import React, {useCallback, useEffect, useMemo, useRef, useState} from 'react'
import {
  ActivityIndicator,
  BackHandler,
  Keyboard,
  KeyboardAvoidingView,
  Platform,
  ScrollView,
  StyleSheet,
  TouchableOpacity,
  View,
} from 'react-native'
import {useSafeAreaInsets} from 'react-native-safe-area-context'
import {LinearGradient} from 'expo-linear-gradient'
import {RichText} from '@atproto/api'
import {FontAwesomeIcon} from '@fortawesome/react-native-fontawesome'
import {msg, Trans} from '@lingui/macro'
import {useLingui} from '@lingui/react'
import {observer} from 'mobx-react-lite'

import {
  createGIFDescription,
  parseAltFromGIFDescription,
} from '#/lib/gif-alt-text'
import {LikelyType} from '#/lib/link-meta/link-meta'
import {logEvent} from '#/lib/statsig/statsig'
import {logger} from '#/logger'
import {emitPostCreated} from '#/state/events'
import {useModals} from '#/state/modals'
import {useRequireAltTextEnabled} from '#/state/preferences'
import {
  toPostLanguages,
  useLanguagePrefs,
  useLanguagePrefsApi,
} from '#/state/preferences/languages'
import {useProfileQuery} from '#/state/queries/profile'
import {Gif} from '#/state/queries/tenor'
import {ThreadgateSetting} from '#/state/queries/threadgate'
import {useAgent, useSession} from '#/state/session'
import {useComposerControls} from '#/state/shell/composer'
import {useAnalytics} from 'lib/analytics/analytics'
import * as apilib from 'lib/api/index'
import {MAX_GRAPHEME_LENGTH} from 'lib/constants'
import {useIsKeyboardVisible} from 'lib/hooks/useIsKeyboardVisible'
import {usePalette} from 'lib/hooks/usePalette'
import {useWebMediaQueries} from 'lib/hooks/useWebMediaQueries'
import {cleanError} from 'lib/strings/errors'
import {insertMentionAt} from 'lib/strings/mention-manip'
import {shortenLinks} from 'lib/strings/rich-text-manip'
import {colors, gradients, s} from 'lib/styles'
import {isAndroid, isIOS, isNative, isWeb} from 'platform/detection'
import {useDialogStateControlContext} from 'state/dialogs'
import {GalleryModel} from 'state/models/media/gallery'
import {ComposerOpts} from 'state/shell/composer'
import {ComposerReplyTo} from 'view/com/composer/ComposerReplyTo'
import {atoms as a} from '#/alf'
import {Button} from '#/components/Button'
import {EmojiArc_Stroke2_Corner0_Rounded as EmojiSmile} from '#/components/icons/Emoji'
import * as Prompt from '#/components/Prompt'
import {QuoteEmbed, QuoteX} from '../util/post-embeds/QuoteEmbed'
import {Text} from '../util/text/Text'
import * as Toast from '../util/Toast'
import {UserAvatar} from '../util/UserAvatar'
import {CharProgress} from './char-progress/CharProgress'
import {ExternalEmbed} from './ExternalEmbed'
import {GifAltText} from './GifAltText'
import {LabelsBtn} from './labels/LabelsBtn'
import {Gallery} from './photos/Gallery'
import {OpenCameraBtn} from './photos/OpenCameraBtn'
import {SelectGifBtn} from './photos/SelectGifBtn'
import {SelectPhotoBtn} from './photos/SelectPhotoBtn'
import {SelectLangBtn} from './select-language/SelectLangBtn'
import {SuggestedLanguage} from './select-language/SuggestedLanguage'
// TODO: Prevent naming components that coincide with RN primitives
// due to linting false positives
import {TextInput, TextInputRef} from './text-input/TextInput'
import {ThreadgateBtn} from './threadgate/ThreadgateBtn'
import {useExternalLinkFetch} from './useExternalLinkFetch'

