/**
 * GraphVisualizer - Bộ Trực Quan Hóa Đồ Thị
 * Hiển thị đồ thị tính toán ONNX bằng Cytoscape.js
 * Requirements: 4.1, 4.2, 4.3, 4.4, 4.5, 4.6
 */

class GraphVisualizer {
    constructor() {
        /** @type {cytoscape.Core|null} */
        this._cy = null;

        /** @type {string|null} */
        this._selectedNodeId = null;

        /** @type {string|null} */
        this._highlightedNodeId = null;

        /** @type {Function|null} Unsubscribe from StateManager */
        this._unsubscribeState = null;

        /** @type {HTMLElement|null} */
        this._container = null;

        /** @type {HTMLElement|null} Tooltip element */
        this._tooltip = null;
    }

    // ─── Public API ────────────────────────────────────────────────────────────

    /**
     * Khởi tạo trực quan hóa đồ thị trong container element.
     * @param {HTMLElement} containerElement
     * @param {Array} graphData - Cytoscape elements array từ GraphProcessor
     */
    initialize(containerElement, graphData) {
        if (!containerElement) {
            console.error('[GraphVisualizer] containerElement is required');
            return;
        }

        this._container = containerElement;

        // Ensure container has an id
        if (!containerElement.id) {
            containerElement.id = 'graph-visualizer-' + Date.now();
        }

        // Destroy existing instance if any
        if (this._cy) {
            this._cy.destroy();
            this._cy = null;
        }

        // Remove old tooltip
        this._removeTooltip();

        // Create tooltip element
        this._createTooltip();

        // Build cytoscape stylesheet
        const stylesheet = this._buildStylesheet();

        // Determine layout
        const layout = this._buildLayout();

        // Initialize Cytoscape
        this._cy = cytoscape({
            container: containerElement,
            elements: graphData || [],
            style: stylesheet,
            layout: layout,
            minZoom: CONFIG.GRAPH.MIN_ZOOM,
            maxZoom: CONFIG.GRAPH.MAX_ZOOM,
            zoom: CONFIG.GRAPH.DEFAULT_ZOOM,
            wheelSensitivity: 0.3,
            boxSelectionEnabled: false,
            autounselectify: false
        });

        // Bind user interactions
        this._bindEvents();

        // Subscribe to StateManager selectedNodeId changes
        this._subscribeToState();

        console.log('[GraphVisualizer] Initialized with', (graphData || []).length, 'elements');
    }

    /**
     * Cập nhật đồ thị với dữ liệu mới.
     * @param {Array} graphData - Cytoscape elements array
     */
    updateGraph(graphData) {
        if (!this._cy) {
            console.warn('[GraphVisualizer] Not initialized. Call initialize() first.');
            return;
        }

        // Use requestAnimationFrame for smooth rendering
        requestAnimationFrame(() => {
            this._cy.elements().remove();
            this._cy.add(graphData || []);

            const layout = this._buildLayout();
            const layoutInstance = this._cy.layout(layout);
            layoutInstance.run();

            this._selectedNodeId = null;
            this._highlightedNodeId = null;
        });
    }

    /**
     * Làm nổi bật một nút theo id.
     * @param {string} nodeId
     */
    highlightNode(nodeId) {
        if (!this._cy) return;

        // Clear previous highlight
        this.clearHighlight();

        const node = this._cy.getElementById(nodeId);
        if (node && node.length > 0) {
            node.addClass('highlighted');
            this._highlightedNodeId = nodeId;

            // Pan to the node
            this._cy.animate({
                center: { eles: node },
                duration: 300
            });
        }
    }

    /**
     * Xóa làm nổi bật tất cả các nút.
     */
    clearHighlight() {
        if (!this._cy) return;
        this._cy.elements().removeClass('highlighted');
        this._highlightedNodeId = null;
    }

    /**
     * Đặt mức phóng to.
     * @param {number} level
     */
    zoom(level) {
        if (!this._cy) return;
        const clamped = Math.min(
            Math.max(level, CONFIG.GRAPH.MIN_ZOOM),
            CONFIG.GRAPH.MAX_ZOOM
        );
        this._cy.zoom(clamped);
        this._cy.center();
        if (typeof StateManager !== 'undefined') {
            StateManager.setZoomLevel(clamped);
        }
    }

    /**
     * Phóng to thêm một bước.
     */
    zoomIn() {
        if (!this._cy) return;
        this.zoom(this._cy.zoom() + CONFIG.GRAPH.ZOOM_STEP);
    }

