/*
 * aminet_browser.js - Aminet Archive Browser v1.2
 *
 * Browse and download files from http://aminet.net
 *
 *   - Cycle gadget      : select main category
 *   - Listview (top)    : subcategories (hardcoded)
 *   - Listview (middle) : file list from aminet.net
 *   - Double-click      : same row twice = Download
 *   - Download button   : ASL requester + http.get
 *   - Readme button     : fetch .readme, show in window
 *   - Search            : query aminet.net/search
 *   - Close window / Esc : close
 *
 * Run:  NodeAmiga examples/aminet_browser.js
 * Req:  bsdsocket.library (TCP/IP stack)
 */

var gui  = require('gui');
var gfx  = gui.gfx;
var http = require('http');
var fs   = require('fs');

/* ================================================================== */
/* Constants                                                           */
/* ================================================================== */

var AMINET = 'http://aminet.net';

var G_SUBCATS = {
    biz:  ['dbase', 'misc', 'spread'],
    comm: ['ambos', 'amiex', 'bbs', 'cnet', 'dlg', 'fido', 'irc',
           'mail', 'maxs', 'mebbs', 'misc', 'mmgr', 'net', 'news',
           'tcp', 'term', 'thor', 'ums', 'uucp', 'www', 'xeno', 'yam'],
    demo: ['40k', 'aga', 'bse', 'disk', 'ecs', 'euro', 'file', 'funet',
           'intro', 'mag', 'mega', 'misc', 'slide', 'sound', 'sp96',
           'ta95', 'ta96', 'ta97', 'tg93', 'tg95', 'tg96', 'tg97',
           'tp92', 'tp94', 'tp95', 'tp96', 'track'],
    dev:  ['amos', 'asm', 'basic', 'blitz', 'c', 'cross', 'debug', 'e',
           'gcc', 'gg', 'gui', 'hwood', 'lang', 'lib', 'm2', 'misc',
           'moni', 'mui', 'obero', 'src'],
    docs: ['anno', 'hard', 'help', 'hyper', 'lists', 'misc', 'rview'],
    game: ['2play', 'actio', 'board', 'data', 'demo', 'edit', 'gag',
           'hint', 'jump', 'misc', 'patch', 'race', 'role', 'shoot',
           'strat', 'text', 'think', 'wb'],
    gfx:  ['3d', 'arteff', 'conv', 'edit', 'fract', 'ifx', 'misc',
           'pbm', 'ppaint', 'show'],
    misc: ['amag', 'antiq', 'edu', 'emu', 'fish', 'imdb', 'kids',
           'math', 'misc', 'os', 'sci', 'unix', 'x11'],
    mods: ['32bit', '4mat', '8voic', 'airon', 'alpma', 'anakir', 'atmos',
           'aweso', 'bhead', 'bladr', 'blasa', 'blk', 'blkha', 'boing',
           'boray', 'casef', 'cato', 'cels', 'chart', 'chip', 'chrom',
           'chryl', 'clawz', 'cloud', 'crash', 'crn', 'csm', 'ctp',
           'cust', 'cutc', 'darde', 'dean', 'delor', 'demo', 'dizzy',
           'dlusn', 'doh', 'dremr', 'dsx', 'elbie', 'emax', 'ephnx',
           'essen', 'evrim', 'exprt', 'facet', 'fby', 'fermx', 'fox2',
           'funet', 'funk', 'grogo', 'hardc', 'hje', 'house', 'huezo',
           'hw', 'ijont', 'inst', 'instr', 'jazzc', 'jogei', 'jorma',
           'jungl', 'k4k', 'kaa', 'kicko', 'lead', 'mark', 'maxym',
           'med', 'melod', 'melom', 'midi', 'misc', 'mnc', 'moods',
           'mpg', 'mryo', 'mvp', 'ncase', 'neuro', 'nkn', 'nork',
           'ooze', 'otis', 'panik', 'pdy', 'pete', 'piano', 'pop',
           'pro', 'przk', 'punn', 'purg', 'racoo', 'rated', 'rock',
           'roz', 's3m', 'sbc', 'sets', 'sidew', 'slc', 'slow', 'smg',
           'smpl', 'sonor', 'spark', 'stame', 'stun', 'symph', 'synth',
           'techn', 'toady', 'tp96', 'tranc', 'uns', 'uprgh', 'vdo',
           'voice', 'voy', 'wmr', 'xceed', 'xm'],
    mus:  ['edit', 'midi', 'misc', 'play'],
    pix:  ['3dani', '3dobj', 'addic', 'anim', 'art', 'astro', 'back',
           'bill', 'boot', 'clip', 'eps', 'eric', 'fauna', 'fract',
           'gicon', 'glenn', 'guard', 'heiko', 'henz', 'icon', 'illu',
           'imagi', 'irc', 'jake', 'jason', 'map', 'mark', 'misc',
           'mpg', 'mwb', 'nevil', 'nicon', 'park', 'picon', 'real3',
           'sport', 'textu', 'theme', 'tp96', 'trace', 'unrl', 'vehic',
           'views', 'wb'],
    text: ['bfont', 'dtp', 'edit', 'font', 'fwrit', 'hyper', 'ifont',
           'misc', 'pfont', 'print', 'show', 'tex', 'tfont'],
    util: ['app', 'arc', 'batch', 'blank', 'boot', 'cdity', 'cli',
           'conv', 'crypt', 'dir', 'dopus', 'dtype', 'libs', 'misc',
           'moni', 'mouse', 'pack', 'rexx', 'shell', 'sys', 'time',
           'virus', 'wb']
};