type Props = ComposerOpts
export const ComposePost = observer(function ComposePost({
  replyTo,
  onPost,
  quote: initQuote,
  mention: initMention,
  openPicker,
  text: initText,
  imageUris: initImageUris,
}: Props) {
  const {currentAccount} = useSession()
  const {getAgent} = useAgent()
  const {data: currentProfile} = useProfileQuery({did: currentAccount!.did})
  const {isModalActive} = useModals()
  const {closeComposer} = useComposerControls()
  const {track} = useAnalytics()
  const pal = usePalette('default')
  const {isDesktop, isMobile} = useWebMediaQueries()
  const {_} = useLingui()
  const requireAltTextEnabled = useRequireAltTextEnabled()
  const langPrefs = useLanguagePrefs()
  const setLangPrefs = useLanguagePrefsApi()
  const textInput = useRef<TextInputRef>(null)
  const discardPromptControl = Prompt.usePromptControl()
  const {closeAllDialogs} = useDialogStateControlContext()

  const [isKeyboardVisible] = useIsKeyboardVisible({iosUseWillEvents: true})
  const [isProcessing, setIsProcessing] = useState(false)
  const [processingState, setProcessingState] = useState('')
  const [error, setError] = useState('')
  const [richtext, setRichText] = useState(
    new RichText({
      text: initText
        ? initText
        : initMention
        ? insertMentionAt(
            `@${initMention}`,
            initMention.length + 1,
            `${initMention}`,
          ) // insert mention if passed in
        : '',
    }),
  )
  const graphemeLength = useMemo(() => {
    return shortenLinks(richtext).graphemeLength
  }, [richtext])
  const [quote, setQuote] = useState<ComposerOpts['quote'] | undefined>(
    initQuote,
  )
  const {extLink, setExtLink} = useExternalLinkFetch({setQuote})
  const [extGif, setExtGif] = useState<Gif>()
  const [labels, setLabels] = useState<string[]>([])
  const [threadgate, setThreadgate] = useState<ThreadgateSetting[]>([])
  const gallery = useMemo(
    () => new GalleryModel(initImageUris),
    [initImageUris],
  )
  const onClose = useCallback(() => {
    closeComposer()
  }, [closeComposer])

  const insets = useSafeAreaInsets()
  const viewStyles = useMemo(
    () => ({
      paddingBottom:
        isAndroid || (isIOS && !isKeyboardVisible) ? insets.bottom : 0,
      paddingTop: isAndroid ? insets.top : isMobile ? 15 : 0,
    }),
    [insets, isKeyboardVisible, isMobile],
  )

  const onPressCancel = useCallback(() => {
    if (graphemeLength > 0 || !gallery.isEmpty) {
      closeAllDialogs()
      if (Keyboard) {
        Keyboard.dismiss()
      }
      discardPromptControl.open()
    } else {
      onClose()
    }
  }, [
    graphemeLength,
    gallery.isEmpty,
    closeAllDialogs,
    discardPromptControl,
    onClose,
  ])
  // android back button
  useEffect(() => {
    if (!isAndroid) {
      return
    }
    const backHandler = BackHandler.addEventListener(
      'hardwareBackPress',
      () => {
        onPressCancel()
        return true
      },
    )

    return () => {
      backHandler.remove()
    }
  }, [onPressCancel])

  // listen to escape key on desktop web
  const onEscape = useCallback(
    (e: KeyboardEvent) => {
      if (e.key === 'Escape') {
        onPressCancel()
      }
    },
    [onPressCancel],
  )
  useEffect(() => {
    if (isWeb && !isModalActive) {
      window.addEventListener('keydown', onEscape)
      return () => window.removeEventListener('keydown', onEscape)
    }
  }, [onEscape, isModalActive])

  const onNewLink = useCallback(
    (uri: string) => {
      if (extLink != null) return
      setExtLink({uri, isLoading: true})
    },
    [extLink, setExtLink],
  )

  const onPhotoPasted = useCallback(
    async (uri: string) => {
      track('Composer:PastedPhotos')
      await gallery.paste(uri)
    },
    [gallery, track],
  )

  const isAltTextRequiredAndMissing = useMemo(() => {
    if (!requireAltTextEnabled) return false

    if (gallery.needsAltText) return true
    if (extGif) {
      if (!extLink?.meta?.description) return true

