'use client'

import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
import dynamic from 'next/dynamic'
import { usePathname, useRouter, useSearchParams } from 'next/navigation'

import { texts } from '@/texts'
import type { PreviousAttendee } from '@/services/events'
import { addToast } from '@/lib/toast'
import WizardStepper from '@/components/events/create/WizardStepper'
import Button from '@/components/formElements/Button'
import { mapEventToWizardCloneData } from '@/components/events/create/cloneFromEvent'
import { DetailSkeleton } from '@/components/feedback/LoadingState'
import {
  combineDateAndMinutes,
  hasRequiredPosters,
  INITIAL_WIZARD_DATA,
  WIZARD_STEPS,
  type EventWizardFormData,
} from '@/components/events/create/types'
import { APP_ROUTES } from '@/constants/routes'
import { createEvent, createEventFaq, fetchEventForEdit } from '@/services/events'
import { fetchEventFaqs, fetchEventMedia } from '@/services/eventDetail'
import { fetchAllCities, type City } from '@/services/geography'
import { extractServerErrorDetail } from '@/services/errorHandler'
import { GET_ME } from '@/services/users'
import useAuth from '@/hooks/useAuth'
import { clearEventDraft, loadEventDraft, saveEventDraft } from '@/features/events/eventDraftStore'
import { usePublicCategoriesQuery } from '@/queries/consumer/usePublicCategoriesQuery'
import { ANALYTICS_EVENTS, trackAnalyticsEvent } from '@/lib/analytics'

const Step1BasicInfo = dynamic(() => import('@/components/events/create/steps/Step1BasicInfo'), {
  ssr: false,
  loading: () => <DetailSkeleton />,
})
const Step2ScheduleLocation = dynamic(() => import('@/components/events/create/steps/Step2ScheduleLocation'), {
  ssr: false,
  loading: () => <DetailSkeleton />,
})
const Step3PricingCapacity = dynamic(() => import('@/components/events/create/steps/Step3PricingCapacity'), {
  ssr: false,
  loading: () => <DetailSkeleton />,
})
const Step4FaqPreview = dynamic(() => import('@/components/events/create/steps/Step4FaqPreview'), {
  ssr: false,
  loading: () => <DetailSkeleton />,
})
const Step5GuestList = dynamic(() => import('@/components/events/create/steps/Step5GuestList'), {
  ssr: false,
})

interface EventCreateWizardProps {
  finishRoute?: string
}

export default function EventCreateWizard({ finishRoute = APP_ROUTES.MANAGE_EVENTS }: EventCreateWizardProps = {}) {
  const router = useRouter()
  const pathname = usePathname()
  const searchParams = useSearchParams()
  const cloneFromIdRef = useRef(searchParams.get('cloneFrom'))
  const hasTrackedStartRef = useRef(false)
  const { user } = useAuth()
  const userId = user?.userId
  const [step, setStep] = useState(1)
  const [data, setData] = useState<EventWizardFormData>(INITIAL_WIZARD_DATA)
  const [isDraftHydrated, setIsDraftHydrated] = useState(false)
  const [wasDraftRestored, setWasDraftRestored] = useState(false)
  const [wasCloneLoaded, setWasCloneLoaded] = useState(false)
  const [isSaving, setIsSaving] = useState(false)
  const [createdEventId, setCreatedEventId] = useState<string | null>(null)
  const [previousAttendees, setPreviousAttendees] = useState<PreviousAttendee[]>([])
  const [showPostCreateInvite, setShowPostCreateInvite] = useState(false)

  useEffect(() => {
    if (!userId || hasTrackedStartRef.current) return

    hasTrackedStartRef.current = true
    trackAnalyticsEvent(ANALYTICS_EVENTS.EVENT_CREATE_STARTED, {
      creation_source: 'admin',
      is_clone: Boolean(cloneFromIdRef.current),
    })
  }, [userId])

  // Shared hook — same key/staleTime as Step1BasicInfo + CategoryBrowse.
  const categoriesQuery = usePublicCategoriesQuery()
  const categories = useMemo(() => categoriesQuery.data?.items ?? [], [categoriesQuery.data])
  const [cities, setCities] = useState<City[]>([])

  useEffect(() => {
    if (!userId) return

    let cancelled = false
    const cloneFromId = cloneFromIdRef.current

    const hydrate = async () => {
      if (cloneFromId) {
        try {
          const [event, media, faqs] = await Promise.all([
            fetchEventForEdit(cloneFromId),
            fetchEventMedia(cloneFromId).catch(() => []),
            fetchEventFaqs(cloneFromId).catch(() => []),
          ])

