class ZoomPanManager {
    constructor(canvasManager) {
        this.canvasManager = canvasManager;
        this.canvas = canvasManager.canvas;
        this.zoomLevel = 1.0;
        this.minZoom = 0.1;
        this.maxZoom = 5.0;
        this.zoomStep = 0.1;
        this.panX = 0;
        this.panY = 0;
        this.isPanning = false;
        this.lastPanX = 0;
        this.lastPanY = 0;
    }

    // Zoom in
    zoomIn() {
        this.zoomLevel = Math.min(this.zoomLevel + this.zoomStep, this.maxZoom);
        this.updateZoomLevel();
    }

    // Zoom out
    zoomOut() {
        this.zoomLevel = Math.max(this.zoomLevel - this.zoomStep, this.minZoom);
        this.updateZoomLevel();
    }

    // Reset zoom and pan
    resetZoom() {
        this.zoomLevel = 1.0;
        this.panX = 0;
        this.panY = 0;
        this.updateZoomLevel();
    }

    // Pan the view
    pan(deltaX, deltaY) {
        this.panX += deltaX;
        this.panY += deltaY;
    }

    // Update zoom level display
    updateZoomLevel() {
        const zoomLevelElement = document.getElementById('zoomLevel');
        if (zoomLevelElement) {
            zoomLevelElement.textContent = Math.round(this.zoomLevel * 100) + '%';
        }
    }

    // Handle mouse wheel for zoom
    handleWheel(e) {
        e.preventDefault();
        const delta = e.deltaY > 0 ? -this.zoomStep : this.zoomStep;
        const newZoom = Math.max(this.minZoom, Math.min(this.maxZoom, this.zoomLevel + delta));
        
        if (newZoom !== this.zoomLevel) {
            this.zoomLevel = newZoom;
            this.updateZoomLevel();
        }
    }

    // Handle mouse down for panning
    handleMouseDown(e) {
        // Check if middle mouse button or Ctrl+click for panning
        if (e.button === 1 || (e.button === 0 && e.ctrlKey)) {
            e.preventDefault();
            this.isPanning = true;
            this.lastPanX = e.clientX;
            this.lastPanY = e.clientY;
            this.canvas.style.cursor = 'grabbing';
        }
    }

    // Handle mouse move for panning
    handleMouseMove(e) {
        if (this.isPanning) {
            const deltaX = e.clientX - this.lastPanX;
            const deltaY = e.clientY - this.lastPanY;
            
            this.panX += deltaX;
            this.panY += deltaY;
            
            this.lastPanX = e.clientX;
            this.lastPanY = e.clientY;
        }
    }

    // Handle mouse up for panning
    handleMouseUp(e) {
        if (this.isPanning) {
            this.isPanning = false;
            this.canvas.style.cursor = 'crosshair';
        }
    }

    // Convert screen coordinates to world coordinates
    screenToWorld(screenX, screenY) {
        return {
            x: (screenX - this.panX) / this.zoomLevel,
            y: (screenY - this.panY) / this.zoomLevel
        };
    }

    // Convert world coordinates to screen coordinates
    worldToScreen(worldX, worldY) {
        return {
            x: worldX * this.zoomLevel + this.panX,
            y: worldY * this.zoomLevel + this.panY
        };
    }

    // Apply transformations to canvas context
    applyTransformations() {
        this.canvasManager.saveContext();
        this.canvasManager.applyTransformations(this.panX, this.panY, this.zoomLevel);
    }

    // Restore canvas context
    restoreTransformations() {
        this.canvasManager.restoreContext();
    }

    // Get current zoom level
    getZoomLevel() {
        return this.zoomLevel;
    }

    // Get current pan values
    getPanValues() {
        return { panX: this.panX, panY: this.panY };
    }

    // Set zoom level
    setZoomLevel(level) {
        this.zoomLevel = Math.max(this.minZoom, Math.min(this.maxZoom, level));
        this.updateZoomLevel();
    }

    // Set pan values
    setPanValues(panX, panY) {
        this.panX = panX;
        this.panY = panY;
    }
}