import { useEffect } from 'react'
import { zodResolver } from '@hookform/resolvers/zod'
import { CalendarCog, Loader2, Plus, RotateCcw, Save, Trash2, X } from 'lucide-react'
import {
  Controller,
  useFieldArray,
  useForm,
  useWatch,
  type Control,
  type FieldErrors,
  type UseFormRegister,
  type UseFormSetValue,
} from 'react-hook-form'
import { Link, useBlocker } from 'react-router'
import { toast } from 'sonner'
import { FormField } from '@/components/form-field'
import { paths } from '@/components/layout/nav-items'
import { MoneyInput } from '@/components/money-input'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { previewWeeks } from '@/lib/budget-preview'
import { formatDayMonth, formatMoney, formatNumber, parseMoney } from '@/lib/format'
import { group, GROUPS } from '@/lib/groups'
import { useSavePlan } from '@/lib/periods'
import { diffPlan, GROUP_CODES, hasChanges, moneyToText, toDraft } from '@/lib/plan-draft'
import { t } from '@/lib/strings'
import { cn } from '@/lib/utils'
import type { GroupBudget } from '@/types/GroupBudget'
import type { Period } from '@/types/Period'
import type { PeriodSummary } from '@/types/PeriodSummary'
import type { PlanItem } from '@/types/PlanItem'
import type { PlanItemKind } from '@/types/PlanItemKind'
import { DistributionBar } from './distribution-bar'
import { PeriodHeading, Section } from './plan-read'
import { planSchema, type PlanForm } from './schema'
import { SuggestionPicker } from './suggestion-picker'
import { SummaryTiles } from './summary-tiles'

const s = t.plan
const itemText = t.wizard.items

/** Metin → kuruş (geçersiz / boş / eksi → 0): önizleme hesapları için */
const k = (text: string | undefined) => Math.max(parseMoney(text ?? '') ?? 0, 0)

/**
 * Düzenleme modu. Hiçbir şey anında kaydedilmez: "Kaydet" yalnızca değişenleri gönderir,
 * "Vazgeç" taslağı atar. Kaydedilmemiş değişiklik varken sayfadan çıkılırsa onay istenir.
 */
export function PlanEdit({
  period,
  items,
  budget,
  summary,
  onClose,
}: {
  period: Period
  items: PlanItem[]
  budget: GroupBudget[]
  summary: PeriodSummary
  onClose: () => void
}) {
  const save = useSavePlan(period)
  const {
    control,
    register,
    handleSubmit,
    setValue,
    formState: { errors, isDirty, isSubmitting },
  } = useForm<PlanForm>({
    resolver: zodResolver(planSchema(period.start_date, period.last_date)),
    mode: 'onTouched',
    defaultValues: toDraft(period, items, budget),
  })
  const v = useWatch({ control })

  // ---- Canlı önizleme: kaydedilmiş özet + taslaktaki farklar (formül backend'de kalır)
  const incomeTotal = (v.incomes ?? []).reduce((a, r) => a + k(r?.amount), 0)
  const fixedTotal = (v.expenses ?? []).reduce((a, r) => a + k(r?.amount), 0)
  const savings = k(v.savings)
  const spendable =
    summary.spendable +
    (incomeTotal - summary.income_total) -
    (fixedTotal - summary.fixed_expense_total) -
    (savings - summary.savings_goal)
  const budgetTotal = GROUP_CODES.reduce((a, g) => a + k(v.budget?.[g]), 0)
  const preview: PeriodSummary = {
    ...summary,
    income_total: incomeTotal,
    fixed_expense_total: fixedTotal,
    savings_goal: savings,
    spendable,
    budget_total: budgetTotal,
    unallocated: spendable - budgetTotal,
  }

  // ---- Kaydedilmemiş değişiklik koruması
  const blocker = useBlocker(
    ({ currentLocation, nextLocation }) =>
      isDirty && !isSubmitting && currentLocation.pathname !== nextLocation.pathname,
  )
  useEffect(() => {
    if (blocker.state !== 'blocked') return
    if (window.confirm(s.leaveConfirm)) blocker.proceed()
    else blocker.reset()
  }, [blocker])
  useEffect(() => {
    if (!isDirty) return
    const warn = (e: BeforeUnloadEvent) => e.preventDefault()
    window.addEventListener('beforeunload', warn)
    return () => window.removeEventListener('beforeunload', warn)
  }, [isDirty])

  const onSubmit = handleSubmit(async (draft) => {
    const ops = diffPlan(period, items, budget, draft)
    if (!hasChanges(ops)) {
      toast(s.noChanges)
      return onClose()
    }
    try {
      await save.mutateAsync(ops)
      toast.success(s.saved)
    } catch (e) {
      toast.error(s.saveFailed(e instanceof Error ? e.message : String(e)))
    }
    onClose()
  })

  const actions = (
    <>
      <Button type="button" variant="outline" onClick={onClose} disabled={isSubmitting}>
        <X aria-hidden />
        {s.cancel}
      </Button>
      <Button type="submit" disabled={isSubmitting}>
        {isSubmitting ? <Loader2 className="animate-spin" aria-hidden /> : <Save aria-hidden />}
        {isSubmitting ? s.saving : s.save}
      </Button>
    </>
  )

  return (
    <form onSubmit={onSubmit} noValidate className="space-y-6">
      <div className="rounded-xl border border-primary/40 bg-primary/5 px-4 py-3 text-sm">
        <span className="font-medium">✏️ {s.editing}</span>
        <span className="text-muted-foreground"> · {s.editingHint}</span>
      </div>