var G_CATS = Object.keys(G_SUBCATS);

/* ================================================================== */
/* State                                                               */
/* ================================================================== */

var g_catIdx    = 0;    /* selected index in G_CATS             */
var g_subcats   = [];   /* current subcategory name strings     */
var g_subcatIdx = -1;   /* selected subcategory listview index  */
var g_files     = [];   /* [{name, size, date, desc}, ...]      */
var g_selFile   = -1;   /* index of selected file in g_files    */
var g_lastCode  = -1;   /* previous fileList evt.code (dbl-clk) */
var g_sortBy    = 0;    /* 0=name, 1=size, 2=date              */
var g_sortDir   = 0;    /* 0=ascending, 1=descending           */

var readmeWin   = null; /* readme viewer window (or null)       */
var g_rmLines   = [];   /* original readme lines (for hscroll)  */
var g_rmScroll  = 0;    /* horizontal scroll offset (chars)     */
var g_rmMaxLen  = 0;    /* longest line length (scroller total) */

/* ================================================================== */
/* Layout                                                              */
/* ================================================================== */

/* Get screen font metrics for proper layout */
var scr = gui.screenInfo();
var fw  = scr.fontWidth;    /* exact char width in pixels  */
var fh  = scr.fontHeight;   /* char height in pixels        */

var gadgets = [];
var gid = 1;
var rh  = fh + 4;  /* row height: font + padding */
var sp  = 4;        /* row spacing px */
var y   = sp;

/* Row 1: Category / Sort / Order cycles */
gadgets.push({ kind: 'cycle', id: gid++,
    left: '1%', top: y, width: '50%', height: rh,
    items: G_CATS, value: 0 });
var ID_CAT = 1;

gadgets.push({ kind: 'cycle', id: gid++,
    left: '53%', top: y, width: '25%', height: rh,
    items: ['name', 'size', 'date'], value: 0 });
var ID_SORT = 2;

gadgets.push({ kind: 'cycle', id: gid++,
    left: '80%', top: y, width: '19%', height: rh,
    items: ['asc', 'desc'], value: 0 });
var ID_ORDER = 3;
y += rh + sp;

/* Bottom area: status + search + buttons = rh*3 + sp*3 */
var btmH   = rh * 3 + sp * 3;
var winH   = rh * 16 + btmH + sp;
var listH  = winH - y - btmH - 2;

