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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license./*! * Adapted directly from negotiator at https://github.com/jshttp/negotiator/ * which is licensed as follows: * * (The MIT License) * * Copyright (c) 2012-2014 Federico Romero * Copyright (c) 2012-2014 Isaac Z. Schlueter * Copyright (c) 2014-2015 Douglas Christopher Wilson * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * 'Software'), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
import { compareSpecs, isQuality, type Specificity } from "./common.ts";
interface MediaTypeSpecificity extends Specificity {  type: string;  subtype: string;  params: { [param: string]: string | undefined };}
const simpleMediaTypeRegExp = /^\s*([^\s\/;]+)\/([^;\s]+)\s*(?:;(.*))?$/;
function splitKeyValuePair(str: string): [string, string | undefined] {  const [key, value] = str.split("=");  return [key!.toLowerCase(), value];}
function parseMediaType(  str: string,  i: number,): MediaTypeSpecificity | undefined {  const match = simpleMediaTypeRegExp.exec(str);
  if (!match) {    return;  }
  const [, type, subtype, parameters] = match;  if (!type || !subtype) {    return;  }
  const params: { [param: string]: string | undefined } = Object.create(null);  let q = 1;  if (parameters) {    const kvps = parameters.split(";").map((p) => p.trim()).map(      splitKeyValuePair,    );
    for (const [key, val] of kvps) {      const value = val && val[0] === `"` && val[val.length - 1] === `"`        ? val.slice(1, val.length - 1)        : val;
      if (key === "q" && value) {        q = parseFloat(value);        break;      }
      params[key] = value;    }  }
  return { type, subtype, params, q, i };}
function parseAccept(accept: string): MediaTypeSpecificity[] {  const accepts = accept.split(",").map((p) => p.trim());
  const mediaTypes: MediaTypeSpecificity[] = [];  for (const [index, accept] of accepts.entries()) {    const mediaType = parseMediaType(accept.trim(), index);
    if (mediaType) {      mediaTypes.push(mediaType);    }  }
  return mediaTypes;}
function getFullType(spec: MediaTypeSpecificity) {  return `${spec.type}/${spec.subtype}`;}
function specify(  type: string,  spec: MediaTypeSpecificity,  index: number,): Specificity | undefined {  const p = parseMediaType(type, index);
  if (!p) {    return;  }
  let s = 0;
  if (spec.type.toLowerCase() === p.type.toLowerCase()) {    s |= 4;  } else if (spec.type !== "*") {    return;  }
  if (spec.subtype.toLowerCase() === p.subtype.toLowerCase()) {    s |= 2;  } else if (spec.subtype !== "*") {    return;  }
  const keys = Object.keys(spec.params);  if (keys.length) {    if (      keys.every((key) =>        (spec.params[key] || "").toLowerCase() ===          (p.params[key] || "").toLowerCase()      )    ) {      s |= 1;    } else {      return;    }  }
  return {    i: index,    o: spec.o,    q: spec.q,    s,  };}
function getMediaTypePriority(  type: string,  accepted: MediaTypeSpecificity[],  index: number,) {  let priority: Specificity = { o: -1, q: 0, s: 0, i: index };
  for (const accepts of accepted) {    const spec = specify(type, accepts, index);
    if (      spec &&      ((priority.s || 0) - (spec.s || 0) ||          (priority.q || 0) - (spec.q || 0) ||          (priority.o || 0) - (spec.o || 0)) < 0    ) {      priority = spec;    }  }
  return priority;}
export function preferredMediaTypes(  accept?: string | null,  provided?: string[],): string[] {  const accepts = parseAccept(accept === undefined ? "*/*" : accept || "");
  if (!provided) {    return accepts      .filter(isQuality)      .sort(compareSpecs)      .map(getFullType);  }
  const priorities = provided.map((type, index) => {    return getMediaTypePriority(type, accepts, index);  });
  return priorities    .filter(isQuality)    .sort(compareSpecs)    .map((priority) => provided[priorities.indexOf(priority)]!);}