/**
 * External dependencies
 */
import { __ } from '@wordpress/i18n';
import { COUNTRIES_STORE_NAME } from '@woocommerce/data';
import { decodeEntities } from '@wordpress/html-entities';
import { escapeRegExp } from 'lodash';
import { useEffect, useMemo, useState, useRef } from '@wordpress/element';
import { SelectControl, TextControl } from '@woocommerce/components';
import { Spinner } from '@wordpress/components';
import { useSelect } from '@wordpress/data';

/**
 * Internal dependencies
 */
import { getAdminSetting } from '~/utils/admin-settings';

const { countries } = getAdminSetting( 'dataEndpoints', { countries: {} } );

type Option = { key: string; label: string };

/**
 * Check if a given address field is required for the locale.
 *
 * @param {string} fieldName Name of the field to check.
 * @param {Object} locale Locale data.
 * @return {boolean} Field requirement.
 */
export function isAddressFieldRequired(
	fieldName: string,
	locale: unknown = {}
): boolean {
	if ( locale[ fieldName ]?.hasOwnProperty( 'required' ) ) {
		return locale[ fieldName ]?.required as boolean;
	}

	if ( fieldName === 'address_2' ) {
		return false;
	}

	return true;
}

/**
 * Form validation.
 *
 * @param {Object} locale The store locale.
 * @return {Function} Validator function.
 */
export function getStoreAddressValidator( locale = {} ) {
	/**
	 * Form validator.
	 *
	 * @param {Object} values Keyed values of all fields in the form.
	 * @return {Object} Key value of fields and error messages, { myField: 'This field is required' }
	 */
	return ( values ) => {
		const errors: {
			[ key: string ]: string;
		} = {};

		if (
			isAddressFieldRequired( 'address_1', locale ) &&
			! values.addressLine1.trim().length
		) {
			errors.addressLine1 = __(
				'Please add an address',
				'woocommerce-admin'
			);
		}
		if ( ! values.countryState.trim().length ) {
			errors.countryState = __(
				'Please select a country / region',
				'woocommerce-admin'
			);
		}
		if (
			isAddressFieldRequired( 'city', locale ) &&
			! values.city.trim().length
		) {
			errors.city = __( 'Please add a city', 'woocommerce-admin' );
		}
		if (
			isAddressFieldRequired( 'postcode', locale ) &&
			! values.postCode.trim().length
		) {
			errors.postCode = __(
				'Please add a post code',
				'woocommerce-admin'
			);
		}

		return errors;
	};
}

/**
 * Get all country and state combinations used for select dropdowns.
 *
 * @return {Object} Select options, { value: 'US:GA', label: 'United States - Georgia' }
 */
export function getCountryStateOptions() {
	const countryStateOptions = countries.reduce( ( acc, country ) => {
		if ( ! country.states.length ) {
			acc.push( {
				key: country.code,
				label: decodeEntities( country.name ),
			} );

			return acc;
		}

		const countryStates = country.states.map( ( state ) => {
			return {
				key: country.code + ':' + state.code,
				label:
					decodeEntities( country.name ) +
					' — ' +
					decodeEntities( state.name ),
			};
		} );

		acc.push( ...countryStates );

		return acc;
	}, [] );

	return countryStateOptions;
}

/**
 * Normalize state string for matching.
 *
 * @param {string} state The state to normalize.
 * @return {Function} filter function.
 */
export const normalizeState = ( state: string ): string => {
	return state.replace( /\s/g, '' ).toLowerCase();
};

/**
 * Get state filter
 *
 * @param {string} isStateAbbreviation Whether to use state abbreviation or not.
 * @param {string} normalizedAutofillState The value of the autofillState field.
 * @return {Function} filter function.
 */
export const getStateFilter = (
	isStateAbbreviation: boolean,
	normalizedAutofillState: string
): ( ( option: Option ) => boolean ) => ( option: Option ) => {
	const countryStateArray = isStateAbbreviation
		? option.key.split( ':' )
		: option.label.split( '—' );

