'use client';

import { useCallback, useEffect, useId, useRef, useState } from 'react';
import { motion, useReducedMotion } from 'motion/react';
import { FloatingLabelInput } from '@/components/interior/floating-label';

const CROSSFADE = { type: 'spring', stiffness: 260, damping: 34, mass: 0.8 } as const;
const INSTANT = { duration: 0 } as const;

const LINE = 16;

export type ValidationStatus = 'idle' | 'pending' | 'valid' | 'invalid';

export type Validator = (value: string) => string | null;

export type UseInlineValidationOptions = {
    value: string;
    validate: Validator;
    debounce?: number;
    validationKey?: unknown;
};

export type UseInlineValidationReturn = {
    status: ValidationStatus;
    error: string | null;
    message: string;
    touched: boolean;
    commit: () => void;
    reset: () => void;
    fieldProps: {
        onBlur: () => void;
        'aria-invalid': boolean;
    };
};

type Settled = {
    status: ValidationStatus;
    error: string | null;
    message: string;
};

const CLEAN: Settled = { status: 'idle', error: null, message: '' };

export function useInlineValidation({
    value,
    validate,
    debounce = 400,
    validationKey,
}: UseInlineValidationOptions): UseInlineValidationReturn {
    const [touched, setTouched] = useState(false);
    const [settled, setSettled] = useState<Settled>(CLEAN);

    const check = useRef(validate);
    const latest = useRef(value);

    useEffect(() => {
        check.current = validate;
        latest.current = value;
    });

    useEffect(() => {
        if (!touched) {
            return;
        }

        const next = check.current(value);
        const resolved: ValidationStatus = value.length > 0 ? 'valid' : 'idle';

        if (next === null) {
            setSettled((prev) =>
                prev.status === resolved && prev.error === null
                    ? prev
                    : { status: resolved, error: null, message: prev.message },
            );
            return;
        }

        setSettled((prev) =>
            prev.status === 'invalid'
                ? prev
                : { status: 'pending', error: null, message: prev.message },
        );

        const t = setTimeout(() => {
            setSettled((prev) =>
                prev.error === next ? prev : { status: 'invalid', error: next, message: next },
            );
        }, debounce);

        return () => clearTimeout(t);
    }, [value, touched, debounce, validationKey]);

    const commit = useCallback(() => {
        setTouched(true);
        const v = latest.current;
        const next = check.current(v);
        setSettled((prev) =>
            next === null
                ? { status: v.length > 0 ? 'valid' : 'idle', error: null, message: prev.message }
                : { status: 'invalid', error: next, message: next },
        );
    }, []);

    const reset = useCallback(() => {
        setTouched(false);
        setSettled(CLEAN);
    }, []);

    return {
        status: settled.status,
        error: settled.error,
        message: settled.message,
        touched,
        commit,
        reset,
        fieldProps: { onBlur: commit, 'aria-invalid': settled.status === 'invalid' },
    };
}

export type InlineValidationProps = {
    label: string;
    value: string;
    onChange: (value: string) => void;
    validate: Validator;
    hint?: string;
    id?: string;
    name?: string;
    type?: 'text' | 'email' | 'password' | 'tel' | 'url' | 'search';
    autoComplete?: string;
    inputMode?: React.ComponentProps<'input'>['inputMode'];
    debounce?: number;
    validationKey?: unknown;
    reserveLines?: number;
    disabled?: boolean;
    required?: boolean;
    spellCheck?: boolean;
    endAdornment?: React.ReactNode;
    showValidIcon?: boolean;
    onFocus?: () => void;
    onBlur?: () => void;
    className?: string;
};

export function InlineValidation({
    label,
    value,
    onChange,
    validate,
    hint,
    id,
    name,
    type = 'text',
    autoComplete,
    inputMode,
    debounce = 400,
    validationKey,
    reserveLines = 1,
    disabled = false,
    required = false,
    spellCheck,
    endAdornment,
    showValidIcon = true,
    onFocus,
    onBlur,
    className = '',
}: InlineValidationProps) {
    const reduced = useReducedMotion();
    const fade = reduced ? INSTANT : CROSSFADE;

