/*
 * Copyright (C) 2017  Alex Yatskov <alex@foosoft.net>
 * Author: Alex Yatskov <alex@foosoft.net>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


/*
 * Audio
 */

function audioBuildUrl(definition, cache={}) {
    return new Promise((resolve, reject) => {
        const response = cache[definition.expression];
        if (response) {
            resolve(response);
        } else {
            const data = {
                post: 'dictionary_reference',
                match_type: 'exact',
                search_query: definition.expression
            };

            const params = [];
            for (const key in data) {
                params.push(`${encodeURIComponent(key)}=${encodeURIComponent(data[key])}`);
            }

            const xhr = new XMLHttpRequest();
            xhr.open('POST', 'https://www.japanesepod101.com/learningcenter/reference/dictionary_post');
            xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            xhr.addEventListener('error', () => reject('failed to scrape audio data'));
            xhr.addEventListener('load', () => {
                cache[definition.expression] = xhr.responseText;
                resolve(xhr.responseText);
            });

            xhr.send(params.join('&'));
        }
    }).then(response => {
        const dom = new DOMParser().parseFromString(response, 'text/html');
        for (const row of dom.getElementsByClassName('dc-result-row')) {
            try {
                const url = row.getElementsByClassName('ill-onebuttonplayer').item(0).getAttribute('data-url');
                const reading = row.getElementsByClassName('dc-vocab_kana').item(0).innerText;
                if (url && reading && (!definition.reading || definition.reading === reading)) {
                    return url;
                }
            } catch (e) {
                // NOP
            }
        }
    });
}

function audioBuildFilename(definition) {
    if (definition.reading && definition.expression) {
        let filename = 'yomichan';
        if (definition.reading) {
            filename += `_${definition.reading}`;
        }
        if (definition.expression) {
            filename += `_${definition.expression}`;
        }

        return filename += '.mp3';
    }
}

function audioInject(definition, fields) {
    const filename = audioBuildFilename(definition);
    if (!filename) {
        return Promise.resolve(true);
    }

    let usesAudio = false;
    for (const name in fields) {
        if (fields[name].includes('{audio}')) {
            usesAudio = true;
            break;
        }
    }

    if (!usesAudio) {
        return Promise.resolve(true);
    }

    return audioBuildUrl(definition).then(url => {
        definition.audio = {url, filename};
        return true;
    }).catch(() => false);
}