import { Button, FormInputValidation, FormLabel } from '@automattic/components';
import styled from '@emotion/styled';
import { sprintf } from '@wordpress/i18n';
import { useI18n } from '@wordpress/react-i18n';
import i18n from 'i18n-calypso';
import { ChangeEvent, useReducer, useState } from 'react';
import FormFieldset from 'calypso/components/forms/form-fieldset';
import * as SSHKeyCard from 'calypso/components/ssh-key-card';
import TextareaAutosize from 'calypso/components/textarea-autosize';
import { SSH_KEY_FORMATS } from './use-ssh-key-query';

const PUBLIC_SSH_KEY_INPUT_ID = 'public_ssh_key';

const initialState = {
	touched: false,
	isValid: false,
	value: '',
};

const sshKeyValidation = new RegExp( `^(?:${ SSH_KEY_FORMATS.join( '|' ) })\\s.+` );

type ReducerAction = { type: 'setValue'; value: string };

const sshKeyFormReducer = ( state = initialState, action: ReducerAction ): typeof initialState => {
	switch ( action.type ) {
		case 'setValue':
			return {
				touched: true,
				isValid: sshKeyValidation.test( action.value ),
				value: action.value,
			};

		default:
			return state;
	}
};

const NewSSHFormFieldContainer = styled.div`
	margin-top: 20px;
`;

interface UpdateSSHKeyFormProps {
	updateSSHKey( args: { name: string; key: string } ): void;
	isUpdating: boolean;
	updateText?: string;
	oldSSHFingerprint: string;
	userLogin: string;
	keyName: string;
	children?: React.ReactNode;
}

export const UpdateSSHKeyForm = ( {
	updateSSHKey,
	isUpdating,
	updateText,
	userLogin,
	oldSSHFingerprint,
	keyName,
	children,
}: UpdateSSHKeyFormProps ) => {
	const [ { isValid, touched, value }, dispatch ] = useReducer( sshKeyFormReducer, initialState );
	const [ initialSSHFingerprint ] = useState( oldSSHFingerprint );

	const { __ } = useI18n();
	const formats = new Intl.ListFormat( i18n.getLocaleSlug() ?? 'en', {
		style: 'long',
		type: 'disjunction',
	} ).format( SSH_KEY_FORMATS );

	const showSSHKeyError = touched && ! isValid;

	return (
		<form
			onSubmit={ ( event ) => {
				event.preventDefault();
				updateSSHKey( { name: keyName || 'default', key: value } );
			} }
		>
			<FormFieldset>
				<FormLabel>{ __( 'Current SSH Public Key' ) }</FormLabel>
				<SSHKeyCard.Root>
					<SSHKeyCard.Details>
						<SSHKeyCard.KeyName>
							{ userLogin }-{ keyName }
						</SSHKeyCard.KeyName>
						<SSHKeyCard.PublicKey>{ initialSSHFingerprint }</SSHKeyCard.PublicKey>
					</SSHKeyCard.Details>
				</SSHKeyCard.Root>
				<NewSSHFormFieldContainer>
					<FormLabel htmlFor={ PUBLIC_SSH_KEY_INPUT_ID }>{ __( 'New SSH Public Key' ) }</FormLabel>
					<TextareaAutosize
						required
						id={ PUBLIC_SSH_KEY_INPUT_ID }
						disabled={ isUpdating }
						value={ value }
						isError={ showSSHKeyError }
						placeholder={ sprintf(
							// translators: "formats" is a list of SSH-key formats.
							__( 'Paste your SSH public key here. It should begin with %(formats)s…' ),
							{
								formats,
							}
						) }
						onChange={ ( event: ChangeEvent< HTMLTextAreaElement > ) =>
							dispatch( { type: 'setValue', value: event.target.value } )
						}
					/>
					{ showSSHKeyError && (
						<FormInputValidation
							isError
							text={ sprintf(
								// translators: "formats" is a list of SSH-key formats.
								__( 'Invalid SSH public key. It should begin with %(formats)s.' ),
								{
									formats,
								}
							) }
						/>
					) }
				</NewSSHFormFieldContainer>
			</FormFieldset>
			<Button busy={ isUpdating } primary type="submit" disabled={ ! isValid || isUpdating }>
				{ updateText || __( 'Save SSH Key' ) }
			</Button>
			{ children }
		</form>
	);
};