From 522a1cdbaf0f478fb23a9f770b9caf732ea13803 Mon Sep 17 00:00:00 2001
From: Vitaly Takmazov
Date: Tue, 29 Oct 2019 17:11:07 +0300
Subject: Hide header on scroll (mobile only)

---
 vnext/src/App.js | 115 +++++++++++++++++++++++++------------------------------
 1 file changed, 53 insertions(+), 62 deletions(-)

(limited to 'vnext/src/App.js')

diff --git a/vnext/src/App.js b/vnext/src/App.js
index f39875c1..011e5cbd 100644
--- a/vnext/src/App.js
+++ b/vnext/src/App.js
@@ -1,5 +1,6 @@
-import React, { useState, useEffect } from 'react';
+import React, { useState, useEffect, useRef } from 'react';
 import { BrowserRouter as Router, Route, Link, Switch } from 'react-router-dom';
+import { useScroll, useRafState } from 'react-use';
 import qs from 'qs';
 
 import svg4everybody from 'svg4everybody';
@@ -10,18 +11,23 @@ import { Friends, Readers } from './ui/Users';
 import Settings from './ui/Settings';
 import Contacts from './ui/Contacts';
 import Chat from './ui/Chat';
+import Header from './ui/Header';
 import Post from './ui/Post';
 import Thread from './ui/Thread';
 import Login from './ui/Login';
-import { UserLink } from './ui/UserInfo';
-import SearchBox from './ui/SearchBox';
 
 import cookie from 'react-cookies';
 
 import { me } from './api';
 
+const elClassHidden = 'header--hidden';
+
+const elClassFull = 'content--full';
+
 export default function App() {
 
+  let contentRef = useRef(null);
+
   useEffect(() => {
     svg4everybody();
   }, []);
@@ -49,6 +55,48 @@ export default function App() {
     });
   };
 
+  const [scrollState, setScrollState] = useRafState({
+    hidden: false,
+    bottom: false,
+    prevScroll: 0
+  });
+
+  let { x, y } = useScroll(contentRef);
+
+  useEffect(() => {
+    let dHeight = contentRef.current.scrollHeight;
+    let wHeight = contentRef.current.clientHeight;
+    setScrollState((scrollState) => {
+      let wScrollDiff = scrollState.prevScroll - y;
+      let hidden = scrollState.hidden;
+      let bottom = scrollState.bottom;
+      if (y <= 0) {
+        // scrolled to the very top; element sticks to the top
+        hidden = false;
+        bottom = false;
+      } else if ((wScrollDiff > 0) && hidden) {
+        // scrolled up; element slides in
+        hidden = false;
+        bottom = false;
+      } else if (wScrollDiff < 0) {
+        // scrolled down
+        if ((y + wHeight) >= dHeight && hidden) {
+          // scrolled to the very bottom; element slides in
+          hidden = false;
+          bottom = true;
+        } else {
+          // scrolled down; element slides out
+          hidden = true;
+          bottom = false;
+        }
+      }
+      return {
+        hidden: hidden,
+        bottom: bottom,
+        prevScroll: y
+      };
+    });
+  }, [x, y, setScrollState]);
   const [hash, setHash] = useState(cookie.load('hash'));
   const [eventSource, setEventSource] = useState({});
 
@@ -111,66 +159,9 @@ export default function App() {
   return (
     <Router>
       <>
-        <div id="header">
-          <div id="header_wrapper">
-            {
-              visitor.uid < 0 ?
-                <>
-                  <div id="logo"><a href="/" /></div>
-                  <nav id="global">
-                    <a href="/">Loading...</a>
-                  </nav>
-                </>
-                : visitor.uid > 0 ?
-                  <UserLink user={visitor} />
-                  : <div id="logo">
-                    <Link to="/">Juick</Link>
-                  </div>
-            }
-            {
-              visitor.uid >= 0 &&
-              <>
-                <div id="search" className="desktop">
-                  <SearchBox pathname="/discover" onSearch={search} />
-                </div>
-                <nav id="global">
-                  {visitor.uid > 0 ?
-                    <Link to={{ pathname: '/' }}>
-                      <Icon name="ei-bell" size="s" /><span className="desktop">Discuss</span>
-                      {
-                        visitor.unreadCount &&
-                        <span className="badge">{visitor.unreadCount}</span>
-                      }
-                    </Link>
-                    :
-                    <Link to='/?media=1' rel="nofollow">
-                      <Icon name="ei-camera" size="s" />
-                      <span className="desktop">Photos</span>
-                    </Link>
-                  }
-                  <Link to={{ pathname: '/discover' }} rel="nofollow">
-                    <Icon name="ei-search" size="s" />
-                    <span className="desktop">Discover</span>
-                  </Link>
-
-                  {visitor.uid > 0 ?
-                    <Link to={{ pathname: '/post' }}>
-                      <Icon name="ei-pencil" size="s" />
-                      <span className="desktop">Post</span>
-                    </Link>
-                    :
-                    <Link to={{ pathname: '/login', state: { retpath: window.location.pathname } }}>
-                      <Icon name="ei-user" size="s" />
-                      <span className="desktop">Login</span>
-                    </Link>
-                  }
-                </nav>
-              </>
-            }
-          </div>
-        </div>
+        <Header visitor={visitor} className={scrollState.hidden ? elClassHidden : ''} />
         <div id="wrapper">
-          <section id="content">
+          <section id="content" ref={contentRef} className={scrollState.hidden || scrollState.bottom ? elClassFull : ''}>
             <Switch>
               <Route exact path="/" render={(props) => <Discussions visitor={visitor} {...props} />} />
               <Route exact path="/home" render={(props) => <Home visitor={visitor} {...props} />} />
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