/* Subcategory listview — 6 chars + scrollbar (16px) + borders (8px) */
var subW = fw * 6 + 24;
gadgets.push({ kind: 'listview', id: gid++,
    left: 4, top: y, width: subW, height: listH, flex: true,
    items: [], value: 0 });
var ID_SUBCAT = 4;

/* File listview — fills remaining width */
var fileL = subW + 8;
gadgets.push({ kind: 'listview', id: gid++,
    left: fileL, top: y, width: -(fileL + 4), height: listH, flex: true,
    items: ['Select a subcategory...'], value: 0 });
var ID_FILES = 5;

/* Status text — top of bottom area */
gadgets.push({ kind: 'text', id: gid++,
    left: '1%', top: -(rh * 3 + sp * 3), width: '98%', height: rh,
    value: 'Ready -- pick a category.' });
var ID_STATUS = 6;

/* Search string — middle row of bottom area */
var searchY = -(rh * 2 + sp * 2);
gadgets.push({ kind: 'string', id: gid++,
    label: 'Find:',
    left: '12%', top: searchY, width: '87%', height: rh,
    value: '' });
var ID_SEARCH_STR = 7;

/* Bottom row: buttons */
var btnY = -(rh + sp);

gadgets.push({ kind: 'button', id: gid++, label: 'Download',
    left: '1%', top: btnY, width: '32%', height: rh });
var ID_DOWNLOAD = 8;

gadgets.push({ kind: 'button', id: gid++, label: 'Readme',
    left: '34%', top: btnY, width: '32%', height: rh });
var ID_README = 9;

gadgets.push({ kind: 'button', id: gid++,
    label: 'Search All',
    left: '67%', top: btnY, width: '32%', height: rh });
var ID_SEARCH = 10;

/* ================================================================== */
/* Create window                                                       */
/* ================================================================== */

var win = gui.createWindow({
    title:     'Aminet Browser 1.2 - NodeAmiga by Juen',
    width:     520,
    height:    winH,
    left:      20,
    top:       15,
    resizable: true,
    minWidth:  300,
    minHeight: 140,
    gadgets:   gadgets
});

/* Download and Readme start disabled (no file selected) */
gui.setDisabled(win, ID_DOWNLOAD, true);
gui.setDisabled(win, ID_README, true);

/* ================================================================== */
/* Utility helpers                                                     */
/* ================================================================== */

function setStatus(msg) {
    gui.set(win, ID_STATUS, msg);
}

/* Enable/disable Download and Readme based on g_selFile */
function updateFileButtons() {
    var dis = (g_selFile < 0);
    gui.setDisabled(win, ID_DOWNLOAD, dis);
    gui.setDisabled(win, ID_README, dis);
}

/* Disable or enable all interactive gadgets.
 * NOTE: ID_SEARCH_STR (string gadget) is excluded
 * because GA_Disabled on STRING_KIND can hang. */
function setAllDisabled(flag) {
    gui.setDisabled(win, ID_CAT, flag);
    gui.setDisabled(win, ID_SORT, flag);
    gui.setDisabled(win, ID_ORDER, flag);
    gui.setDisabled(win, ID_SUBCAT, flag);
    gui.setDisabled(win, ID_FILES, flag);
    gui.setDisabled(win, ID_DOWNLOAD, flag);
    gui.setDisabled(win, ID_README, flag);
    gui.setDisabled(win, ID_SEARCH, flag);
}

/* Scan html for all substrings between literal before/after markers */
function extractBetween(html, before, after) {
    var results = [];
    var pos = 0;
    var s, e;
    while (true) {
        s = html.indexOf(before, pos);
        if (s === -1) break;
        s += before.length;
        e = html.indexOf(after, s);
        if (e === -1) break;
        results.push(html.substring(s, e));
        pos = e + after.length;
    }
    return results;
}

/* Strip all HTML tags from a string */
function stripTags(s) {
    var out = '', inTag = false, i, c;
    for (i = 0; i < s.length; i++) {
        c = s.charAt(i);
        if      (c === '<') { inTag = true;  }
        else if (c === '>') { inTag = false; }
        else if (!inTag)    { out  += c;     }
    }
    return out;
}