    /**
     * Thu nhỏ một bước.
     */
    zoomOut() {
        if (!this._cy) return;
        this.zoom(this._cy.zoom() - CONFIG.GRAPH.ZOOM_STEP);
    }

    /**
     * Fit đồ thị vào container.
     */
    fit() {
        if (!this._cy) return;
        this._cy.fit();
        if (typeof StateManager !== 'undefined') {
            StateManager.setZoomLevel(this._cy.zoom());
        }
    }

    /**
     * Reset về zoom mặc định và vị trí trung tâm.
     */
    reset() {
        if (!this._cy) return;
        this._cy.zoom(CONFIG.GRAPH.DEFAULT_ZOOM);
        this._cy.center();
        if (typeof StateManager !== 'undefined') {
            StateManager.setZoomLevel(CONFIG.GRAPH.DEFAULT_ZOOM);
        }
    }

    /**
     * Lấy nút đang được chọn.
     * @returns {Object|null} Node data object hoặc null
     */
    getSelectedNode() {
        if (!this._cy || !this._selectedNodeId) return null;
        const node = this._cy.getElementById(this._selectedNodeId);
        if (node && node.length > 0) {
            return node.data();
        }
        return null;
    }

    /**
     * Hủy và dọn dẹp tài nguyên.
     */
    destroy() {
        if (this._unsubscribeState) {
            this._unsubscribeState();
            this._unsubscribeState = null;
        }
        this._removeTooltip();
        if (this._cy) {
            this._cy.destroy();
            this._cy = null;
        }
        this._container = null;
        this._selectedNodeId = null;
        this._highlightedNodeId = null;
    }

