'use client'

import { useState, useTransition } from 'react'

const FONT = 'var(--font-montserrat, Montserrat), sans-serif'

const INPUT_CLS =
  'w-full rounded-[12px] border-2 border-white/20 bg-white/10 px-4 py-3 text-[15px] text-white placeholder-white/40 focus:border-[#f28b4a] focus:outline-none'

interface FieldOption {
  label: string
  value: string
}

interface FormField {
  blockType: string
  id?: string
  name: string
  label?: string
  required?: boolean
  placeholder?: string
  defaultValue?: string
  options?: FieldOption[]
  message?: string
  width?: number
}

interface FormData {
  id: string
  title?: string
  fields?: FormField[]
  confirmationType?: 'message' | 'redirect'
  confirmationMessage?: unknown
  redirect?: { url: string }
  submitButtonLabel?: string
}

interface FormBlockProps {
  form: FormData
  submitLabel?: string
}

export function FormBlock({ form, submitLabel }: FormBlockProps) {
  const [values, setValues] = useState<Record<string, string>>({})
  const [success, setSuccess] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const [isPending, startTransition] = useTransition()

  function setValue(name: string, value: string) {
    setValues((prev) => ({ ...prev, [name]: value }))
  }

  function handleSubmit(e: React.FormEvent) {
    e.preventDefault()
    setError(null)
    startTransition(async () => {
      try {
        const submissionData = Object.entries(values).map(([field, value]) => ({ field, value }))
        const res = await fetch('/api/form-submissions', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ form: form.id, submissionData }),
        })
        if (!res.ok) {
          setError('Щось пішло не так. Спробуйте ще раз.')
          return
        }
        if (form.confirmationType === 'redirect' && form.redirect?.url) {
          window.location.href = form.redirect.url
          return
        }
        setSuccess(true)
      } catch {
        setError("Помилка мережі. Перевірте з'єднання та спробуйте ще раз.")
      }
    })
  }

  if (success) {
    return (
      <div className="flex flex-col items-center gap-4 py-10 text-center">
        <div className="text-[48px]">✅</div>
        <h3 className="text-[24px] font-bold text-white" style={{ fontFamily: FONT }}>
          Заявку отримано!
        </h3>
        <p className="text-[16px] text-white/70" style={{ fontFamily: FONT }}>
          Менеджер зв&apos;яжеться з вами найближчим часом.
        </p>
      </div>
    )
  }

  const fields = form.fields ?? []

  return (
    <form onSubmit={handleSubmit} className="flex flex-col gap-5">
      <div className="grid grid-cols-1 gap-5 md:grid-cols-2">
        {fields.map((field) => {
          if (field.blockType === 'message') {
            return (
              <div
                key={field.id ?? field.name}
                className="text-[14px] text-white/60 md:col-span-2"
                style={{ fontFamily: FONT }}
                dangerouslySetInnerHTML={{ __html: field.message ?? '' }}
              />
            )
          }

          const isFullWidth =
            field.blockType === 'textarea' || (field.width != null && field.width > 50)

          return (
            <div
              key={field.id ?? field.name}
              className={isFullWidth ? 'flex flex-col gap-2 md:col-span-2' : 'flex flex-col gap-2'}
            >
              {field.label && (
                <label
                  htmlFor={field.name}
                  className="text-[14px] font-medium text-white/80"
                  style={{ fontFamily: FONT }}
                >
                  {field.label}
                  {field.required && ' *'}
                </label>
              )}
              {renderInput(field, values[field.name] ?? '', setValue)}
            </div>
          )
        })}
      </div>

      {error && (
        <div className="rounded-xl border border-red-400 bg-red-900/30 px-4 py-3 text-[14px] text-red-300">
          {error}
        </div>
      )}

      <button
        type="submit"
        disabled={isPending}
        className="mt-2 inline-flex items-center justify-center rounded-[64px] bg-[#f28b4a] px-10 py-4 text-[16px] font-bold text-white transition-shadow hover:shadow-[0_0_20px_0_#f28b4a] disabled:opacity-60"
        style={{ fontFamily: FONT }}
      >
        {isPending
          ? 'Надсилаємо...'
          : (form.submitButtonLabel ?? submitLabel ?? 'Надіслати заявку')}
      </button>
    </form>
  )
}

function renderInput(
  field: FormField,
  value: string,
  setValue: (name: string, val: string) => void
) {
  const cls = INPUT_CLS
  const font = { fontFamily: FONT }
  const { name, required, placeholder } = field

  switch (field.blockType) {
    case 'textarea':
      return (
        <textarea
          id={name}
          rows={4}
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          placeholder={placeholder}
          className={cls + ' resize-none'}
          style={font}
        />
      )
    case 'select':
      return (
        <select
          id={name}
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          className={cls}
          style={font}
        >
          <option value="">Оберіть...</option>
          {field.options?.map((opt) => (
            <option key={opt.value} value={opt.value}>
              {opt.label}
            </option>
          ))}
        </select>
      )
    case 'email':
      return (
        <input
          id={name}
          type="email"
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          placeholder={placeholder ?? 'your@email.com'}
          className={cls}
          style={font}
        />
      )
    case 'number':
      return (
        <input
          id={name}
          type="number"
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          placeholder={placeholder}
          className={cls}
          style={font}
        />
      )
    case 'date':
      return (
        <input
          id={name}
          type="date"
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          className={cls}
          style={font}
        />
      )
    case 'checkbox':
      return (
        <input
          id={name}
          type="checkbox"
          required={required}
          checked={value === 'true'}
          onChange={(e) => setValue(name, String(e.target.checked))}
          className="h-5 w-5 rounded accent-[#f28b4a]"
        />
      )
    default:
      return (
        <input
          id={name}
          type="text"
          required={required}
          value={value}
          onChange={(e) => setValue(name, e.target.value)}
          placeholder={placeholder}
          className={cls}
          style={font}
        />
      )
  }
}