	// No region options in the country
	if ( countryStateArray.length <= 1 ) {
		return false;
	}

	const state = countryStateArray[ 1 ];
	// Handle special case, for example: China — Beijing / 北京
	if ( state.includes( '/' ) ) {
		const stateStrList = state.split( '/' );
		return (
			normalizeState( stateStrList[ 0 ] ) === normalizedAutofillState ||
			normalizeState( stateStrList[ 1 ] ) === normalizedAutofillState
		);
	}

	// Handle special case, for example: Iran — Alborz (البرز)
	if ( state.includes( '(' ) && state.includes( ')' ) ) {
		const stateStrList = state.replace( ')', '' ).split( '(' );
		return (
			normalizeState( stateStrList[ 0 ] ) === normalizedAutofillState ||
			normalizeState( stateStrList[ 1 ] ) === normalizedAutofillState
		);
	}

	return normalizeState( state ) === normalizedAutofillState;
};

/**
 * Get the autofill countryState fields and set value from filtered options.
 *
 * @param {Array} options Array of filterable options.
 * @param {string} countryState The value of the countryState field.
 * @param {Function} setValue Set value of the countryState input.
 * @return {Object} React component.
 */
export function useGetCountryStateAutofill(
	options: Option[],
	countryState: string,
	setValue: ( key: string, value: string ) => void
): JSX.Element {
	const [ autofillCountry, setAutofillCountry ] = useState( '' );
	const [ autofillState, setAutofillState ] = useState( '' );
	const isAutofillChange: {
		current: boolean;
	} = useRef();

	// Sync the autofill fields on first render and the countryState value changes.
	useEffect( () => {
		if ( ! isAutofillChange.current ) {
			const option = options.find( ( opt ) => opt.key === countryState );
			const labels = option
				? option.label.split( /\u2013|\u2014|\-/ )
				: [];
			const newCountry = ( labels[ 0 ] || '' ).trim();
			const newState = ( labels[ 1 ] || '' ).trim();

			if (
				newCountry !== autofillCountry ||
				newState !== autofillState
			) {
				setAutofillCountry( newCountry );
				setAutofillState( newState );
			}
		}
		isAutofillChange.current = false;
		// Disable reason: If we include autofillCountry/autofillState in the dependency array, we will have an unnecessary function call because we also update them in this function.
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [ countryState, options ] );

	// Sync the countryState value the autofill fields changes
	useEffect( () => {
		// Skip on first render since we only want to update the value when the autofill fields changes.
		if ( isAutofillChange.current === undefined ) {
			return;
		}

		if ( ! autofillCountry && ! autofillState && countryState ) {
			// Clear form
			isAutofillChange.current = true;
			setValue( 'countryState', '' );
			return;
		}
		const countrySearch = new RegExp(
			escapeRegExp( autofillCountry ),
			'i'
		);
		const isCountryAbbreviation = autofillCountry.length < 3;
		const isStateAbbreviation =
			autofillState.length < 3 && !! autofillState.match( /^[\w]+$/ );
		let filteredOptions = [];

		if ( autofillCountry.length && autofillState.length ) {
			filteredOptions = options.filter( ( option ) =>
				countrySearch.test(
					isCountryAbbreviation ? option.key : option.label
				)
			);
			// no country matches so use all options for state filter.
			if ( ! filteredOptions.length ) {
				filteredOptions = [ ...options ];
			}
			if ( filteredOptions.length > 1 ) {
				filteredOptions = filteredOptions.filter(
					getStateFilter(
						isStateAbbreviation,
						normalizeState( autofillState )
					)
				);
			}
		} else if ( autofillCountry.length ) {
			filteredOptions = options.filter( ( option ) =>
				countrySearch.test(
					isCountryAbbreviation ? option.key : option.label
				)
			);
		} else if ( autofillState.length ) {
			filteredOptions = options.filter(
				getStateFilter(
					isStateAbbreviation,
					normalizeState( autofillState )
				)
			);
		}
		if (
			filteredOptions.length === 1 &&
			countryState !== filteredOptions[ 0 ].key
		) {
			isAutofillChange.current = true;
			setValue( 'countryState', filteredOptions[ 0 ].key );
		}
		// Disable reason: If we include countryState in the dependency array, we will have an unnecessary function call because we also update it in this function.
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [ autofillCountry, autofillState, options, setValue ] );