    // ─── Private Helpers ───────────────────────────────────────────────────────

    /**
     * Xây dựng stylesheet cho Cytoscape.
     * @private
     */
    _buildStylesheet() {
        return [
            // ── Base node style ──────────────────────────────────────────────
            {
                selector: 'node',
                style: {
                    'label': 'data(label)',
                    'text-valign': 'center',
                    'text-halign': 'center',
                    'font-size': '10px',
                    'color': '#fff',
                    'text-outline-width': 1,
                    'text-outline-color': '#555',
                    'width': 'label',
                    'height': 'label',
                    'padding': '8px',
                    'shape': 'roundrectangle',
                    'background-color': CONFIG.GRAPH.NODE_DEFAULT_COLOR,
                    'border-width': 1,
                    'border-color': '#5a9ab5',
                    'cursor': 'pointer',
                    'transition-property': 'background-color, border-color, border-width',
                    'transition-duration': '0.15s'
                }
            },
            // ── Input node ───────────────────────────────────────────────────
            {
                selector: '.input-node',
                style: {
                    'background-color': '#28a745',
                    'border-color': '#1e7e34',
                    'shape': 'ellipse'
                }
            },
            // ── Output node ──────────────────────────────────────────────────
            {
                selector: '.output-node',
                style: {
                    'background-color': '#dc3545',
                    'border-color': '#bd2130',
                    'shape': 'ellipse'
                }
            },
            // ── Op node ──────────────────────────────────────────────────────
            {
                selector: '.op-node',
                style: {
                    'background-color': CONFIG.GRAPH.NODE_DEFAULT_COLOR,
                    'border-color': '#5a9ab5'
                }
            },
            // ── Initializer node ─────────────────────────────────────────────
            {
                selector: '.initializer-node',
                style: {
                    'background-color': '#6c757d',
                    'border-color': '#545b62',
                    'shape': 'diamond',
                    'font-size': '9px'
                }
            },
            // ── Cluster node ─────────────────────────────────────────────────
            {
                selector: '.cluster-node',
                style: {
                    'background-color': '#6f42c1',
                    'border-color': '#5a32a3',
                    'shape': 'roundrectangle'
                }
            },
            // ── Highlighted node ─────────────────────────────────────────────
            {
                selector: '.highlighted',
                style: {
                    'background-color': CONFIG.GRAPH.NODE_HIGHLIGHT_COLOR,
                    'border-color': '#e6b800',
                    'border-width': 3,
                    'color': '#333',
                    'text-outline-color': '#fff',
                    'z-index': 999
                }
            },
            // ── Selected node ────────────────────────────────────────────────
            {
                selector: 'node:selected',
                style: {
                    'border-width': 3,
                    'border-color': '#0d6efd',
                    'background-color': CONFIG.GRAPH.NODE_HIGHLIGHT_COLOR,
                    'color': '#333',
                    'text-outline-color': '#fff'
                }
            },
            // ── Edge ─────────────────────────────────────────────────────────
            {
                selector: 'edge',
                style: {
                    'width': 1.5,
                    'line-color': CONFIG.GRAPH.EDGE_DEFAULT_COLOR,
                    'target-arrow-color': CONFIG.GRAPH.EDGE_DEFAULT_COLOR,
                    'target-arrow-shape': 'triangle',
                    'curve-style': 'bezier',
                    'arrow-scale': 0.8,
                    'opacity': 0.8
                }
            },
            // ── Edge label ───────────────────────────────────────────────────
            {
                selector: 'edge[label]',
                style: {
                    'label': 'data(label)',
                    'font-size': '8px',
                    'color': '#666',
                    'text-rotation': 'autorotate',
                    'text-margin-y': -6
                }
            },
            // ── Path highlighted (node/edge on traced path) ─────────────────
            {
                selector: '.path-highlighted',
                style: {
                    'opacity': 1,
                    'z-index': 900
                }
            },
            {
                selector: 'node.path-highlighted',
                style: {
                    'border-width': 3,
                    'border-color': '#0d6efd',
                    'background-color': '#4dabf7'
                }
            },
            {
                selector: 'edge.path-highlighted',
                style: {
                    'line-color': '#0d6efd',
                    'target-arrow-color': '#0d6efd',
                    'width': 2.5,
                    'opacity': 1
                }
            },
            // ── Path dimmed (elements NOT on traced path) ───────────────────
            {
                selector: '.path-dimmed',
                style: {
                    'opacity': 0.15
                }
            },
            // ── Path source (the node the trace started from) ───────────────
            {
                selector: '.path-source',
                style: {
                    'border-width': 4,
                    'border-color': '#ff6b6b',
                    'background-color': '#ffa94d',
                    'z-index': 999
                }
            },
            // ── Search highlighted node ──────────────────────────────────────
            {
                selector: '.search-highlighted',
                style: {
                    'background-color': '#ff6b6b',
                    'border-color': '#e03131',
                    'border-width': 3,
                    'z-index': 998
                }
            },
            // ── Current search result (active) ──────────────────────────────
            {
                selector: '.search-active',
                style: {
                    'background-color': '#ff922b',
                    'border-color': '#e8590c',
                    'border-width': 4,
                    'z-index': 999
                }
            },
            // ── Compound group parent node ──────────────────────────────────
            {
                selector: '.group-parent, .group-node',
                style: {
                    'background-color': 'rgba(108, 117, 125, 0.12)',
                    'background-opacity': 0.12,
                    'border-width': 2,
                    'border-color': '#6c757d',
                    'border-style': 'dashed',
                    'shape': 'roundrectangle',
                    'padding': '16px',
                    'text-valign': 'top',
                    'text-halign': 'center',
                    'font-size': '12px',
                    'font-weight': 'bold',
                    'color': '#495057',
                    'text-outline-width': 0,
                    'label': 'data(label)',
                    'min-width': '80px',
                    'min-height': '40px'
                }
            },
            // ── Collapsed compound group ────────────────────────────────────
            {
                selector: '.group-parent.collapsed',
                style: {
                    'background-color': 'rgba(13, 110, 253, 0.15)',
                    'background-opacity': 0.15,
                    'border-color': '#0d6efd',
                    'border-style': 'solid',
                    'padding': '12px',
                    'min-width': '100px',
                    'min-height': '36px',
                    'text-valign': 'center',
                    'text-halign': 'center',
                    'color': '#0d6efd'
                }
            },
            // ── Node with annotation badge ──────────────────────────────────
            {
                selector: '.has-annotation',
                style: {
                    'border-width': 3,
                    'border-color': '#fd7e14',
                    'border-style': 'double'
                }
            }
        ];
    }

    /**
     * Xây dựng cấu hình layout.
     * @private
     */
    _buildLayout() {
        // Try dagre first (requires cytoscape-dagre plugin), fallback to breadthfirst
        const hasDagre = typeof cytoscapeDagre !== 'undefined' ||
            (cytoscape && cytoscape('layout', 'dagre'));

        return {
            name: 'breadthfirst',
            directed: true,
            padding: 20,
            spacingFactor: 1.2,
            avoidOverlap: true,
            nodeDimensionsIncludeLabels: true,
            animate: false
        };
    }

