// grid.js — "Grid mode" plugin for browse. Activated by the
// view-mode toggle in the toolbar. Loads the standalone classifier
// tool as an iframe scoped to the current directory; the user gets
// classifier's full bulk-rename workflow without leaving browse.
//
// This is a v1 — a future iteration could bundle classifier's
// modules directly into browse for tighter integration (shared
// state, no iframe chrome). For now the iframe is a clean separation
// that preserves classifier's full feature set.
//
// Iframe src resolution:
//   - server mode: <currentDirURL>/classifier.html. classifier is
//     auto-served at any working/staging/incoming subtree per
//     zddc-server's apps/availability.go. Outside those locations the
//     iframe will 404 — we surface a friendly message instead of an
//     opaque blank page.
//   - file:// or unknown: show a "switch to server mode for grid"
//     hint. classifier needs FS-API access; embedding it via file://
//     iframe is blocked by browser security.
(function () {
    'use strict';

    var state = window.app.state;
    var mounted = false;

    function escapeHtml(s) {
        return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;')
            .replace(/>/g, '&gt;').replace(/"/g, '&quot;');
    }

    function classifierAvailableHere() {
        // classifier auto-serves under any path containing a segment
        // named working / staging / incoming (case-insensitive).
        // browse mode-toggle should reflect that.
        var path = (window.location && window.location.pathname) || '';
        return /\/(working|staging|incoming)(\/|$)/i.test(path);
    }

    function activate() {
        var host = document.getElementById('gridView');
        if (!host) return;

        if (mounted) return;

        host.innerHTML = '';

        if (state.source !== 'server') {
            host.innerHTML =
                '<div class="grid-empty">'
                + '<h3 style="margin-bottom:0.5rem">Grid mode</h3>'
                + '<p>The classifier (bulk ZDDC rename) workflow runs as an embedded'
                + ' iframe and requires the page be served by zddc-server.</p>'
                + '<p>If you opened this file directly (file://), open the standalone'
                + ' <code>classifier.html</code> tool instead — it provides the same'
                + ' workflow against a local folder you pick from the file system.</p>'
                + '</div>';
            return;
        }

        if (!classifierAvailableHere()) {
            host.innerHTML =
                '<div class="grid-empty">'
                + '<h3 style="margin-bottom:0.5rem">Grid mode</h3>'
                + '<p>The classifier (bulk ZDDC rename) workflow auto-serves at'
                + ' <code>working/</code>, <code>staging/</code>, and'
                + ' <code>incoming/</code> URLs. The current page'
                + ' (<code>' + escapeHtml(window.location.pathname) + '</code>) isn\'t'
                + ' inside any of those, so classifier isn\'t available here.</p>'
                + '<p>Navigate browse into a working/ or staging/ folder, then'
                + ' switch to Grid.</p>'
                + '</div>';
            return;
        }

        // Compute the iframe src: current page's directory + classifier.html.
        var pathname = window.location.pathname || '/';
        if (!pathname.endsWith('/')) {
            // Strip trailing /<file>.html or similar — keep up to the last "/".
            var lastSlash = pathname.lastIndexOf('/');
            pathname = lastSlash >= 0 ? pathname.substring(0, lastSlash + 1) : '/';
        }
        var src = pathname + 'classifier.html';

        host.innerHTML = '';
        var frame = document.createElement('iframe');
        frame.src = src;
        frame.title = 'ZDDC Classifier (Grid mode)';
        frame.style.cssText = 'width:100%;height:100%;border:0;display:block;'
            + 'background:var(--bg);';
        host.appendChild(frame);
        mounted = true;
    }

    window.app.modules.grid = {
        activate: activate,
        // Hook the toggle button visibility / hint to the activation
        // predicate so users at non-classifier paths see the button
        // in a disabled state with explanation. Callers run this
        // after the initial directory is loaded.
        availableHere: function () {
            return state.source === 'server' && classifierAvailableHere();
        }
    };
})();