/* Trim leading/trailing whitespace */
function trimStr(s) {
    return s.replace(/^\s+|\s+$/g, '');
}

/* Pad/truncate string to exactly w characters for column alignment */
function col(s, w) {
    s = String(s);
    while (s.length < w) { s += ' '; }
    return s.length > w ? s.substring(0, w) : s;
}

/* Strip tag-attribute prefix "...>" from a raw <td chunk, then stripTags */
function tdText(raw) {
    var gt = raw.indexOf('>');
    return trimStr(stripTags(gt >= 0 ? raw.substring(gt + 1) : raw));
}

/* ================================================================== */
/* Readme viewer window                                                */
/* ================================================================== */

function closeReadmeWin() {
    if (readmeWin) {
        gui.closeWindow(readmeWin);
        readmeWin = null;
    }
}

/* Shift all readme lines by g_rmScroll and update listview */
function updateReadmeView() {
    var shifted = [];
    var i, ln;
    if (!readmeWin) return;
    for (i = 0; i < g_rmLines.length; i++) {
        ln = g_rmLines[i];
        if (g_rmScroll > 0 && ln.length > g_rmScroll) {
            shifted.push(ln.substring(g_rmScroll));
        } else if (g_rmScroll > 0) {
            shifted.push('');
        } else {
            shifted.push(ln);
        }
    }
    gui.set(readmeWin, 1, shifted);
}

function doReadme() {
    var fi, dot, base, readmeName, pathBase, url;
    var res, text, maxLen, maxCols, winW, i;

    if (g_selFile < 0 || g_selFile >= g_files.length) {
        setStatus('Select a file first');
        return;
    }

    fi = g_files[g_selFile];

    /* Replace extension with .readme */
    dot = fi.name.lastIndexOf('.');
    base = (dot > 0) ? fi.name.substring(0, dot) : fi.name;
    readmeName = base + '.readme';

    /* Build URL from fi.path */
    dot = fi.path.lastIndexOf('.');
    pathBase = (dot > 0) ? fi.path.substring(0, dot) : fi.path;
    url = AMINET + '/' + pathBase + '.readme';

    setStatus('Fetching ' + readmeName + '...');
    setAllDisabled(true);

    try {
        res = http.get(url);
        if (!res || !res.body || res.body.length === 0) {
            /* Fallback: strip one more extension
             * e.g. file.tar.gz -> file.tar.readme
             * failed, now try file.readme */
            dot = pathBase.lastIndexOf('.');
            if (dot > 0) {
                pathBase = pathBase.substring(0, dot);
                url = AMINET + '/' +
                      pathBase + '.readme';
                res = http.get(url);
            }
        }

        if (!res || !res.body || res.body.length === 0) {
            setStatus('No readme for ' + fi.name);
            setAllDisabled(false);
            updateFileButtons();
            return;
        }

        /* Split into lines, strip CR */
        text = String(res.body).replace(/\r/g, '');
        g_rmLines  = text.split('\n');
        g_rmScroll = 0;

        /* Find longest line for scroller range */
        g_rmMaxLen = 0;
        for (i = 0; i < g_rmLines.length; i++) {
            if (g_rmLines[i].length > g_rmMaxLen)
                g_rmMaxLen = g_rmLines[i].length;
        }

        winW    = 560;
        maxCols = Math.floor((winW - 30) / fw);

        /* Close previous readme window */
        closeReadmeWin();

        /* Open readme window: listview + h-scroller */
        readmeWin = gui.createWindow({
            title:     readmeName,
            width:     winW,
            height:    300,
            left:      60,
            top:       30,
            resizable: true,
            minWidth:  200,
            minHeight: 100,
            gadgets: [
                { kind: 'listview', id: 1,
                  left: 0, top: 0,
                  width: '100%', height: -(rh + sp),
                  flex: true,
                  items: g_rmLines },
                { kind: 'scroller', id: 2,
                  left: 0, top: -(rh),
                  width: '100%', height: rh,
                  min: 0, max: g_rmMaxLen,
                  value: 0, visible: maxCols }
            ]
        });

