// Modified for targeted chat realtime recovery; see docs/fixes/chat-realtime-recovery.md.
"use client"

import {
  CheckCircle2Icon,
  MessageSquarePlusIcon,
  RotateCwIcon,
  XIcon,
} from "lucide-react"
import {
  useCallback,
  useEffect,
  useLayoutEffect,
  useRef,
  useState,
  type ComponentProps,
  type CSSProperties,
} from "react"
import { useShallow } from "zustand/react/shallow"

import { SupportChatErrorBoundary } from "@/components/support-chat/chat-error-boundary"
import { SupportChatConnectionStatus } from "@/components/support-chat/connection-status"
import { SupportChatConversationSwitcher } from "@/components/support-chat/conversation-switcher"
import { SupportChatNewRequestDialog } from "@/components/support-chat/new-request-dialog"
import { getStandaloneClosedUrl } from "@/components/support-chat/close-navigation"
import { CSATCard } from "@/components/support-chat/csat-card"
import { CustomerMessageEditor } from "@/components/support-chat/customer-message-editor"
import { getCustomerSessionToken } from "@/lib/api/im"
import {
  SupportChatMessageList,
  type SupportChatMessageListHandle,
} from "@/components/support-chat/message-list"
import {
  bindSupportHostBridge,
  requestSupportHostMinimize,
} from "@/lib/support-host-bridge"
import { useSupportChatStore } from "@/lib/stores/support-chat"
import { Button } from "@/components/ui/button"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog"
import { cn } from "@/lib/utils"
import { useI18n } from "@/i18n/provider"

const windowActionButtonClass =
  "size-8 rounded-full border-0 bg-transparent text-muted-foreground shadow-none hover:bg-foreground/[0.06] hover:text-foreground focus-visible:ring-primary/20 dark:hover:bg-white/10"

function WindowActionButton({
  className,
  ...props
}: ComponentProps<typeof Button>) {
  return (
    <Button
      type="button"
      variant="ghost"
      size="icon"
      className={cn(windowActionButtonClass, className)}
      {...props}
    />
  )
}

function useSupportChatSystemTheme() {
  useLayoutEffect(() => {
    if (typeof window === "undefined") {
      return
    }
    const root = document.documentElement
    const query = window.matchMedia("(prefers-color-scheme: dark)")
    const previousDarkClass = root.classList.contains("dark")
    const previousColorScheme = root.style.colorScheme

    const syncTheme = () => {
      const isDark = query.matches
      root.classList.toggle("dark", isDark)
      root.style.colorScheme = isDark ? "dark" : "light"
    }

    syncTheme()
    query.addEventListener("change", syncTheme)

    return () => {
      query.removeEventListener("change", syncTheme)
      root.classList.toggle("dark", previousDarkClass)
      root.style.colorScheme = previousColorScheme
    }
  }, [])
}

export function isEmbeddedInHost() {
  if (typeof window === "undefined") {
    return false
  }

  try {
    return window.parent !== window
  } catch {
    return false
  }
}

/**
 * The chat panel without any outer sizing. Both the embedded iframe frame and
 * the standalone support page render this, so the surrounding chrome decides
 * how much room it gets.
 */
function SupportChatPanelContent() {
  const t = useI18n()
  useSupportChatSystemTheme()

  const messageListRef = useRef<SupportChatMessageListHandle | null>(null)
  const [isEmbedded, setIsEmbedded] = useState(false)
  const [isCloseDialogOpen, setIsCloseDialogOpen] = useState(false)
  const [isClosingConversation, setIsClosingConversation] = useState(false)
  const [isNewRequestDialogOpen, setIsNewRequestDialogOpen] = useState(false)

  const {
    title,
    subtitle,
    themeColor,
    conversation,
    messages,
    messagesHasMore,
    messagesLoadingMore,
    loadOlderMessages,
    status,
    error,
    isOpen,
    isVisible,
    setIsOpen,
    setIsVisible,
    bootstrap,
    handleSendMessage,
    uploadMessageImage,
    sendAttachment,
    retry,
    disconnectSocket,
    recoverConnection,
    markConversationRead,
    closeConversation,
    setConversationSatisfaction,
  } = useSupportChatStore(
    useShallow((state) => ({
      title: state.title,
      subtitle: state.subtitle,
      themeColor: state.themeColor,
      conversation: state.conversation,
      messages: state.messages,
      messagesHasMore: state.messagesHasMore,
      messagesLoadingMore: state.messagesLoadingMore,
      loadOlderMessages: state.loadOlderMessages,
      status: state.status,
      error: state.error,
      isOpen: state.isOpen,
      isVisible: state.isVisible,
      setIsOpen: state.setIsOpen,
      setIsVisible: state.setIsVisible,
      bootstrap: state.bootstrap,
      handleSendMessage: state.handleSendMessage,
      uploadMessageImage: state.uploadMessageImage,
      sendAttachment: state.sendAttachment,
      retry: state.retry,
      disconnectSocket: state.disconnectSocket,
      recoverConnection: state.recoverConnection,
      markConversationRead: state.markConversationRead,
      closeConversation: state.closeConversation,
      setConversationSatisfaction: state.setConversationSatisfaction,
    }))
  )
  const safeMessages = Array.isArray(messages) ? messages : []