    /**
     * Bind Cytoscape event handlers.
     * @private
     */
    _bindEvents() {
        if (!this._cy) return;

        // Node click
        this._cy.on('tap', 'node', (evt) => {
            // Skip normal node click when Shift is held (path highlighter handles it)
            if (evt.originalEvent && evt.originalEvent.shiftKey) return;

            const node = evt.target;
            const nodeData = node.data();
            this._onNodeClick(nodeData, evt);
        });

        // Background click → deselect
        this._cy.on('tap', (evt) => {
            if (evt.target === this._cy) {
                this._onBackgroundClick();
            }
        });

        // Node mouseover → show tooltip
        this._cy.on('mouseover', 'node', (evt) => {
            const node = evt.target;
            this._showTooltip(node, evt.originalEvent);
        });

        // Node mouseout → hide tooltip
        this._cy.on('mouseout', 'node', () => {
            this._hideTooltip();
        });

        // Zoom change → update StateManager
        this._cy.on('zoom', () => {
            if (typeof StateManager !== 'undefined') {
                StateManager.setZoomLevel(this._cy.zoom());
            }
            // Persist zoom preference to localStorage
            try {
                const key = (typeof CONFIG !== 'undefined' && CONFIG.STORAGE)
                    ? CONFIG.STORAGE.USER_PREFERENCES
                    : 'onnx_explorer_preferences';
                const existing = JSON.parse(localStorage.getItem(key) || '{}');
                existing.zoomLevel = this._cy.zoom();
                localStorage.setItem(key, JSON.stringify(existing));
            } catch (_) { /* ignore */ }
        });
    }

    /**
     * Handle node click.
     * @private
     */
    _onNodeClick(nodeData, evt) {
        this._selectedNodeId = nodeData.id;

        // Update StateManager
        if (typeof StateManager !== 'undefined') {
            StateManager.setSelectedNodeId(nodeData.id);
        }

        // Emit NODE_SELECTED event via EventBus
        if (typeof EventBus !== 'undefined') {
            EventBus.emit(CONFIG.EVENTS.NODE_SELECTED, { nodeId: nodeData.id, nodeData });
        }

        // Highlight the clicked node
        this.clearHighlight();
        const node = this._cy.getElementById(nodeData.id);
        if (node && node.length > 0) {
            node.addClass('highlighted');
            this._highlightedNodeId = nodeData.id;
        }

        // Show node details in tooltip (positioned near click)
        if (evt && evt.originalEvent) {
            this._showTooltip(this._cy.getElementById(nodeData.id), evt.originalEvent);
        }
    }

    /**
     * Handle background click.
     * @private
     */
    _onBackgroundClick() {
        this._selectedNodeId = null;
        this.clearHighlight();
        this._hideTooltip();

        if (typeof StateManager !== 'undefined') {
            StateManager.setSelectedNodeId(null);
        }

        // Clear path highlighting if active
        if (typeof EventBus !== 'undefined') {
            EventBus.emit('path:clear-requested', {});
        }
    }

    /**
     * Subscribe to StateManager selectedNodeId changes.
     * @private
     */
    _subscribeToState() {
        if (typeof StateManager === 'undefined') return;

        this._unsubscribeState = StateManager.subscribe('selectedNodeId', (newNodeId) => {
            if (newNodeId && newNodeId !== this._highlightedNodeId) {
                this.highlightNode(newNodeId);
            } else if (!newNodeId) {
                this.clearHighlight();
            }
        });
    }

    /**
     * Create tooltip DOM element.
     * @private
     */
    _createTooltip() {
        const tooltip = document.createElement('div');
        tooltip.className = 'graph-node-tooltip';
        tooltip.style.cssText = [
            'position: fixed',
            'z-index: 9999',
            'background: rgba(30,30,30,0.95)',
            'color: #fff',
            'padding: 8px 12px',
            'border-radius: 6px',
            'font-size: 12px',
            'max-width: 280px',
            'pointer-events: none',
            'display: none',
            'box-shadow: 0 2px 8px rgba(0,0,0,0.4)',
            'line-height: 1.5'
        ].join(';');
        document.body.appendChild(tooltip);
        this._tooltip = tooltip;
    }