      const parsedAlt = parseAltFromGIFDescription(extLink.meta.description)
      if (!parsedAlt.isPreferred) return true
    }
    return false
  }, [gallery.needsAltText, extLink, extGif, requireAltTextEnabled])

  const onPressPublish = async () => {
    if (isProcessing || graphemeLength > MAX_GRAPHEME_LENGTH) {
      return
    }

    if (isAltTextRequiredAndMissing) {
      return
    }

    setError('')

    if (
      richtext.text.trim().length === 0 &&
      gallery.isEmpty &&
      !extLink &&
      !quote
    ) {
      setError(_(msg`Did you want to say anything?`))
      return
    }
    if (extLink?.isLoading) {
      setError(_(msg`Please wait for your link card to finish loading`))
      return
    }

    setIsProcessing(true)

    let postUri
    try {
      postUri = (
        await apilib.post(getAgent(), {
          rawText: richtext.text,
          replyTo: replyTo?.uri,
          images: gallery.images,
          quote,
          extLink,
          labels,
          threadgate,
          onStateChange: setProcessingState,
          langs: toPostLanguages(langPrefs.postLanguage),
        })
      ).uri
    } catch (e: any) {
      logger.error(e, {
        message: `Composer: create post failed`,
        hasImages: gallery.size > 0,
      })

      if (extLink) {
        setExtLink({
          ...extLink,
          isLoading: true,
          localThumb: undefined,
        } as apilib.ExternalEmbedDraft)
      }
      setError(cleanError(e.message))
      setIsProcessing(false)
      return
    } finally {
      if (postUri) {
        logEvent('post:create', {
          imageCount: gallery.size,
          isReply: replyTo != null,
          hasLink: extLink != null,
          hasQuote: quote != null,
          langs: langPrefs.postLanguage,
          logContext: 'Composer',
        })
      }
      track('Create Post', {
        imageCount: gallery.size,
      })
      if (replyTo && replyTo.uri) track('Post:Reply')
    }
    if (postUri && !replyTo) {
      emitPostCreated()
    }
    setLangPrefs.savePostLanguageToHistory()
    onPost?.()
    onClose()
    Toast.show(
      replyTo
        ? _(msg`Your reply has been published`)
        : _(msg`Your post has been published`),
    )
  }

  const canPost = useMemo(
    () => graphemeLength <= MAX_GRAPHEME_LENGTH && !isAltTextRequiredAndMissing,
    [graphemeLength, isAltTextRequiredAndMissing],
  )
  const selectTextInputPlaceholder = replyTo
    ? _(msg`Write your reply`)
    : _(msg`What's up?`)

  const canSelectImages = gallery.size < 4 && !extLink
  const hasMedia = gallery.size > 0 || Boolean(extLink)

  const onEmojiButtonPress = useCallback(() => {
    openPicker?.(textInput.current?.getCursorPosition())
  }, [openPicker])

  const focusTextInput = useCallback(() => {
    textInput.current?.focus()
  }, [])

  const onSelectGif = useCallback(
    (gif: Gif) => {
      setExtLink({
        uri: `${gif.media_formats.gif.url}?hh=${gif.media_formats.gif.dims[1]}&ww=${gif.media_formats.gif.dims[0]}`,
        isLoading: true,
        meta: {
          url: gif.media_formats.gif.url,
          image: gif.media_formats.preview.url,
          likelyType: LikelyType.HTML,
          title: gif.content_description,
          description: createGIFDescription(gif.content_description),
        },
      })
      setExtGif(gif)
    },
    [setExtLink],
  )

  const handleChangeGifAltText = useCallback(
    (altText: string) => {
      setExtLink(ext =>
        ext && ext.meta
          ? {
              ...ext,
              meta: {
                ...ext.meta,
                description: createGIFDescription(
                  ext.meta.title ?? '',
                  altText,
                ),
              },
            }
          : ext,
      )
    },
    [setExtLink],
  )

