// Copyright 2018-2022 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 } from "./common.ts";
const SIMPLE_LANGUAGE_REGEXP = /^\s*([^\s\-;]+)(?:-([^\s;]+))?\s*(?:;(.*))?$/;
function parseLanguage(str, i) {
    const match = SIMPLE_LANGUAGE_REGEXP.exec(str);
    if (!match) {
        return undefined;
    }
    const [, prefix, suffix] = match;
    const full = suffix ? `${prefix}-${suffix}` : prefix;
    let q = 1;
    if (match[3]) {
        const params = match[3].split(";");
        for (const param of params){
            const [key, value] = param.trim().split("=");
            if (key === "q") {
                q = parseFloat(value);
                break;
            }
        }
    }
    return {
        prefix,
        suffix,
        full,
        q,
        i
    };
}
function parseAcceptLanguage(accept) {
    const accepts = accept.split(",");
    const result = [];
    for(let i = 0; i < accepts.length; i++){
        const language = parseLanguage(accepts[i].trim(), i);
        if (language) {
            result.push(language);
        }
    }
    return result;
}
function specify(language, spec, i) {
    const p = parseLanguage(language, i);
    if (!p) {
        return undefined;
    }
    let s = 0;
    if (spec.full.toLowerCase() === p.full.toLowerCase()) {
        s |= 4;
    } else if (spec.prefix.toLowerCase() === p.prefix.toLowerCase()) {
        s |= 2;
    } else if (spec.full.toLowerCase() === p.prefix.toLowerCase()) {
        s |= 1;
    } else if (spec.full !== "*") {
        return;
    }
    return {
        i,
        o: spec.i,
        q: spec.q,
        s
    };
}
function getLanguagePriority(language, accepted, index) {
    let priority = {
        i: -1,
        o: -1,
        q: 0,
        s: 0
    };
    for (const accepts of accepted){
        const spec = specify(language, accepts, index);
        if (spec && ((priority.s ?? 0) - (spec.s ?? 0) || priority.q - spec.q || (priority.o ?? 0) - (spec.o ?? 0)) < 0) {
            priority = spec;
        }
    }
    return priority;
}
export function preferredLanguages(accept = "*", provided) {
    const accepts = parseAcceptLanguage(accept);
    if (!provided) {
        return accepts.filter(isQuality).sort(compareSpecs).map((spec)=>spec.full);
    }
    const priorities = provided.map((type, index)=>getLanguagePriority(type, accepts, index));
    return priorities.filter(isQuality).sort(compareSpecs).map((priority)=>provided[priorities.indexOf(priority)]);
}
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