      <PeriodHeading period={period} actions={actions} />
      <SummaryTiles summary={preview} />

      <div className="grid gap-4">
        <ItemsEdit
          kind="income"
          period={period}
          control={control}
          register={register}
          errors={errors}
        />
        <ItemsEdit
          kind="expense"
          period={period}
          control={control}
          register={register}
          errors={errors}
        />
      </div>

      <Section
        title={s.savings}
        action={
          <Button asChild variant="ghost" size="sm">
            <Link to={`${paths.periodWizard}?adim=1`}>
              <CalendarCog aria-hidden />
              {s.changeDates}
            </Link>
          </Button>
        }
      >
        <FormField label={s.savings} error={errors.savings} className="max-w-xs">
          {(f) => (
            <Controller
              control={control}
              name="savings"
              render={({ field }) => <MoneyInput {...f} {...field} placeholder="0,00" />}
            />
          )}
        </FormField>
      </Section>

      <BudgetEdit
        period={period}
        control={control}
        setValue={setValue}
        errors={errors}
        values={v}
        spendable={spendable}
        budgetTotal={budgetTotal}
      />

      <div className="flex justify-end gap-2 border-t pt-5">{actions}</div>
    </form>
  )
}

// ---------- Gelir / gider satırları ----------

function ItemsEdit({
  kind,
  period,
  control,
  register,
  errors,
}: {
  kind: PlanItemKind
  period: Period
  control: Control<PlanForm>
  register: UseFormRegister<PlanForm>
  errors: FieldErrors<PlanForm>
}) {
  const name = kind === 'income' ? 'incomes' : 'expenses'
  // keyName: kalemlerin kendi `id` alanı var, RHF'nin iç anahtarı onu ezmesin
  const { fields, append, remove } = useFieldArray({ control, name, keyName: 'key' })
  const rows = useWatch({ control, name })
  const total = (rows ?? []).reduce((a, r) => a + k(r?.amount), 0)
  const text = itemText[kind]

  return (
    <Section title={text.title}>
      {fields.length === 0 && <p className="mb-3 text-sm text-muted-foreground">{text.empty}</p>}
      <ul className="space-y-3">
        {fields.map((field, i) => {
          const e = errors[name]?.[i]
          const messages = [e?.name?.message, e?.amount?.message, e?.date?.message].filter(Boolean)
          const label = rows?.[i]?.name || text.placeholder
          return (
            <li
              key={field.key}
              className="grid grid-cols-2 gap-2 sm:grid-cols-[minmax(0,1fr)_10rem_10.5rem_auto]"
            >
              {/* Mobilde ad + sil aynı satırda; geniş ekranda `contents` → ızgaraya katılır */}
              <div className="col-span-2 flex gap-2 sm:contents">
                <Input
                  className="flex-1"
                  placeholder={text.placeholder}
                  aria-label={itemText.name}
                  aria-invalid={!!e?.name}
                  maxLength={60}
                  {...register(`${name}.${i}.name`)}
                />
                <Button
                  type="button"
                  variant="ghost"
                  size="icon"
                  className="sm:order-last"
                  aria-label={itemText.remove(label)}
                  onClick={() => remove(i)}
                >
                  <Trash2 className="text-muted-foreground" aria-hidden />
                </Button>
              </div>
              <Controller
                control={control}
                name={`${name}.${i}.amount`}
                render={({ field: f }) => (
                  <MoneyInput
                    {...f}
                    aria-label={itemText.amount}
                    aria-invalid={!!e?.amount}
                    placeholder="0,00"
                  />
                )}
              />
              <Input
                type="date"
                min={period.start_date}
                max={period.last_date}
                aria-label={itemText.date}
                aria-invalid={!!e?.date}
                {...register(`${name}.${i}.date`)}
              />
              {messages.length > 0 && (
                <p className="col-span-2 text-sm text-expense sm:order-last sm:col-span-4">
                  {messages.join(' · ')}
                </p>
              )}
            </li>
          )
        })}
      </ul>
      <Button
        type="button"
        variant="secondary"
        className="mt-3"
        onClick={() => append({ name: '', amount: '', date: '' }, { shouldFocus: true })}
      >
        <Plus aria-hidden />
        {s.add[kind]}
      </Button>
      <div className="mt-3 flex justify-between border-t pt-3 font-medium">
        <span>{text.total}</span>
        <span className={cn('money', kind === 'income' ? 'text-income' : 'text-expense')}>
          {formatMoney(total)}
        </span>
      </div>
    </Section>
  )
}

