// Pan, zoom, parallax, and keyboard navigation for the tree.
//
// All shared mutable state lives on the controller (see controller.ts); these
// handlers read/write it by reference. attach* functions return a cleanup that
// removes the window-level listeners they added.
import { gsap } from 'gsap';
import { ZOOM, PARALLAX, PAN_SPEED } from '$lib/config';
import type { SkillTreeController } from './controller';

/** Offset the background layers behind the tree to create parallax depth. */
export function updateParallax(ctrl: SkillTreeController) {
	const treeDeltaX = ctrl.treeContainer.x - ctrl.initialTreeX;
	const treeDeltaY = ctrl.treeContainer.y - ctrl.initialTreeY;

	ctrl.bg.starContainer.x = treeDeltaX * PARALLAX.star;
	ctrl.bg.starContainer.y = treeDeltaY * PARALLAX.star;

	ctrl.bg.nebulaContainer.x = treeDeltaX * PARALLAX.nebula;
	ctrl.bg.nebulaContainer.y = treeDeltaY * PARALLAX.nebula;

	ctrl.bg.deepBackgroundContainer.x = treeDeltaX * PARALLAX.gradient;
	ctrl.bg.deepBackgroundContainer.y = treeDeltaY * PARALLAX.gradient;
	// No scale parallax - backgrounds keep scale 1.0
}

interface PanZoomOpts {
	onTooltipMove: (x: number, y: number) => void;
}

/** Wire mouse/touch/wheel pan + zoom. Returns a cleanup for window listeners. */
export function attachPanZoom(ctrl: SkillTreeController, opts: PanZoomOpts): () => void {
	const { app, treeContainer } = ctrl;
	const minZoom = ZOOM.min;
	const maxZoom = ZOOM.max;

	// ===== MOUSE PANNING =====
	app.canvas.addEventListener('mousedown', (e: MouseEvent) => {
		ctrl.isDragging = true;
		ctrl.hasMoved = false;
		ctrl.dragStartX = e.clientX;
		ctrl.dragStartY = e.clientY;
		ctrl.containerStartX = treeContainer.x;
		ctrl.containerStartY = treeContainer.y;
		app.canvas.style.cursor = 'grabbing';
	});

	const onWindowMouseMove = (e: MouseEvent) => {
		if (!ctrl.isDragging) return;
		const dx = e.clientX - ctrl.dragStartX;
		const dy = e.clientY - ctrl.dragStartY;
		if (Math.abs(dx) > 5 || Math.abs(dy) > 5) {
			ctrl.hasMoved = true;
		}
		treeContainer.x = ctrl.containerStartX + dx;
		treeContainer.y = ctrl.containerStartY + dy;
		updateParallax(ctrl);
	};
	window.addEventListener('mousemove', onWindowMouseMove);

	const onWindowMouseUp = () => {
		ctrl.isDragging = false;
		app.canvas.style.cursor = 'grab';
	};
	window.addEventListener('mouseup', onWindowMouseUp);

	app.canvas.style.cursor = 'grab';

	// Track mouse position for tooltip
	app.canvas.addEventListener('mousemove', (e: MouseEvent) => {
		opts.onTooltipMove(e.clientX, e.clientY);
	});

	// ===== TOUCH PANNING & PINCH ZOOM =====
	app.canvas.addEventListener(
		'touchstart',
		(e: TouchEvent) => {
			if (e.touches.length === 1) {
				ctrl.isDragging = true;
				ctrl.hasMoved = false;
				ctrl.isTouchZooming = false;
				ctrl.dragStartX = e.touches[0].clientX;
				ctrl.dragStartY = e.touches[0].clientY;
				ctrl.containerStartX = treeContainer.x;
				ctrl.containerStartY = treeContainer.y;
			} else if (e.touches.length === 2) {
				ctrl.isDragging = false;
				ctrl.isTouchZooming = true;
				ctrl.hasMoved = true; // Pinch zoom counts as movement
				const dx = e.touches[0].clientX - e.touches[1].clientX;
				const dy = e.touches[0].clientY - e.touches[1].clientY;
				ctrl.lastTouchDistance = Math.sqrt(dx * dx + dy * dy);
			}
		},
		{ passive: true }
	);

	app.canvas.addEventListener(
		'touchmove',
		(e: TouchEvent) => {
			if (e.touches.length === 1 && ctrl.isDragging && !ctrl.isTouchZooming) {
				const dx = e.touches[0].clientX - ctrl.dragStartX;
				const dy = e.touches[0].clientY - ctrl.dragStartY;

				if (Math.abs(dx) > 10 || Math.abs(dy) > 10) {
					ctrl.hasMoved = true;
					treeContainer.x = ctrl.containerStartX + dx;
					treeContainer.y = ctrl.containerStartY + dy;
					updateParallax(ctrl);
				}
			} else if (e.touches.length === 2 && ctrl.isTouchZooming) {
				const dx = e.touches[0].clientX - e.touches[1].clientX;
				const dy = e.touches[0].clientY - e.touches[1].clientY;
				const distance = Math.sqrt(dx * dx + dy * dy);

				if (ctrl.lastTouchDistance > 0) {
					const scale = distance / ctrl.lastTouchDistance;
					let newScale = treeContainer.scale.x * scale;
					newScale = Math.max(minZoom, Math.min(maxZoom, newScale));