          if (cancelled) return

          clearEventDraft(userId)
          setData(mapEventToWizardCloneData(event, media, faqs))
          setStep(1)
          setWasCloneLoaded(true)
          setWasDraftRestored(false)
          setIsDraftHydrated(true)
          router.replace(pathname)

          return
        } catch {
          if (cancelled) return
          addToast({ title: texts.events.wizardCloneLoadFailed, color: 'danger' })
        }
      }

      const stored = loadEventDraft<EventWizardFormData>(userId)

      if (stored) {
        setData({ ...INITIAL_WIZARD_DATA, ...stored.data })
        setStep(stored.step)
        setWasDraftRestored(true)
        setIsDraftHydrated(true)

        return
      }

      // Fresh create: prefill host default venue from profile contact info.
      try {
        const [meResult, cityRows] = await Promise.all([GET_ME(), fetchAllCities()])

        if (cancelled) return

        setCities(cityRows)

        if (meResult.ok) {
          const city = meResult.data.cityId ? cityRows.find((row) => row.id === meResult.data.cityId) : undefined

          setData({
            ...INITIAL_WIZARD_DATA,
            ...(meResult.data.defaultAddress ? { address: meResult.data.defaultAddress } : {}),
            ...(city ? { cityId: String(city.id), provinceId: String(city.provinceId) } : {}),
          })
        }
      } catch {
        // Prefill is best-effort; wizard still opens with empty location.
      }

      setIsDraftHydrated(true)
    }

    void hydrate()

    return () => {
      cancelled = true
    }
    // Hydrate once per userId. pathname/router are read from the render that starts hydration.
    // eslint-disable-next-line react-hooks/exhaustive-deps -- avoid re-cloning after URL cleanup
  }, [userId])

  useEffect(() => {
    if (!userId || !isDraftHydrated || createdEventId) return

    const timeout = window.setTimeout(() => {
      saveEventDraft(userId, data, step)
    }, 250)

    return () => {
      window.clearTimeout(timeout)
    }
  }, [createdEventId, data, isDraftHydrated, step, userId])

  useEffect(() => {
    // دریافت استان‌ها فعلاً غیرفعال است؛ نام شهر مستقیماً از فهرست شهرها خوانده می‌شود.
    // void fetchProvinces().then(setProvinces)
    void fetchAllCities().then(setCities)
  }, [])

  const patchData = useCallback((patch: Partial<EventWizardFormData>) => {
    setData((prev) => ({ ...prev, ...patch }))
  }, [])

  const categoryName = useMemo(() => categories.find((item) => String(item.id) === data.categoryId)?.name, [categories, data.categoryId])

  // نام استان فعلاً در پیش‌نمایش رویداد نمایش داده نمی‌شود.
  // const provinceName = useMemo(() => provinces.find((item) => String(item.id) === data.provinceId)?.name, [provinces, data.provinceId])

  const cityName = useMemo(() => cities.find((item) => String(item.id) === data.cityId)?.name, [cities, data.cityId])

  const currentStepTitle = WIZARD_STEPS.find((item) => item.key === step)?.label

  const handleSaveDraft = async () => {
    if (!hasRequiredPosters(data.media)) {
      addToast({
        title: texts.events.postersRequiredTitle,
        description: texts.events.postersRequiredDescription,
        color: 'danger',
      })
      setStep(1)

      return
    }

    setIsSaving(true)

    let eventId: string | null = null

    try {
      const startsAt = combineDateAndMinutes(data.startDate, data.startTime)
      const endsAt = combineDateAndMinutes(data.endDate, data.endTime)

      if (new Date(endsAt) <= new Date(startsAt)) {
        addToast({ title: texts.validation.eventWizard.endAfterStart, color: 'danger' })

        return
      }

      const event = await createEvent({
        title: data.title,
        slug: data.slug,
        categoryId: Number(data.categoryId),
        shortDescription: data.shortDescription || undefined,
        description: data.description || undefined,
        startsAt,
        endsAt,
        provinceId: Number(data.provinceId),
        cityId: Number(data.cityId),
        address: data.address,
        lat: data.lat,
        lng: data.lng,
        isFree: data.isFree,
        price: data.isFree ? 0 : data.price,
        capacity: data.capacity,
        reservedCapacity: data.reservedCapacity,
        genderRestriction: data.genderRestriction,
        ageRestriction: data.ageRestriction,
        cancellationFeePercent: data.cancellationFeePercent,
        cancellationFeePercent12To24Hours: data.cancellationFeePercent12To24Hours,
        cancellationFeePercentMoreThan24Hours: data.cancellationFeePercentMoreThan24Hours,
        settings: {
          isDiscoverable: data.isDiscoverable,
          autoCreateGroup: data.autoCreateGroup,
          waitlistAutoOffer: data.waitlistAutoOffer,
          sendReviewRequestSms: data.sendReviewRequestSms,
          addressVisibility: data.addressVisibility,
          generalArea: data.addressVisibility === 'attendees_only' ? data.generalArea : undefined,
        },
        media: data.media.map((item) => ({
          mediaType: 'image' as const,
          url: item.url,
          sortOrder: item.sortOrder,
          isPoster: item.isPoster,
          isSquarePoster: item.isSquarePoster,
        })),
      })

