<script lang="ts">
  import type {Snippet} from "svelte"
  import {onMount} from "svelte"
  import {
    int,
    ms,
    partition,
    spec,
    nthEq,
    nthNe,
    MINUTE,
    sortBy,
    remove,
    enumerate,
    formatTimestampAsDate,
  } from "@welshman/lib"
  import type {TrustedEvent, EventTemplate, EventContent} from "@welshman/util"
  import {parse, isLink} from "@welshman/content"
  import {
    makeEvent,
    tagsFromIMeta,
    getTags,
    DIRECT_MESSAGE,
    DIRECT_MESSAGE_FILE,
  } from "@welshman/util"
  import {
    pubkey,
    tagPubkey,
    sendWrapped,
    mergeThunks,
    loadMessagingRelayList,
    messagingRelayListsByPubkey,
  } from "@welshman/app"
  import Danger from "@assets/icons/danger-triangle.svg?dataurl"
  import Icon from "@lib/components/Icon.svelte"
  import Link from "@lib/components/Link.svelte"
  import Spinner from "@lib/components/Spinner.svelte"
  import PageBar from "@lib/components/PageBar.svelte"
  import PageContent from "@lib/components/PageContent.svelte"
  import Divider from "@lib/components/Divider.svelte"
  import Button from "@lib/components/Button.svelte"
  import ProfileName from "@app/components/ProfileName.svelte"
  import ProfileCircle from "@app/components/ProfileCircle.svelte"
  import ProfileCircles from "@app/components/ProfileCircles.svelte"
  import ProfileDetail from "@app/components/ProfileDetail.svelte"
  import ChatMembers from "@app/components/ChatMembers.svelte"
  import ChatMessage from "@app/components/ChatMessage.svelte"
  import ChatCompose from "@app/components/ChatCompose.svelte"
  import ChatComposeParent from "@app/components/ChatComposeParent.svelte"
  import ThunkToast from "@app/components/ThunkToast.svelte"
  import {INDEXER_RELAYS, userSettingsValues, PLATFORM_NAME, deriveChat} from "@app/core/state"
  import {pushModal} from "@app/util/modal"
  import {prependParent} from "@app/core/commands"
  import {pushToast} from "@app/util/toast"

  type Props = {
    pubkeys: string[]
    info?: Snippet
  }

  const {pubkeys, info}: Props = $props()

  const chat = deriveChat(pubkeys)
  const others = remove($pubkey!, pubkeys)
  const missingRelayLists = $derived(pubkeys.filter(pk => !$messagingRelayListsByPubkey.has(pk)))

  const showMembers = () =>
    others.length === 1
      ? pushModal(ProfileDetail, {pubkey: others[0]})
      : pushModal(ChatMembers, {pubkeys: others})

  const replyTo = (event: TrustedEvent) => {
    parent = event
    compose?.focus()
  }

  const clearParent = () => {
    parent = undefined
  }

  const onSubmit = async (params: EventContent) => {
    const ptags = remove($pubkey!, pubkeys).map(tagPubkey)

    // Remove p tags since they result in forking the conversation
    params.tags = params.tags.filter(nthNe(0, "p"))

    // Add our reply quote to content
    params = prependParent(parent, params)

    const [imetaTags, tags] = partition(nthEq(0, "imeta"), params.tags)
    const imetas = getTags("imeta", imetaTags).map(tagsFromIMeta)
    const templates: EventTemplate[] = []
    const buffer = []

    const addTemplate = (kind: number, content: string, tags: string[][]) => {
      content = content.trim()

      if (content) {
        templates.push(makeEvent(kind, {content, tags: [...tags, ...ptags]}))
      }
    }

    for (const p of parse(params)) {
      const imeta = isLink(p)
        ? imetas.find(tags => tags.find(spec(["url", p.value.url.toString()])))
        : undefined

      if (isLink(p) && imeta) {
        addTemplate(DIRECT_MESSAGE, buffer.splice(0).join(""), tags)
        addTemplate(
          DIRECT_MESSAGE_FILE,
          p.value.url.toString(),
          imeta.slice(1).filter(nthNe(0, "url")),
        )
      } else {
        buffer.push(p.raw)
      }
    }

    addTemplate(DIRECT_MESSAGE, buffer.splice(0).join(""), tags)

