/**
 * OxiCloud WOPI Editor Integration
 *
 * Opens document files in Collabora Online / OnlyOffice via WOPI protocol.
 * Supports two modes: in-app modal (default) and new browser tab.
 */
class WopiEditor {
    constructor() {
        this.editorModal = null;
        this._escHandler = null;
        this._messageHandler = null;
        this._supportedExtensions = null;
    }

    /**
     * Check if a file can be opened in a WOPI editor by extension.
     * Fetches supported extensions from the server (cached after first call).
     */
    async canEdit(filename) {
        var ext = filename.split('.').pop().toLowerCase();
        var supported = await this._getSupportedExtensions();
        return supported.includes(ext);
    }

    /**
     * Open file in a modal overlay (default mode).
     */
    async openInModal(fileId, fileName, action) {
        action = action || 'edit';
        try {
            var data = await this._getEditorUrl(fileId, action);
            this._showModal(data, fileName);
        } catch (error) {
            console.error('Failed to open WOPI editor:', error);
            if (window.showNotification) {
                window.showNotification('Could not open the document editor.', 'error');
            }
        }
    }

    /**
     * Open file in a new browser tab.
     */
    async openInTab(fileId, fileName, action) {
        action = action || 'edit';
        try {
            var data = await this._getEditorUrl(fileId, action);
            var hostUrl = '/wopi/edit/' + encodeURIComponent(fileId)
                + '?access_token=' + encodeURIComponent(data.access_token);
            window.open(hostUrl, '_blank');
        } catch (error) {
            console.error('Failed to open WOPI editor in tab:', error);
            if (window.showNotification) {
                window.showNotification('Could not open the document editor.', 'error');
            }
        }
    }

    /**
     * Fetch editor URL and WOPI token from the backend.
     */
    async _getEditorUrl(fileId, action) {
        var token = localStorage.getItem('oxicloud_token') || '';
        var response = await fetch(
            '/api/wopi/editor-url?file_id=' + encodeURIComponent(fileId) + '&action=' + encodeURIComponent(action),
            {
                headers: { 'Authorization': 'Bearer ' + token }
            }
        );
        if (!response.ok) {
            var text = await response.text();
            throw new Error('Editor URL request failed: ' + response.status + ' ' + text);
        }
        return response.json();
    }

    /**
     * Show the editor in a full-screen modal with iframe.
     */
    _showModal(editorData, fileName) {
        this.closeEditor();

        var modal = document.createElement('div');
        modal.id = 'wopi-editor-modal';
        modal.style.cssText = 'position:fixed;top:0;left:0;width:100%;height:100%;z-index:10000;background:#fff;';

        var header = document.createElement('div');
        header.style.cssText = 'height:40px;background:#333;color:#fff;display:flex;align-items:center;justify-content:space-between;padding:0 16px;font-family:sans-serif;font-size:14px;';

        var title = document.createElement('span');
        title.textContent = fileName;
        header.appendChild(title);

        var closeBtn = document.createElement('button');
        closeBtn.textContent = '\u2715';
        closeBtn.style.cssText = 'background:none;border:none;color:#fff;cursor:pointer;font-size:18px;padding:4px 8px;';
        closeBtn.onclick = this.closeEditor.bind(this);
        header.appendChild(closeBtn);

        var form = document.createElement('form');
        form.id = 'wopi_form';
        form.target = 'wopi_frame';
        form.action = editorData.editor_url;
        form.method = 'post';
        form.style.display = 'none';

        var tokenInput = document.createElement('input');
        tokenInput.name = 'access_token';
        tokenInput.value = editorData.access_token;
        tokenInput.type = 'hidden';
        form.appendChild(tokenInput);

        var ttlInput = document.createElement('input');
        ttlInput.name = 'access_token_ttl';
        ttlInput.value = editorData.access_token_ttl;
        ttlInput.type = 'hidden';
        form.appendChild(ttlInput);

        var frameHolder = document.createElement('div');
        frameHolder.style.cssText = 'position:absolute;top:40px;left:0;right:0;bottom:0;';

