'use client'

import Link from 'next/link'
import { Plus } from 'lucide-react'
import { useEffect, useState } from 'react'
import { getWatchlistQuote, type MappedQuote } from '@/lib/stockApi'
import { getUserSymbols, getUserTopics, deleteUserInterest } from '@/lib/userInterestsApi'
import { getNewsFeed } from '@/lib/newsApi'
import { StockWatchlistRow } from '@/components/widgets/StockWatchlistRow'
import { InterestHeadlineRow } from '@/components/widgets/InterestHeadlineRow'

interface TopicItem {
  id: string
  topic: string
  headline: string
}

export function InterestsPage() {
  // Symbols state
  const [watchlist, setWatchlist] = useState<(MappedQuote & { id: string })[]>([])
  const [loadingWatchlist, setLoadingWatchlist] = useState(true)
  const [watchlistError, setWatchlistError] = useState<string | null>(null)
  const [watchlistEmpty, setWatchlistEmpty] = useState(false)

  // Topics state
  const [topics, setTopics] = useState<TopicItem[]>([])
  const [loadingTopics, setLoadingTopics] = useState(true)
  const [topicsError, setTopicsError] = useState<string | null>(null)
  const [topicsEmpty, setTopicsEmpty] = useState(false)

  // Track which row is currently open (only one at a time)
  const [openRowId, setOpenRowId] = useState<string | null>(null)

  // Fetch symbols from backend, then fetch quotes for each
  useEffect(() => {
    setLoadingWatchlist(true)
    setWatchlistError(null)
    setWatchlistEmpty(false)

    getUserSymbols()
      .then((symbols) => {
        if (symbols.length === 0) {
          setWatchlistEmpty(true)
          setWatchlist([])
          setLoadingWatchlist(false)
          return
        }
        return Promise.all(symbols.map((sym) => getWatchlistQuote(sym)))
          .then((quotes) =>
            setWatchlist(quotes.map((q, i) => ({ ...q, id: String(i + 1) })))
          )
      })
      .catch((err) => setWatchlistError(err.message))
      .finally(() => setLoadingWatchlist(false))
  }, [])

  // Fetch topics from backend
  useEffect(() => {
    setLoadingTopics(true)
    setTopicsError(null)
    setTopicsEmpty(false)

    getUserTopics()
      .then(async (topicNames) => {
        if (topicNames.length === 0) {
          setTopicsEmpty(true)
          setTopics([])
          return
        }
        // Fetch top headline for each topic concurrently (request-amount=1)
        const topicItems = await Promise.all(
          topicNames.map(async (t, i) => {
            let headline = ''
            try {
              const news = await getNewsFeed(t, 'frontend', 1)
              headline = news[0]?.title ?? ''
            } catch {
              // Non-fatal: card still renders without a headline preview
            }
            return { id: String(i + 1), topic: t, headline }
          })
        )
        setTopics(topicItems)
      })
      .catch((err) => setTopicsError(err.message))
      .finally(() => setLoadingTopics(false))
  }, [])

  // Delete handlers — return Promise so SwipeableRow can manage async state
  const handleDeleteSymbol = async (symbol: string): Promise<void> => {
    await deleteUserInterest('symbol', symbol)
    setWatchlist((prev) => {
      const next = prev.filter((s) => s.symbol !== symbol)
      if (next.length === 0) setWatchlistEmpty(true)
      return next
    })
    setOpenRowId(null)
  }

  const handleDeleteTopic = async (topicName: string): Promise<void> => {
    await deleteUserInterest('topic', topicName)
    setTopics((prev) => {
      const next = prev.filter((t) => t.topic !== topicName)
      if (next.length === 0) setTopicsEmpty(true)
      return next
    })
    setOpenRowId(null)
  }

  return (
    <div className="h-full flex flex-col">
      {/* Header */}
      <div className="bg-background border-b border-border px-6 py-4 flex items-center justify-between">
        <h1 className="text-2xl font-bold">Interests</h1>
        <Link
          href="/add-item"
          className="w-10 h-10 flex items-center justify-center bg-primary text-primary-foreground hover:bg-blue-700 transition-colors"
          title="Add new item"
        >
          <Plus size={20} />
        </Link>
      </div>

      {/* Content - Split into two halves */}
      <div className="flex-1 flex flex-col">
        {/* Top Half: Watchlist */}
        <div className="flex-1 border-b border-border overflow-y-auto">
          <div className="p-6 space-y-4">
            <h2 className="text-lg font-semibold">Symbol Watchlist</h2>
            {loadingWatchlist && (
              <div className="text-sm text-muted-foreground">Loading symbols...</div>
            )}
            {watchlistError && (
              <div className="text-sm text-negative">{watchlistError}</div>
            )}
            {!loadingWatchlist && !watchlistError && watchlistEmpty && (
              <div className="text-sm text-muted-foreground">
                You are not currently following any symbols. Please add a symbol first.
              </div>
            )}
            {!loadingWatchlist && !watchlistError && !watchlistEmpty && watchlist.map((stock) => (
              <StockWatchlistRow
                key={stock.id}
                stock={stock}
                onDelete={() => handleDeleteSymbol(stock.symbol)}
                isOpen={openRowId === `symbol-${stock.symbol}`}
                onOpenChange={(open) => setOpenRowId(open ? `symbol-${stock.symbol}` : null)}
              />
            ))}
          </div>
        </div>

        {/* Bottom Half: Topic Watchlist */}
        <div className="flex-1 overflow-y-auto">
          <div className="p-6 space-y-4">
            <h2 className="text-lg font-semibold">Topic Watchlist</h2>
            {loadingTopics && (
              <div className="text-sm text-muted-foreground">Loading topics...</div>
            )}
            {topicsError && (
              <div className="text-sm text-negative">{topicsError}</div>
            )}
            {!loadingTopics && !topicsError && topicsEmpty && (
              <div className="text-sm text-muted-foreground">
                You are not currently following any topics. Please add a topic first.
              </div>
            )}
            {!loadingTopics && !topicsError && !topicsEmpty && topics.map((interest) => (
              <InterestHeadlineRow
                key={interest.id}
                interest={interest}
                onDelete={() => handleDeleteTopic(interest.topic)}
                isOpen={openRowId === `topic-${interest.topic}`}
                onOpenChange={(open) => setOpenRowId(open ? `topic-${interest.topic}` : null)}
              />
            ))}
          </div>
        </div>
      </div>
    </div>
  )
}