        setStatus('Readme: ' + readmeName +
                  ' (' + g_rmLines.length + ' lines)');
    } catch (ex) {
        setStatus('Readme error: ' +
                  (ex.message || String(ex)));
    }

    setAllDisabled(false);
    updateFileButtons();
}

/* ================================================================== */
/* Display subcategories for a category (from hardcoded G_SUBCATS)     */
/* ================================================================== */

function loadSubcats(cat) {
    g_subcats   = G_SUBCATS[cat] || [];
    g_subcatIdx = -1;
    g_files     = [];
    g_selFile   = -1;
    g_lastCode  = -1;
    gui.set(win, ID_FILES,  ['Select a subcategory...']);
    updateFileButtons();

    if (g_subcats.length === 0) {
        gui.set(win, ID_SUBCAT, []);
        setStatus('No subcategories for ' + cat);
    } else {
        gui.set(win, ID_SUBCAT, g_subcats);
        setStatus(cat + ': ' + g_subcats.length +
                  ' subcategories');
    }
}

/* ================================================================== */
/* Sorting and display helpers                                         */
/* ================================================================== */

/* Parse size string like "123K", "1.2M" to bytes for comparison */
function parseSizeKB(s) {
    var n, last;
    if (!s || s.length === 0) return 0;
    last = s.charAt(s.length - 1);
    n = parseFloat(s);
    if (isNaN(n)) return 0;
    if (last === 'M' || last === 'm') return n * 1024;
    if (last === 'G' || last === 'g') return n * 1024 * 1024;
    return n;  /* already K or plain number */
}

/* Sort g_files in-place according to g_sortBy / g_sortDir */
function sortFiles() {
    /* Note: g_files.sort(compareFiles) produces undefined values
     * due to engine bug — using manual sort as workaround */
    var i, j, tmp;
    for (i = 1; i < g_files.length; i++) {
        tmp = g_files[i];
        j = i - 1;
        while (j >= 0 && compareFiles(g_files[j], tmp) > 0) {
            g_files[j + 1] = g_files[j];
            j--;
        }
        g_files[j + 1] = tmp;
    }
}

function compareFiles(a, b) {
    var cmp = 0;
    if (g_sortBy === 0) {
        /* name */
        cmp = a.name < b.name ? -1 : (a.name > b.name ? 1 : 0);
    } else if (g_sortBy === 1) {
        /* size */
        cmp = parseSizeKB(a.size) - parseSizeKB(b.size);
    } else {
        /* date — string comparison works for YYYY-MM-DD format */
        cmp = a.date < b.date ? -1 : (a.date > b.date ? 1 : 0);
    }
    return g_sortDir ? -cmp : cmp;
}

/* Rebuild display list from g_files and update listview */
function refreshFileList() {
    var displayList = [];
    var i, f;
    for (i = 0; i < g_files.length; i++) {
        f = g_files[i];
        displayList.push(col(f.name, 28) + '  ' +
                         col(f.size, 5) + '  ' + f.date);
    }
    g_selFile  = -1;
    g_lastCode = -1;
    updateFileButtons();
    if (displayList.length === 0) {
        gui.set(win, ID_FILES, ['(empty)']);
    } else {
        gui.set(win, ID_FILES, displayList);
    }
}

/* ================================================================== */
/* Fetch and display file listing for category/subcategory             */
/* ================================================================== */

/*
 * Parse file rows from an HTML page and append to g_files.
 * Returns the number of new entries found.
 */
function parseRows(html, cat, sub) {
    var linkPat, pos, rs, re, row, ls, le;
    var name, size, date, desc;
    var tds, i, t, count;

    linkPat = 'href="/' + cat + '/' + sub + '/';
    pos     = 0;
    count   = 0;

    while (true) {
        rs = html.indexOf('<tr', pos);
        if (rs === -1) break;
        re = html.indexOf('</tr>', rs);
        if (re === -1) break;
        row = html.substring(rs, re + 5);
        pos = re + 5;

