/**
 * Table utilities for handling data tables with pagination, sorting, and filtering
 */

class TableHandler {
  constructor(tableId, options = {}) {
    this.table = document.getElementById(tableId);
    this.options = {
      enableSorting: true,
      enableFiltering: true,
      enablePagination: true,
      loadingText: "Loading...",
      noDataText: "No data available",
      ...options,
    };

    this.currentPage = 1;
    this.itemsPerPage = options.itemsPerPage || 20;
    this.sortColumn = null;
    this.sortDirection = "asc";
    this.filters = {};

    this.initializeTable();
  }

  /**
   * Initialize table features
   */
  initializeTable() {
    if (!this.table) return;

    if (this.options.enableSorting) {
      this.setupSortingHandlers();
    }

    if (this.options.enableFiltering) {
      this.setupFilteringHandlers();
    }
  }

  /**
   * Set up sorting handlers for table headers
   */
  setupSortingHandlers() {
    const headers = this.table.querySelectorAll("th[data-sortable]");

    headers.forEach((header) => {
      header.style.cursor = "pointer";
      header.addEventListener("click", () => {
        const column = header.dataset.sortable;
        this.sortByColumn(column);
      });
    });
  }

  /**
   * Sort table by column
   * @param {string} column - Column to sort by
   */
  sortByColumn(column) {
    if (this.sortColumn === column) {
      this.sortDirection = this.sortDirection === "asc" ? "desc" : "asc";
    } else {
      this.sortColumn = column;
      this.sortDirection = "asc";
    }

    this.updateSortIndicators();
    this.refreshData();
  }

  /**
   * Update sort direction indicators in table headers
   */
  updateSortIndicators() {
    // Remove existing sort indicators
    this.table.querySelectorAll("th .sort-indicator").forEach((indicator) => {
      indicator.remove();
    });

    // Add indicator to current sort column
    if (this.sortColumn) {
      const header = this.table.querySelector(
        `th[data-sortable="${this.sortColumn}"]`
      );
      if (header) {
        const indicator = document.createElement("span");
        indicator.className = "sort-indicator";
        indicator.innerHTML = this.sortDirection === "asc" ? " ↑" : " ↓";
        header.appendChild(indicator);
      }
    }
  }

  /**
   * Set up filtering handlers
   */
  setupFilteringHandlers() {
    const filterInputs = document.querySelectorAll("[data-table-filter]");

    filterInputs.forEach((input) => {
      input.addEventListener("input", (e) => {
        const filterKey = e.target.dataset.tableFilter;
        this.setFilter(filterKey, e.target.value);
      });
    });
  }

  /**
   * Set a filter value
   * @param {string} key - Filter key
   * @param {string} value - Filter value
   */
  setFilter(key, value) {
    if (value && value.trim() !== "") {
      this.filters[key] = value.trim();
    } else {
      delete this.filters[key];
    }

    this.currentPage = 1; // Reset to first page when filtering
    this.refreshData();
  }

  /**
   * Show loading state
   */
  showLoading() {
    const tbody = this.table.querySelector("tbody");
    if (tbody) {
      const colCount = this.table.querySelectorAll("th").length;
      tbody.innerHTML = `
                <tr>
                    <td colspan="${colCount}" class="text-center">${this.options.loadingText}</td>
                </tr>
            `;
    }
  }

  /**
   * Show no data message
   */
  showNoData() {
    const tbody = this.table.querySelector("tbody");
    if (tbody) {
      const colCount = this.table.querySelectorAll("th").length;
      tbody.innerHTML = `
                <tr>
                    <td colspan="${colCount}" class="text-center">${this.options.noDataText}</td>
                </tr>
            `;
    }
  }

  /**
   * Render table data
   * @param {Array} data - Array of data objects
   * @param {Function} rowRenderer - Function to render each row
   */
  renderData(data, rowRenderer) {
    const tbody = this.table.querySelector("tbody");
    if (!tbody) return;

    if (!data || data.length === 0) {
      this.showNoData();
      return;
    }

    tbody.innerHTML = data.map(rowRenderer).join("");
  }

  /**
   * Build query parameters for API requests
   * @returns {object} Query parameters object
   */
  buildQueryParams() {
    const params = {
      page: this.currentPage,
      per_page: this.itemsPerPage,
      ...this.filters,
    };

    if (this.sortColumn) {
      params.sort_by = this.sortColumn;
      params.sort_dir = this.sortDirection;
    }

    return params;
  }

  /**
   * Refresh table data (to be implemented by subclasses or passed as callback)
   */
  refreshData() {
    if (this.options.onRefresh) {
      this.options.onRefresh(this.buildQueryParams());
    }
  }

