transcript.js

'use strict';
const electron = require('electron');
const fs = require('fs');
const fsp = require('fs/promises');
const path_mod = require('path');

const traread = require('./traread.js');

var darklight_flag = false;

var transcriptdir = null;
var tralist = []; // filenames, ordered by modtime
var tramap = new Map(); // maps filenames to data

var dirmodtime = null; // last time we checked the dir timestamp
var reading_dir = false; // set while in the middle of get_transcript_info()

var curselected = null;

function set_dir_path(dir)
{
    transcriptdir = dir;
    reload_transcripts();
}

/* Read the list of transcript files, grabbing the metadata for each
   (if possible).
*/
function reload_transcripts()
{
    //### should only call rebuild_list() if the list has materially changed (order, size, any modtimes)
    
    if (!transcriptdir) {
        return;
    }

    if (reading_dir) {
        // async op in progress; let that finish.
        return;
    }
    
    get_transcript_info()
        .then((ls) => {
            if (ls === null)
                return;
            tramap.clear();
            tralist.length = 0;
            for (var obj of ls) {
                tralist.push(obj.filename);
                tramap.set(obj.filename, obj);
            }
            tralist.sort( (o1, o2) => (tramap.get(o2).modtime - tramap.get(o1).modtime) );
            rebuild_list();
        })
        .catch((ex) => {
            console.log('get_transcript_info failed:', ex);
        });
}

async function get_transcript_info()
{
    async function readone(filename) {
        var path = path_mod.join(transcriptdir, filename);
        var stat = await fsp.stat(path);
        if (!stat.isFile()) {
            throw new Error('not a file');
        }
        
        var res = { 'title': '???' };
        
        var iter = traread.stanza_reader(path);
        for await (var obj of iter) {
            if (obj.timestamp) {
                res.starttime = obj.timestamp;
            }
            if (obj.metadata) {
                Object.assign(res, obj.metadata);
            }
            // break after the first stanza, regardless
            iter.return();
            break;
        }
        
        res.modtime = stat.mtime.getTime();
        res.filesize = stat.size;
        res.filename = filename;
        res.filepath = path;
        return res;
    }

    if (reading_dir) {
        return null;
    }
    reading_dir = true;

    try {
        try {
            var stat = await fsp.stat(transcriptdir);
            dirmodtime = stat.mtime;
        }
        catch (ex) {
            // It's not an error for the transcript dir to not exist yet.
            return null;
        }
        
        var ls = await fsp.readdir(transcriptdir);
        
        var reqs = []; // array of Promises
        for (var filename of ls) {
            if (filename.endsWith('.glktra')) {
                reqs.push(readone(filename));
            }
        }
        
        var settled = await Promise.allSettled(reqs);
        var results = [];
        for (var obj of settled) {
            if (obj.status == 'fulfilled') {
                results.push(obj.value);
            }
        }
        
        return results;
    }
    finally {
        reading_dir = false;
    }
}

/* Format a Unix timestamp (in milliseconds) as "12:30, Oct 31 2024".
*/
function format_timestamp(val)
{
    var date = new Date(val);
    var res = date.toTimeString().slice(0, 5) + ', ' + date.toDateString().slice(4);
    return res;
}

var idmap = new Map();

/* Very simple mechanism to make sure every filename is associated with
   a DOM id. (We don't want to use the filename directory, because who
   knows what funny characters it might contain.)

   We make no effort to clean up old entries. The idmap will grow until
   the transcript window is closed. Big deal.
*/
function id_for_filename(filename)
{
    var id = idmap.get(filename);
    if (!id) {
        id = 'entry_' + idmap.size;
        idmap.set(filename, id);
    }
    return id;
}

/* Recreate the displayed list of transcript entries.
*/
function rebuild_list()
{
    var listel = $('#list');
    listel.empty();

    var foundselected = false;

    for (var filename of tralist) {
        var obj = tramap.get(filename);

        var parel = $('<div>', { 'class':'EntryBox' });
        var el = $('<div>', { 'class':'Entry', id:id_for_filename(filename) });
        if (filename == curselected) {
            el.addClass('Selected');
            foundselected = true;
        }

        var subel = $('<div>', { 'class':'Data' });
        subel.append($('<span>', { 'class':'Title' }).text(obj.title ?? '???'));
        if (obj.author) {
            subel.append($('<span>', { 'class':'' }).text(' \u2014 '));
            subel.append($('<span>', { 'class':'' }).text(obj.author));
        }
        el.append(subel);

        var subel = $('<div>', { 'class':'Data' });
        var modstr = format_timestamp(obj.modtime);
        subel.append($('<span>', { 'class':'Label' }).text('updated: '));
        subel.append($('<span>', { 'class':'' }).text(modstr));
        if (obj.starttime) {
            var startstr = format_timestamp(obj.starttime);
            subel.append($('<span>', { 'class':'' }).text(' \xA0 '));
            subel.append($('<span>', { 'class':'Label' }).text('created: '));
            subel.append($('<span>', { 'class':'' }).text(startstr));
        }
        el.append(subel);

        var butel = $('<button>');
        butel.text('Open');
        butel.on('click', { filename:filename }, evhan_open_transcript);
        el.append(butel);
        
        el.on('click', { filename:filename }, evhan_set_selection);

        parel.append(el);
        listel.append(parel);
    }

    if (!foundselected) {
        curselected = null;
    }
}

/* Check to see if the transcript directory has changed. This will notice
   if a file is added or deleted. (But not if an existing transcript file
   has been extended.)

   Called once per second.
*/
function timer_watchdirtime()
{
    if (!transcriptdir)
        return;

    var stat = null;
    try {
        stat = fs.statSync(transcriptdir);
    }
    catch (ex) {
        return;
    }

    if (dirmodtime === null || dirmodtime < stat.mtime) {
        reload_transcripts();
    }
}

function evhan_open_transcript(ev)
{
    electron.ipcRenderer.send('open_transcript', ev.data.filename);
}

function evhan_set_selection(ev)
{
    ev.stopPropagation();
    ev.preventDefault();

    if (curselected) {
        var id = id_for_filename(curselected);
        var el = $('#'+id);
        if (el.length)
            el.removeClass('Selected');
    }

    curselected = ev.data.filename;
    
    if (curselected) {
        var id = id_for_filename(curselected);
        var el = $('#'+id);
        if (el.length)
            el.addClass('Selected');
        else
            curselected = null;
    }

    electron.ipcRenderer.send('set_selected_transcript', curselected);
}

function apply_darklight(val)
{
    darklight_flag = val;
    
    var el = $('body');
    if (!darklight_flag) {
        el.addClass('LightMode');
        el.removeClass('DarkMode');
    }
    else {
        el.addClass('DarkMode');
        el.removeClass('LightMode');
    }
}

electron.ipcRenderer.on('set-dir-path', function(ev, arg) {
    set_dir_path(arg);
});
electron.ipcRenderer.on('reload_transcripts', function(ev, arg) {
    reload_transcripts();
});
electron.ipcRenderer.on('set-darklight-mode', function(ev, arg) {
    apply_darklight(arg);
});
electron.ipcRenderer.on('on-focus', function(ev, arg) {
    var el = $('body');
    if (arg) {
        el.removeClass('InBackground');
    }
    else {
        el.addClass('InBackground');
    }
});

$(document).on('ready', function() {
    $('#list').on('click', { filename:null }, evhan_set_selection);

    setInterval(timer_watchdirtime, 1000); // every second
});