/*
    List cluster files - the job half

    Walks the whole cluster:/ drive and returns every file with its size and
    extension, plus a total per extension. It can run on any node: cluster:/
    looks the same everywhere, so the scheduler is free to pick the least
    busy one.

    args (all optional):
        root   folder to list, default "cluster:/"
        limit  how many files to put in the list, default 5000. The totals
               always cover every file; the limit only keeps the reply small
               on a very large drive.
*/

requirelib("filelib");

function humanSize(bytes) {
    var units = ["B", "KB", "MB", "GB", "TB"];
    var i = 0;
    var v = bytes;
    while (v >= 1024 && i < units.length - 1) {
        v = v / 1024;
        i++;
    }
    return (i === 0 ? v : v.toFixed(1)) + " " + units[i];
}

function extensionOf(name) {
    var dot = name.lastIndexOf(".");
    if (dot <= 0 || dot === name.length - 1) {
        return "";     //no extension, or a dot file such as .gitignore
    }
    return name.substring(dot + 1).toLowerCase();
}

function run(job) {
    var args = job.args || {};
    var root = args.root || "cluster:/";
    var limit = args.limit > 0 ? args.limit : 5000;

    job.log("Walking " + root);
    var paths = filelib.walk(root, "file");
    if (!paths) {
        throw new Error("cannot read " + root);
    }

    var files = [];
    var byExtension = {};
    var totalBytes = 0;

    for (var i = 0; i < paths.length; i++) {
        job.abortIfCancelled();

        var path = paths[i];
        var name = path.split("/").pop();
        var ext = extensionOf(name);
        var size = filelib.filesize(path);

        totalBytes += size;
        var key = ext === "" ? "(none)" : ext;
        if (!byExtension[key]) {
            byExtension[key] = { files: 0, bytes: 0 };
        }
        byExtension[key].files++;
        byExtension[key].bytes += size;

        if (files.length < limit) {
            files.push({ path: path, name: name, extension: ext, size: size, sizeText: humanSize(size) });
        }

        if (i % 200 === 0) {
            job.progress(i / paths.length);
        }
    }

    for (var k in byExtension) {
        byExtension[k].sizeText = humanSize(byExtension[k].bytes);
    }

    return {
        root: root,
        listedOn: job.node,
        totalFiles: paths.length,
        totalBytes: totalBytes,
        totalSizeText: humanSize(totalBytes),
        truncated: paths.length > files.length,
        byExtension: byExtension,
        files: files
    };
}