/**
 * GraphSearch - Tìm Kiếm Node Trong Đồ Thị
 * Cung cấp ô tìm kiếm trong khu vực đồ thị, highlight và auto-zoom đến node tìm thấy.
 * Requirements: 30.1, 30.2, 30.3, 30.4, 30.5, 30.6
 */

class GraphSearch {
    /**
     * @param {string} graphContainerSelector - CSS selector cho container đồ thị (ví dụ: '#graphContainer')
     */
    constructor(graphContainerSelector) {
        /** @type {string} */
        this._graphContainerSelector = graphContainerSelector;

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

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

        /** @type {HTMLInputElement|null} */
        this._searchInput = null;

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

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

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

        /** @type {Array<string>} - List of matched node IDs */
        this._results = [];

        /** @type {number} - Current result index */
        this._currentIndex = -1;

        /** @type {number|null} - Debounce timer ID */
        this._debounceTimer = null;

        /** @type {number} - Debounce delay in ms */
        this._debounceDelay = 300;
    }

    /**
     * Khởi tạo: tạo ô tìm kiếm, gắn event listeners.
     */
    init() {
        this._graphContainer = document.querySelector(this._graphContainerSelector);
        if (!this._graphContainer) {
            console.warn('[GraphSearch] Graph container not found:', this._graphContainerSelector);
            return;
        }

        this._createSearchUI();
        this._bindEvents();

        console.log('[GraphSearch] Initialized');
    }

    /**
     * Tìm kiếm node theo từ khóa (tên hoặc opType).
     * @param {string} query - Từ khóa tìm kiếm
     * @returns {Array<string>} Danh sách node IDs khớp
     */
    search(query) {
        var cy = this._getCy();
        this._clearHighlights();
        this._results = [];
        this._currentIndex = -1;

        if (!query || !query.trim() || !cy) {
            this._updateDisplay();
            return this._results;
        }

        var lowerQuery = query.trim().toLowerCase();

        cy.nodes().forEach(function (node) {
            var label = (node.data('label') || '').toLowerCase();
            var name = (node.data('name') || '').toLowerCase();
            var opType = (node.data('opType') || '').toLowerCase();

            if (label.indexOf(lowerQuery) !== -1 ||
                name.indexOf(lowerQuery) !== -1 ||
                opType.indexOf(lowerQuery) !== -1) {
                this._results.push(node.id());
            }
        }.bind(this));

        // Highlight all matched nodes
        for (var i = 0; i < this._results.length; i++) {
            var node = cy.getElementById(this._results[i]);
            if (node && node.length > 0) {
                node.addClass('search-highlighted');
            }
        }

        // Navigate to first result
        if (this._results.length > 0) {
            this._currentIndex = 0;
            this._goToCurrentResult();
        }

        this._updateDisplay();
        return this._results;
    }

    /**
     * Highlight và zoom đến node tiếp theo trong kết quả.
     */
    next() {
        if (this._results.length === 0) return;
        this._currentIndex = (this._currentIndex + 1) % this._results.length;
        this._goToCurrentResult();
        this._updateDisplay();
    }

    /**
     * Highlight và zoom đến node trước đó trong kết quả.
     */
    prev() {
        if (this._results.length === 0) return;
        this._currentIndex = (this._currentIndex - 1 + this._results.length) % this._results.length;
        this._goToCurrentResult();
        this._updateDisplay();
    }

    /**
     * Xóa tất cả highlight tìm kiếm.
     */
    clearSearch() {
        this._clearHighlights();
        this._results = [];
        this._currentIndex = -1;
        if (this._searchInput) {
            this._searchInput.value = '';
        }
        this._updateDisplay();
    }

    /**
     * Hủy và dọn dẹp.
     */
    destroy() {
        if (this._debounceTimer) {
            clearTimeout(this._debounceTimer);
            this._debounceTimer = null;
        }
        this._clearHighlights();
        if (this._searchContainer && this._searchContainer.parentNode) {
            this._searchContainer.parentNode.removeChild(this._searchContainer);
        }
        this._searchContainer = null;
        this._searchInput = null;
        this._countDisplay = null;
        this._noResultsDisplay = null;
        this._navContainer = null;
        this._results = [];
        this._currentIndex = -1;
    }

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

    /**
     * Get the Cytoscape instance from the app.
     * @returns {cytoscape.Core|null}
     * @private
     */
    _getCy() {
        try {
            if (window._onnxApp && typeof window._onnxApp.getGraphVisualizer === 'function') {
                var gv = window._onnxApp.getGraphVisualizer();
                if (gv && gv._cy) {
                    return gv._cy;
                }
            }
        } catch (e) {
            console.warn('[GraphSearch] Could not access Cytoscape instance:', e);
        }
        return null;
    }

