import { useMemo, useState, useCallback } from "react"
import { message } from "antd"
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query"
import { getTitles, createTitle, updateTitle, deleteTitle } from "@/api/titles"
import type { TitleData, CategoryItem, Frequency } from "../types/titleLibrary"
import { toTitleData, copyToClipboard } from "../utils/titleLibrary"
import { ALL_CATEGORY_ID, FREQUENCY_THRESHOLDS } from "../constants/titleLibrary"

export const useTitleLibrary = () => {
  const queryClient = useQueryClient()

  /* 分类 */
  const [activeCatId, setActiveCatId] = useState<string>(ALL_CATEGORY_ID)

  /* 数据获取 */
  const { data: apiTitles = [] } = useQuery({
    queryKey: ["titles"],
    queryFn: getTitles,
    staleTime: 30_000,
  })

  const titles: TitleData[] = useMemo(() => apiTitles.map(toTitleData), [apiTitles])

  /* 动态派生分类 */
  const categories: CategoryItem[] = useMemo(() => {
    const cats = new Map<string, number>()
    apiTitles.forEach((t) => {
      const cat = t.category || "未分类"
      cats.set(cat, (cats.get(cat) || 0) + 1)
    })
    return [
      { id: ALL_CATEGORY_ID, name: "全部标题", count: apiTitles.length },
      ...Array.from(cats.entries()).map(([name, count]) => ({
        id: `cat-${name}`,
        name,
        count,
      })),
    ]
  }, [apiTitles])

  /* CRUD mutations */
  const createMutation = useMutation({
    mutationFn: (content: string) => createTitle({ content }),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["titles"] })
    },
    onError: () => message.error("创建标题失败"),
  })

  const updateMutation = useMutation({
    mutationFn: ({ id, content }: { id: string; content: string }) => updateTitle(id, { content }),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["titles"] })
    },
    onError: () => message.error("更新标题失败"),
  })

  const deleteMutation = useMutation({
    mutationFn: (id: string) => deleteTitle(id),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["titles"] })
    },
    onError: () => message.error("删除标题失败"),
  })

  /* 筛选状态 */
  const [searchText, setSearchText] = useState("")
  const [filterType, setFilterType] = useState<string>("all")
  const [filterIndustry, setFilterIndustry] = useState<string>("all")
  const [filterFrequency, setFilterFrequency] = useState<Frequency>("all")

  /* 派生：筛选后的标题列表 */
  const activeCategory = categories.find((c) => c.id === activeCatId)

  const filteredTitles = useMemo(() => {
    let list = titles

    /* 按分类过滤 */
    if (activeCatId !== ALL_CATEGORY_ID) {
      const catName = activeCategory?.name || ""
      if (catName) {
        list = list.filter((t) => t.category === catName)
      }
    }

    /* 按类型筛选 */
    if (filterType !== "all") {
      list = list.filter((t) => t.type === filterType)
    }

    /* 按行业筛选 */
    if (filterIndustry !== "all") {
      list = list.filter((t) => t.industry === filterIndustry)
    }

    /* 按使用频率筛选 */
    if (filterFrequency !== "all") {
      switch (filterFrequency) {
        case "high":
          list = list.filter((t) => t.usageCount >= FREQUENCY_THRESHOLDS.high)
          break
        case "medium":
          list = list.filter(
            (t) =>
              t.usageCount >= FREQUENCY_THRESHOLDS.medium &&
              t.usageCount < FREQUENCY_THRESHOLDS.high,
          )
          break
        case "low":
          list = list.filter((t) => t.usageCount < FREQUENCY_THRESHOLDS.medium)
          break
      }
    }

    /* 搜索 */
    if (searchText.trim()) {
      const q = searchText.trim().toLowerCase()
      list = list.filter((t) => t.content.toLowerCase().includes(q))
    }

    return list
  }, [titles, activeCatId, activeCategory, filterType, filterIndustry, filterFrequency, searchText])

  /* 操作：收藏 */
  const handleToggleFavorite = useCallback((_id: string) => {
    message.info("收藏功能即将上线")
  }, [])

  /* 操作：复制 */
  const handleCopy = useCallback(async (title: TitleData) => {
    const ok = await copyToClipboard(title.content)
    if (ok) {
      message.success("已复制到剪贴板")
    } else {
      message.error("复制失败")
    }
  }, [])

  /* 操作：删除 */
  const handleDelete = useCallback(
    (id: string) => {
      deleteMutation.mutate(id)
      message.success("标题已删除")
    },
    [deleteMutation],
  )

  return {
    /* 状态 */
    titles,
    categories,
    activeCatId,
    activeCategory,
    filteredTitles,
    searchText,
    filterType,
    filterIndustry,
    filterFrequency,
    /* mutations */
    createMutation,
    updateMutation,
    deleteMutation,
    /* setters */
    setActiveCatId,
    setSearchText,
    setFilterType,
    setFilterIndustry,
    setFilterFrequency,
    /* handlers */
    handleToggleFavorite,
    handleCopy,
    handleDelete,
  }
}