        // Loading spinner (removed once the editor signals ready)
        var spinner = document.createElement('div');
        spinner.id = 'wopi-loading-spinner';
        spinner.style.cssText = 'position:absolute;top:0;left:0;right:0;bottom:0;display:flex;align-items:center;justify-content:center;background:#f5f5f5;z-index:1;';
        spinner.innerHTML = '<i class="fas fa-spinner fa-spin" style="font-size:48px;color:#666;"></i>';
        frameHolder.appendChild(spinner);

        var iframe = document.createElement('iframe');
        iframe.name = 'wopi_frame';
        iframe.title = 'Document Editor';
        iframe.style.cssText = 'width:100%;height:100%;border:none;';
        iframe.setAttribute('allowfullscreen', 'true');
        // Fix 9: allow clipboard access for copy/paste inside the editor
        iframe.setAttribute('allow', 'clipboard-read; clipboard-write');
        iframe.setAttribute('sandbox',
            'allow-scripts allow-same-origin allow-forms allow-popups allow-top-navigation allow-popups-to-escape-sandbox');
        frameHolder.appendChild(iframe);

        modal.appendChild(header);
        modal.appendChild(form);
        modal.appendChild(frameHolder);
        document.body.appendChild(modal);

        // ESC key handler
        this._escHandler = function(e) {
            if (e.key === 'Escape') this.closeEditor();
        }.bind(this);
        document.addEventListener('keydown', this._escHandler);

        // Fix 7: Listen for postMessage from the editor iframe
        this._messageHandler = function(e) {
            var data;
            try {
                data = JSON.parse(e.data);
            } catch (_) {
                return; // Not a JSON message — ignore
            }
            var msgId = data.MessageId || data.messageId || '';
            if (msgId === 'UI_Close' || msgId === 'close') {
                this.closeEditor();
            } else if (msgId === 'App_LoadingStatus') {
                var status = data.Values && data.Values.Status;
                if (status === 'Document_Loaded' || status === 'Frame_Ready') {
                    var sp = document.getElementById('wopi-loading-spinner');
                    if (sp) sp.remove();
                }
            }
        }.bind(this);
        window.addEventListener('message', this._messageHandler);

        form.submit();
        this.editorModal = modal;
    }

    /**
     * Close the editor modal and refresh the file list.
     */
    closeEditor() {
        var modal = document.getElementById('wopi-editor-modal');
        if (modal) modal.remove();
        if (this._escHandler) {
            document.removeEventListener('keydown', this._escHandler);
            this._escHandler = null;
        }
        if (this._messageHandler) {
            window.removeEventListener('message', this._messageHandler);
            this._messageHandler = null;
        }
        this.editorModal = null;
        // Refresh file list to pick up any saves
        if (typeof loadFiles === 'function') {
            loadFiles();
        }
    }

    /**
     * Fetch supported extensions from the server (cached).
     */
    async _getSupportedExtensions() {
        if (this._supportedExtensions !== null) {
            return this._supportedExtensions;
        }
        return this._fetchSupportedExtensions();
    }

    /**
     * Fetch supported extensions from /wopi/supported-extensions.
     * Falls back to a hardcoded list on failure.
     */
    async _fetchSupportedExtensions() {
        try {
            var response = await fetch('/wopi/supported-extensions');
            if (response.ok) {
                var exts = await response.json();
                if (Array.isArray(exts) && exts.length > 0) {
                    this._supportedExtensions = exts;
                    return exts;
                }
            }
        } catch (_) {
            // Ignore — fall through to hardcoded list
        }
        // Fallback hardcoded list
        this._supportedExtensions = [
            'docx', 'doc', 'odt', 'rtf', 'txt',
            'xlsx', 'xls', 'ods', 'csv',
            'pptx', 'ppt', 'odp',
        ];
        return this._supportedExtensions;
    }
}

// Global instance
window.wopiEditor = new WopiEditor();

// Prefetch supported extensions so canEdit() is fast on first use
window.wopiEditor._fetchSupportedExtensions();