    const auto = useId();
    const fieldId = id ?? `${auto}-field`;
    const hintId = `${auto}-hint`;
    const errorId = `${auto}-error`;

    const { status, error, message, fieldProps } = useInlineValidation({
        value,
        validate,
        debounce,
        validationKey,
    });

    const invalid = status === 'invalid';
    const valid = status === 'valid';

    const described = [hint ? hintId : null, invalid ? errorId : null].filter(Boolean).join(' ');

    const clamp = {
        display: '-webkit-box' as const,
        WebkitBoxOrient: 'vertical' as const,
        WebkitLineClamp: reserveLines,
        overflow: 'hidden' as const,
    };

    const statusGlyph = (
        <span className="pointer-events-none grid size-3.5 shrink-0 place-items-center" aria-hidden>
            <motion.svg
                viewBox="0 0 12 12"
                width="14"
                height="14"
                fill="none"
                className="col-start-1 row-start-1 text-success"
                initial={false}
                animate={{
                    opacity: showValidIcon && valid ? 1 : 0,
                    scale: showValidIcon && valid ? 1 : 0.7,
                }}
                transition={fade}
            >
                <path
                    d="M2 6.3 4.7 9 10 3.2"
                    stroke="currentColor"
                    strokeWidth="1.6"
                    strokeLinecap="round"
                    strokeLinejoin="round"
                />
            </motion.svg>
            <motion.svg
                viewBox="0 0 12 12"
                width="14"
                height="14"
                fill="none"
                className="col-start-1 row-start-1 text-destructive"
                initial={false}
                animate={{ opacity: invalid ? 1 : 0, scale: invalid ? 1 : 0.7 }}
                transition={fade}
            >
                <path d="M6 2v4.4" stroke="currentColor" strokeWidth="1.7" strokeLinecap="round" />
                <rect x="5.15" y="8.4" width="1.7" height="1.7" rx="0.5" fill="currentColor" />
            </motion.svg>
        </span>
    );

    return (
        <div className={`w-full ${className}`}>
            <FloatingLabelInput
                id={fieldId}
                label={label}
                name={name}
                type={type}
                value={value}
                autoComplete={autoComplete}
                inputMode={inputMode}
                disabled={disabled}
                required={required}
                spellCheck={spellCheck}
                invalid={invalid}
                ariaDescribedBy={described || undefined}
                reserveHintSpace={false}
                onFocus={onFocus}
                onBlur={() => {
                    fieldProps.onBlur();
                    onBlur?.();
                }}
                onChange={onChange}
                endAdornment={
                    <div className="flex items-center gap-1">
                        {statusGlyph}
                        {endAdornment}
                    </div>
                }
            />

            <div className="relative mt-1.5 grid" style={{ height: reserveLines * LINE }}>
                {hint ? (
                    <motion.p
                        aria-hidden
                        style={clamp}
                        className="col-start-1 row-start-1 text-[11.5px] leading-[16px] text-muted-foreground"
                        initial={false}
                        animate={{ opacity: invalid ? 0 : 1, y: invalid ? 3 : 0 }}
                        transition={fade}
                    >
                        {hint}
                    </motion.p>
                ) : null}

                <motion.p
                    aria-hidden
                    style={clamp}
                    className="col-start-1 row-start-1 text-[11.5px] leading-[16px] text-destructive"
                    initial={false}
                    animate={{ opacity: invalid ? 1 : 0, y: invalid ? 0 : -3 }}
                    transition={fade}
                >
                    {error ?? message}
                </motion.p>

                {hint ? (
                    <span id={hintId} className="sr-only">
                        {hint}
                    </span>
                ) : null}

                <span
                    id={errorId}
                    role="status"
                    aria-live="polite"
                    aria-atomic="true"
                    className="sr-only"
                >
                    {error ?? ''}
                </span>
            </div>
        </div>
    );
}