From e3de337769e7d5a535b4a03f0fb725bc84188ce7 Mon Sep 17 00:00:00 2001
From: Sebastian Martinez <sebastinez@me.com>
Date: Tue, 1 Feb 2022 18:57:53 +0100
Subject: [PATCH] Move reactive config part into session state

This PR moves the signer "clones" the signer property from the `Config`
object into the `session` state, to allow Svelte reactivity, e.g. in the
Testnet Faucet, where we rely on `config.signer` but since it only
changes when the `Config` object in `App.svelte` changes we can't react
on it.

For now I only cloned the signer property, if we see in the future that
there are other properties that need to change with session we can add
them.

Signed-off-by: Sebastian Martinez <sebastinez@me.com>
Signed-off-by: Alexis Sellier <self@cloudhead.io>
---
 src/Header.svelte               |  3 +--
 src/base/faucet/Index.svelte    | 38 ++++++++++++++++++++-------------
 src/base/faucet/Withdraw.svelte | 14 +++++++-----
 src/base/faucet/lib.ts          | 30 +++++++++++++++-----------
 src/session.ts                  | 28 ++++++++++++++++++------
 5 files changed, 71 insertions(+), 42 deletions(-)

diff --git a/src/Header.svelte b/src/Header.svelte
index d54dfc5d6..872595605 100644
--- a/src/Header.svelte
+++ b/src/Header.svelte
@@ -17,7 +17,6 @@
   export let session: Session | null;
   export let config: Config;
 
-  let sessionButton: HTMLElement | null = null;
   let sessionButtonHover = false;
   let mobileNavbarDisplayed = false;
 
@@ -182,7 +181,7 @@
         {/if}
       </span>
 
-      <button class="address outline small" bind:this={sessionButton}
+      <button class="address outline small"
         on:click={() => disconnectWallet(config)}
         on:mouseover={() => sessionButtonHover = true}
         on:focus={() => sessionButtonHover = true}
diff --git a/src/base/faucet/Index.svelte b/src/base/faucet/Index.svelte
index fd5d5e992..3bfb5c291 100644
--- a/src/base/faucet/Index.svelte
+++ b/src/base/faucet/Index.svelte
@@ -1,9 +1,9 @@
 <script lang="ts">
   import type { Config } from "@app/config";
   import type { BigNumber } from "@ethersproject/bignumber";
+  import { session } from "@app/session";
   import { toWei } from "@app/utils";
   import { formatEther } from "@ethersproject/units";
-  import { onMount } from "svelte";
   import { navigate } from "svelte-routing";
   import { getMaxWithdrawAmount, lastWithdrawalByUser, calculateTimeLock } from "./lib";
 
@@ -21,22 +21,30 @@
   }
 
   async function isAbleToWithdraw(amount: string): Promise<[boolean, string?]> {
-    if (!amount || amount === "0") { return [false, "Not able to withdraw zero tokens"]; }
-    if (toWei(amount).gt(maxWithdrawAmount)) return [false, `Reduce amount, max withdrawal is ${formatEther(maxWithdrawAmount)}`];
-    let currentTime = new Date().getTime();
-    let timelock = await calculateTimeLock(amount, config);
-    // Converting a 10 digit to 13 digit timestamp by multiplying by 1000
-    // since JS doesn't display a correct Date string when passing a 10 digit timestamp.
-    let nextAvailableWithdraw = lastWithdrawal.add(timelock).mul(1000);
-    if (nextAvailableWithdraw.gt(currentTime)) return [false, `Not ready to withdraw, return after ${new Date(nextAvailableWithdraw.toNumber()).toLocaleString('en-GB')}`];
+    try {
+      if (!$session) { return [false]; }
+      if (!amount || amount === "0") { return [false, "Not able to withdraw zero tokens"]; }
+      if (toWei(amount).gt(maxWithdrawAmount)) return [false, `Reduce amount, max withdrawal is ${formatEther(maxWithdrawAmount)}`];
+      let currentTime = new Date().getTime();
+      let timelock = await calculateTimeLock(amount, $session.config.signer, config);
+      // Converting a 10 digit to 13 digit timestamp by multiplying by 1000
+      // since JS doesn't display a correct Date string when passing a 10 digit timestamp.
+      let nextAvailableWithdraw = lastWithdrawal.add(timelock).mul(1000);
+      if (nextAvailableWithdraw.gt(currentTime)) return [false, `Not ready to withdraw, return after ${new Date(nextAvailableWithdraw.toNumber()).toLocaleString('en-GB')}`];
 
