import { useState } from "react"
import { useTranslation } from "react-i18next"
import { useNavigate } from "react-router-dom"
import { useQueryClient } from "@tanstack/react-query"
import { toast } from "sonner"
import { useAuth } from "@/hooks/useAuth"
import { useWizardState } from "@/hooks/useWizardState"
import { useCategories } from "@/hooks/useCategories"
import { useTemplate } from "@/hooks/useTemplate"
import { supabase } from "@/lib/supabase"
import { PRESETS } from "@/data/presets"
import type { Profile } from "@/lib/types"
import { WizardStepper } from "@/components/setup/WizardStepper"
import { IncomeStep } from "@/components/setup/IncomeStep"
import { RecurringItemsStep } from "@/components/setup/RecurringItemsStep"
import { ReviewStep } from "@/components/setup/ReviewStep"
import { Button } from "@/components/ui/button"
import {
  Card,
  CardContent,
  CardHeader,
  CardTitle,
} from "@/components/ui/card"
import { Skeleton } from "@/components/ui/skeleton"
import { useEffect } from "react"

export default function SetupPage() {
  const { t } = useTranslation()
  const { user, loading: authLoading } = useAuth()
  const navigate = useNavigate()
  const queryClient = useQueryClient()
  const [profile, setProfile] = useState<Profile | null>(null)
  const [profileLoading, setProfileLoading] = useState(true)
  const [completing, setCompleting] = useState(false)

  const { categories, create } = useCategories()
  const { createItem } = useTemplate()

  useEffect(() => {
    if (!user) return
    supabase
      .from("profiles")
      .select("*")
      .eq("id", user.id)
      .single()
      .then(({ data }) => {
        if (data) setProfile(data)
        setProfileLoading(false)
      })
  }, [user])

  const userId = user?.id ?? ""
  const currency = profile?.currency ?? "EUR"
  const { state, setStep, setIncome, toggleItem, setItemAmount, clearState } =
    useWizardState(userId)

  const [incomeError, setIncomeError] = useState<string | null>(null)

  const loading = authLoading || profileLoading

  if (loading) {
    return (
      <div className="flex min-h-screen items-center justify-center bg-background p-4">
        <div className="w-full max-w-2xl">
          <Skeleton className="h-12 w-64 mx-auto mb-6" />
          <Skeleton className="h-64 w-full" />
        </div>
      </div>
    )
  }

  const stepTitles: Record<1 | 2 | 3, string> = {
    1: t("setup.step1.title"),
    2: t("setup.step2.title"),
    3: t("setup.step3.title"),
  }

  const stepDescriptions: Record<1 | 2 | 3, string> = {
    1: t("setup.step1.description"),
    2: t("setup.step2.description"),
    3: t("setup.step3.description"),
  }

  function handleNext() {
    if (state.currentStep === 1) {
      if (!state.income || state.income <= 0) {
        setIncomeError(t("setup.step1.validation"))
        return
      }
      setIncomeError(null)
      setStep(2)
    } else if (state.currentStep === 2) {
      setStep(3)
    }
  }

  function handleBack() {
    if (state.currentStep === 2) setStep(1)
    else if (state.currentStep === 3) setStep(2)
  }

  function handleSkipStep() {
    if (state.currentStep === 1) setStep(2)
    else if (state.currentStep === 2) setStep(3)
    else if (state.currentStep === 3) handleSkipSetup()
  }

  function handleStepClick(step: 1 | 2 | 3) {
    if (step <= state.currentStep) {
      setStep(step)
    }
  }

  async function handleComplete() {
    setCompleting(true)
    try {
      const checkedItems = PRESETS.filter(
        (p) => state.selectedItems[p.slug]?.checked
      )

      // 1. Determine unique category types needed
      const typesNeeded = [...new Set(checkedItems.map((i) => i.type))]

