[APP-690] better handling of post languages language filtering (#893)

* add SelectLangBtn

* memoized objects that are created to reduce re-creation on re-render

* add langs when uploading post

* only send the top 3 languages otherwise backend will throw error

* mv ContentLanguagesSettings to folder

* add post languages settings modal and state

* fix typos

* modify feed manip to also check langs label on post

* Fix tests

* Remove log

* Update feed-manip.ts

* Fix syntax errors

* UI tuneups

* Show the currently selected languages in the composer

* fix linting

* Use a bcp-47 matching function

* Fix a duplicate language issue

* Fix web

* Dont include lang in prompt

* Make select language btn an observer

* Keep device languages on top of language selection UIs

* Fix android build settings

* Enforce a max of 3 languages in posts

* Fix tests

* Fix types

---------

Co-authored-by: Paul Frazee <pfrazee@gmail.com>

src/view/com/modals/lang-settings/PostLanguagesSettings.tsx

@@ -0,0 +1,97 @@
+import React from 'react'
+import {StyleSheet, View} from 'react-native'
+import {ScrollView} from '../util'
+import {useStores} from 'state/index'
+import {Text} from '../../util/text/Text'
+import {usePalette} from 'lib/hooks/usePalette'
+import {isDesktopWeb, deviceLocales} from 'platform/detection'
+import {LANGUAGES, LANGUAGES_MAP_CODE2} from '../../../../locale/languages'
+import {LanguageToggle} from './LanguageToggle'
+import {ConfirmLanguagesButton} from './ConfirmLanguagesButton'
+
+export const snapPoints = ['100%']
+
+export function Component({}: {}) {
+  const store = useStores()
+  const pal = usePalette('default')
+  const onPressDone = React.useCallback(() => {
+    store.shell.closeModal()
+  }, [store])
+
+  const languages = React.useMemo(() => {
+    const langs = LANGUAGES.filter(
+      lang =>
+        !!lang.code2.trim() &&
+        LANGUAGES_MAP_CODE2[lang.code2].code3 === lang.code3,
+    )
+    // sort so that device & selected languages are on top, then alphabetically
+    langs.sort((a, b) => {
+      const hasA =
+        store.preferences.hasPostLanguage(a.code2) ||
+        deviceLocales.includes(a.code2)
+      const hasB =
+        store.preferences.hasPostLanguage(b.code2) ||
+        deviceLocales.includes(b.code2)
+      if (hasA === hasB) return a.name.localeCompare(b.name)
+      if (hasA) return -1
+      return 1
+    })
+    return langs
+  }, [store])
+
+  const onPress = React.useCallback(
+    (code2: string) => {
+      store.preferences.togglePostLanguage(code2)
+    },
+    [store],
+  )
+
+  return (
+    <View testID="postLanguagesModal" style={[pal.view, styles.container]}>
+      <Text style={[pal.text, styles.title]}>Post Languages</Text>
+      <Text style={[pal.text, styles.description]}>
+        Which languages are used in this post?
+      </Text>
+      <ScrollView style={styles.scrollContainer}>
+        {languages.map(lang => (
+          <LanguageToggle
+            key={lang.code2}
+            code2={lang.code2}
+            langType="postLanguages"
+            name={lang.name}
+            onPress={() => {
+              onPress(lang.code2)
+            }}
+          />
+        ))}
+        <View style={styles.bottomSpacer} />
+      </ScrollView>
+      <ConfirmLanguagesButton onPress={onPressDone} />
+    </View>
+  )
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    paddingTop: 20,
+  },
+  title: {
+    textAlign: 'center',
+    fontWeight: 'bold',
+    fontSize: 24,
+    marginBottom: 12,
+  },
+  description: {
+    textAlign: 'center',
+    paddingHorizontal: 16,
+    marginBottom: 10,
+  },
+  scrollContainer: {
+    flex: 1,
+    paddingHorizontal: 10,
+  },
+  bottomSpacer: {
+    height: isDesktopWeb ? 0 : 60,
+  },
+})