        /* Does this row contain a file download link? */
        ls = row.indexOf(linkPat);
        if (ls === -1) continue;
        ls += linkPat.length;
        le  = row.indexOf('"', ls);
        if (le === -1) continue;
        name = row.substring(ls, le);
        /* Reject empty names or sub-paths */
        if (name.length === 0 || name.indexOf('/') !== -1) { continue; }

        try {
            /* Extract <td> cells */
            tds  = extractBetween(row, '<td', '</td>');
            size = ''; date = ''; desc = '';
            for (i = 0; i < tds.length; i++) {
                t = tdText(tds[i]);
                if      (i === 4) { size = t; }
                else if (i === 5) { date = t; }
                else if (i === 7) { desc = t; }
            }
        } catch (ex2) {
            /* If cell parsing fails, use defaults */
            console.log('parse warning: ' + name +
                        ': ' + String(ex2));
            size = ''; date = ''; desc = '';
        }

        g_files.push({ name: name,
                        path: cat + '/' + sub + '/' + name,
                        size: size, date: date, desc: desc });
        count++;
    }
    return count;
}

/*
 * Detect whether aminet HTML contains a link to the next page.
 * Returns the next page number, or -1 if no more pages.
 */
function findNextPage(html, currentPage) {
    var needle = 'page=' + (currentPage + 1);
    if (html.indexOf(needle) !== -1) {
        return currentPage + 1;
    }
    return -1;
}

/* Map g_sortBy (0=name,1=size,2=date) to aminet sort parameter */
function aminetSortParam() {
    if (g_sortBy === 1) return 'size';
    if (g_sortBy === 2) return 'date';
    return 'name';
}

/* Map g_sortDir (0=asc,1=desc) to aminet ord parameter */
function aminetOrdParam() {
    return g_sortDir ? 'DESC' : 'ASC';
}

function loadFiles(cat, sub) {
    var baseUrl, url, res, html, errMsg;
    var page, nextPage, pageCount;

    setStatus('Loading ' + cat + '/' + sub + '...');
    g_files    = [];
    g_selFile  = -1;
    g_lastCode = -1;
    gui.set(win, ID_FILES, ['Loading...']);

    /* Disable all gadgets during network fetch */
    setAllDisabled(true);

    baseUrl = AMINET + '/' + cat + '/' + sub;
    page    = 1;   /* aminet pages are 1-based */

    try {
        while (true) {
            url = baseUrl + '?sort=' + aminetSortParam() +
                  '&ord=' + aminetOrdParam() +
                  '&page=' + page;

            if (page > 1) {
                setStatus('Loading ' + cat + '/' + sub +
                          ' (page ' + page + ')...');
            }

            res = http.get(url);
            if (!res || !res.body) {
                if (page === 1) {
                    setStatus('No response from aminet.net');
                    gui.set(win, ID_FILES,
                            ['(no response)']);
                    setAllDisabled(false);
                    updateFileButtons();
                    return;
                }
                break;  /* no more pages */
            }
            html = String(res.body);

            pageCount = parseRows(html, cat, sub);

            /* If this page yielded no files, we're done */
            if (pageCount === 0) {
                break;
            }

            /* Check if there is a next page link */
            nextPage = findNextPage(html, page);
            if (nextPage === -1) {
                break;
            }
            page = nextPage;
        }
    } catch (ex) {
        errMsg = ex && ex.message ? ex.message : String(ex);
        console.log('loadFiles fetch error: ' + errMsg);
        if (g_files.length === 0) {
            setStatus('Fetch error: ' + errMsg);
            gui.set(win, ID_FILES,
                    ['Fetch error: ' + errMsg]);
            setAllDisabled(false);
            updateFileButtons();
            return;
        }
        /* Partial results — show what we got */
    }

    /* Re-enable all gadgets */
    setAllDisabled(false);
    updateFileButtons();

    if (g_files.length === 0) {
        setStatus('No files in ' + cat + '/' + sub);
        gui.set(win, ID_FILES, ['(empty)']);
    } else {
        sortFiles();
        refreshFileList();
        setStatus(cat + '/' + sub + ': ' +
                  g_files.length + ' files' +
                  (page > 1 ? ' (' + page + ' pages)' : ''));
    }
}

