'use client'

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

import { texts } from '@/texts'
import type { PreviousAttendee } from '@/services/events'
import { addToast } from '@/lib/toast'
import ConsumerActionButtons from '@/components/consumer/ConsumerActionButtons'
import ConsumerWizardStepper from '@/components/events/create/consumer/ConsumerWizardStepper'
import Step1BasicInfo from '@/components/events/create/consumer/steps/Step1BasicInfo'
import Step2ScheduleLocation from '@/components/events/create/consumer/steps/Step2ScheduleLocation'
import Step3PricingCapacity from '@/components/events/create/consumer/steps/Step3PricingCapacity'
import Step4FaqPreview from '@/components/events/create/consumer/steps/Step4FaqPreview'
import Step5GuestList, { loadPreviousAttendeesForStep5 } from '@/components/events/create/consumer/steps/Step5GuestList'
import { mapEventToWizardCloneData } from '@/components/events/create/consumer/cloneFromEvent'
import { DetailSkeleton } from '@/components/feedback/LoadingState'
import {
  combineDateAndMinutes,
  hasRequiredPosters,
  INITIAL_WIZARD_DATA,
  type EventWizardFormData,
} from '@/components/events/create/consumer/types'
import { CONSUMER_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'
import AngleLeftIcon from '@/components/icons/AngleLeftIcon'
import CloseLinearIcon from '@/components/icons/CloseLinearIcon'

interface HostCityPrefill {
  cityId: string
  provinceId: string
  address?: string
  lat?: number
  lng?: number
}

interface ConsumerEventCreateWizardProps {
  finishRoute?: string
}

export default function ConsumerEventCreateWizard({ finishRoute = CONSUMER_ROUTES.MY_EVENTS }: ConsumerEventCreateWizardProps = {}) {
  const router = useRouter()
  const pathname = usePathname()
  const searchParams = useSearchParams()
  const cloneFromIdRef = useRef(searchParams.get('cloneFrom'))
  const hasTrackedStartRef = useRef(false)
  const stepSubmitRef = useRef<(() => void) | null>(null)
  const stepScrollRef = useRef<HTMLDivElement>(null)
  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 [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: 'consumer',
      is_clone: Boolean(cloneFromIdRef.current),
    })
  }, [userId])

  const categoriesQuery = usePublicCategoriesQuery()
  const categories = useMemo(() => categoriesQuery.data?.items ?? [], [categoriesQuery.data])
  const [cities, setCities] = useState<City[]>([])
  const [hostCityName, setHostCityName] = useState<string | undefined>()

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

    let cancelled = false
    const cloneFromId = cloneFromIdRef.current

    const resolveHostCity = async (): Promise<HostCityPrefill | null> => {
      const [meResult, cityRows] = await Promise.all([GET_ME(), fetchAllCities()])

      if (cancelled) return null

      setCities(cityRows)

      if (!meResult.ok || !meResult.data.cityId) return null

      const city = cityRows.find((row) => row.id === meResult.data.cityId)

      if (!city) return null

      setHostCityName(city.name || meResult.data.cityName || undefined)

      return {
        cityId: String(city.id),
        provinceId: String(city.provinceId),
        address: meResult.data.defaultAddress || undefined,
        lat: city.lat,
        lng: city.lng,
      }
    }

    const applyHostCity = (
      base: EventWizardFormData,
      hostCity: HostCityPrefill | null,
      options?: { preferHostAddress?: boolean; preferHostMapCenter?: boolean }
    ): EventWizardFormData => {
      if (!hostCity) return base

      return {
        ...base,
        cityId: hostCity.cityId,
        provinceId: hostCity.provinceId,
        ...(options?.preferHostAddress && hostCity.address ? { address: hostCity.address } : {}),
        ...(options?.preferHostMapCenter && hostCity.lat != null && hostCity.lng != null ? { lat: hostCity.lat, lng: hostCity.lng } : {}),
      }
    }

    const hydrate = async () => {
      let hostCity: HostCityPrefill | null = null

      try {
        hostCity = await resolveHostCity()
      } catch {
        // Prefill is best-effort; wizard still opens without city until save guard.
      }

      if (cancelled) return

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

          if (cancelled) return

          clearEventDraft(userId)
          setData(applyHostCity(mapEventToWizardCloneData(event, media, faqs), hostCity))
          setStep(1)
          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(applyHostCity({ ...INITIAL_WIZARD_DATA, ...stored.data }, hostCity))
        setStep(stored.step)
        setIsDraftHydrated(true)

        return
      }

      setData(
        applyHostCity(INITIAL_WIZARD_DATA, hostCity, {
          preferHostAddress: true,
          preferHostMapCenter: true,
        })
      )
      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])

  // کانتینر اسکرول والد است و با عوض شدن step unmount نمی‌شود؛ باید دستی به بالا برگردد
  useEffect(() => {
    const el = stepScrollRef.current

    if (!el) return
    el.scrollTop = 0
  }, [step])

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

  const bindStepSubmit = useCallback((submit: (() => void) | null) => {
    stepSubmitRef.current = submit
  }, [])

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

  const submitCurrentStep = useCallback(() => {
    stepSubmitRef.current?.()
  }, [])

  const handleSaveDraft = async () => {
    if (isSaving) return

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

      return
    }

    const cityId = Number(data.cityId)
    const provinceId = Number(data.provinceId)

    if (!Number.isFinite(cityId) || cityId < 1 || !Number.isFinite(provinceId) || provinceId < 1) {
      addToast({ title: texts.events.hostCityMissing, color: 'danger' })
      setStep(2)

      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,
        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,
        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 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(CONSUMER_ROUTES.EVENT_DETAIL(eventId))

        return
      }

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

  if (!userId || !isDraftHydrated) {
    return (
      <div className="min-h-0 flex-1 overflow-y-auto">
        <DetailSkeleton />
      </div>
    )
  }

  return (
    <div className="flex h-full min-h-0 flex-1 flex-col overflow-hidden">
      <div className="shrink-0">
        <ConsumerWizardStepper currentStep={step} />
      </div>

      <div
        ref={stepScrollRef}
        className="min-h-0 flex-1 overflow-y-auto overscroll-y-contain pt-4"
      >
        {step === 1 && (
          <Step1BasicInfo
            data={data}
            onBindSubmit={bindStepSubmit}
            onChange={patchData}
            onNext={(patch) => {
              patchData(patch)
              setStep(2)
            }}
          />
        )}

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

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

        {step === 4 && (
          <Step4FaqPreview
            categoryName={categoryName}
            cityName={cityName}
            data={data}
            onBindSubmit={bindStepSubmit}
            onChange={patchData}
            onSaveDraft={() => void handleSaveDraft()}
          />
        )}
      </div>

      <div className="shrink-0">
        <ConsumerActionButtons
          cancelIcon={step === 1 ? <CloseLinearIcon className="size-3" /> : <AngleLeftIcon className="size-4" />}
          cancelLabel={step === 1 ? texts.common.cancel : texts.events.return}
          className="w-full rounded-consumer-modal bg-white p-4"
          isPrimaryLoading={step === 4 && isSaving}
          primaryLabel={step === 4 ? texts.events.saveDraft : texts.events.saveAndContinue}
          primaryType="button"
          onCancel={() => {
            if (step === 1) {
              router.push(finishRoute)

              return
            }

            setStep((current) => current - 1)
          }}
          onPrimary={submitCurrentStep}
        />
      </div>

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