(WIP) Add initial API client

src/screens/Login.tsx

@@ -1,18 +1,34 @@
 import React from 'react'
-import {Text, Button, View} from 'react-native'
+import {Text, Button, View, ActivityIndicator} from 'react-native'
+import {observer} from 'mobx-react-lite'
 import {Shell} from '../platform/shell'
 import type {RootTabsScreenProps} from '../routes/types'
 import {useStores} from '../state'
 
-export function Login({navigation}: RootTabsScreenProps<'Login'>) {
+export const Login = observer(({navigation}: RootTabsScreenProps<'Login'>) => {
   const store = useStores()
   return (
     <Shell>
       <View style={{justifyContent: 'center', alignItems: 'center'}}>
         <Text style={{fontSize: 20, fontWeight: 'bold'}}>Sign In</Text>
-        <Button title="Login" onPress={() => store.session.setAuthed(true)} />
-        <Button title="Sign Up" onPress={() => navigation.navigate('Signup')} />
+        {store.session.uiError ?? <Text>{store.session.uiError}</Text>}
+        {store.session.uiState === 'idle' ? (
+          <>
+            {store.session.hasAccount ?? (
+              <Button
+                title="Login"
+                onPress={() => store.session.loadAccount()}
+              />
+            )}
+            <Button
+              title="Sign Up"
+              onPress={() => navigation.navigate('Signup')}
+            />
+          </>
+        ) : (
+          <ActivityIndicator />
+        )}
       </View>
     </Shell>
   )
-}
+})