  useEffect(() => {
    setIsEmbedded(isEmbeddedInHost())
  }, [])

  const maybeMarkConversationRead = useCallback(() => {
    if (!isVisible || !conversation || typeof document === "undefined") {
      return
    }
    if (document.visibilityState !== "visible") {
      return
    }
    void markConversationRead().catch((readError) => {
      console.error("Failed to mark support chat conversation read", readError)
    })
  }, [conversation?.id, isVisible, markConversationRead])

  useEffect(() => {
    return bindSupportHostBridge({
      onInit: () => {
        if (useSupportChatStore.getState().isOpen) {
          bootstrap()
        }
      },
      onOpen: () => {
        setIsOpen(true)
        setIsVisible(true)
      },
      onMinimize: () => {
        setIsVisible(false)
      },
    })
  }, [bootstrap, setIsOpen, setIsVisible])

  useEffect(() => {
    bootstrap()
  }, [isOpen, bootstrap])

  useEffect(() => () => disconnectSocket(), [disconnectSocket])

  useEffect(() => {
    maybeMarkConversationRead()
  }, [maybeMarkConversationRead, safeMessages.length])

  useEffect(() => {
    const handleVisibilityChange = () => {
      recoverConnection()
      if (document.visibilityState === "visible") {
        maybeMarkConversationRead()
      }
    }
    const handleFocus = () => {
      recoverConnection()
      maybeMarkConversationRead()
    }

    document.addEventListener("visibilitychange", handleVisibilityChange)
    window.addEventListener("focus", handleFocus)
    window.addEventListener("online", recoverConnection)
    return () => {
      document.removeEventListener("visibilitychange", handleVisibilityChange)
      window.removeEventListener("focus", handleFocus)
      window.removeEventListener("online", recoverConnection)
    }
  }, [maybeMarkConversationRead, recoverConnection])

  async function handleSend(content: string) {
    await handleSendMessage(content)
    messageListRef.current?.scrollToBottom()
  }

  function handleCloseWindow() {
    setIsVisible(false)
    if (isEmbedded) {
      requestSupportHostMinimize()
    } else {
      window.location.replace(getStandaloneClosedUrl())
    }
  }

  async function confirmCloseConversation() {
    if (isClosingConversation) {
      return
    }
    setIsClosingConversation(true)
    try {
      if (conversation?.id) {
        await closeConversation()
      }
      setIsCloseDialogOpen(false)
    } catch (closeError) {
      window.alert(closeError instanceof Error ? closeError.message : t("supportChat.closeConversationFailed"))
    } finally {
      setIsClosingConversation(false)
    }
  }

  useEffect(() => {
    if (!isCloseDialogOpen) {
      return
    }
    const handleKeyDown = (event: KeyboardEvent) => {
      if (event.key === "Escape" && !isClosingConversation) {
        setIsCloseDialogOpen(false)
      }
    }
    window.addEventListener("keydown", handleKeyDown)
    return () => window.removeEventListener("keydown", handleKeyDown)
  }, [isCloseDialogOpen, isClosingConversation])