					// Zoom centered on origin node (same as mouse wheel zoom)
					treeContainer.scale.set(newScale);
					updateParallax(ctrl);
				}

				ctrl.lastTouchDistance = distance;
				ctrl.hasMoved = true;
			}
		},
		{ passive: true }
	);

	app.canvas.addEventListener(
		'touchend',
		(e: TouchEvent) => {
			if (e.touches.length === 0) {
				ctrl.isDragging = false;
				ctrl.isTouchZooming = false;
				ctrl.lastTouchDistance = 0;
			} else if (e.touches.length === 1) {
				ctrl.isTouchZooming = false;
				ctrl.isDragging = true;
				ctrl.hasMoved = true; // Consider this movement since we were zooming
				ctrl.dragStartX = e.touches[0].clientX;
				ctrl.dragStartY = e.touches[0].clientY;
				ctrl.containerStartX = treeContainer.x;
				ctrl.containerStartY = treeContainer.y;
			}
		},
		{ passive: true }
	);

	// ===== WHEEL ZOOM =====
	app.canvas.addEventListener('wheel', (e: WheelEvent) => {
		e.preventDefault();
		const oldScale = treeContainer.scale.x;
		const zoomFactor = e.deltaY > 0 ? ZOOM.wheelOut : ZOOM.wheelIn;
		const newScale = Math.max(minZoom, Math.min(maxZoom, oldScale * zoomFactor));

		// Zoom centered on origin node (0,0 in tree space): origin sits at
		// (treeContainer.x, treeContainer.y), so scaling keeps it anchored.
		treeContainer.scale.set(newScale);
		updateParallax(ctrl);
	});

	return () => {
		window.removeEventListener('mousemove', onWindowMouseMove);
		window.removeEventListener('mouseup', onWindowMouseUp);
	};
}

interface KeyboardOpts {
	onToggleStats: () => void;
	onCloseModal: () => void;
	isModalVisible: () => boolean;
	isStatsVisible: () => boolean;
}

/** Wire keyboard navigation (pan/zoom/reset/stats/escape). Returns cleanup. */
export function attachKeyboard(ctrl: SkillTreeController, opts: KeyboardOpts): () => void {
	const { app, treeContainer } = ctrl;
	const minZoom = ZOOM.min;
	const maxZoom = ZOOM.max;

	function handleKeydown(e: KeyboardEvent) {
		// Toggle stats panel with 'C' key
		if (e.key === 'c' || e.key === 'C') {
			if (!opts.isModalVisible()) {
				opts.onToggleStats();
			}
		}

		// Escape key priority: modal > stats panel
		if (e.key === 'Escape') {
			if (opts.isModalVisible()) {
				opts.onCloseModal();
			} else if (opts.isStatsVisible()) {
				opts.onToggleStats();
			}
		}

		const panSpeed = PAN_SPEED;
		const zoomSpeed = ZOOM.keyStep;

		// Arrow keys for panning
		if (e.key === 'ArrowUp') {
			e.preventDefault();
			treeContainer.y += panSpeed;
			updateParallax(ctrl);
		} else if (e.key === 'ArrowDown') {
			e.preventDefault();
			treeContainer.y -= panSpeed;
			updateParallax(ctrl);
		} else if (e.key === 'ArrowLeft') {
			e.preventDefault();
			treeContainer.x += panSpeed;
			updateParallax(ctrl);
		} else if (e.key === 'ArrowRight') {
			e.preventDefault();
			treeContainer.x -= panSpeed;
			updateParallax(ctrl);
		}

		// + and = for zoom in
		if (e.key === '+' || e.key === '=') {
			e.preventDefault();
			const currentScale = treeContainer.scale.x;
			const newScale = Math.min(maxZoom, currentScale + zoomSpeed);
			treeContainer.scale.set(newScale);
			updateParallax(ctrl);
		}

		// - for zoom out
		if (e.key === '-') {
			e.preventDefault();
			const currentScale = treeContainer.scale.x;
			const newScale = Math.max(minZoom, currentScale - zoomSpeed);
			treeContainer.scale.set(newScale);
			updateParallax(ctrl);
		}

		// R to reset view to origin
		if (e.key === 'r' || e.key === 'R') {
			e.preventDefault();
			gsap.to(treeContainer, {
				x: app.screen.width / 2,
				y: app.screen.height / 2,
				duration: 0.5,
				ease: 'power2.out',
				onUpdate: () => updateParallax(ctrl),
				onComplete: () => {
					// Update parallax baseline after reset
					ctrl.initialTreeX = treeContainer.x;
					ctrl.initialTreeY = treeContainer.y;
				}
			});
			gsap.to(treeContainer.scale, {
				x: ctrl.endScale,
				y: ctrl.endScale,
				duration: 0.5,
				ease: 'power2.out',
				onUpdate: () => updateParallax(ctrl)
			});
		}
	}

	window.addEventListener('keydown', handleKeydown);
	return () => window.removeEventListener('keydown', handleKeydown);
}