// grid.js — "Grid mode" plugin for browse. Loads the classifier tool
// as an iframe scoped to the current directory so users get classifier's
// full bulk-rename workflow without leaving browse.
//
// Availability: the cascade decides. Grid auto-activates wherever the
// .zddc cascade resolves default_tool=classifier (defaults.zddc.yaml
// declares this for archive/<party>/incoming/). Operators can extend
// — e.g. setting default_tool=classifier on a custom dir activates
// grid mode there too — without touching this code.
//
// Iframe src resolution: <currentDirURL>/classifier.html. Iframe
// embedding only works in server mode; file:// pages don't get the
// Grid toggle.
(function () {
    'use strict';

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

    function classifierAvailableHere() {
        // state.scopeDefaultTool is set by the loader from the
        // X-ZDDC-Default-Tool response header on every listing fetch.
        // Grid mode is meaningful exactly where the cascade picks
        // classifier as the default — no client-side path matching.
        return state.scopeDefaultTool === 'classifier';
    }

    function activate() {
        var host = document.getElementById('gridView');
        if (!host) return;
        if (mounted) return;
        if (state.source !== 'server' || !classifierAvailableHere()) return;

        // Compute the iframe src: current page's directory + classifier.html.
        var pathname = window.location.pathname || '/';
        if (!pathname.endsWith('/')) {
            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;
    }

    // When the user navigates between scopes (client-side rescope on
    // dblclick), the iframe needs to be reloaded for the new path.
    // Callers reset before re-activating.
    function reset() {
        mounted = false;
        var host = document.getElementById('gridView');
        if (host) host.innerHTML = '';
    }

    window.app.modules.grid = {
        activate: activate,
        reset: reset,
        // Hook for events.js to show/hide the Grid toggle button.
        availableHere: function () {
            return state.source === 'server' && classifierAvailableHere();
        }
    };
})();