"use client"

import { useMemo } from "react"
import { useQueries, useQuery } from "@tanstack/react-query"
import { format } from "date-fns"
import { apiClient } from "@/lib/api/client"
import { useAuthReady } from "@/lib/api/use-auth-ready"
import { expandApiEvents } from "@/lib/agenda/agenda-events"
import type {
  AgendaCalendar,
  AgendaCalendarsResponse,
  AgendaEvent,
  AgendaEventsResponse,
} from "@/lib/agenda/agenda-types"

export const agendaCalendarsKey = ["agenda", "calendars"] as const

export function agendaEventsKey(calendarId: string, from: string, to: string) {
  return ["agenda", "events", calendarId, from, to] as const
}

export function useAgendaCalendars() {
  const { ready, authenticated } = useAuthReady()
  return useQuery({
    queryKey: agendaCalendarsKey,
    enabled: ready && authenticated,
    staleTime: 5 * 60_000,
    queryFn: async () => {
      const res = await apiClient.get<AgendaCalendarsResponse>("/calendar")
      return res.calendars ?? []
    },
  })
}

/**
 * Charge et développe les événements de plusieurs agendas sur une fenêtre.
 * La fenêtre est élargie au mois pour profiter du cache entre vues.
 */
export function useAgendaEvents(
  calendars: AgendaCalendar[],
  rangeStart: Date,
  rangeEnd: Date,
) {
  const { ready, authenticated } = useAuthReady()
  const from = format(rangeStart, "yyyy-MM-dd")
  const to = format(rangeEnd, "yyyy-MM-dd")

  const results = useQueries({
    queries: calendars.map((cal) => ({
      queryKey: agendaEventsKey(cal.id, from, to),
      enabled: ready && authenticated,
      staleTime: 30_000,
      queryFn: async () => {
        const res = await apiClient.get<AgendaEventsResponse>(
          `/calendar/${encodeURIComponent(cal.id)}/events`,
          { from, to, page_size: "500" },
        )
        return res.events ?? []
      },
    })),
  })

  const isLoading = results.some((r) => r.isLoading)
  const isError = results.every((r) => r.isError) && results.length > 0

  const events: AgendaEvent[] = useMemo(() => {
    const all: AgendaEvent[] = []
    calendars.forEach((cal, i) => {
      const data = results[i]?.data
      if (data) all.push(...expandApiEvents(cal, data, rangeStart, rangeEnd))
    })
    return all.sort((a, b) => a.start.getTime() - b.start.getTime())
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [calendars, rangeStart.getTime(), rangeEnd.getTime(), ...results.map((r) => r.data)])

  return { events, isLoading, isError }
}