      eventId = event.id
      setCreatedEventId(event.id)
      if (userId) clearEventDraft(userId)

      for (let index = 0; index < data.faqs.length; index += 1) {
        const faq = data.faqs[index]

        await createEventFaq(event.id, {
          question: faq.question,
          answer: faq.answer,
          sortOrder: index,
        })
      }

      addToast({ title: texts.events.draftSaved, color: 'success' })

      const { loadPreviousAttendeesForStep5 } = await import('@/components/events/create/steps/Step5GuestList')
      const attendees = await loadPreviousAttendeesForStep5()

      if (attendees.length === 0) {
        router.push(finishRoute)

        return
      }

      setPreviousAttendees(attendees)
      setShowPostCreateInvite(true)
    } catch (error) {
      const detail = extractServerErrorDetail((error as { response?: { data?: unknown } })?.response?.data)

      if (eventId) {
        addToast({
          title: texts.events.createdPartialTitle,
          description: detail ?? texts.events.createdPartialDescription,
          color: 'warning',
        })
        router.push(APP_ROUTES.MANAGE_EVENT_DETAIL(eventId))

        return
      }

      addToast({
        title: texts.events.draftSaveFailed,
        description: detail ?? undefined,
        color: 'danger',
      })
    } finally {
      setIsSaving(false)
    }
  }

  if (!userId || !isDraftHydrated) return <DetailSkeleton />

  return (
    <div className="mx-auto flex w-full max-w-6xl flex-col gap-8">
      <div className="flex flex-col gap-2 rounded-xl border border-primary-100 bg-primary-50 px-3 py-2 text-xs text-primary sm:flex-row sm:items-center sm:justify-between">
        <span>
          {wasCloneLoaded
            ? texts.events.wizardCloneHint
            : wasDraftRestored
              ? texts.events.wizardDraftRestoredHint
              : texts.events.wizardAutosaveHint}
        </span>
        <Button
          className="text-xs text-secondary-20"
          size="sm"
          variant="light"
          onClick={() => {
            if (userId) clearEventDraft(userId)
            setData({ ...INITIAL_WIZARD_DATA, media: [], faqs: [] })
            setStep(1)
            setWasDraftRestored(false)
            setWasCloneLoaded(false)
            setCreatedEventId(null)
            setShowPostCreateInvite(false)
          }}
        >
          {texts.events.startOver}
        </Button>
      </div>

      <WizardStepper currentStep={step} />
      <div>
        {currentStepTitle ? <h2 className="mb-6 text-lg font-semibold text-text-dark">{currentStepTitle}</h2> : null}
        {step === 1 && (
          <Step1BasicInfo
            data={data}
            onChange={patchData}
            onNext={(patch) => {
              patchData(patch)
              setStep(2)
            }}
          />
        )}

        {step === 2 && (
          <Step2ScheduleLocation
            data={data}
            onBack={() => {
              setStep(1)
            }}
            onChange={patchData}
            onNext={(patch) => {
              patchData(patch)
              setStep(3)
            }}
          />
        )}

        {step === 3 && (
          <Step3PricingCapacity
            data={data}
            onBack={() => {
              setStep(2)
            }}
            onChange={patchData}
            onNext={(patch) => {
              patchData(patch)
              setStep(4)
            }}
          />
        )}

        {step === 4 && (
          <Step4FaqPreview
            categoryName={categoryName}
            cityName={cityName}
            data={data}
            isSaving={isSaving}
            /* استان فعلاً در پیش‌نمایش نمایش داده نمی‌شود. */
            /* provinceName={provinceName} */
            onBack={() => {
              setStep(3)
            }}
            onChange={patchData}
            onSaveDraft={() => void handleSaveDraft()}
          />
        )}
      </div>

      {createdEventId ? (
        <Step5GuestList
          attendees={previousAttendees}
          eventId={createdEventId}
          isOpen={showPostCreateInvite}
          onFinish={() => {
            router.push(finishRoute)
          }}
          onOpenChange={setShowPostCreateInvite}
        />
      ) : null}
    </div>
  )
}