// SVG Monitor JavaScript Module for RobotMonitor
// Handles mouse events for zoom and pan (simplified version of svgEditor.js)

let svgElement = null;
let dotNetRef = null;
let isInitialized = false;

/**
 * Initialize the SVG monitor with event listeners
 * @param {SVGElement} svg - The SVG element
 * @param {DotNetObjectReference} dotNet - Reference to Blazor component
 */
export function initMonitor(svg, dotNet) {
    svgElement = svg;
    dotNetRef = dotNet;
    
    if (!svgElement || !dotNetRef) {
        console.error('SVG Monitor: Invalid initialization parameters');
        return;
    }
    
    // Mouse events (only zoom and pan)
    svgElement.addEventListener('mousemove', handleMouseMove);
    svgElement.addEventListener('mousedown', handleMouseDown);
    svgElement.addEventListener('mouseup', handleMouseUp);
    svgElement.addEventListener('wheel', handleWheel, { passive: false });
    svgElement.addEventListener('contextmenu', handleContextMenu);
    
    // Prevent default drag behavior
    svgElement.addEventListener('dragstart', (e) => e.preventDefault());
    
    isInitialized = true;
    console.log('SVG Monitor initialized');
}

/**
 * Dispose the monitor and remove event listeners
 */
export function disposeMonitor() {
    if (svgElement) {
        svgElement.removeEventListener('mousemove', handleMouseMove);
        svgElement.removeEventListener('mousedown', handleMouseDown);
        svgElement.removeEventListener('mouseup', handleMouseUp);
        svgElement.removeEventListener('wheel', handleWheel);
        svgElement.removeEventListener('contextmenu', handleContextMenu);
    }
    
    svgElement = null;
    dotNetRef = null;
    isInitialized = false;
    console.log('SVG Monitor disposed');
}

/**
 * Convert screen coordinates to SVG coordinates
 * @param {number} screenX - Screen X coordinate
 * @param {number} screenY - Screen Y coordinate
 * @returns {{x: number, y: number}} SVG coordinates
 */
function screenToSvg(screenX, screenY) {
    if (!svgElement) return { x: 0, y: 0 };
    
    const pt = svgElement.createSVGPoint();
    pt.x = screenX;
    pt.y = screenY;
    
    const ctm = svgElement.getScreenCTM();
    if (!ctm) return { x: 0, y: 0 };
    
    const svgPt = pt.matrixTransform(ctm.inverse());
    return { x: svgPt.x, y: svgPt.y };
}

/**
 * Export screenToSvg for use from Blazor
 * @param {number} screenX - Screen X coordinate
 * @param {number} screenY - Screen Y coordinate
 * @returns {number[]} SVG coordinates as [x, y]
 */
export function screenToSvgArray(screenX, screenY) {
    const coords = screenToSvg(screenX, screenY);
    return [coords.x, coords.y];
}

/**
 * Handle mouse move event
 * @param {MouseEvent} e 
 */
function handleMouseMove(e) {
    if (!dotNetRef) return;
    
    const svgCoords = screenToSvg(e.clientX, e.clientY);
    // Pass SVG coordinates and screen coordinates for panning
    dotNetRef.invokeMethodAsync('OnMouseMove', svgCoords.x, svgCoords.y, e.clientX, e.clientY);
}

/**
 * Handle mouse down event
 * @param {MouseEvent} e 
 */
function handleMouseDown(e) {
    if (!dotNetRef) return;
    
    const svgCoords = screenToSvg(e.clientX, e.clientY);
    
    // Middle mouse button (button 1) - start pan
    // Also pass screen coordinates for incremental pan calculation
    dotNetRef.invokeMethodAsync('OnMouseDown', svgCoords.x, svgCoords.y, e.button, e.clientX, e.clientY);
}

/**
 * Handle mouse up event
 * @param {MouseEvent} e 
 */
function handleMouseUp(e) {
    if (!dotNetRef) return;
    
    const svgCoords = screenToSvg(e.clientX, e.clientY);
    dotNetRef.invokeMethodAsync('OnMouseUp', svgCoords.x, svgCoords.y, e.button);
}

/**
 * Handle mouse wheel event (zoom)
 * @param {WheelEvent} e 
 */
function handleWheel(e) {
    if (!dotNetRef) return;
    
    e.preventDefault();
    
    const svgCoords = screenToSvg(e.clientX, e.clientY);
    dotNetRef.invokeMethodAsync('OnWheel', svgCoords.x, svgCoords.y, e.deltaY);
}

/**
 * Handle context menu (right click)
 * @param {MouseEvent} e 
 */
function handleContextMenu(e) {
    // Prevent default context menu
    e.preventDefault();
}