import { useCallback, useEffect, useRef, useState } from "react"

interface ReportResult<T> {
  key: string
  data: T | null
  loading: boolean
  error: string | null
  updatedAt: Date | null
}

/** Keep successful refresh data, but never show another query's results. */
export function useReportQuery<T>(key: string, read: (signal: AbortSignal) => Promise<T>, delay = 0) {
  const [result, setResult] = useState<ReportResult<T>>({ key, data: null, loading: true, error: null, updatedAt: null })
  const sequence = useRef(0)
  const controller = useRef<AbortController | null>(null)
  const timer = useRef<ReturnType<typeof setTimeout> | null>(null)

  const refresh = useCallback(async () => {
    if (timer.current !== null) clearTimeout(timer.current)
    controller.current?.abort()
    const current = ++sequence.current
    const request = new AbortController()
    controller.current = request
    const timeout = setTimeout(() => {
      if (current !== sequence.current) return
      request.abort()
      setResult(previous => ({ ...previous, loading: false, error: "The request took too long. Please try again." }))
    }, 30000)
    setResult(previous => ({
      key, data: previous.key === key ? previous.data : null,
      updatedAt: previous.key === key ? previous.updatedAt : null, loading: true, error: null,
    }))
    try {
      const data = await read(request.signal)
      if (current !== sequence.current || request.signal.aborted) return
      setResult({ key, data, loading: false, error: null, updatedAt: new Date() })
    } catch (error) {
      if (current !== sequence.current || request.signal.aborted) return
      setResult(previous => ({ ...previous, loading: false, error: error instanceof ReportReadError ? error.message : "The data could not be loaded. Please try again." }))
    } finally {
      clearTimeout(timeout)
    }
  }, [key, read])

  useEffect(() => {
    if (delay > 0) timer.current = setTimeout(() => { void refresh() }, delay)
    else void refresh()
    return () => {
      if (timer.current !== null) clearTimeout(timer.current)
      ++sequence.current
      controller.current?.abort()
    }
  }, [refresh, delay])

  const matches = result.key === key
  return {
    data: matches ? result.data : null,
    loading: !matches || result.loading,
    error: matches ? result.error : null,
    updatedAt: matches ? result.updatedAt : null,
    refresh,
  }
}

export class ReportReadError extends Error {}

export async function readReportJson<T>(url: string, signal: AbortSignal): Promise<T> {
  const response = await fetch(url, {
    signal,
    credentials: "same-origin",
    headers: { "X-WP-Nonce": window.swiftCommerceData?.restNonce || "" },
  })
  if (!response.ok) {
    if (response.status === 401 || response.status === 403) {
      throw new ReportReadError("Access could not be verified. Reload the dashboard and try again.")
    }
    throw new ReportReadError("The server could not load this data. Please try again.")
  }
  const result = await response.json()
  if (result?.success !== true) throw new ReportReadError("The server did not return a successful report. Please try again.")
  return result as T
}