import { useState, useEffect, useRef } from 'react'
import { IconCheck, IconX, IconAlertCircle } from '@tabler/icons-react'

/**
 * ValidatedInput - input с real-time валидацией
 * @param {function} validate - функция валидации, возвращает { valid: boolean, message: string }
 * @param {number} debounce - задержка перед валидацией в ms
 */
function ValidatedInput({ 
  value, 
  onChange, 
  validate,
  debounce = 300,
  label,
  placeholder,
  hint,
  required = false,
  type = 'text',
  className = '',
  showValidIcon = true,
  validateOnChange = true,
  ...props
}) {
  const [validationState, setValidationState] = useState({ 
    valid: null, 
    message: '', 
    isValidating: false 
  })
  const [isTouched, setIsTouched] = useState(false)
  const timeoutRef = useRef(null)

  useEffect(() => {
    // Не валидируем, пока пользователь не начал вводить
    if (!isTouched || !validateOnChange) return
    if (!validate) {
      setValidationState({ valid: null, message: '', isValidating: false })
      return
    }

    // Очищаем предыдущий таймер
    if (timeoutRef.current) {
      clearTimeout(timeoutRef.current)
    }

    // Показываем индикатор валидации
    setValidationState(prev => ({ ...prev, isValidating: true }))

    // Запускаем валидацию с debounce
    timeoutRef.current = setTimeout(async () => {
      try {
        const result = validate(value)
        
        // Поддержка как синхронной, так и асинхронной валидации
        const validationResult = result instanceof Promise ? await result : result
        
        setValidationState({ 
          valid: validationResult.valid, 
          message: validationResult.message || '',
          isValidating: false
        })
      } catch (error) {
        setValidationState({ 
          valid: false, 
          message: 'Ошибка валидации',
          isValidating: false
        })
      }
    }, debounce)

    return () => {
      if (timeoutRef.current) {
        clearTimeout(timeoutRef.current)
      }
    }
  }, [value, validate, debounce, isTouched, validateOnChange])

  const handleChange = (e) => {
    if (!isTouched) setIsTouched(true)
    onChange(e)
  }

  const handleBlur = () => {
    setIsTouched(true)
    // Запускаем валидацию сразу при потере фокуса
    if (validate && !validateOnChange) {
      const result = validate(value)
      const validationResult = result instanceof Promise ? result.then(r => {
        setValidationState({ 
          valid: r.valid, 
          message: r.message || '',
          isValidating: false
        })
      }) : setValidationState({ 
        valid: result.valid, 
        message: result.message || '',
        isValidating: false
      })
    }
  }

  const getInputClass = () => {
    const classes = ['form-control']
    
    if (isTouched && validationState.valid === true) {
      classes.push('is-valid')
    } else if (isTouched && validationState.valid === false) {
      classes.push('is-invalid')
    }
    
    return classes.join(' ')
  }

  return (
    <div className={`mb-3 ${className}`}>
      {label && (
        <label className="form-label">
          {label}
          {required && <span className="text-danger ms-1">*</span>}
        </label>
      )}
      
      <div className="input-group">
        <input
          type={type}
          className={getInputClass()}
          value={value}
          onChange={handleChange}
          onBlur={handleBlur}
          placeholder={placeholder}
          aria-invalid={validationState.valid === false}
          aria-describedby={`${props.id}-feedback ${props.id}-hint`}
          {...props}
        />
        
        {/* Индикатор валидации */}
        {showValidIcon && isTouched && !validationState.isValidating && (
          <span className="input-group-text">
            {validationState.valid === true && (
              <IconCheck size={18} className="text-success" />
            )}
            {validationState.valid === false && (
              <IconX size={18} className="text-danger" />
            )}
          </span>
        )}
        
        {/* Индикатор процесса валидации */}
        {validationState.isValidating && (
          <span className="input-group-text">
            <span className="spinner-border spinner-border-sm" role="status"></span>
          </span>
        )}
      </div>
      
      {/* Подсказка */}
      {hint && !validationState.message && (
        <small id={`${props.id}-hint`} className="form-hint text-muted">
          {hint}
        </small>
      )}
      
      {/* Сообщение об ошибке */}
      {isTouched && validationState.message && (
        <div 
          id={`${props.id}-feedback`}
          className={`invalid-feedback d-block ${validationState.valid ? 'text-success' : 'text-danger'}`}
        >
          <IconAlertCircle size={14} className="me-1" />
          {validationState.message}
        </div>
      )}
    </div>
  )
}

export default ValidatedInput