    /**
     * Remove tooltip from DOM.
     * @private
     */
    _removeTooltip() {
        if (this._tooltip && this._tooltip.parentNode) {
            this._tooltip.parentNode.removeChild(this._tooltip);
        }
        this._tooltip = null;
    }

    /**
     * Show tooltip for a node.
     * @param {cytoscape.NodeSingular} node
     * @param {MouseEvent} mouseEvent
     * @private
     */
    _showTooltip(node, mouseEvent) {
        if (!this._tooltip || !node || node.length === 0) return;

        const data = node.data();
        const html = this._buildTooltipHTML(data);
        this._tooltip.innerHTML = html;
        this._tooltip.style.display = 'block';

        this._positionTooltip(mouseEvent);
    }

    /**
     * Hide tooltip.
     * @private
     */
    _hideTooltip() {
        if (this._tooltip) {
            this._tooltip.style.display = 'none';
        }
    }

    /**
     * Position tooltip near the mouse cursor.
     * @param {MouseEvent} mouseEvent
     * @private
     */
    _positionTooltip(mouseEvent) {
        if (!this._tooltip || !mouseEvent) return;

        const offset = 12;
        let x = mouseEvent.clientX + offset;
        let y = mouseEvent.clientY + offset;

        // Keep within viewport
        const rect = this._tooltip.getBoundingClientRect();
        if (x + rect.width > window.innerWidth) {
            x = mouseEvent.clientX - rect.width - offset;
        }
        if (y + rect.height > window.innerHeight) {
            y = mouseEvent.clientY - rect.height - offset;
        }

        this._tooltip.style.left = x + 'px';
        this._tooltip.style.top = y + 'px';
    }

    /**
     * Build tooltip HTML content for a node.
     * @param {Object} data - Node data
     * @returns {string}
     * @private
     */
    _buildTooltipHTML(data) {
        const lines = [];

        // Name / label
        if (data.name && data.name !== data.label) {
            lines.push(`<strong>${this._escapeHtml(data.label || data.id)}</strong>`);
            lines.push(`<span style="color:#aaa">Name: ${this._escapeHtml(data.name)}</span>`);
        } else {
            lines.push(`<strong>${this._escapeHtml(data.label || data.id)}</strong>`);
        }

        // Op type
        if (data.opType) {
            lines.push(`<span>Type: <em>${this._escapeHtml(data.opType)}</em></span>`);
        }

        // Shape (for input/output/initializer)
        if (data.shape && data.shape.length > 0) {
            lines.push(`<span>Shape: [${data.shape.join(', ')}]</span>`);
        }

        // Data type
        if (data.dataType) {
            lines.push(`<span>DType: ${this._escapeHtml(String(data.dataType))}</span>`);
        }

        // Attributes (for op nodes)
        if (data.attributes && typeof data.attributes === 'object') {
            const attrKeys = Object.keys(data.attributes);
            if (attrKeys.length > 0) {
                lines.push('<span style="color:#aaa;margin-top:4px;display:block">Attributes:</span>');
                attrKeys.slice(0, 6).forEach((key) => {
                    const val = data.attributes[key];
                    const valStr = this._formatAttrValue(val);
                    lines.push(`<span style="padding-left:8px">${this._escapeHtml(key)}: ${valStr}</span>`);
                });
                if (attrKeys.length > 6) {
                    lines.push(`<span style="color:#aaa;padding-left:8px">...+${attrKeys.length - 6} more</span>`);
                }
            }
        }

        // Cluster info
        if (data.isCluster && data.nodeCount) {
            lines.push(`<span style="color:#aaa">${data.nodeCount} nodes</span>`);
        }

        return lines.join('<br>');
    }

    /**
     * Format an attribute value for display.
     * @param {*} val
     * @returns {string}
     * @private
     */
    _formatAttrValue(val) {
        if (val === null || val === undefined) return '<em>null</em>';
        if (Array.isArray(val)) {
            const preview = val.slice(0, 4).join(', ');
            return `[${this._escapeHtml(preview)}${val.length > 4 ? '...' : ''}]`;
        }
        const str = String(val);
        return this._escapeHtml(str.length > 40 ? str.slice(0, 40) + '…' : str);
    }

    /**
     * Escape HTML special characters.
     * @param {string} str
     * @returns {string}
     * @private
     */
    _escapeHtml(str) {
        return String(str)
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;');
    }
}

// Export as global for browser usage
window.GraphVisualizer = GraphVisualizer;