import { useEffect, useRef, memo } from 'react'
import { cn } from '@/lib'
import { useChatStore } from '@/features/chat/stores/useChatStore'
import type { ChatMessage as ChatMessageType } from '@/features/chat/types'
import { Indicator } from '@/features/chat/components/templates/Indicator'
import { Summary } from '@/features/chat/components/templates/Summary'
import { BidSummary } from '@/features/chat/components/templates/BidSummary'
import { RejectRSP } from '@/features/chat/components/templates/RejectRSP'
import { RejectCM } from '@/features/chat/components/templates/RejectCM'

export function ChatMessage() {
  return (
    <div className="flex-1 w-full min-h-0 pr-[16px]">
      {/* pt-[64px]: 첫 메시지를 우측 협상절차 카드 상단과 맞추되, 스크롤 시 여백도 함께 밀려 올라가도록 스크롤 컨테이너 안쪽에 둔다 */}
      <div className="chat-scroll h-full overflow-y-auto flex flex-col pt-[64px] pl-[140px] pr-[126px]">
        <ChatList />
      </div>
    </div>
  )
}

function ChatList() {
  const bottomRef = useRef<HTMLDivElement | null>(null)
  const chats = useChatStore((s) => s.messages)
  const isLoading = useChatStore((s) => s.isLoading)

  // 메시지 추가/타이핑 표시 시 항상 맨 아래로 스크롤
  useEffect(() => {
    bottomRef.current?.scrollIntoView({ behavior: 'smooth' })
  }, [chats, isLoading])

  if (!chats || chats.length === 0) {
    return (
      <div className="flex items-center justify-center h-full">
        <p className="body-1 text-neutral-70">채팅 내역이 없습니다.</p>
      </div>
    )
  }

  return (
    <div className="flex flex-col w-full">
      {chats.map((message, index) => (
        <MessageItem key={message.chat_id || index} message={message} isFirst={index === 0} messages={chats} currentIndex={index} />
      ))}
      {isLoading && <TypingBubble />}
      <div ref={bottomRef} />
    </div>
  )
}

// agent 응답을 기다리는 동안(협상 중) 대화 흐름에 표시하는 타이핑 인디케이터.
function TypingBubble() {
  return (
    <div className="mb-[56px] pt-[36px]" aria-label="협상 중" role="status">
      <div className="inline-flex items-center gap-[6px]">
        <span className="size-[8px] rounded-full bg-neutral-50 animate-bounce [animation-delay:-0.3s]" />
        <span className="size-[8px] rounded-full bg-neutral-50 animate-bounce [animation-delay:-0.15s]" />
        <span className="size-[8px] rounded-full bg-neutral-50 animate-bounce" />
      </div>
    </div>
  )
}

const MessageItem = memo(function MessageItem({
  message,
  isFirst,
  messages,
  currentIndex,
}: {
  message: ChatMessageType
  isFirst: boolean
  messages: ChatMessageType[]
  currentIndex: number
}) {
  const isBot = message.sender === 'bot'

  // 직전이 reject 폼이면 사용자 답변은 숨기고 구분선만 표시
  if (!isBot && currentIndex > 0) {
    const prev = messages[currentIndex - 1]
    if (prev?.bot_chat_type === 'rejectRSP' || prev?.bot_chat_type === 'rejectCM') {
      return (
        <>
          <div className="text-right mb-[56px]" />
          <div className="flex w-full bg-neutral-30 h-[1px] mb-[20px]" />
        </>
      )
    }
  }

  return <div>{isBot ? <BotMessage message={message} isFirst={isFirst} /> : <UserMessage text={message.script || ''} />}</div>
})

const BotMessage = memo(function BotMessage({ message, isFirst }: { message: ChatMessageType; isFirst?: boolean }) {
  return (
    <div className="mb-[56px]">
      <div className={cn('flex flex-col', !isFirst && 'pt-[36px]')}>
        <div className="body-1-read-r">{message.script || ''}</div>
      </div>

      <div className="flex flex-col gap-4 w-full mt-[32px]">
        {message.bot_chat_type === 'indicator' && message.indicator_value != null && (
          <Indicator number={message.indicator_value} />
        )}
        {message.bot_chat_type === 'summaryRSP' && message.summary && <Summary data={message.summary} />}
        {message.bot_chat_type === 'summaryCM' && message.summary && (
          <BidSummary
            itemName={message.summary.item_name}
            itemCode={message.summary.item_code}
            bidPrice={message.summary.final_price}
            deliveryType={message.summary.delivery_type || ''}
            isVAT={message.summary.item_isVAT}
          />
        )}
        {message.bot_chat_type === 'rejectRSP' && <RejectRSP />}
        {message.bot_chat_type === 'rejectCM' && <RejectCM />}
      </div>
    </div>
  )
})

const UserMessage = memo(function UserMessage({ text }: { text: string }) {
  return (
    <>
      <div className="text-right mb-[56px]">
        <div className="inline-block max-w-[87%] bg-neutral-40 text-neutral-90 text-lg leading-[150%] tracking-[-0.18px] px-[20px] py-[10px] rounded-full break-keep">
          {text}
        </div>
      </div>
      <div className="flex w-full bg-neutral-30 h-[1px] mb-[20px]" />
    </>
  )
})