    /**
     * Create the search UI elements and insert above the graph container.
     * @private
     */
    _createSearchUI() {
        // Main container
        var container = document.createElement('div');
        container.className = 'graph-search-container';

        // Search input
        var input = document.createElement('input');
        input.type = 'text';
        input.className = 'graph-search-input';
        input.placeholder = 'Tìm kiếm node (tên hoặc opType)...';
        input.setAttribute('aria-label', 'Search graph nodes');
        this._searchInput = input;

        // Navigation container (hidden by default)
        var navContainer = document.createElement('div');
        navContainer.className = 'graph-search-nav';
        navContainer.style.display = 'none';
        this._navContainer = navContainer;

        // Count display
        var countDisplay = document.createElement('span');
        countDisplay.className = 'graph-search-count';
        this._countDisplay = countDisplay;

        // Prev button
        var prevBtn = document.createElement('button');
        prevBtn.type = 'button';
        prevBtn.innerHTML = '<i class="fas fa-chevron-up"></i>';
        prevBtn.title = 'Previous result';
        prevBtn.setAttribute('aria-label', 'Previous search result');
        prevBtn.addEventListener('click', this.prev.bind(this));

        // Next button
        var nextBtn = document.createElement('button');
        nextBtn.type = 'button';
        nextBtn.innerHTML = '<i class="fas fa-chevron-down"></i>';
        nextBtn.title = 'Next result';
        nextBtn.setAttribute('aria-label', 'Next search result');
        nextBtn.addEventListener('click', this.next.bind(this));

        navContainer.appendChild(countDisplay);
        navContainer.appendChild(prevBtn);
        navContainer.appendChild(nextBtn);

        // No results display (hidden by default)
        var noResults = document.createElement('span');
        noResults.className = 'graph-search-count';
        noResults.textContent = 'Không tìm thấy kết quả';
        noResults.style.display = 'none';
        noResults.style.color = '#dc3545';
        this._noResultsDisplay = noResults;

        container.appendChild(input);
        container.appendChild(navContainer);
        container.appendChild(noResults);

        // Insert above #graphContainer in the card body
        var parent = this._graphContainer.parentNode;
        if (parent) {
            parent.insertBefore(container, this._graphContainer);
        }

        this._searchContainer = container;
    }

    /**
     * Bind event listeners.
     * @private
     */
    _bindEvents() {
        if (!this._searchInput) return;

        this._searchInput.addEventListener('input', function () {
            if (this._debounceTimer) {
                clearTimeout(this._debounceTimer);
            }
            this._debounceTimer = setTimeout(function () {
                var query = this._searchInput.value;
                this.search(query);
            }.bind(this), this._debounceDelay);
        }.bind(this));

        // Allow Enter to go to next result
        this._searchInput.addEventListener('keydown', function (e) {
            if (e.key === 'Enter') {
                e.preventDefault();
                if (e.shiftKey) {
                    this.prev();
                } else {
                    this.next();
                }
            }
            if (e.key === 'Escape') {
                this.clearSearch();
                this._searchInput.blur();
            }
        }.bind(this));
    }

    /**
     * Navigate to the current result node (highlight + zoom).
     * @private
     */
    _goToCurrentResult() {
        var cy = this._getCy();
        if (!cy || this._currentIndex < 0 || this._currentIndex >= this._results.length) return;

        // Remove 'search-active' from all nodes
        cy.nodes().removeClass('search-active');

        var nodeId = this._results[this._currentIndex];
        var node = cy.getElementById(nodeId);
        if (node && node.length > 0) {
            node.addClass('search-active');
            cy.animate({
                center: { eles: node },
                zoom: 1.5,
                duration: 300
            });
        }
    }

    /**
     * Clear all search highlights from the graph.
     * @private
     */
    _clearHighlights() {
        var cy = this._getCy();
        if (!cy) return;
        cy.nodes().removeClass('search-highlighted');
        cy.nodes().removeClass('search-active');
    }

    /**
     * Update the display (count, nav visibility, no-results message).
     * @private
     */
    _updateDisplay() {
        var hasQuery = this._searchInput && this._searchInput.value.trim().length > 0;
        var hasResults = this._results.length > 0;

        // Navigation container
        if (this._navContainer) {
            this._navContainer.style.display = (hasQuery && hasResults) ? 'flex' : 'none';
        }

        // Count display
        if (this._countDisplay) {
            if (hasResults) {
                this._countDisplay.textContent = (this._currentIndex + 1) + '/' + this._results.length;
            } else {
                this._countDisplay.textContent = '';
            }
        }

        // No results message
        if (this._noResultsDisplay) {
            this._noResultsDisplay.style.display = (hasQuery && !hasResults) ? 'inline' : 'none';
        }
    }
}

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