// ---------- Bütçe: aylık + haftalık ----------

function BudgetEdit({
  period,
  control,
  setValue,
  errors,
  values,
  spendable,
  budgetTotal,
}: {
  period: Period
  control: Control<PlanForm>
  setValue: UseFormSetValue<PlanForm>
  errors: FieldErrors<PlanForm>
  values: ReturnType<typeof useWatch<PlanForm>>
  spendable: number
  budgetTotal: number
}) {
  return (
    <Section title={s.budget}>
      <div className="space-y-4">
        <SuggestionPicker
          periodId={period.id}
          hint={s.suggestionHint}
          onApply={(a) =>
            GROUP_CODES.forEach((g) =>
              setValue(`budget.${g}`, moneyToText(a[g]), {
                shouldDirty: true,
                shouldValidate: true,
              }),
            )
          }
        />
        <DistributionBar distributed={budgetTotal} spendable={spendable} />

        <div className="grid items-start gap-4 md:grid-cols-2">
          {GROUPS.map((g) => {
            const weekTexts = values.weeks?.[g.code] ?? []
            const pv = previewWeeks(
              k(values.budget?.[g.code]),
              period.weeks.map((w, i) => {
                const txt = weekTexts[i] ?? ''
                return { days: w.days, manual: txt.trim() === '' ? null : k(txt) }
              }),
            )
            return (
              <div key={g.code} className="overflow-hidden rounded-xl border">
                <div className={cn('space-y-2 px-4 py-3', g.className.soft)}>
                  <FormField label={`${g.emoji} ${g.label}`} error={errors.budget?.[g.code]}>
                    {(f) => (
                      <Controller
                        control={control}
                        name={`budget.${g.code}`}
                        render={({ field }) => (
                          <MoneyInput
                            {...f}
                            {...field}
                            placeholder="0,00"
                            className="bg-background"
                          />
                        )}
                      />
                    )}
                  </FormField>
                </div>
                <details open={pv.weeks.some((w) => w.isManual)} className="group/weeks">
                  <summary className="cursor-pointer px-4 py-3 text-sm font-medium select-none">
                    {s.weekly}
                  </summary>
                  <p className="px-4 pb-2 text-xs text-muted-foreground">{s.weekHint}</p>
                  <ul className="divide-y text-sm">
                    {period.weeks.map((w, i) => (
                      <WeekRow
                        key={w.start_date}
                        control={control}
                        setValue={setValue}
                        groupCode={g.code}
                        index={i}
                        label={s.week(w.index)}
                        range={`${formatDayMonth(w.start_date)}–${formatDayMonth(w.last_date)}`}
                        days={w.days}
                        auto={pv.weeks[i]?.amount ?? 0}
                        manual={pv.weeks[i]?.isManual ?? false}
                        error={errors.weeks?.[g.code]?.[i]?.message}
                      />
                    ))}
                  </ul>
                </details>
                {pv.weeklyOver && (
                  <p role="status" className="border-t px-4 py-2 text-sm text-warning">
                    {s.weeklyOver}
                  </p>
                )}
              </div>
            )
          })}
        </div>
      </div>
    </Section>
  )
}

function WeekRow({
  control,
  setValue,
  groupCode,
  index,
  label,
  range,
  days,
  auto,
  manual,
  error,
}: {
  control: Control<PlanForm>
  setValue: UseFormSetValue<PlanForm>
  groupCode: (typeof GROUP_CODES)[number]
  index: number
  label: string
  range: string
  days: number
  auto: number
  manual: boolean
  error?: string
}) {
  const fieldName = `weeks.${groupCode}.${index}` as const
  return (
    <li className="flex flex-wrap items-center gap-2 px-4 py-2">
      <span className="min-w-0 flex-1">
        <span className="block">{label}</span>
        <span className="text-xs text-muted-foreground">
          {range} · {s.weekDays(days)}
          {manual && ` · ${s.manual}`}
        </span>
      </span>
      <div className="w-36">
        <Controller
          control={control}
          name={fieldName}
          render={({ field }) => (
            <MoneyInput
              {...field}
              aria-label={`${group(groupCode).label} · ${label} (${range})`}
              aria-invalid={!!error}
              // Boşsa otomatik tutar silik görünür; yazınca elle girilmiş olur
              placeholder={formatNumber(auto / 100)}
            />
          )}
        />
      </div>
      {manual ? (
        <Button
          type="button"
          variant="ghost"
          size="icon"
          aria-label={s.resetWeek(index + 1)}
          onClick={() => setValue(fieldName, '', { shouldDirty: true, shouldValidate: true })}
        >
          <RotateCcw className="text-muted-foreground" aria-hidden />
        </Button>
      ) : (
        <span className="size-11" aria-hidden />
      )}
      {error && <p className="w-full text-sm text-expense">{error}</p>}
    </li>
  )
}