-    return [true];
+      return [true];
+    } catch (e: any) {
+      console.error(e);
+      error = e.message;
+
+      return [false];
+    }
   }
   
-  onMount(async () => {
-    maxWithdrawAmount = await getMaxWithdrawAmount(config);
-    lastWithdrawal = await lastWithdrawalByUser(config);
-  });
+  $: if ($session) {
+    getMaxWithdrawAmount($session.config.signer, config).then(x => maxWithdrawAmount = x);
+    lastWithdrawalByUser($session.config.signer, config).then(x => lastWithdrawal = x);
+  }
 </script>
 
 <style>
@@ -89,7 +97,7 @@
         To get RAD tokens on <strong>{config.network.name}</strong>, please
         check the known exchanges.
       </div>
-    {:else if !config.signer}
+    {:else if !$session}
       <div class="input-caption">
         To get RAD tokens on <strong>{config.network.name}</strong>, please
         connect your wallet.
diff --git a/src/base/faucet/Withdraw.svelte b/src/base/faucet/Withdraw.svelte
index c959e8e7b..68cdaac51 100644
--- a/src/base/faucet/Withdraw.svelte
+++ b/src/base/faucet/Withdraw.svelte
@@ -23,11 +23,15 @@
 
   onMount(async () => {
     try {
-      state.status = Status.Signing;
-      const tx = await withdraw(amount, config);
-      state.status = Status.Pending;
-      await tx.wait();
-      state.status = Status.Success;
+      if ($session) {
+        state.status = Status.Signing;
+        const tx = await withdraw(amount, $session.config.signer, config);
+        state.status = Status.Pending;
+        await tx.wait();
+        state.status = Status.Success;
+      } else {
+        back();
+      }
     } catch (e: any) {
       console.error(e);
       error = e;
diff --git a/src/base/faucet/lib.ts b/src/base/faucet/lib.ts
index 85fe18881..ca2fd22fb 100644
--- a/src/base/faucet/lib.ts
+++ b/src/base/faucet/lib.ts
@@ -4,52 +4,56 @@ import type { Config } from '@app/config';
 import { assert } from '@app/error';
 import type { TransactionResponse } from '@ethersproject/providers';
 import { toWei } from '@app/utils';
+import type { WalletConnectSigner } from "@app/WalletConnectSigner";
+import type { TypedDataSigner } from '@ethersproject/abstract-signer';
 
-export async function withdraw(amount: string, config: Config): Promise<TransactionResponse> {
-  assert(config.signer);
+type Signer = ethers.Signer & TypedDataSigner | WalletConnectSigner | null;
+
+export async function withdraw(amount: string, signer: Signer, config: Config): Promise<TransactionResponse> {
+  assert(signer);
 
   const faucet = new ethers.Contract(
     config.radToken.faucet,
     config.abi.faucet,
-    config.signer
+    signer
   );
 
   return faucet.withdraw(config.radToken.address, toWei(amount));
 }
 
-export async function getMaxWithdrawAmount(config: Config): Promise<ethers.BigNumber> {
-  assert(config.signer);
+export async function getMaxWithdrawAmount(signer: Signer, config: Config): Promise<ethers.BigNumber> {
+  assert(signer);
 
   const faucet = new ethers.Contract(
     config.radToken.faucet,
     config.abi.faucet,
-    config.signer
+    signer
   );
 
   return faucet.maxWithdrawAmount();
 }
 
-export async function calculateTimeLock(amount: string, config: Config): Promise<ethers.BigNumber> {
-  assert(config.signer);
+export async function calculateTimeLock(amount: string, signer: Signer, config: Config): Promise<ethers.BigNumber> {
+  assert(signer);
 
   const faucet = new ethers.Contract(
     config.radToken.faucet,
     config.abi.faucet,
-    config.signer
+    signer
   );
 
   return faucet.calculateTimeLock(toWei(amount));
 }
 
-export async function lastWithdrawalByUser(config: Config): Promise<ethers.BigNumber> {
-  assert(config.signer);
+export async function lastWithdrawalByUser(signer: Signer, config: Config): Promise<ethers.BigNumber> {
+  assert(signer);
 
