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import { Component } from '../component.ts'import { appendChildren, h, isSSR } from '../core.ts'
class Attributes extends Map {  toString() {    let string = ''    for (const [key, value] of this) string += ` ${key}="${value}"`    return string.trim()  }}
export class Helmet extends Component {  static SSR(body: string) {    const reg = /(<helmet\b[^>]*>)((.|\r|\n)*?)(<\/helmet>)/gm
    // collect all elements    const head: HTMLElement[] = []    const footer: HTMLElement[] = []    const attributes = {      html: new Attributes(),      body: new Attributes()    }
    // get what's in the head    if (typeof document !== 'undefined' && document.head) {      let children: HTMLElement[] = []      children = [].slice.call(document.head.children)      for (let i = 0; i < children.length; i++) {        // check if the same element already exists        if (head.indexOf(children[i]) === -1) {          head.push(children[i])        }      }    }
    let result!: any    while ((result = reg.exec(body)) !== null) {      const first = result[1]      let second = result[2]
      const regHTML = /<html\s([^>]+)><\/html>/gm      const regBody = /<body\s([^>]+)><\/body>/gm      const regAttr = /(\w+)="([^"]+)"/gm      let res = null
      // extract html attributes      body.match(regHTML)?.forEach(h => {        second = second.replace(h, '')        while ((res = regAttr.exec(h)) !== null) {          attributes.html.set(res[1], res[2])        }      })      // extract body attributes      body.match(regBody)?.forEach(b => {        second = second.replace(b, '')        while ((res = regAttr.exec(b)) !== null) {          attributes.body.set(res[1], res[2])        }      })
      const toHead = first.includes('data-placement="head"')
      // do not add an element if it already exists      if (toHead && !head.includes(second)) head.push(second)      else if (!toHead && !footer.includes(second)) footer.push(second)    }
    // clean the body from all matches    const cleanBody = body.replace(reg, '')    return {      body: cleanBody,      head: head as unknown as string[],      footer: footer as unknown as string[],      attributes    }  }
  didMount() {    this.props.children.forEach((element: HTMLElement) => {      // return if it is not an html element      if (!(element instanceof HTMLElement)) return
      const parent = this.props.footer ? document.body : document.head      const tag = element.tagName      let attrs: string[] = []
      // get the inner text      attrs.push(element.innerText as string)
      // get all attributes      for (let attr = 0; attr < element.attributes.length; attr++) {        attrs.push(element.attributes.item(attr)?.name.toLowerCase() as string)        attrs.push(element.attributes.item(attr)?.value.toLowerCase() as string)      }
      // handle special tags      if (tag === 'HTML' || tag === 'BODY') {        const htmlTag = document.getElementsByTagName(tag)[0]        for (let attr = 1; attr < attrs.length; attr += 2) {          htmlTag.setAttribute(attrs[attr], attrs[attr + 1])        }        return      } else if (tag === 'TITLE') {        const titleTags = document.getElementsByTagName('TITLE') as HTMLCollectionOf<HTMLTitleElement>        if (titleTags.length > 0) {          const e = element as HTMLTitleElement          titleTags[0].text = e.text        } else {          const titleTag = h('title', null, element.innerHTML) as HTMLTitleElement          appendChildren(parent, [titleTag], false)        }        return      }
      // check if the element already exists      let exists = false      attrs = attrs.sort()
      const el = document.getElementsByTagName(tag) as unknown as HTMLElement[]
      for (let i = 0; i < el.length; i++) {        let attrs2: string[] = []
        // get the inner text        attrs2.push(el[i].innerText as string)
        for (let attr = 0; attr < el[i].attributes.length; attr++) {          attrs2.push(el[i].attributes.item(attr)?.name.toLowerCase() as string)          attrs2.push(el[i].attributes.item(attr)?.value.toLowerCase() as string)        }        attrs2 = attrs2.sort()
        if (attrs.length > 0 && attrs2.length > 0 && JSON.stringify(attrs) === JSON.stringify(attrs2)) exists = true      }
      // add to dom      if (!exists) appendChildren(parent, [element], false)    })  }
  render() {    const placement = this.props.footer ? 'footer' : 'head'
    if (isSSR()) return h('helmet', { 'data-ssr': true, 'data-placement': placement }, this.props.children)    else return []  }}