  return (
    <>
      <section
        className="flex h-full min-h-0 w-full flex-col overflow-hidden bg-card text-card-foreground"
        style={{ "--primary": themeColor } as CSSProperties}
      >
        <header className="shrink-0 border-b border-border/70 bg-card/95 px-3 py-2 shadow-[0_1px_0_rgba(15,23,42,0.02)] backdrop-blur dark:border-border/60 dark:bg-card/90 sm:px-4">
          <div className="flex min-w-0 items-center justify-between gap-2.5">
            <SupportChatConversationSwitcher
              title={title}
              subtitle={subtitle}
              status={status}
              onNewRequest={() => setIsNewRequestDialogOpen(true)}
              onCloseActiveRequest={() => setIsCloseDialogOpen(true)}
            />
            <div className="flex shrink-0 items-center gap-0.5">
              <WindowActionButton
                onClick={() => setIsNewRequestDialogOpen(true)}
                aria-label={t("supportChat.newRequest")}
                title={t("supportChat.newRequest")}
              >
                <MessageSquarePlusIcon className="size-4" />
              </WindowActionButton>
              {status !== "connected" ? (
                <WindowActionButton
                  onClick={retry}
                  aria-label={t("supportChat.retry")}
                  title={t("supportChat.retry")}
                >
                  <RotateCwIcon className="size-4" />
                </WindowActionButton>
              ) : null}
              {conversation && conversation.status !== 4 ? (
                <WindowActionButton
                  onClick={() => setIsCloseDialogOpen(true)}
                  aria-label={t("supportChat.confirmClose")}
                  title={t("supportChat.confirmClose")}
                  className="hover:bg-foreground/[0.06] hover:text-foreground"
                >
                  <CheckCircle2Icon className="size-4" />
                </WindowActionButton>
              ) : null}
              <WindowActionButton
                onClick={handleCloseWindow}
                aria-label={t("supportChat.closeWindow")}
                title={t("supportChat.closeWindow")}
                className="hover:bg-rose-50 hover:text-rose-600 dark:hover:bg-rose-950/45 dark:hover:text-rose-300"
              >
                <XIcon className="size-4" />
              </WindowActionButton>
            </div>
          </div>
        </header>

        <div className="grid min-h-0 flex-1 grid-rows-[minmax(0,1fr)_auto] overflow-hidden bg-muted/60 dark:bg-muted/30">
          <SupportChatMessageList
            ref={messageListRef}
            messages={safeMessages}
            onNearBottomVisible={maybeMarkConversationRead}
            hasMoreOlder={messagesHasMore}
            loadingOlder={messagesLoadingMore}
            onLoadOlder={loadOlderMessages}
          />
          <div className="shrink-0 border-t border-border/80 bg-card/95 pb-[env(safe-area-inset-bottom)] shadow-[0_-10px_24px_rgba(15,23,42,0.05)] dark:bg-card/90 dark:shadow-none">
            {conversation && (conversation.status === 4 || conversation.satisfaction) ? (
              <div className="border-b border-border/60 p-3">
                <CSATCard
                  key={conversation.id}
                  conversationId={conversation.id}
                  customerToken={getCustomerSessionToken()}
                  initialSatisfaction={conversation.satisfaction}
                  onSubmitted={setConversationSatisfaction}
                />
              </div>
            ) : null}
            <CustomerMessageEditor
              disabled={!conversation || conversation.status === 4}
              onSend={handleSend}
              onUploadImage={uploadMessageImage}
              onSendAttachment={sendAttachment}
            />
          </div>
        </div>

        {error ? (
          <div className="border-t border-destructive/20 bg-destructive/10 px-4 py-3 text-sm text-destructive">
            {error}
          </div>
        ) : null}
      </section>

      <Dialog
        open={isCloseDialogOpen}
        onOpenChange={(open) => {
          if (!isClosingConversation) {
            setIsCloseDialogOpen(open)
          }
        }}
      >
        <DialogContent className="max-w-[320px]" showCloseButton={!isClosingConversation}>
          <DialogHeader>
            <DialogTitle>{t("supportChat.closeDialogTitle")}</DialogTitle>
            <DialogDescription className="text-xs leading-5">
              {t("supportChat.closeDialogDescription")}
            </DialogDescription>
          </DialogHeader>
          <DialogFooter>
            <Button
              type="button"
              variant="outline"
              disabled={isClosingConversation}
              onClick={() => setIsCloseDialogOpen(false)}
            >
              {t("supportChat.continueConversation")}
            </Button>
            <Button
              type="button"
              variant="destructive"
              disabled={isClosingConversation}
              onClick={() => void confirmCloseConversation()}
            >
              {isClosingConversation ? t("supportChat.closing") : t("supportChat.confirmClose")}
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      <SupportChatNewRequestDialog
        open={isNewRequestDialogOpen}
        onOpenChange={setIsNewRequestDialogOpen}
        onCreated={() => {
          messageListRef.current?.scrollToBottom()
        }}
      />
    </>
  )
}

export function SupportChatPanel() {
  return (
    <SupportChatErrorBoundary>
      <SupportChatPanelContent />
    </SupportChatErrorBoundary>
  )
}

/**
 * The embedded widget frame. The host sizes the iframe, so the panel always
 * fills the whole document box.
 */
export function SupportChatShell() {
  return (
    <main className="relative flex h-[100dvh] min-h-[100dvh] overflow-hidden bg-muted text-foreground supports-not-[height:100dvh]:h-screen supports-not-[height:100dvh]:min-h-screen">
      <SupportChatPanel />
    </main>
  )
}