/**
 * Theme Management
 */
const themeToggleBtn = document.getElementById('theme-toggle');
const htmlElement = document.documentElement;
const sunIcon = document.getElementById('sun-icon');
const moonIcon = document.getElementById('moon-icon');

// Initialize Theme
function initTheme() {
    const savedTheme = localStorage.getItem('theme');
    const systemPrefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
    
    // Default to dark if no save, or if saved is dark
    const isDark = savedTheme === 'dark' || (!savedTheme && systemPrefersDark);
    
    applyTheme(isDark ? 'dark' : 'light');
}

function applyTheme(theme) {
    htmlElement.setAttribute('data-theme', theme);
    localStorage.setItem('theme', theme);
    
    // Toggle Icons
    if (theme === 'dark') {
        sunIcon.style.display = 'block';
        moonIcon.style.display = 'none';
    } else {
        sunIcon.style.display = 'none';
        moonIcon.style.display = 'block';
    }

    // Trigger graph update if it exists (to recolor canvas/svg)
    if (window.updateGraphTheme) {
        window.updateGraphTheme();
    }
}

themeToggleBtn.addEventListener('click', () => {
    const currentTheme = htmlElement.getAttribute('data-theme');
    const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
    applyTheme(newTheme);
});

// Initialize on load
initTheme();


/**
 * Graph Visualization (Mock D3 Implementation for Demonstration)
 * Replaces or Augments existing logic
 */

const graphContainer = document.getElementById('graph-container');
const width = graphContainer.clientWidth;
const height = graphContainer.clientHeight;

// Clear loading text
graphContainer.innerHTML = '';

// Create SVG
const svg = d3.select("#graph-container")
    .append("svg")
    .attr("width", "100%")
    .attr("height", "100%")
    .call(d3.zoom().on("zoom", (event) => {
        g.attr("transform", event.transform);
    }));

const g = svg.append("g");

// Sample Data
const graphData = {
    nodes: [
        { id: "Root", group: 1 },
        { id: "Config", group: 2 },
        { id: "Assets", group: 2 },
        { id: "Theme", group: 2 },
        { id: "Scripts", group: 3 },
        { id: "Styles", group: 3 }
    ],
    links: [
        { source: "Root", target: "Config" },
        { source: "Root", target: "Assets" },
        { source: "Assets", target: "Theme" },
        { source: "Config", target: "Scripts" },
        { source: "Config", target: "Styles" }
    ]
};

// Simulation Setup
const simulation = d3.forceSimulation(graphData.nodes)
    .force("link", d3.forceLink(graphData.links).id(d => d.id).distance(100))
    .force("charge", d3.forceManyBody().strength(-300))
    .force("center", d3.forceCenter(width / 2, height / 2));

// Elements
const link = g.append("g")
    .attr("class", "links")
    .selectAll("line")
    .data(graphData.links)
    .enter().append("line");

const node = g.append("g")
    .attr("class", "nodes")
    .selectAll("circle")
    .data(graphData.nodes)
    .enter().append("circle")
    .attr("r", 8)
    .call(d3.drag()
        .on("start", dragstarted)
        .on("drag", dragged)
        .on("end", dragended));

const labels = g.append("g")
    .attr("class", "labels")
    .selectAll("text")
    .data(graphData.nodes)
    .enter().append("text")
    .attr("dx", 12)
    .attr("dy", ".35em")
    .text(d => d.id);

// Sidebar population
const nodeList = document.getElementById('node-list');
graphData.nodes.forEach(n => {
    const div = document.createElement('div');
    div.className = 'node-list-item';
    div.textContent = `> ${n.id}`; // Terminal style prefix
    div.addEventListener('click', () => {
        // Zoom to node logic could go here
        console.log(`Clicked ${n.id}`);
    });
    nodeList.appendChild(div);
});

// Simulation Tick
simulation.on("tick", () => {
    link
        .attr("x1", d => d.source.x)
        .attr("y1", d => d.source.y)
        .attr("x2", d => d.target.x)
        .attr("y2", d => d.target.y);

    node
        .attr("cx", d => d.x)
        .attr("cy", d => d.y);

    labels
        .attr("x", d => d.x)
        .attr("y", d => d.y);
});

// Drag functions
function dragstarted(event, d) {
    if (!event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x;
    d.fy = d.y;
}

function dragged(event, d) {
    d.fx = event.x;
    d.fy = event.y;
}

function dragended(event, d) {
    if (!event.active) simulation.alphaTarget(0);
    d.fx = null;
    d.fy = null;
}

// Window Resize Handling
window.addEventListener('resize', () => {
    simulation.force("center", d3.forceCenter(graphContainer.clientWidth / 2, graphContainer.clientHeight / 2));
    simulation.alpha(0.3).restart();
});

// Expose update function for theme changes (CSS vars handle most, but sometimes D3 needs explicit updates)
window.updateGraphTheme = function() {
    // Current CSS handles colors via variables, but if complex logic needed:
    // const isDark = htmlElement.getAttribute('data-theme') === 'dark';
    // link.style('stroke', isDark ? '#...' : '#...');
};