      // 2. Create one category per type
      const categoryMap: Record<string, string> = {}
      for (const type of typesNeeded) {
        try {
          const cat = await create.mutateAsync({
            name: t(`categories.types.${type}`),
            type,
          })
          categoryMap[type] = cat.id
        } catch (e: any) {
          // Unique constraint violation (23505) = category already exists, fetch it
          if (e?.code === "23505" || e?.message?.includes("duplicate")) {
            const existing = categories.find((c) => c.type === type)
            if (existing) categoryMap[type] = existing.id
          } else {
            throw e
          }
        }
      }

      // 3. If categories were fetched from cache but not found, refetch
      if (Object.keys(categoryMap).length < typesNeeded.length) {
        await queryClient.invalidateQueries({ queryKey: ["categories"] })
      }

      // 4. Create template items for each checked preset
      let partialFailure = false
      for (const item of checkedItems) {
        try {
          await createItem.mutateAsync({
            category_id: categoryMap[item.type],
            item_tier: item.item_tier,
            budgeted_amount: state.selectedItems[item.slug].amount,
          })
        } catch {
          partialFailure = true
        }
      }

      // 5. Mark setup complete
      await supabase
        .from("profiles")
        .update({ setup_completed: true })
        .eq("id", user!.id)

      // 6. Clear wizard state
      clearState()

      // 7. Invalidate queries to prevent redirect loop
      await queryClient.invalidateQueries({ queryKey: ["categories"] })
      await queryClient.invalidateQueries({ queryKey: ["template-items"] })

      // 8. Toast and redirect
      if (partialFailure) {
        toast.error(t("setup.toast.partialError"))
      } else {
        toast.success(t("setup.toast.success"))
      }
      navigate("/", { replace: true })
    } catch {
      toast.error(t("setup.toast.error"))
    } finally {
      setCompleting(false)
    }
  }

  async function handleSkipSetup() {
    clearState()
    await supabase
      .from("profiles")
      .update({ setup_completed: true })
      .eq("id", user!.id)
    navigate("/", { replace: true })
  }

  return (
    <div className="flex min-h-screen items-center justify-center bg-background p-4">
      <div className="w-full max-w-2xl">
        <WizardStepper
          currentStep={state.currentStep}
          onStepClick={handleStepClick}
        />

        <Card className="w-full border border-border shadow-sm">
          <CardHeader className="pb-2">
            <CardTitle className="text-xl font-semibold">
              {stepTitles[state.currentStep]}
            </CardTitle>
            <p className="text-sm text-muted-foreground">
              {stepDescriptions[state.currentStep]}
            </p>
          </CardHeader>
          <CardContent className="space-y-6">
            {state.currentStep === 1 && (
              <IncomeStep
                income={state.income}
                onIncomeChange={setIncome}
                currency={currency}
                error={incomeError}
              />
            )}

            {state.currentStep === 2 && (
              <RecurringItemsStep
                selectedItems={state.selectedItems}
                income={state.income}
                currency={currency}
                onToggle={toggleItem}
                onAmountChange={setItemAmount}
              />
            )}

            {state.currentStep === 3 && (
              <ReviewStep
                income={state.income}
                selectedItems={state.selectedItems}
                currency={currency}
              />
            )}

            {/* Bottom navigation */}
            <div className="flex justify-between items-center pt-4 border-t border-border">
              <div className="flex gap-2">
                {state.currentStep > 1 && (
                  <Button
                    variant="ghost"
                    onClick={handleBack}
                    disabled={completing}
                  >
                    {t("setup.back")}
                  </Button>
                )}
                <Button
                  variant="ghost"
                  className="text-muted-foreground"
                  onClick={handleSkipStep}
                  disabled={completing}
                >
                  {t("setup.skip")}
                </Button>
              </div>
              <div>
                {state.currentStep < 3 && (
                  <Button onClick={handleNext}>{t("setup.next")}</Button>
                )}
                {state.currentStep === 3 && (
                  <Button onClick={handleComplete} disabled={completing}>
                    {t("setup.complete")}
                  </Button>
                )}
              </div>
            </div>
          </CardContent>
        </Card>

        <button
          type="button"
          className="mt-4 text-sm text-muted-foreground underline block mx-auto"
          onClick={handleSkipSetup}
          disabled={completing}
        >
          {t("setup.skipSetup")}
        </button>
      </div>
    </div>
  )
}