import { useState, useEffect, useCallback } from 'react'
import * as api from '@/services/api'
import { useLatestRequest } from './useLatestRequest'
import { useWorkspace } from '@/context'
import type { WorkspaceOverview } from '@/types'

interface UseAnalyticsResult {
  data: WorkspaceOverview | null
  isLoading: boolean
  error: string | null
  refresh: () => Promise<void>
}

export function useAnalytics(workspaceId: string | null, childId?: string): UseAnalyticsResult {
  const [data, setData] = useState<WorkspaceOverview | null>(null)
  const [isLoading, setIsLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const { start, isCurrent } = useLatestRequest()
  const { planVersion } = useWorkspace()

  const fetch = useCallback(async () => {
    const requestId = start()
    if (!workspaceId || !childId) {
      // The identity this data belongs to is gone (e.g. a logout cleared
      // the workspace/child selection) — clear rather than leave the
      // previous account's figures rendered until a new id arrives.
      setData(null)
      setError(null)
      return
    }
    setIsLoading(true)
    setError(null)
    try {
      const response = await api.getWorkspaceOverview(workspaceId, childId)
      if (!isCurrent(requestId)) return
      setData(response)
    } catch (err) {
      if (!isCurrent(requestId)) return
      setError(err instanceof Error ? err.message : 'Failed to fetch analytics')
      setData(null)
    } finally {
      // Unguarded: `isCurrent` decides which response's DATA wins, not
      // whether a superseded call's own busy flag gets cleared — a stale
      // call must still release the flag IT raised, or it can strand that
      // flag true forever (see usePlannedDays.ts for the hang this exact
      // guard caused there).
      setIsLoading(false)
    }
  }, [workspaceId, childId, start, isCurrent])

  // `planVersion` (bumped by usePlannedDays/useDayOverrides mutations) is
  // included so a plan edit made through a different hook instance — e.g.
  // the Calendar's `usePlannedDays` — refreshes the at-risk figures here
  // too, without this hook knowing anything about who mutated. See
  // `WorkspaceContext.planVersion`.
  useEffect(() => {
    fetch()
  }, [fetch, planVersion])

  return { data, isLoading, error, refresh: fetch }
}