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import React, { Children, createElement, isValidElement, PropsWithChildren, ReactElement, ReactNode, useContext, useEffect } from 'https://esm.sh/react'import { RendererContext } from './context.ts'import util from './util.ts'
export const serverStyles: Map<string, { css: string, asLink: boolean }> = new Map()
export default function Head(props: PropsWithChildren<{}>) {    const renderer = useContext(RendererContext)
    if (window.Deno) {        parse(props.children).forEach(({ type, props }, key) => renderer.cache.headElements.set(key, { type, props }))    }
    useEffect(() => {        const doc = (window as any).document        const nodes = parse(props.children)        const insertedEls: Array<Object> = []
        if (nodes.size > 0) {            let charset = doc.querySelector('meta[charset]')            if (!charset) {                charset = doc.createElement('meta')                charset.setAttribute('charset', 'utf-8')                doc.head.prepend(charset)            }
            const anchor = doc.createElement('meta')            if (charset.nextElementSibling) {                doc.head.insertBefore(anchor, charset.nextElementSibling)            } else {                doc.head.appendChild(anchor)            }
            nodes.forEach(({ type, props }) => {                const el = doc.createElement(type)                Object.keys(props).forEach(key => {                    const value = props[key]                    if (key === 'children') {                        if (util.isNEString(value)) {                            el.innerText = value                        } else if (util.isNEArray(value)) {                            el.innerText = value.join('')                        }                    } else {                        el.setAttribute(key, String(value || ''))                    }                })                doc.head.insertBefore(el, anchor)                insertedEls.push(el)            })            doc.head.removeChild(anchor)        }
        return () => {            insertedEls.forEach(el => doc.head.removeChild(el))        }    }, [props.children])
    return null}
export function Scripts(props: PropsWithChildren<{}>) {    const renderer = useContext(RendererContext)
    if (window.Deno) {        parse(props.children).forEach(({ type, props }, key) => {            if (type === 'script') {                renderer.cache.scriptsElements.set(key, { type, props })            }        })    }
    // todo: insert page scripts in browser
    return null}
interface SEOProps {    title?: string    description?: string    keywords?: string | string[]    url?: string    image?: string    twitter?: {        card?: 'summary' | 'summary_large_image' | 'app' | 'player'        site?: string        creator?: string    }}
export function SEO(props: SEOProps) {    const { title, description, keywords, url, image, twitter } = props    return createElement(        Head,        undefined,        title && createElement('title', undefined, title),        description && createElement('meta', { name: 'description', content: description }),        keywords && createElement('meta', { name: 'keywords', content: util.isArray(keywords) ? keywords.join(',') : keywords }),        title && createElement('meta', { name: 'og:title', content: title }),        description && createElement('meta', { name: 'og:description', content: description }),        title && createElement('meta', { name: 'twitter:title', content: title }),        description && createElement('meta', { name: 'twitter:description', content: description }),        url && createElement('meta', { name: 'og:url', content: url }),        image && createElement('meta', { name: 'og:image', content: image }),        image && createElement('meta', { name: 'twitter:image', content: image }),        image && createElement('meta', { name: 'twitter:card', content: twitter?.card || 'summary_large_image' }),        twitter?.site && createElement('meta', { name: 'twitter:site', content: twitter.site }),        twitter?.creator && createElement('meta', { name: 'twitter:creator', content: twitter.creator }),    )}
interface ViewportProps {    width?: number | 'device-width'    height?: number | 'device-height'    initialScale?: number    minimumScale?: number    maximumScale?: number    userScalable?: 'yes' | 'no'    targetDensitydpi?: number | 'device-dpi' | 'low-dpi' | 'medium-dpi' | 'high-dpi'}
export function Viewport(props: ViewportProps) {    const content = Object.entries(props)        .map(([key, value]) => {            key = key.replace(/[A-Z]/g, c => '-' + c.toLowerCase())            return `${key}=${value}`        })        .join(',')    return createElement(        Head,        undefined,        content && createElement('meta', { name: 'viewport', content })    )}
export function applyCSS(id: string, css: string, asLink: boolean = false) {    if (window.Deno) {        serverStyles.set(id, { css, asLink })    } else {        const { document } = (window as any)        const styleEl = document.createElement(asLink ? 'link' : 'style')        const prevStyleEls = Array.from(document.head.children).filter((el: any) => el.getAttribute('data-module-id') === id)        if (asLink) {            styleEl.rel = 'stylesheet'            styleEl.href = css        } else {            styleEl.type = 'text/css'            styleEl.appendChild(document.createTextNode(css))        }        styleEl.setAttribute('data-module-id', id)        document.head.appendChild(styleEl)        if (prevStyleEls.length > 0) {            if (asLink) {                styleEl.addEventListener('load', () => {                    prevStyleEls.forEach(el => document.head.removeChild(el))                })            } else {                setTimeout(() => {                    prevStyleEls.forEach(el => document.head.removeChild(el))                }, 0)            }        }    }}
function parse(node: ReactNode, els: Map<string, { type: string, props: Record<string, any> }> = new Map()) {    Children.forEach(node, child => {        if (!isValidElement(child)) {            return        }
        const { type, props } = child        switch (type) {            case React.Fragment:                parse(props.children, els)                break            case SEO:            case Viewport:                parse((type(props) as ReactElement).props.children, els)                break            case 'base':            case 'title':            case 'meta':            case 'link':            case 'style':            case 'script':            case 'no-script':                {                    let key = type                    if (type === 'meta') {                        const propKeys = Object.keys(props).map(k => k.toLowerCase())                        if (propKeys.includes('charset')) {                            return // ignore charset, always use utf-8                        }                        if (propKeys.includes('name')) {                            key += `[name=${JSON.stringify(props['name'])}]`                        } else if (propKeys.includes('property')) {                            key += `[property=${JSON.stringify(props['property'])}]`                        } else if (propKeys.includes('http-equiv')) {                            key += `[http-equiv=${JSON.stringify(props['http-equiv'])}]`                        } else {                            key += Object.keys(props).filter(k => !(/^content|children$/i.test(k))).map(k => `[${k.toLowerCase()}=${JSON.stringify(props[k])}]`).join('')                        }                    } else if (type !== 'title') {                        key += '-' + (els.size + 1)                    }                    // remove the children prop of base/meta/link                    if (['base', 'meta', 'link'].includes(type) && 'children' in props) {                        const { children, ...rest } = props                        els.set(key, { type, props: rest })                    } else {                        els.set(key, { type, props })                    }                }                break        }    })
    return els}