// Lightweight Terminal Panel singleton
(() => {
    class TerminalPanelImpl {
        constructor() {
            this.container = null; // external container passed by DrawerComponent
            this.panelEl = null;
            this.logEl = null;
            this.inputEl = null;
            this.socket = null;
            this.connectedIp = null;
            this.isOpen = false;
            this.resizeHandler = null;
        }

        open(container, nodeIp) {
            try {
                this.container = container;
                if (!this.container) return;

                if (!this.panelEl) {
                    this._buildPanel();
                }

                // Reset any leftover inline positioning so CSS centering applies
                if (this.container) {
                    this.container.style.right = '';
                    this.container.style.left = '';
                    this.container.style.top = '';
                    this.container.style.bottom = '';
                    this.container.style.width = '';
                }

                // Show panel with animation
                requestAnimationFrame(() => {
                    this.panelEl.classList.add('visible');
                    this.isOpen = true;
                    this.inputEl && this.inputEl.focus();
                });

                // Connect websocket
                if (nodeIp) {
                    this._connect(nodeIp);
                }
            } catch (err) {
                console.error('TerminalPanel.open error:', err);
            }
        }

        close() {
            try {
                if (!this.isOpen) return;
                this.panelEl && this.panelEl.classList.remove('visible');
                this.isOpen = false;
                if (this.socket) {
                    try { this.socket.close(); } catch (_) {}
                    this.socket = null;
                }
            } catch (err) {
                console.error('TerminalPanel.close error:', err);
            }
        }

        _buildPanel() {
            // Ensure container baseline positioning
            this.container.classList.add('terminal-panel-container');
            // Create panel DOM
            this.panelEl = document.createElement('div');
            this.panelEl.className = 'terminal-panel';
            this.panelEl.innerHTML = `
                <div class="terminal-header">
                    <div class="terminal-title">Terminal</div>
                    <div class="terminal-actions">
                        <button class="terminal-clear-btn" title="Clear">Clear</button>
                        <button class="terminal-close-btn" title="Close">✕</button>
                    </div>
                </div>
                <div class="terminal-body">
                    <pre class="terminal-log"></pre>
                </div>
                <div class="terminal-input-row">
                    <input type="text" class="terminal-input" placeholder="Type and press Enter to send" />
                    <button class="terminal-send-btn">Send</button>
                </div>
            `;
            this.container.appendChild(this.panelEl);

            this.logEl = this.panelEl.querySelector('.terminal-log');
            this.inputEl = this.panelEl.querySelector('.terminal-input');
            const sendBtn = this.panelEl.querySelector('.terminal-send-btn');
            const closeBtn = this.panelEl.querySelector('.terminal-close-btn');
            const clearBtn = this.panelEl.querySelector('.terminal-clear-btn');

            const sendHandler = () => {
                const value = (this.inputEl && this.inputEl.value) || '';
                if (!value) return;
                this._send(value);
                this.inputEl.value = '';
            };

            if (sendBtn) sendBtn.addEventListener('click', (e) => { e.stopPropagation(); sendHandler(); });
            if (this.inputEl) this.inputEl.addEventListener('keydown', (e) => {
                if (e.key === 'Enter') {
                    e.preventDefault();
                    sendHandler();
                }
            });
            if (closeBtn) closeBtn.addEventListener('click', (e) => { e.stopPropagation(); this.close(); });
            if (clearBtn) clearBtn.addEventListener('click', (e) => { e.stopPropagation(); this._clear(); });
        }

        _connect(nodeIp) {
            try {
                const titleEl = this.panelEl.querySelector('.terminal-title');
                if (titleEl) titleEl.textContent = `Terminal — ${nodeIp}`;

                // Close previous socket if switching node
                if (this.socket) {
                    try { this.socket.close(); } catch (_) {}
                    this.socket = null;
                }

                const protocol = (window.location && window.location.protocol === 'https:') ? 'wss' : 'ws';
                const url = `${protocol}://${nodeIp}/ws`;
                this.connectedIp = nodeIp;
                this._appendLine(`[connecting] ${url}`);

                const ws = new WebSocket(url);
                this.socket = ws;

                ws.addEventListener('open', () => {
                    this._appendLine('[open] WebSocket connection established');
                });
                ws.addEventListener('message', (evt) => {
                    let dataStr = typeof evt.data === 'string' ? evt.data : '[binary]';
                    // Decode any HTML entities so JSON isn't shown as &quot; etc.
                    dataStr = this._decodeHtmlEntities(dataStr);
                    // Try to pretty-print JSON if applicable
                    const trimmed = dataStr.trim();
                    if ((trimmed.startsWith('{') && trimmed.endsWith('}')) || (trimmed.startsWith('[') && trimmed.endsWith(']'))) {
                        try {
                            const obj = JSON.parse(trimmed);
                            const pretty = JSON.stringify(obj, null, 2);
                            this._appendLine(pretty);
                            return;
                        } catch (_) {
                            // fall through if not valid JSON
                        }
                    }
                    this._appendLine(dataStr);
                });
                ws.addEventListener('error', (evt) => {
                    this._appendLine('[error] WebSocket error');
                });
                ws.addEventListener('close', () => {
                    this._appendLine('[close] WebSocket connection closed');
                });
            } catch (err) {
                console.error('TerminalPanel._connect error:', err);
                this._appendLine(`[error] ${err.message || err}`);
            }
        }

        _send(text) {
            try {
                if (!this.socket || this.socket.readyState !== 1) {
                    this._appendLine('[warn] Socket not open');
                    return;
                }
                this.socket.send(text);
                this._appendLine(`> ${text}`);
            } catch (err) {
                this._appendLine(`[error] ${err.message || err}`);
            }
        }

        _clear() {
            if (this.logEl) this.logEl.textContent = '';
        }

        _appendLine(line) {
            if (!this.logEl) return;
            const timestamp = new Date().toLocaleTimeString();
            this.logEl.textContent += `[${timestamp}] ${line}\n`;
            // Auto-scroll to bottom
            const bodyEl = this.panelEl.querySelector('.terminal-body');
            if (bodyEl) bodyEl.scrollTop = bodyEl.scrollHeight;
        }

        _decodeHtmlEntities(text) {
            try {
                const div = document.createElement('div');
                div.innerHTML = text;
                return div.textContent || div.innerText || '';
            } catch (_) {
                return text;
            }
        }
    }

    // Expose singleton API
    window.TerminalPanel = window.TerminalPanel || new TerminalPanelImpl();
})();