From 0d9d14025997c16d46bb081e601d155d49a0c99a Mon Sep 17 00:00:00 2001
From: Chef Cheems <chefcheems@protonmail.com>
Date: Thu, 1 Jul 2021 08:08:13 +0300
Subject: [PATCH] feat: Reactive modals

---
 .../src/widgets/Modal/ModalContext.tsx        | 19 ++++++++-
 .../src/widgets/Modal/index.stories.tsx       | 42 ++++++++++++++++++-
 .../src/widgets/Modal/useModal.ts             | 36 +++++++++++++---
 3 files changed, 89 insertions(+), 8 deletions(-)

diff --git a/packages/pancake-uikit/src/widgets/Modal/ModalContext.tsx b/packages/pancake-uikit/src/widgets/Modal/ModalContext.tsx
index b3ec164fe..7ac69faa0 100644
--- a/packages/pancake-uikit/src/widgets/Modal/ModalContext.tsx
+++ b/packages/pancake-uikit/src/widgets/Modal/ModalContext.tsx
@@ -4,7 +4,11 @@ import Overlay from "../../components/Overlay/Overlay";
 import { Handler } from "./types";
 
 interface ModalsContext {
-  onPresent: (node: React.ReactNode, key?: string) => void;
+  isOpen: boolean;
+  nodeId: string;
+  modalNode: React.ReactNode;
+  setModalNode: React.Dispatch<React.SetStateAction<React.ReactNode>>;
+  onPresent: (node: React.ReactNode, newNodeId: string) => void;
   onDismiss: Handler;
   setCloseOnOverlayClick: React.Dispatch<React.SetStateAction<boolean>>;
 }
@@ -23,6 +27,10 @@ const ModalWrapper = styled.div`
 `;
 
 export const Context = createContext<ModalsContext>({
+  isOpen: false,
+  nodeId: "",
+  modalNode: null,
+  setModalNode: () => null,
   onPresent: () => null,
   onDismiss: () => null,
   setCloseOnOverlayClick: () => true,
@@ -31,16 +39,19 @@ export const Context = createContext<ModalsContext>({
 const ModalProvider: React.FC = ({ children }) => {
   const [isOpen, setIsOpen] = useState(false);
   const [modalNode, setModalNode] = useState<React.ReactNode>();
+  const [nodeId, setNodeId] = useState("");
   const [closeOnOverlayClick, setCloseOnOverlayClick] = useState(true);
 
-  const handlePresent = (node: React.ReactNode) => {
+  const handlePresent = (node: React.ReactNode, newNodeId: string) => {
     setModalNode(node);
     setIsOpen(true);
+    setNodeId(newNodeId);
   };
 
   const handleDismiss = () => {
     setModalNode(undefined);
     setIsOpen(false);
+    setNodeId("");
   };
 
