import _Vue, { VNode, VNodeData, RenderContext } from 'vue';
import { IconifyIcon } from '@iconify/types';
import {
	FullIconCustomisations,
	defaults,
} from '@iconify/core/lib/customisations';
import {
	flipFromString,
	alignmentFromString,
} from '@iconify/core/lib/customisations/shorthand';
import { rotateFromString } from '@iconify/core/lib/customisations/rotate';
import { iconToSVG } from '@iconify/core/lib/builder';
import { replaceIDs } from '@iconify/core/lib/builder/ids';
import { merge } from '@iconify/core/lib/misc/merge';
import { IconifyIconCustomisations, IconProps } from './props';

/**
 * Default SVG attributes
 */
const svgDefaults: Record<string, unknown> = {
	'xmlns': 'http://www.w3.org/2000/svg',
	'xmlns:xlink': 'http://www.w3.org/1999/xlink',
	'aria-hidden': true,
	'role': 'img',
};

/**
 * Aliases for customisations.
 * In Vue 'v-' properties are reserved, so v-align and v-flip must be renamed
 */
let customisationAliases = {};
['horizontal', 'vertical'].forEach((prefix) => {
	['Align', 'Flip'].forEach((suffix) => {
		const attr = prefix.slice(0, 1) + suffix;
		// vertical-align
		customisationAliases[prefix + '-' + suffix.toLowerCase()] = attr;
		// v-align
		customisationAliases[
			prefix.slice(0, 1) + '-' + suffix.toLowerCase()
		] = attr;
		// verticalAlign
		customisationAliases[prefix + suffix] = attr;
	});
});

/**
 * Interface for inline style
 */
type VNodeStyle = (string | Record<string, unknown>)[];

/**
 * Render icon
 */
export const render = (
	createElement: typeof _Vue.prototype.$createElement,

	// context.props
	props: IconProps,

	// context.data
	contextData: VNodeData,

	// Icon must be validated before calling this function
	icon: Required<IconifyIcon>
): VNode => {
	// Split properties
	const customisations = merge(
		defaults,
		props as IconifyIconCustomisations
	) as FullIconCustomisations;
	const componentProps = merge(svgDefaults);

	// Style in Vue 2 components is always passed to rendered component, so no point in parsing it
	const style: Record<string, unknown> = {};

	// Get element properties
	for (let key in props) {
		const value = props[key];
		switch (key) {
			// Properties to ignore
			case 'icon':
			case 'style':
				break;

			// Flip as string: 'horizontal,vertical'
			case 'flip':
				if (typeof value === 'string') {
					flipFromString(customisations, value);
				}
				break;

			// Alignment as string
			case 'align':
				if (typeof value === 'string') {
					alignmentFromString(customisations, value);
				}
				break;

			// Color: override style
			case 'color':
				style.color = value;
				break;

			// Rotation as string
			case 'rotate':
				if (typeof value === 'string') {
					customisations[key] = rotateFromString(value);
				} else if (typeof value === 'number') {
					customisations[key] = value;
				}
				break;

			// Remove aria-hidden
			case 'ariaHidden':
			case 'aria-hidden':
				// Vue transforms 'aria-hidden' property to 'ariaHidden'
				if (value !== true && value !== 'true') {
					delete componentProps['aria-hidden'];
				}
				break;

			default:
				if (customisationAliases[key] !== void 0) {
					// Aliases for customisations
					customisations[customisationAliases[key]] = value;
				} else if (defaults[key] === void 0) {
					// Copy missing property if it does not exist in customisations
					componentProps[key] = value;
				}
		}
	}

	// Generate icon
	const item = iconToSVG(icon, customisations);

	// Add icon stuff
	for (let key in item.attributes) {
		componentProps[key] = item.attributes[key];
	}

	if (item.inline) {
		style.verticalAlign = '-0.125em';
	}

	// Counter for ids based on "id" property to render icons consistently on server and client
	let localCounter = 0;
	const id = props.id;

	// Generate node data
	const data: VNodeData = {
		attrs: componentProps,
		domProps: {
			innerHTML: replaceIDs(
				item.body,
				id ? () => id + '-' + localCounter++ : 'iconify-vue-'
			),
		},
	};
	if (Object.keys(style).length > 0) {
		data.style = style;
	}

	if (contextData) {
		['on', 'ref'].forEach((attr) => {
			if (contextData[attr] !== void 0) {
				data[attr] = contextData[attr];
			}
		});
		['staticClass', 'class'].forEach((attr) => {
			if (contextData[attr] !== void 0) {
				data.class = contextData[attr];
			}
		});
	}

	// Render icon
	return createElement('svg', data);
};