/**
 * ajax-pagination.js - Common JavaScript for AJAX pagination across the application
 *
 * This script handles AJAX-based pagination for all pages in the Chat Analytics Dashboard.
 * It intercepts pagination link clicks, loads content via AJAX, and updates the browser history.
 */

document.addEventListener("DOMContentLoaded", function () {
    // Initialize AJAX pagination
    setupAjaxPagination();

    // Function to set up AJAX pagination for the entire application
    function setupAjaxPagination() {
        // Configuration - can be customized per page if needed
        const config = {
            contentContainerId: "ajax-content-container", // ID of the container to update
            loadingSpinnerId: "ajax-loading-spinner", // ID of the loading spinner
            paginationLinkClass: "pagination-link", // Class for pagination links
            retryMessage: "An error occurred while loading data. Please try again.",
        };

        // Get container elements
        const contentContainer = document.getElementById(config.contentContainerId);
        const loadingSpinner = document.getElementById(config.loadingSpinnerId);

        // Exit if the page doesn't have the required elements
        if (!contentContainer || !loadingSpinner) return;

        // Function to handle pagination clicks
        function setupPaginationListeners() {
            document.querySelectorAll("." + config.paginationLinkClass).forEach((link) => {
                link.addEventListener("click", function (e) {
                    e.preventDefault();
                    handleAjaxNavigation(this.href);

                    // Get the page number if available
                    const page = this.getAttribute("data-page");

                    // Update browser URL without refreshing
                    const newUrl = this.href;
                    history.pushState({ url: newUrl, page: page }, "", newUrl);
                });
            });
        }

        // Function to handle AJAX navigation
        function handleAjaxNavigation(url) {
            // Show loading spinner
            contentContainer.classList.add("d-none");
            loadingSpinner.classList.remove("d-none");

            // Fetch data via AJAX
            fetch(url, {
                headers: {
                    "X-Requested-With": "XMLHttpRequest",
                },
            })
                .then((response) => {
                    if (!response.ok) {
                        throw new Error(`Network response was not ok: ${response.status}`);
                    }
                    return response.json();
                })
                .then((data) => {
                    if (data.status === "success") {
                        // Update the content
                        contentContainer.innerHTML = data.html_data;

                        // Re-attach event listeners to new pagination links
                        setupPaginationListeners();

                        // Update any summary data if present and the page provides it
                        if (typeof updateSummary === "function" && data.summary) {
                            updateSummary(data);
                        }

                        // Hide loading spinner, show content
                        loadingSpinner.classList.add("d-none");
                        contentContainer.classList.remove("d-none");

                        // Scroll to top of the content container
                        contentContainer.scrollIntoView({ behavior: "smooth", block: "start" });
                    }
                })
                .catch((error) => {
                    console.error("Error fetching data:", error);
                    loadingSpinner.classList.add("d-none");
                    contentContainer.classList.remove("d-none");
                    alert(config.retryMessage);
                });
        }

        // Initial setup of event listeners
        setupPaginationListeners();

        // Handle browser back/forward buttons
        window.addEventListener("popstate", function (event) {
            if (event.state && event.state.url) {
                handleAjaxNavigation(event.state.url);
            } else {
                // If no state, fetch current URL
                handleAjaxNavigation(window.location.href);
            }
        });
    }
});