  /**
   * Update pagination controls
   * @param {object} paginationInfo - Pagination information
   */
  updatePagination(paginationInfo) {
    const paginationContainer = document.querySelector(".pagination-container");
    if (!paginationContainer || !paginationInfo) return;

    // This is a basic implementation - you might want to enhance this
    const { current_page, total_pages, has_prev, has_next } = paginationInfo;

    let paginationHTML = '<nav><ul class="pagination justify-content-center">';

    // Previous button
    if (has_prev) {
      paginationHTML += `<li class="page-item"><a class="page-link" href="#" data-page="${
        current_page - 1
      }">Previous</a></li>`;
    } else {
      paginationHTML +=
        '<li class="page-item disabled"><span class="page-link">Previous</span></li>';
    }

    // Page numbers (simplified - show current and adjacent pages)
    const startPage = Math.max(1, current_page - 2);
    const endPage = Math.min(total_pages, current_page + 2);

    for (let i = startPage; i <= endPage; i++) {
      if (i === current_page) {
        paginationHTML += `<li class="page-item active"><span class="page-link">${i}</span></li>`;
      } else {
        paginationHTML += `<li class="page-item"><a class="page-link" href="#" data-page="${i}">${i}</a></li>`;
      }
    }

    // Next button
    if (has_next) {
      paginationHTML += `<li class="page-item"><a class="page-link" href="#" data-page="${
        current_page + 1
      }">Next</a></li>`;
    } else {
      paginationHTML +=
        '<li class="page-item disabled"><span class="page-link">Next</span></li>';
    }

    paginationHTML += "</ul></nav>";
    paginationContainer.innerHTML = paginationHTML;

    // Add click handlers for pagination links
    paginationContainer.querySelectorAll("a[data-page]").forEach((link) => {
      link.addEventListener("click", (e) => {
        e.preventDefault();
        this.currentPage = parseInt(e.target.dataset.page);
        this.refreshData();
      });
    });
  }
}

/**
 * Specialized table handler for papers
 */
class PapersTableHandler extends TableHandler {
  constructor(tableId, options = {}) {
    super(tableId, {
      apiEndpoint: "/api/papers",
      ...options,
    });
  }

  /**
   * Render a paper row
   * @param {object} paper - Paper data object
   * @returns {string} HTML string for table row
   */
  renderPaperRow(paper) {
    const statusBadge = createStatusBadge(paper.status);
    const truncatedTitle = truncateText(paper.title, 70);

    return `
            <tr>
                <td>
                    <a href="#" class="paper-link" data-url="/papers/${
                      paper.id
                    }/detail">
                        ${truncatedTitle}
                    </a>
                </td>
                <td>
                    <a href="https://doi.org/${paper.doi}" target="_blank">
                        ${paper.doi || "N/A"}
                    </a>
                </td>
                <td>${paper.journal || "N/A"}</td>
                <td>${paper.issn || "N/A"}</td>
                <td>${statusBadge}</td>
                <td>${formatTimestamp(paper.created_at)}</td>
                <td>${formatTimestamp(paper.updated_at)}</td>
            </tr>
        `;
  }

  /**
   * Load and display papers data
   * @param {object} params - Query parameters
   */
  async loadPapers(params = {}) {
    this.showLoading();

    try {
      const queryString = new URLSearchParams(params).toString();
      const url = `${this.options.apiEndpoint}?${queryString}`;

      const response = await fetch(url);
      const data = await response.json();

      if (data.papers) {
        this.renderData(data.papers, (paper) => this.renderPaperRow(paper));

        if (data.pagination) {
          this.updatePagination(data.pagination);
        }
      } else {
        this.showNoData();
      }
    } catch (error) {
      console.error("Error loading papers:", error);
      this.showNoData();
    }
  }

  /**
   * Refresh data implementation
   */
  refreshData() {
    this.loadPapers(this.buildQueryParams());
  }
}