/* ================================================================== */
/* Download selected file — ASL file requester for destination         */
/* ================================================================== */

function doDownload() {
    var fi, url, dest, res;

    if (g_selFile < 0 || g_selFile >= g_files.length) {
        setStatus('Select a file from the list first');
        return;
    }

    fi  = g_files[g_selFile];
    url = AMINET + '/' + fi.path;

    /* Ask user where to save */
    dest = gui.fileRequest({
        title:  'Save: ' + fi.name,
        save:   true,
        drawer: 'RAM:',
        file:   fi.name
    });
    if (!dest) {
        setStatus('Download cancelled');
        return;
    }

    /* Disable all gadgets during download */
    setAllDisabled(true);

    setStatus('Downloading ' + fi.name + ' ...');
    try {
        res = http.get(url);
        if (!res || !res.body) {
            setStatus('Download failed: empty response');
            return;
        }
        fs.writeFileSync(dest.path, res.body);
        setStatus('Saved ' + fi.name + ' (' +
                  res.body.length + ' B)  \xbb ' +
                  dest.path);
    } catch (ex) {
        setStatus('Download error: ' +
                  (ex.message || String(ex)));
    } finally {
        /* Re-enable all gadgets */
        setAllDisabled(false);
        updateFileButtons();
    }
}


/* ================================================================== */
/* Search aminet.net                                                   */
/* ================================================================== */

/*
 * Parse search result rows from aminet search HTML.
 * Search results have links like href="/cat/sub/filename".
 * Returns count of entries appended to g_files.
 */
function parseSearchRows(html) {
    var pos, rs, re, row, ls, le, href;
    var name, size, date, desc, path;
    var tds, i, t, count, parts;

    pos   = 0;
    count = 0;

    while (true) {
        rs = html.indexOf('<tr', pos);
        if (rs === -1) break;
        re = html.indexOf('</tr>', rs);
        if (re === -1) break;
        row = html.substring(rs, re + 5);
        pos = re + 5;

        /* Look for file download links like href="/cat/sub/file" */
        ls = row.indexOf('href="/');
        if (ls === -1) continue;
        ls += 7;   /* skip href="/ */
        le = row.indexOf('"', ls);
        if (le === -1) continue;
        href = row.substring(ls, le);

        /* Must have exactly 2 slashes: cat/sub/file */
        parts = href.split('/');
        if (parts.length !== 3) continue;
        if (parts[2].length === 0) continue;
        /* Skip non-file links (dirs, pages, etc.) */
        if (parts[2].indexOf('.') === -1) continue;

        name = parts[2];
        path = href;

        try {
            tds  = extractBetween(row, '<td', '</td>');
            size = ''; date = ''; desc = '';
            for (i = 0; i < tds.length; i++) {
                t = tdText(tds[i]);
                if      (i === 4) { size = t; }
                else if (i === 5) { date = t; }
                else if (i === 7) { desc = t; }
            }
        } catch (ex2) {
            size = ''; date = ''; desc = '';
        }

        g_files.push({ name: name, path: path,
                        size: size, date: date, desc: desc });
        count++;
    }
    return count;
}

function doSearch() {
    var query, url, res, html, count;

    /* Read search term from string gadget */
    query = trimStr(gui.get(win, ID_SEARCH_STR) || '');
    if (query.length === 0) {
        setStatus('Type a search term in Find');
        return;
    }

    setStatus('Searching ALL of Aminet: ' +
              query + '...');
    g_files    = [];
    g_selFile  = -1;
    g_lastCode = -1;
    gui.set(win, ID_FILES, ['Searching...']);
    setAllDisabled(true);

    try {
        url = AMINET + '/search?query=' + query;
        res = http.get(url);
        if (!res || !res.body) {
            setStatus('No response from aminet.net');
            gui.set(win, ID_FILES, ['(no response)']);
            setAllDisabled(false);
            updateFileButtons();
            return;
        }
        html  = String(res.body);
        count = parseSearchRows(html);
    } catch (ex) {
        setStatus('Search error: ' +
                  (ex.message || String(ex)));
        gui.set(win, ID_FILES,
                ['Search error']);
        setAllDisabled(false);
        updateFileButtons();
        return;
    }

    setAllDisabled(false);
    updateFileButtons();

    if (g_files.length === 0) {
        setStatus('No results for: ' + query);
        gui.set(win, ID_FILES, ['(no results)']);
    } else {
        sortFiles();
        refreshFileList();
        setStatus('Found ' + g_files.length +
                  ' in all Aminet for: ' + query);
    }
}