	return (
		<>
			<input
				onChange={ ( event ) =>
					setAutofillCountry( event.target.value )
				}
				value={ autofillCountry }
				name="country"
				type="text"
				className="woocommerce-select-control__autofill-input"
				tabIndex={ -1 }
				autoComplete="country"
			/>

			<input
				onChange={ ( event ) => setAutofillState( event.target.value ) }
				value={ autofillState }
				name="state"
				type="text"
				className="woocommerce-select-control__autofill-input"
				tabIndex={ -1 }
				autoComplete="address-level1"
			/>
		</>
	);
}

type StoreAddressProps = {
	// Disable reason: The getInputProps type are not provided by the caller and source.
	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	getInputProps: any;
	setValue: ( key: string, value: string ) => void;
};

/**
 * Store address fields.
 *
 * @param {Object} props Props for input components.
 * @param {Function} props.getInputProps Get input props.
 * @param {Function} props.setValue Set value of the countryState input.
 * @return {Object} -
 */
export function StoreAddress( {
	getInputProps,
	setValue,
}: StoreAddressProps ): JSX.Element {
	const countryState = getInputProps( 'countryState' ).value;
	const { locale, hasFinishedResolution } = useSelect( ( select ) => {
		return {
			locale: select( COUNTRIES_STORE_NAME ).getLocale( countryState ),
			hasFinishedResolution: select(
				COUNTRIES_STORE_NAME
			).hasFinishedResolution( 'getLocales' ),
		};
	} );
	const countryStateOptions = useMemo( () => getCountryStateOptions(), [] );
	const countryStateAutofill = useGetCountryStateAutofill(
		countryStateOptions,
		countryState,
		setValue
	);
	if ( ! hasFinishedResolution ) {
		return <Spinner />;
	}

	return (
		<div className="woocommerce-store-address-fields">
			{ ! locale?.address_1?.hidden && (
				<TextControl
					label={
						locale?.address_1?.label ||
						__( 'Address line 1', 'woocommerce-admin' )
					}
					required={ isAddressFieldRequired( 'address_1', locale ) }
					autoComplete="address-line1"
					{ ...getInputProps( 'addressLine1' ) }
				/>
			) }

			{ ! locale?.address_2?.hidden && (
				<TextControl
					label={
						locale?.address_2?.label ||
						__( 'Address line 2 (optional)', 'woocommerce-admin' )
					}
					required={ isAddressFieldRequired( 'address_2', locale ) }
					autoComplete="address-line2"
					{ ...getInputProps( 'addressLine2' ) }
				/>
			) }

			<SelectControl
				label={ __( 'Country / Region', 'woocommerce-admin' ) }
				required
				autoComplete="new-password" // disable autocomplete and autofill
				options={ countryStateOptions }
				excludeSelectedOptions={ false }
				showAllOnFocus
				isSearchable
				{ ...getInputProps( 'countryState' ) }
				controlClassName={ getInputProps( 'countryState' ).className }
			>
				{ countryStateAutofill }
			</SelectControl>

			{ ! locale?.city?.hidden && (
				<TextControl
					label={
						locale?.city?.label || __( 'City', 'woocommerce-admin' )
					}
					required={ isAddressFieldRequired( 'city', locale ) }
					{ ...getInputProps( 'city' ) }
					autoComplete="address-level2"
				/>
			) }

			{ ! locale?.postcode?.hidden && (
				<TextControl
					label={
						locale?.postcode?.label ||
						__( 'Post code', 'woocommerce-admin' )
					}
					required={ isAddressFieldRequired( 'postcode', locale ) }
					autoComplete="postal-code"
					{ ...getInputProps( 'postCode' ) }
				/>
			) }
		</div>
	);
}