document.addEventListener("DOMContentLoaded", function () {
    const searchBar = document.getElementById("search-bar");
    const degreeFilter = document.getElementById("degree-filter");
    const graduationDateFilter = document.getElementById("graduation-date-filter");
    const filterButton = document.getElementById("filter-button");


    const alumniBlocks = Array.from(document.querySelectorAll(".alumni-block"));
    const alumniResults = document.getElementById("alumni-results");


    // Function to count degrees and update dropdown options
    function updateDegreeCounts() {
        const degreeCounts = { PhD: 0, "M.S.": 0 };
        let totalCount = 0;


        alumniBlocks.forEach((block) => {
            totalCount++;
            const details = block.querySelector(".details").textContent;
            if (details.includes("PhD")) {
                degreeCounts.PhD++;
            } else if (details.includes("M.S.")) {
                degreeCounts["M.S."]++;
            }
        });


        // Add counts to the degree filter
        degreeFilter.innerHTML = `
            <option value="">All Degrees (${totalCount}Έν)</option>
            <option value="PhD">PhD (${degreeCounts.PhD}Έν)</option>
            <option value="M.S.">M.S. (${degreeCounts["M.S."]}Έν)</option>
        `;
    }


    // Function to group alumni by graduation year and render them
    function renderAlumniWithDividers(filteredBlocks = alumniBlocks) {
        // Group alumni by graduation year
        const groupedAlumni = filteredBlocks.reduce((groups, block) => {
            const graduationYearElement = block.querySelector(".graduation-year");
            const graduationYear = graduationYearElement
                ? graduationYearElement.textContent.replace("Graduation Year: ", "").trim()
                : "Unknown";


            if (!groups[graduationYear]) {
                groups[graduationYear] = [];
            }
            groups[graduationYear].push(block);
            return groups;
        }, {});


        // Sort graduation years in descending order
        const sortedYears = Object.keys(groupedAlumni).sort((a, b) => b - a);


        // Clear alumniResults and re-render with dividers
        alumniResults.innerHTML = "";
        sortedYears.forEach((year) => {
            // Create a divider for the year
            const yearDivider = document.createElement("div");
            yearDivider.className = "year-divider";
            yearDivider.textContent = `Graduation Year: ${year}`;
            alumniResults.appendChild(yearDivider);


            // Append all alumni for the year
            groupedAlumni[year].forEach((block) => {
                alumniResults.appendChild(block);
            });
        });
    }


    // Filter function
    function applyFilters() {
        const searchValue = searchBar.value.toLowerCase();
        const degreeValue = degreeFilter.value; // Exact match for degrees
        const graduationDateValue = graduationDateFilter.value.trim();


        const filteredBlocks = alumniBlocks.filter((block) => {
            const name = block.querySelector(".alumni-name").textContent.toLowerCase();
            const details = block.querySelector(".details").textContent;
            const topic = block.querySelector(".topic").textContent.toLowerCase();
            const graduationYearElement = block.querySelector(".graduation-year");
            const graduationYear = graduationYearElement
                ? graduationYearElement.textContent.replace("Graduation Year: ", "").trim()
                : "";


            const matchesName = searchValue === "" || name.includes(searchValue);
            const matchesDegree = degreeValue === "" || details.includes(degreeValue);
            const matchesGraduationDate =
                graduationDateValue === "" || graduationYear === graduationDateValue;


            return matchesName && matchesDegree && matchesGraduationDate;
        });


        // Render filtered alumni with dividers
        renderAlumniWithDividers(filteredBlocks);


        // Update All Degrees count based on filtered results
        const allOption = degreeFilter.querySelector('option[value=""]');
        if (allOption) {
            allOption.textContent = `All Degrees (${filteredBlocks.length}Έν)`;
        }
    }


    // Event listener for filtering
    filterButton.addEventListener("click", applyFilters);
    searchBar.addEventListener("input", applyFilters);
    degreeFilter.addEventListener("change", applyFilters);
    graduationDateFilter.addEventListener("input", applyFilters);


    // Initialize degree counts and render alumni on page load
    updateDegreeCounts();
    renderAlumniWithDividers();
});