/* ================================================================== */
/* Startup — display subcategories for first category                  */
/* ================================================================== */

loadSubcats(G_CATS[g_catIdx]);

/* ================================================================== */
/* Main event loop (polls both windows via waitTOF)                    */
/* ================================================================== */

/* Process a single main-window event; returns false to quit */
function handleEvent(evt) {
    if (evt.type === 'close') return false;

    if (evt.type === 'key' && evt.key === '\x1b') return false;

    if (evt.type === 'gadgetup') {

        if (evt.id === ID_DOWNLOAD) {
            doDownload();

        } else if (evt.id === ID_README) {
            doReadme();

        } else if (evt.id === ID_SEARCH) {
            doSearch();

        } else if (evt.id === ID_SEARCH_STR) {
            /* Enter pressed in search field */
            doSearch();

        } else if (evt.id === ID_CAT) {
            g_catIdx = evt.code;
            loadSubcats(G_CATS[g_catIdx]);

        } else if (evt.id === ID_SORT) {
            g_sortBy = evt.code;
            if (g_files.length > 0) {
                setAllDisabled(true);
                sortFiles();
                refreshFileList();
                setAllDisabled(false);
                updateFileButtons();
            }

        } else if (evt.id === ID_ORDER) {
            g_sortDir = evt.code;
            if (g_files.length > 0) {
                setAllDisabled(true);
                sortFiles();
                refreshFileList();
                setAllDisabled(false);
                updateFileButtons();
            }

        } else if (evt.id === ID_SUBCAT) {
            g_subcatIdx = evt.code;
            g_lastCode  = -1;
            if (g_subcatIdx >= 0 &&
                g_subcatIdx < g_subcats.length) {
                loadFiles(G_CATS[g_catIdx],
                          g_subcats[g_subcatIdx]);
            }

        } else if (evt.id === ID_FILES) {
            if (evt.code === g_lastCode) {
                g_selFile  = evt.code;
                g_lastCode = -1;
                doDownload();
            } else {
                g_selFile  = evt.code;
                g_lastCode = evt.code;
                updateFileButtons();
                if (g_selFile >= 0 &&
                    g_selFile < g_files.length) {
                    var finfo = g_files[g_selFile];
                    var info  = finfo.name;
                    if (finfo.size) {
                        info += '   ' + finfo.size;
                    }
                    if (finfo.desc) {
                        info += '   ' + finfo.desc;
                    }
                    setStatus(info);
                }
            }
        }
    }
    return true;
}

var running = true;
while (running) {
    var evt, revt;

    if (readmeWin) {
        /* Both windows open — poll both, sleep on TOF */
        evt  = gui.pollEvent(win);
        revt = gui.pollEvent(readmeWin);

        if (revt) {
            if (revt.type === 'close') {
                closeReadmeWin();
            } else if (revt.type === 'resize') {
                /* Recalculate visible chars for new width */
                var newCols = Math.floor(
                    (revt.width - 30) / fw);
                gui.set(readmeWin, 2,
                    { visible: newCols,
                      total: g_rmMaxLen });
            } else if (revt.id === 2) {
                g_rmScroll = gui.get(readmeWin, 2);
                updateReadmeView();
            }
        }

        if (!evt) {
            gfx.waitTOF();
            continue;
        }
    } else {
        /* Only main window — block efficiently */
        evt = gui.waitEvent(win);
        if (!evt) break;
    }

    if (!handleEvent(evt)) {
        running = false;
    }
}

closeReadmeWin();
gui.closeWindow(win);