer tx.Commit()
+
+		u = c.Get("session").(db.User)
+		w.Pubkey = u.Pubkey
+
+		// TODO deduct network fee from user balance
+		if u.Msats < int64(*inv.MilliSat) {
+			tx.Rollback()
+			code := http.StatusBadRequest
+			return c.JSON(code, map[string]any{"status": code, "reason": "insufficient balance"})
+		}
+
+		// create withdrawal
+		if err = sc.Db.CreateWithdrawal(tx, ctx, &w); err != nil {
+			tx.Rollback()
+			if strings.Contains(err.Error(), "violates unique constraint") {
+				code := http.StatusBadRequest
+				return c.JSON(code, map[string]any{"status": code, "reason": "bolt11 already submitted"})
+			}
+			return err
+		}
+
+		// pay invoice via LND
+		if err = sc.Lnd.PayInvoice(tx, w.Bolt11); err != nil {
+			tx.Rollback()
+			return err
+		}
+
+		// deduct balance from user
+		if _, err = tx.ExecContext(ctx, "UPDATE users SET msats = msats - $1 WHERE pubkey = $2", int64(*inv.MilliSat), u.Pubkey); err != nil {
+			tx.Rollback()
+			return err
+		}
+
+		tx.Commit()
+
+		return c.JSON(http.StatusOK, nil)
+	}
+}

server/router/router.go

@@ -68,6 +68,10 @@ func addBackendRoutes(e *echo.Echo, sc ServerContext) {
 	GET(e, sc, "/api/invoices",
 		handler.HandleInvoices,
 		middleware.SessionGuard)
+	POST(e, sc, "/api/withdrawal",
+		handler.HandleWithdrawal,
+		middleware.SessionGuard,
+		middleware.LNDGuard)
 }
 
 func GET(e *echo.Echo, sc ServerContext, path string, scF HandlerFunc, scM ...MiddlewareFunc) *echo.Route {

vue/src/components/UserSettings.vue

@@ -1,18 +0,0 @@
-<template>
-  <div v-if="session.pubkey" class="flex flex-row items-center">
-    <div>authenticated as {{ session.pubkey.slice(0, 8) }}</div>
-    <button class="ms-2 my-3" @click="logout">logout</button>
-  </div>
-</template>
-
-<script setup>
-import { useSession } from '@/stores/session'
-import { useRouter } from 'vue-router'
-const session = useSession()
-const router = useRouter()
-
-const logout = async () => {
-  await session.logout()
-  router.push('/')
-}
-</script>

vue/src/components/UserWallet.vue

@@ -0,0 +1,80 @@
+<template>
+  <div>
+    <div v-if="session.pubkey" class="grid flex-row items-center">
+      <div>authenticated as {{ session.pubkey.slice(0, 8) }}</div>
+      <button class="ms-2 my-3" @click="logout">logout</button>
+      <div>you have {{ session.msats / 1000 }} sats</div>
+      <button class="ms-2 my-3" @click="toggleWithdrawalForm">
+        <span v-if="showWithdrawalForm">cancel</span>
+        <span v-else>withdraw</span></button>
+    </div>
+    <form v-show="showWithdrawalForm" @submit.prevent="submitWithdrawal">
+      <label for="bolt11">bolt11</label>
+      <input name="bolt11" id="bolt11" type="text" required v-model="bolt11" />
+      <button type="submit" class="col-span-2">submit withdrawal</button>
+    </form>
+    <div v-if="err" class="red text-center">{{ err }}</div>
+    <div v-if="success" class="green text-center">{{ success }}</div>
+  </div>
+</template>
+
+<script setup>
+import { useSession } from '@/stores/session'
+import { ref } from 'vue'
+import { useRouter } from 'vue-router'
+const session = useSession()
+const router = useRouter()
+
+const logout = async () => {
+  await session.logout()
+  router.push('/')
+}
+
+const showWithdrawalForm = ref(false)
+const bolt11 = ref(null)
+const toggleWithdrawalForm = () => {
+  showWithdrawalForm.value = !showWithdrawalForm.value
+}
+const err = ref(null)
+const success = ref(null)
+const submitWithdrawal = async () => {
+  success.value = null
+  err.value = null
+  const url = '/api/withdrawal'
+  const body = JSON.stringify({ bolt11: bolt11.value })
+  try {
+    const res = await fetch(url, { method: 'POST', headers: { 'Content-type': 'application/json' }, body })
+    if (res.status === 200) {
+      success.value = 'invoice paid'
+      return session.checkSession()
+    }
+    const resBody = await res.json()
+    err.value = resBody.reason || `error: server responded with HTTP ${res.status}`
+  } catch (err) {
+    console.error(err)
+  }
+}
+
+</script>
+
+<style scoped>
+.grid {
+  grid-template-columns: auto auto;
+}
+
+form {
+  margin: 0 auto;
+  display: grid;
+  grid-template-columns: auto auto;
+}
+
+form>* {
+  margin: 0.5em 1em;
+}
+
+label {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+</style>

vue/src/main.js

@@ -11,7 +11,7 @@ import LoginView from '@/views/LoginView'
 import UserView from '@/views/UserView'
 import MarketView from '@/views/MarketView'
 import InvoiceView from '@/views/InvoiceView'
-import UserSettings from '@/components/UserSettings'
+import UserWallet from '@/components/UserWallet'
 import UserInvoices from '@/components/UserInvoices'
 import UserOrders from '@/components/UserOrders'
 import OrderForm from '@/components/OrderForm'
@@ -32,7 +32,7 @@ const routes = [
     path: '/user',
     component: UserView,
     children: [
-      { path: 'settings', name: 'user', component: UserSettings },
+      { path: 'wallet', name: 'user', component: UserWallet },
       { path: 'invoices', name: 'invoices', component: UserInvoices },
       { path: 'orders', name: 'orders', component: UserOrders }
     ]

vue/src/views/UserView.vue

@@ -11,7 +11,7 @@
   <!-- eslint-enable -->
   <header class="flex flex-row text-center justify-center pt-1">
     <nav>
-      <StyledLink to="/user/settings">settings</StyledLink>
+      <StyledLink to="/user/wallet">wallet</StyledLink>
       <StyledLink to="/user/invoices">invoices</StyledLink>
       <StyledLink to="/user/orders">orders</StyledLink>
     </nav>