  return (
    <KeyboardAvoidingView
      testID="composePostView"
      behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
      style={styles.outer}>
      <View style={[s.flex1, viewStyles]} aria-modal accessibilityViewIsModal>
        <View style={[styles.topbar, isDesktop && styles.topbarDesktop]}>
          <TouchableOpacity
            testID="composerDiscardButton"
            onPress={onPressCancel}
            onAccessibilityEscape={onPressCancel}
            accessibilityRole="button"
            accessibilityLabel={_(msg`Cancel`)}
            accessibilityHint={_(
              msg`Closes post composer and discards post draft`,
            )}>
            <Text style={[pal.link, s.f18]}>
              <Trans>Cancel</Trans>
            </Text>
          </TouchableOpacity>
          <View style={s.flex1} />
          {isProcessing ? (
            <>
              <Text style={pal.textLight}>{processingState}</Text>
              <View style={styles.postBtn}>
                <ActivityIndicator />
              </View>
            </>
          ) : (
            <>
              <LabelsBtn
                labels={labels}
                onChange={setLabels}
                hasMedia={hasMedia}
              />
              {replyTo ? null : (
                <ThreadgateBtn
                  threadgate={threadgate}
                  onChange={setThreadgate}
                />
              )}
              {canPost ? (
                <TouchableOpacity
                  testID="composerPublishBtn"
                  onPress={onPressPublish}
                  accessibilityRole="button"
                  accessibilityLabel={
                    replyTo ? _(msg`Publish reply`) : _(msg`Publish post`)
                  }
                  accessibilityHint="">
                  <LinearGradient
                    colors={[
                      gradients.blueLight.start,
                      gradients.blueLight.end,
                    ]}
                    start={{x: 0, y: 0}}
                    end={{x: 1, y: 1}}
                    style={styles.postBtn}>
                    <Text style={[s.white, s.f16, s.bold]}>
                      {replyTo ? (
                        <Trans context="action">Reply</Trans>
                      ) : (
                        <Trans context="action">Post</Trans>
                      )}
                    </Text>
                  </LinearGradient>
                </TouchableOpacity>
              ) : (
                <View style={[styles.postBtn, pal.btn]}>
                  <Text style={[pal.textLight, s.f16, s.bold]}>
                    <Trans context="action">Post</Trans>
                  </Text>
                </View>
              )}
            </>
          )}
        </View>
        {isAltTextRequiredAndMissing && (
          <View style={[styles.reminderLine, pal.viewLight]}>
            <View style={styles.errorIcon}>
              <FontAwesomeIcon
                icon="exclamation"
                style={{color: colors.red4}}
                size={10}
              />
            </View>
            <Text style={[pal.text, s.flex1]}>
              <Trans>One or more images is missing alt text.</Trans>
            </Text>
          </View>
        )}
        {error !== '' && (
          <View style={styles.errorLine}>
            <View style={styles.errorIcon}>
              <FontAwesomeIcon
                icon="exclamation"
                style={{color: colors.red4}}
                size={10}
              />
            </View>
            <Text style={[s.red4, s.flex1]}>{error}</Text>
          </View>
        )}
        <ScrollView
          style={styles.scrollView}
          keyboardShouldPersistTaps="always">
          {replyTo ? <ComposerReplyTo replyTo={replyTo} /> : undefined}

          <View
            style={[
              pal.border,
              styles.textInputLayout,
              isNative && styles.textInputLayoutMobile,
            ]}>
            <UserAvatar
              avatar={currentProfile?.avatar}
              size={50}
              type={currentProfile?.associated?.labeler ? 'labeler' : 'user'}
            />
            <TextInput
              ref={textInput}
              richtext={richtext}
              placeholder={selectTextInputPlaceholder}
              autoFocus={true}
              setRichText={setRichText}
              onPhotoPasted={onPhotoPasted}
              onPressPublish={onPressPublish}
              onNewLink={onNewLink}
              onError={setError}
              accessible={true}
              accessibilityLabel={_(msg`Write post`)}
              accessibilityHint={_(
                msg`Compose posts up to ${MAX_GRAPHEME_LENGTH} characters in length`,
              )}
            />
          </View>

