general-conference-talks.js

"use strict";

function $(sel, $el) {
    return ($el || document).querySelector(sel);
}

function $$(sel, $el) {
    return ($el || document).querySelectorAll(sel);
}

// There should be 5 sessions with 6-9 talks per session
// (plus one header per each)
var CARDS_MINIMUM = 5 * 6;
var CARDS_SELECTOR = "nav ul.doc-map ul.doc-map li a";
var TITLE_SELECTOR = "h4";
var SESSION_SUFFIX = "Session";
var MP3_PAGE_STATE_RE = /window.__INITIAL_STATE__\s*=\s*"([^"]+)"/;
var MP3_CDN_URL_RE = /("https:[^"]*cdn[^"]*[^"]*mp3[^"]*")/g;

function parseTalk($session, $talk, talkNumber, domListIndex) {
    // TODO add session info

    let title = parseTitle($talk);
    if (!title) {
        let err = new Error(`the title selectors have changed`);
        console.warn($talk);
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    let speaker;
    try {
        speaker = parseSpeaker($talk);
    } catch (e) {
        console.warn($talk);
        let err = new Error(
            `Could not parse speaker info for '${title}': e.message`
        );
        window.alert(err.message);
        throw err;
    }

    let description = parseDescription($talk);
    let url = $talk.href;

    let sessionNumberStr = $session.index.toString();

    let talkNumberStr = talkNumber.toString();
    talkNumberStr = talkNumberStr.padStart(2, "0");

    let talk = {
        session_number: sessionNumberStr,
        talk_number: talkNumberStr,
        title: title,
        speaker: speaker,
        description: description,
        talk_url: url,
        _domListIndex: domListIndex,
        $session: $session,
        $talk: $talk,
    };
    console.info(
        `✅ was able to parse talk ${$session.index}.${talkNumber}'s description:`,
        talk
    );

    if (!talk.talk_url) {
        let err = new Error(`the talk details link has changed`);
        console.warn($talk);
        window.alert(`Error: ${err.message}`);
        throw err;
    }
    console.info(
        `✅ Found "${talk.title}" by ${talk.speaker}'s description with link:`
    );
    console.info(`   ${talk.talk_url}`);

    return talk;
}

function parseMp3Link(html) {
    // Un-react-ify the page data
    var m = html.match(MP3_PAGE_STATE_RE);
    if (!m) {
        let err = new Error(
            `could not get talk description page state: ${MP3_PAGE_STATE_RE} is no longer the valid selector`
        );
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    var jsonText;
    try {
        jsonText = atob(m[1]);
    } catch (e) {
        // catch more exactly below
    }
    if (!jsonText) {
        let err = new Error(
            `could not parse talk description page state: ${MP3_PAGE_STATE_RE} is no longer the valid selector`
        );
        console.warn(html);
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    var mp3Match = jsonText.match(MP3_CDN_URL_RE);
    if (!mp3Match?.[0]) {
        let err = new Error(
            `could not find talk's mp3 link: ${MP3_CDN_URL_RE} is no longer the valid selector`
        );
        console.warn(jsonText);
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    var mp3Url;
    try {
        mp3Url = JSON.parse(mp3Match[0]);
    } catch (e) {
        // catch more exactly on next line
    }
    if (!mp3Url) {
        let err = new Error(
            `could not parse talk's mp3 link: ${MP3_CDN_URL_RE} is no longer the valid selector`
        );
        console.warn(mp3Match);
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    return mp3Url;
}

function parseTitle($card) {
    return $(TITLE_SELECTOR, $card)?.innerText?.trim() ?? "";
}

function parseSpeaker($card) {
    return $("h6", $card).innerText.trim();
}

function parseDescription($card) {
    // sustainings do not have a description
    return $(".description", $card)?.innerText?.trim() ?? "";
}

function parseNameByIndex(mp3Url, prefix) {
    let url = new URL(mp3Url);
    let filename = url.pathname.split("/").pop();
    let name = `${prefix}_${filename}`;
    return name;
}

async function main() {
    // using var on purpose because it's easier to test in the console

    var $$cards = $$(CARDS_SELECTOR);
    var hasCards = $$cards?.length >= CARDS_MINIMUM;
    if (!hasCards) {
        let err = new Error(
            `the talk card selector has changed: '${CARDS_SELECTOR}' is no longer correct.`
        );
        window.alert(`Error: ${err.message}`);
        throw err;
    }
    $$cards = Array.from($$cards);
    console.info(`✅ selected ${$$cards.length} talk cards`);
    console.log($$cards);

    var $$sessions = [];
    var $session;
    var talks = [];
    var sessionTalkNumber = 0;
    $$cards.forEach(function ($card, i) {
        let title = parseTitle($card);
        console.log(`Title: ${title}`);

        if (title.endsWith("Session")) {
            $session = $card;
            $$sessions.push($card);
            // TODO parse session info
            $session.index = $$sessions.length;
            sessionTalkNumber = 0;
            return;
        }
        console.log($card);

        sessionTalkNumber += 1;
        let talk = parseTalk($session, $card, sessionTalkNumber, i);

        talks.push(talk);
        console.info("");
    });
    var hasTalks = talks?.length >= CARDS_MINIMUM;
    if (!hasTalks) {
        let err = new Error(
            `the talk card parser has changed: not enough talks found`
        );
        window.alert(`Error: ${err.message}`);
        throw err;
    }

    console.log(talks);
    console.info("");
    console.info(`✅✅ Parsed Descriptions of All Talks!`);
    console.info("");

    let curls = [];
    for (let talk of talks) {
        let page = await window.fetch(talk.talk_url);
        let html = await page.text();
        let mp3Url = parseMp3Link(html);
        console.info(
            `✅ Found ${talk.session_number}.${talk.talk_number} "${talk.title}" by ${talk.speaker}'s mp3 url:`
        );
        console.info(`   ${mp3Url}`);

        let filename = parseNameByIndex(
            mp3Url,
            `${talk.session_number}-${talk.talk_number}`
        );
        let curl = [
            `echo Downloading ${filename} ...`,
            `curl -fsSL -A 'ChJCDev/1.0' -o "${filename}" '${mp3Url}'`,
        ].join("\n");
        curls.push(curl);

        let downloadHtml = `<h6 style="font-size: 8pt;">${talk.session_number}.${talk.talk_number} Download <a href="${talk.mp3Url}" target="_blank" download="${talk.filename}">"${talk.title}" by ${talk.speaker} ⬇️</a></h6>`;
        talk.$talk.insertAdjacentHTML("beforeend", downloadHtml);
        talk.$talk.children[0].remove();
    }
    let sh = curls.join("\n\n");

    console.log(talks);
    console.info("");
    console.info(`✅✅ Fetched MP3s URLs for of All Talks!`);
    console.info("");

    console.info(sh);
}

main().catch(function (err) {
    console.error("Error:");
    console.error(err);
});