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import type { ServerRequest, ServerResponse } from '../types.ts'
const brotliMod = 'https://deno.land/x/brotli@v0.1.4/mod.ts'const flateMod = 'https://deno.land/x/denoflate@1.1/mod.ts'
class Compression {  #brotli: ((data: Uint8Array) => Uint8Array) | null = null  #gzip: ((data: Uint8Array) => Uint8Array) | null = null  #ready: boolean = false
  async init() {    if (this.#brotli === null) {      const { compress } = await import(brotliMod)      this.#brotli = compress    }    if (this.#gzip === null) {      const denoflate = await import(flateMod)      this.#gzip = (data: Uint8Array) => denoflate.gzip(data, undefined)    }    this.#ready = true  }
  apply(req: ServerRequest, resp: ServerResponse, contentType: string, content: Uint8Array): Uint8Array {    if (!this.#ready) {      return content    }
    let shouldCompress = false    if (contentType) {      if (contentType.startsWith('text/')) {        shouldCompress = true      } else if (/^application\/(javascript|json|xml|wasm)/i.test(contentType)) {        shouldCompress = true      } else if (/^image\/svg\+xml/i.test(contentType)) {        shouldCompress = true      }    }
    if (shouldCompress && content.length > 1024) {      const ae = req.headers.get('accept-encoding') || ''      if (ae.includes('br') && this.#brotli !== null) {        resp.headers?.set('Vary', 'Origin')        resp.headers?.set('Content-Encoding', 'br')        return this.#brotli(content)      } else if (ae.includes('gzip') && this.#gzip !== null) {        resp.headers?.set('Vary', 'Origin')        resp.headers?.set('Content-Encoding', 'gzip')        return this.#gzip(content)      }    }
    return content  }}
export default new Compression()