-  const address = config.signer.getAddress();
+  const address = signer.getAddress();
 
   const faucet = new ethers.Contract(
     config.radToken.faucet,
     config.abi.faucet,
-    config.signer
+    signer
   );
 
   return faucet.lastWithdrawalByUser(address);
diff --git a/src/session.ts b/src/session.ts
index 4c3c8912f..dd2a3cca9 100644
--- a/src/session.ts
+++ b/src/session.ts
@@ -4,6 +4,8 @@ import type { BigNumber } from 'ethers';
 import type { TransactionReceipt, TransactionResponse } from '@ethersproject/providers';
 import { Config, getConfig, isMetamaskInstalled } from "@app/config";
 import { Unreachable, assert, assertEq } from "@app/error";
+import type { TypedDataSigner } from '@ethersproject/abstract-signer';
+import type { WalletConnectSigner } from "./WalletConnectSigner";
 import * as ethers from "ethers";
 
 export enum Connection {
@@ -19,6 +21,13 @@ export type TxState =
   | { state: 'fail'; hash: string; blockHash: string; blockNumber: number; error: string }
   | null;
 
+// Definitions made in `Config` that need to be part of the session,
+// to provide reactivity based on events i.e. accountsChanged
+// TODO: Eventually there will be more reactive config needs, e.g. seeds
+export interface SessionConfig {
+  signer: ethers.Signer & TypedDataSigner | WalletConnectSigner | null;
+}
+
 export type State =
     { connection: Connection.Disconnected }
   | { connection: Connection.Connecting }
@@ -26,6 +35,7 @@ export type State =
 
 export interface Session {
   address: string;
+  config: SessionConfig;
   tokenBalance: BigNumber | null; // `null` means it isn't loaded yet.
   tx: TxState;
 }
@@ -38,7 +48,7 @@ export interface Store extends Readable<State> {
   setTxSigning(): void;
   setTxPending(tx: TransactionResponse): void;
   setTxConfirmed(tx: TransactionReceipt): void;
-  setChangedAccount(address: string): void;
+  setChangedAccount(address: string, config: Config): void;
 }
 
 export const loadState = (initial: State): Store => {
@@ -52,8 +62,9 @@ export const loadState = (initial: State): Store => {
       // Re-connect using previous session.
       if (config.metamask.connected) {
         const metamask = config.metamask.session;
+        const sessionConfig = { signer: config.signer };
         const tokenBalance: BigNumber = await config.token.balanceOf(metamask.address);
-        const session = { tokenBalance, tx: null, address: metamask.address };
+        const session = { tokenBalance, tx: null, config: sessionConfig, address: metamask.address };
 
         store.set({ connection: Connection.Connected, session });
         config.setSigner(config.metamask.signer);
@@ -77,7 +88,8 @@ export const loadState = (initial: State): Store => {
         config.walletConnect.state.set({ state: "close" });
 
         const tokenBalance: BigNumber = await config.token.balanceOf(address);
-        const session = { address, tokenBalance, tx: null };
+        const sessionConfig = { signer: config.signer };
+        const session = { config: sessionConfig, address, tokenBalance, tx: null };
 
         store.set({
           connection: Connection.Connected,
@@ -99,7 +111,8 @@ export const loadState = (initial: State): Store => {
 
         const address = await signer.getAddress();
         const tokenBalance: BigNumber = await config.token.balanceOf(address);
-        const session = { address, tokenBalance, tx: null };
+        const sessionConfig = { signer: config.signer };
+        const session = { config: sessionConfig, address, tokenBalance, tx: null };
         const network = await ethers.providers.getNetwork(
           signer.walletConnect.chainId
         );
@@ -232,7 +245,7 @@ export const loadState = (initial: State): Store => {
       });
     },
 
-    setChangedAccount: (address: string) => {
+    setChangedAccount: (address: string, config: Config) => {
       store.update(s => {
         switch (s.connection) {
           case Connection.Connected:
@@ -242,6 +255,7 @@ export const loadState = (initial: State): Store => {
               disconnectMetamask();
             } else {
               s.session.address = address;
+              s.session.config = { signer: config.signer };
               saveSession(s.session);
             }
             return s;
@@ -275,7 +289,7 @@ window.ethereum?.on("accountsChanged", async ([address]: string) => {
 
 export async function changeAccounts(address: string): Promise<void> {
   const config = await getConfig();
-  state.setChangedAccount(address);
+  state.setChangedAccount(address, config);
   state.refreshBalance(config);
 }
 
@@ -311,6 +325,6 @@ export function disconnectWallet(config: Config): void {
 
 function saveSession(session: Session): void {
   window.localStorage.setItem("metamask", JSON.stringify({
-    ...session, tokenBalance: null
+    ...session, tokenBalance: null, config: null
   }));
 }