          <Gallery gallery={gallery} />
          {gallery.isEmpty && extLink && (
            <View style={a.relative}>
              <ExternalEmbed
                link={extLink}
                gif={extGif}
                onRemove={() => {
                  setExtLink(undefined)
                  setExtGif(undefined)
                }}
              />
              <GifAltText
                link={extLink}
                gif={extGif}
                onSubmit={handleChangeGifAltText}
              />
            </View>
          )}
          {quote ? (
            <View style={[s.mt5, isWeb && s.mb10]}>
              <View style={{pointerEvents: 'none'}}>
                <QuoteEmbed quote={quote} />
              </View>
              {quote.uri !== initQuote?.uri && (
                <QuoteX onRemove={() => setQuote(undefined)} />
              )}
            </View>
          ) : undefined}
        </ScrollView>
        <SuggestedLanguage text={richtext.text} />
        <View style={[pal.border, styles.bottomBar]}>
          <View style={[a.flex_row, a.align_center, a.gap_xs]}>
            <SelectPhotoBtn gallery={gallery} disabled={!canSelectImages} />
            <OpenCameraBtn gallery={gallery} disabled={!canSelectImages} />
            <SelectGifBtn
              onClose={focusTextInput}
              onSelectGif={onSelectGif}
              disabled={hasMedia}
            />
            {!isMobile ? (
              <Button
                onPress={onEmojiButtonPress}
                style={a.p_sm}
                label={_(msg`Open emoji picker`)}
                accessibilityHint={_(msg`Open emoji picker`)}
                variant="ghost"
                shape="round"
                color="primary">
                <EmojiSmile size="lg" />
              </Button>
            ) : null}
          </View>
          <View style={s.flex1} />
          <SelectLangBtn />
          <CharProgress count={graphemeLength} />
        </View>
      </View>

      <Prompt.Basic
        control={discardPromptControl}
        title={_(msg`Discard draft?`)}
        description={_(msg`Are you sure you'd like to discard this draft?`)}
        onConfirm={onClose}
        confirmButtonCta={_(msg`Discard`)}
        confirmButtonColor="negative"
      />
    </KeyboardAvoidingView>
  )
})

const styles = StyleSheet.create({
  outer: {
    flexDirection: 'column',
    flex: 1,
    height: '100%',
  },
  topbar: {
    flexDirection: 'row',
    alignItems: 'center',
    paddingTop: 6,
    paddingBottom: 4,
    paddingHorizontal: 20,
    height: 55,
    gap: 4,
  },
  topbarDesktop: {
    paddingTop: 10,
    paddingBottom: 10,
  },
  postBtn: {
    borderRadius: 20,
    paddingHorizontal: 20,
    paddingVertical: 6,
    marginLeft: 12,
  },
  errorLine: {
    flexDirection: 'row',
    backgroundColor: colors.red1,
    borderRadius: 6,
    marginHorizontal: 15,
    paddingHorizontal: 8,
    paddingVertical: 6,
    marginVertical: 6,
  },
  reminderLine: {
    flexDirection: 'row',
    alignItems: 'center',
    borderRadius: 6,
    marginHorizontal: 15,
    paddingHorizontal: 8,
    paddingVertical: 6,
    marginBottom: 6,
  },
  errorIcon: {
    borderWidth: 1,
    borderColor: colors.red4,
    color: colors.red4,
    borderRadius: 30,
    width: 16,
    height: 16,
    alignItems: 'center',
    justifyContent: 'center',
    marginRight: 5,
  },
  scrollView: {
    flex: 1,
    paddingHorizontal: 15,
  },
  textInputLayout: {
    flexDirection: 'row',
    borderTopWidth: 1,
    paddingTop: 16,
  },
  textInputLayoutMobile: {
    flex: 1,
  },
  addExtLinkBtn: {
    borderWidth: 1,
    borderRadius: 24,
    paddingHorizontal: 16,
    paddingVertical: 12,
    marginHorizontal: 10,
    marginBottom: 4,
  },
  bottomBar: {
    flexDirection: 'row',
    paddingVertical: 4,
    paddingLeft: 15,
    paddingRight: 20,
    alignItems: 'center',
    borderTopWidth: 1,
  },
})