    // Split the message into multiple pieces so that we can use kind 15 to send images per nip 17
    // Sleep 1 second between each one to make sure timestamps are distinct
    const thunks = Array.from(enumerate(templates)).map(([i, event]) =>
      sendWrapped({
        event,
        recipients: pubkeys,
        delay: $userSettingsValues.send_delay + ms(i),
      }),
    )

    pushToast({
      timeout: 30_000,
      children: {
        component: ThunkToast,
        props: {thunk: mergeThunks(thunks)},
      },
    })

    clearParent()
  }

  let loading = $state(true)
  let compose: ChatCompose | undefined = $state()
  let parent: TrustedEvent | undefined = $state()
  let chatCompose: HTMLElement | undefined = $state()
  let dynamicPadding: HTMLElement | undefined = $state()

  const elements = $derived.by(() => {
    const elements = []

    let previousDate
    let previousPubkey
    let previousCreatedAt = 0

    for (const event of sortBy(e => e.created_at, $chat?.messages || [])) {
      const {id, pubkey, created_at} = event
      const date = formatTimestampAsDate(created_at)

      if (date !== previousDate) {
        elements.push({type: "date", value: date, id: date, showPubkey: false})
      }

      elements.push({
        id,
        type: "note",
        value: event,
        showPubkey: created_at - previousCreatedAt > int(2, MINUTE) || previousPubkey !== pubkey,
      })

      previousDate = date
      previousPubkey = pubkey
      previousCreatedAt = created_at
    }

    return elements.reverse()
  })

  onMount(() => {
    for (const pubkey of others) {
      loadMessagingRelayList(pubkey, INDEXER_RELAYS, true)
    }

    const observer = new ResizeObserver(() => {
      if (dynamicPadding && chatCompose) {
        dynamicPadding.style.minHeight = `${chatCompose.offsetHeight}px`
      }
    })

    observer.observe(chatCompose!)
    observer.observe(dynamicPadding!)

    return () => {
      observer.unobserve(chatCompose!)
      observer.unobserve(dynamicPadding!)
    }
  })

  setTimeout(() => {
    loading = false
  }, 5000)
</script>

<PageBar>
  {#snippet title()}
    <Button class="flex flex-col gap-1 sm:flex-row sm:gap-2" onclick={showMembers}>
      {#if others.length === 0}
        <div class="row-2">
          <ProfileCircle pubkey={$pubkey!} size={5} />
          <ProfileName pubkey={$pubkey!} />
        </div>
      {:else if others.length === 1}
        <div class="row-2">
          <ProfileCircle pubkey={others[0]} size={5} />
          <ProfileName pubkey={others[0]} />
        </div>
      {:else}
        <div class="flex items-center gap-2">
          <ProfileCircles pubkeys={others} size={5} />
          <p class="overflow-hidden text-ellipsis whitespace-nowrap">
            <ProfileName pubkey={others[0]} />
            and
            {#if others.length === 2}
              <ProfileName pubkey={others[1]} />
            {:else}
              {others.length - 1}
              {others.length > 2 ? "others" : "other"}
            {/if}
          </p>
        </div>
      {/if}
    </Button>
  {/snippet}
  {#snippet action()}
    {#if remove($pubkey, missingRelayLists).length > 0}
      {@const count = remove($pubkey, missingRelayLists).length}
      {@const label = count > 1 ? "lists are" : "list is"}
      <div
        class="row-2 badge badge-error badge-lg tooltip tooltip-left cursor-pointer"
        data-tip="{count} messaging {label} not configured.">
        <Icon icon={Danger} />
        {count}
      </div>
    {/if}
  {/snippet}
</PageBar>

<PageContent class="flex flex-col-reverse gap-2 pt-4">
  <div bind:this={dynamicPadding}></div>
  {#if missingRelayLists.includes($pubkey!)}
    <div class="py-12">
      <div class="card2 col-2 m-auto max-w-md items-center text-center">
        <p class="row-2 text-lg text-error">
          <Icon icon={Danger} />
          Your messaging relays are not configured.
        </p>
        <p>
          In order to deliver messages, {PLATFORM_NAME} needs to know where to send them. Please visit
          your <Link class="link" href="/settings/relays">relay settings page</Link> to receive messages.
        </p>
      </div>
    </div>
  {:else if missingRelayLists.length > 0}
    <div class="py-12">
      <div class="card2 col-2 m-auto max-w-md items-center text-center">
        <p class="row-2 text-lg text-error">
          <Icon icon={Danger} />
          {missingRelayLists.length} messaging
          {missingRelayLists.length > 1 ? "lists are" : "list is"} not configured.
        </p>
        <p>
          In order to deliver messages, {PLATFORM_NAME} needs to know where to send them. Please make
          sure everyone in this conversation has set up their messaging relays.
        </p>
      </div>
    </div>
  {/if}
  {#each elements as { type, id, value, showPubkey } (id)}
    {#if type === "date"}
      <Divider>{value}</Divider>
    {:else}
      <ChatMessage
        event={$state.snapshot(value as TrustedEvent)}
        {pubkeys}
        {showPubkey}
        {replyTo} />
    {/if}
  {/each}
  <p class="m-auto flex h-10 max-w-sm flex-col items-center justify-center gap-4 py-20 text-center">
    <Spinner {loading}>
      {#if loading}
        Looking for messages...
      {:else}
        End of message history
      {/if}
    </Spinner>
    {@render info?.()}
  </p>
</PageContent>

<div class="chat__compose bg-base-200" bind:this={chatCompose}>
  <div>
    {#if parent}
      <ChatComposeParent event={parent} clear={clearParent} verb="Replying to" />
    {/if}
  </div>
  <ChatCompose bind:this={compose} {onSubmit} />
</div>
