import { useSearchParams } from "react-router-dom"

export function useMonthParam() {
  const [searchParams, setSearchParams] = useSearchParams()

  const monthParam = searchParams.get("month")
  const now = new Date()
  const currentMonth = `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, "0")}`
  const month = monthParam || currentMonth

  const setMonth = (newMonth: string) => {
    setSearchParams((prev) => {
      prev.set("month", newMonth)
      return prev
    })
  }

  const navigateMonth = (delta: number) => {
    const [year, mo] = month.split("-").map(Number)
    const d = new Date(year, mo - 1 + delta, 1)
    const next = `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, "0")}`
    setMonth(next)
  }

  return { month, setMonth, navigateMonth }
}