import {useMemo} from 'react'
import {View} from 'react-native'
import {
  type AppBskyActorDefs,
  type ModerationCause,
  type ModerationDecision,
} from '@atproto/api'
import {useLingui} from '@lingui/react/macro'

import {makeProfileLink} from '#/lib/routes/links'
import {sanitizeDisplayName} from '#/lib/strings/display-names'
import {type Shadow} from '#/state/cache/profile-shadow'
import {isConvoActive, useConvo} from '#/state/messages/convo'
import {type ConvoItem} from '#/state/messages/convo/types'
import {useSession} from '#/state/session'
import {PreviewableUserAvatar} from '#/view/com/util/UserAvatar'
import {atoms as a, useTheme} from '#/alf'
import {AvatarBubbles} from '#/components/AvatarBubbles'
import {ConvoMenu} from '#/components/dms/ConvoMenu'
import {Bell2Off_Filled_Corner0_Rounded as BellOffIcon} from '#/components/icons/Bell2'
import * as Layout from '#/components/Layout'
import {Link} from '#/components/Link'
import {PostAlerts} from '#/components/moderation/PostAlerts'
import {ProfileBadges} from '#/components/ProfileBadges'
import {Text} from '#/components/Typography'
import {IS_WEB} from '#/env'

const PFP_SIZE = IS_WEB ? 40 : Layout.HEADER_SLOT_SIZE

export function MessagesListHeader({
  profile,
  moderation,
}: {
  profile?: Shadow<AppBskyActorDefs.ProfileViewDetailed>
  moderation?: ModerationDecision
}) {
  const t = useTheme()
  const convoState = useConvo()

  const blockInfo = useMemo(() => {
    if (!moderation) return
    const modui = moderation.ui('profileView')
    const blocks = modui.alerts.filter(alert => alert.type === 'blocking')
    const listBlocks = blocks.filter(alert => alert.source.type === 'list')
    const userBlock = blocks.find(alert => alert.source.type === 'user')
    return {
      listBlocks,
      userBlock,
    }
  }, [moderation])

  return (
    <Layout.Header.Outer>
      <View style={[a.w_full, a.flex_row, a.gap_xs, a.align_start]}>
        <View style={[{minHeight: PFP_SIZE}, a.justify_center]}>
          <Layout.Header.BackButton />
        </View>
        {profile && moderation && blockInfo ? (
          <HeaderReady
            profile={profile}
            moderation={moderation}
            blockInfo={blockInfo}
          />
        ) : (
          <>
            <View style={[a.flex_row, a.align_center, a.gap_md, a.flex_1]}>
              <View
                style={[
                  {width: PFP_SIZE, height: PFP_SIZE},
                  a.rounded_full,
                  t.atoms.bg_contrast_25,
                ]}
              />
              <View style={a.gap_xs}>
                <View
                  style={[
                    {width: 120, height: 16},
                    a.rounded_xs,
                    t.atoms.bg_contrast_25,
                    a.mt_xs,
                  ]}
                />
                {!convoState.isGroup?.() && (
                  <View
                    style={[
                      {width: 175, height: 12},
                      a.rounded_xs,
                      t.atoms.bg_contrast_25,
                    ]}
                  />
                )}
              </View>
            </View>

            <Layout.Header.Slot />
          </>
        )}
      </View>
    </Layout.Header.Outer>
  )
}

function HeaderReady({
  profile,
  moderation,
  blockInfo,
}: {
  profile: Shadow<AppBskyActorDefs.ProfileViewDetailed>
  moderation: ModerationDecision
  blockInfo: {
    listBlocks: ModerationCause[]
    userBlock?: ModerationCause
  }
}) {
  const {t: l} = useLingui()
  const t = useTheme()
  const convoState = useConvo()
  const {currentAccount} = useSession()

  const groupInfo = convoState.getGroupInfo?.()
  const isGroupChat = groupInfo != null

  const isDeletedAccount = profile?.handle === 'missing.invalid'
  const displayName = isGroupChat
    ? (groupInfo.name ?? l`${profile.handle}'s group chat`)
    : isDeletedAccount
      ? l`Deleted Account`
      : sanitizeDisplayName(
          profile.displayName || profile.handle,
          moderation.ui('displayName'),
        )

  const latestMessageFromOther = convoState.items.findLast(
    (item: ConvoItem) =>
      item.type === 'message' &&
      item.message.sender.did !== currentAccount?.did,
  )

  const latestReportableMessage =
    latestMessageFromOther?.type === 'message'
      ? latestMessageFromOther.message
      : undefined

  return (
    <View style={[a.flex_1]}>
      <View style={[a.w_full, a.flex_row, a.align_center, a.justify_between]}>
        {isGroupChat ? (
          <View
            style={[a.flex_row, a.align_center, a.gap_md, a.flex_1, a.pr_md]}>
            <AvatarBubbles
              size="small"
              profiles={convoState.recipients ?? []}
            />
            <Text style={[a.text_md, a.font_semi_bold]} numberOfLines={1}>
              {displayName}
            </Text>
          </View>
        ) : (
          <Link
            label={l`View ${displayName}'s profile`}
            style={[a.flex_row, a.align_start, a.gap_md, a.flex_1, a.pr_md]}
            to={makeProfileLink(profile)}>
            <PreviewableUserAvatar
              size={PFP_SIZE}
              profile={profile}
              moderation={moderation.ui('avatar')}
              disableHoverCard={moderation.blocked}
            />
            <View style={[a.flex_1]}>
              <View style={[a.flex_row, a.align_center]}>
                <Text
                  emoji
                  style={[a.text_md, a.font_semi_bold, a.self_start]}
                  numberOfLines={1}>
                  {displayName}
                </Text>
                <ProfileBadges profile={profile} size="md" style={[a.pl_xs]} />
              </View>
              {!isDeletedAccount && (
                <Text
                  style={[t.atoms.text_contrast_medium, a.text_xs]}
                  numberOfLines={1}>
                  @{profile.handle}
                  {convoState.convo?.muted && (
                    <>
                      {' '}
                      &middot;{' '}
                      <BellOffIcon
                        size="xs"
                        style={t.atoms.text_contrast_medium}
                      />
                    </>
                  )}
                </Text>
              )}
            </View>
          </Link>
        )}

        <View style={[{minHeight: PFP_SIZE}, a.justify_center]}>
          <Layout.Header.Slot>
            {isConvoActive(convoState) && (
              <ConvoMenu
                convo={convoState.convo}
                profile={profile}
                currentScreen="conversation"
                blockInfo={blockInfo}
                latestReportableMessage={latestReportableMessage}
              />
            )}
          </Layout.Header.Slot>
        </View>
      </View>

      <View
        style={[
          {
            paddingLeft: PFP_SIZE + a.gap_md.gap,
          },
        ]}>
        <PostAlerts
          modui={moderation.ui('contentList')}
          size="lg"
          style={[a.pt_xs]}
        />
      </View>
    </View>
  )
}