import { provideRequestEvent } from '@solidjs/web/storage'
import { createMemoryHistory } from '@tanstack/solid-router'
import { attachRouterServerSsrUtils } from '@tanstack/solid-router/ssr/server'
import {
  getStartContext,
  runWithStartContext,
} from '@tanstack/start-storage-context'
import { createSolidStartFlightMatch } from './solid-rpc-flight'
import type {
  CollectFlightDataHook,
  ServerFunctionOutcome,
} from '@solidjs/web/server-functions/server'
import type { ServerFunctionEvent } from '@solidjs/web/server-functions/server'

export const collectSolidStartFlightData: CollectFlightDataHook = async (
  event,
  outcome,
) => {
  const href = getTargetHref(outcome)
  if (!href) {
    return undefined
  }

  const startContext = getStartContext({ throwIfNotFound: false })
  if (!startContext) {
    return undefined
  }

  const targetUrl = new URL(href)
  const request = new Request(targetUrl, {
    headers: outcome.foldedHeaders,
    signal: outcome.request.signal,
  })
  const flightEvent: ServerFunctionEvent = {
    ...event,
    request,
  }
  const router = await startContext.getRouter()
  router.update({
    history: createMemoryHistory({
      initialEntries: [targetUrl.pathname + targetUrl.search + targetUrl.hash],
    }),
    origin: targetUrl.origin,
  })

  return await provideRequestEvent(flightEvent, async () => {
    return await runWithStartContext(
      {
        ...startContext,
        handlerType: 'router',
        request,
      },
      async () => {
        let attachedServerSsr = false
        try {
          if (router.options.dehydrate && !router.serverSsr) {
            attachRouterServerSsrUtils({ router, manifest: undefined })
            attachedServerSsr = true
          }

          await router.load({ _signal: outcome.request.signal })
          const dehydratedData = await router.options.dehydrate?.()
          router.serverSsr?.setRenderFinished()

          return {
            ...(dehydratedData === undefined ? {} : { dehydratedData }),
            href: targetUrl.href,
            matches: router.stores.matches
              .get()
              .map(createSolidStartFlightMatch),
          }
        } catch (error) {
          console.error('Unable to collect TanStack Start flight data', error)
          return undefined
        } finally {
          if (attachedServerSsr) {
            router.serverSsr?.cleanup()
          }
        }
      },
    )
  })
}

function getTargetHref(outcome: ServerFunctionOutcome) {
  const redirectHref = getTanStackRedirectHref(outcome.value)
  const target = redirectHref
    ? new URL(
        redirectHref,
        outcome.request.headers.get('referer') ?? outcome.request.url,
      )
    : outcome.targetUrl
      ? new URL(outcome.targetUrl)
      : undefined

  if (!target || target.origin !== new URL(outcome.request.url).origin) {
    return undefined
  }
  return target.href
}

function getTanStackRedirectHref(value: unknown) {
  if (!isObject(value) || !isObject(value.error)) {
    return undefined
  }
  const error = value.error
  if (error.isSerializedRedirect !== true) {
    return undefined
  }
  if (typeof error.href === 'string') {
    return error.href
  }
  if (isObject(error.headers) && typeof error.headers.location === 'string') {
    return error.headers.location
  }
  return typeof error.to === 'string' ? error.to : undefined
}

function isObject(value: unknown): value is Record<string, any> {
  return !!value && typeof value === 'object'
}