   const handleOverlayDismiss = () => {
@@ -52,6 +63,10 @@ const ModalProvider: React.FC = ({ children }) => {
   return (
     <Context.Provider
       value={{
+        isOpen,
+        nodeId,
+        modalNode,
+        setModalNode,
         onPresent: handlePresent,
         onDismiss: handleDismiss,
         setCloseOnOverlayClick,
diff --git a/packages/pancake-uikit/src/widgets/Modal/index.stories.tsx b/packages/pancake-uikit/src/widgets/Modal/index.stories.tsx
index 93e3b8d51..466a322ac 100644
--- a/packages/pancake-uikit/src/widgets/Modal/index.stories.tsx
+++ b/packages/pancake-uikit/src/widgets/Modal/index.stories.tsx
@@ -1,4 +1,4 @@
-import React from "react";
+import React, { useEffect, useState } from "react";
 import { useTheme } from "styled-components";
 import { Modal, useModal } from ".";
 import { ModalProps } from "./types";
@@ -95,3 +95,43 @@ export const WithCustomHeader: React.FC = () => {
   const [onPresent1] = useModal(<CustomHeaderModal title="Modal with custom header" />);
   return <Button onClick={onPresent1}>Modal with custom header</Button>;
 };
+
+export const ReactingToOusideChanges: React.FC = () => {
+  const [counter, setCounter] = useState(0);
+  useEffect(() => {
+    const intervalId = setInterval(() => {
+      setCounter((prev) => prev + 1);
+    }, 500);
+    return () => clearInterval(intervalId);
+  }, []);
+  const ReactiveModal: React.FC<ModalProps & { count: number }> = ({ title, count, onDismiss }) => {
+    return (
+      <Modal title={title} onDismiss={onDismiss}>
+        <h2>Counter: {count}</h2>
+        <Button mt="8px" onClick={onDismiss}>
+          Close
+        </Button>
+      </Modal>
+    );
+  };
+
+  const [onPresent1] = useModal(
+    <ReactiveModal title={`[${counter}] Modal that reacts to outside change`} count={counter} />,
+    true,
+    true,
+    "reactiveModal"
+  );
+
+  const [onPresent2] = useModal(
+    <ReactiveModal title={`[${counter}] Modal that does NOT react to outside change`} count={counter} />
+  );
+  return (
+    <div>
+      <h2>Counter: {counter}</h2>
+      <Button onClick={onPresent1}>Reactive modal</Button>
+      <Button ml="16px" onClick={onPresent2}>
+        Non-reactive modal
+      </Button>
+    </div>
+  );
+};
diff --git a/packages/pancake-uikit/src/widgets/Modal/useModal.ts b/packages/pancake-uikit/src/widgets/Modal/useModal.ts
index 653d06414..7df6f8674 100644
--- a/packages/pancake-uikit/src/widgets/Modal/useModal.ts
+++ b/packages/pancake-uikit/src/widgets/Modal/useModal.ts
@@ -1,12 +1,38 @@
-import { useCallback, useContext, useEffect } from "react";
+import React, { useCallback, useContext, useEffect } from "react";
+import get from "lodash/get";
 import { Context } from "./ModalContext";
 import { Handler } from "./types";
 
-const useModal = (modal: React.ReactNode, closeOnOverlayClick = true): [Handler, Handler] => {
-  const { onPresent, onDismiss, setCloseOnOverlayClick } = useContext(Context);
+const useModal = (
+  modal: React.ReactNode,
+  closeOnOverlayClick = true,
+  updateOnPropsChange = false,
+  modalId = "defaultNodeId"
+): [Handler, Handler] => {
+  const { isOpen, nodeId, modalNode, setModalNode, onPresent, onDismiss, setCloseOnOverlayClick } = useContext(Context);
   const onPresentCallback = useCallback(() => {
-    onPresent(modal);
-  }, [modal, onPresent]);
+    onPresent(modal, modalId);
+  }, [modal, modalId, onPresent]);
+
+  // Updates the "modal" component if props are changed
+  // Use carefully since it might result in unnecessary rerenders
+  // Typically if modal is staic there is no need for updates, use when you expect props to change
+  useEffect(() => {
+    // NodeId is needed in case there are 2 useModal hooks on the same page and one has updateOnPropsChange
+    if (updateOnPropsChange && isOpen && nodeId === modalId) {
+      const modalProps = get(modal, "props");
+      const oldModalProps = get(modalNode, "props");
+      // Note: I tried to use lodash isEqual to compare props but it is giving false-negatives too easily
+      // For example ConfirmSwapModal in exchange has ~500 lines prop object that stringifies to same string
+      // and online diff checker says both objects are identical but lodash isEqual thinks they are different
+      // Do not try to replace JSON.stringify with isEqual, high risk of infinite rerenders
+      // TODO: Find a good way to handle modal updates, this whole flow is just backwards-compatible workaround,
+      // would be great to simplify the logic here
+      if (modalProps && oldModalProps && JSON.stringify(modalProps) !== JSON.stringify(oldModalProps)) {
+        setModalNode(modal);
+      }
+    }
+  }, [updateOnPropsChange, nodeId, modalId, isOpen, modal, modalNode, setModalNode]);
 
   useEffect(() => {
     setCloseOnOverlayClick(closeOnOverlayClick);