import * as THREE from 'three';
import type { GraphNode } from '$types';
import { NODE_TYPE_COLORS } from '$types';

function easeOutElastic(t: number): number {
	if (t === 0 || t === 1) return t;
	const p = 0.3;
	return Math.pow(2, -10 * t) * Math.sin(((t - p / 4) * (2 * Math.PI)) / p) + 1;
}

function easeInBack(t: number): number {
	const s = 1.70158;
	return t * t * ((s + 1) * t - s);
}

interface MaterializingNode {
	id: string;
	frame: number;
	totalFrames: number;
	mesh: THREE.Mesh;
	glow: THREE.Sprite;
	label: THREE.Sprite;
	targetScale: number;
}

interface DissolvingNode {
	id: string;
	frame: number;
	totalFrames: number;
	mesh: THREE.Mesh;
	glow: THREE.Sprite;
	label: THREE.Sprite;
	originalScale: number;
}

interface GrowingNode {
	id: string;
	frame: number;
	totalFrames: number;
	startScale: number;
	targetScale: number;
}

export class NodeManager {
	group: THREE.Group;
	meshMap = new Map<string, THREE.Mesh>();
	glowMap = new Map<string, THREE.Sprite>();
	positions = new Map<string, THREE.Vector3>();
	labelSprites = new Map<string, THREE.Sprite>();
	hoveredNode: string | null = null;
	selectedNode: string | null = null;

	private materializingNodes: MaterializingNode[] = [];
	private dissolvingNodes: DissolvingNode[] = [];
	private growingNodes: GrowingNode[] = [];

	constructor() {
		this.group = new THREE.Group();
	}

	createNodes(nodes: GraphNode[]): Map<string, THREE.Vector3> {
		const phi = (1 + Math.sqrt(5)) / 2;
		const count = nodes.length;

		for (let i = 0; i < count; i++) {
			const node = nodes[i];

			// Fibonacci sphere distribution for initial positions
			const y = 1 - (2 * i) / (count - 1 || 1);
			const radius = Math.sqrt(1 - y * y);
			const theta = (2 * Math.PI * i) / phi;
			const spread = 30 + count * 0.5;

			const pos = new THREE.Vector3(
				radius * Math.cos(theta) * spread,
				y * spread,
				radius * Math.sin(theta) * spread
			);

			if (node.isCenter) pos.set(0, 0, 0);

			this.positions.set(node.id, pos);
			this.createNodeMeshes(node, pos, 1.0);
		}

		return this.positions;
	}

	private createNodeMeshes(node: GraphNode, pos: THREE.Vector3, initialScale: number) {
		const size = 0.5 + node.retention * 2;
		const color = NODE_TYPE_COLORS[node.type] || '#8B95A5';

		// Node mesh
		const geometry = new THREE.SphereGeometry(size, 16, 16);
		const material = new THREE.MeshStandardMaterial({
			color: new THREE.Color(color),
			emissive: new THREE.Color(color),
			emissiveIntensity: 0.3 + node.retention * 0.5,
			roughness: 0.3,
			metalness: 0.1,
			transparent: true,
			opacity: 0.3 + node.retention * 0.7,
		});

		const mesh = new THREE.Mesh(geometry, material);
		mesh.position.copy(pos);
		mesh.scale.setScalar(initialScale);
		mesh.userData = { nodeId: node.id, type: node.type, retention: node.retention };
		this.meshMap.set(node.id, mesh);
		this.group.add(mesh);

		// Glow sprite
		const spriteMat = new THREE.SpriteMaterial({
			color: new THREE.Color(color),
			transparent: true,
			opacity: initialScale > 0 ? 0.15 + node.retention * 0.2 : 0,
			blending: THREE.AdditiveBlending,
		});
		const sprite = new THREE.Sprite(spriteMat);
		sprite.scale.set(size * 4 * initialScale, size * 4 * initialScale, 1);
		sprite.position.copy(pos);
		sprite.userData = { isGlow: true, nodeId: node.id };
		this.glowMap.set(node.id, sprite);
		this.group.add(sprite);

		// Text label sprite
		const labelText = node.label || node.type;
		const labelSprite = this.createTextSprite(labelText, '#e2e8f0');
		labelSprite.position.copy(pos);
		labelSprite.position.y += size * 2 + 1.5;
		labelSprite.userData = { isLabel: true, nodeId: node.id, offset: size * 2 + 1.5 };
		this.group.add(labelSprite);
		this.labelSprites.set(node.id, labelSprite);

		return { mesh, glow: sprite, label: labelSprite, size };
	}

	addNode(node: GraphNode, initialPosition?: THREE.Vector3): THREE.Vector3 {
		const pos =
			initialPosition?.clone() ??
			new THREE.Vector3(
				(Math.random() - 0.5) * 40,
				(Math.random() - 0.5) * 40,
				(Math.random() - 0.5) * 40
			);

		this.positions.set(node.id, pos);

		// Create meshes at scale 0
		const { mesh, glow, label } = this.createNodeMeshes(node, pos, 0);
		mesh.scale.setScalar(0.001); // Avoid zero-scale issues
		glow.scale.set(0.001, 0.001, 1);
		(glow.material as THREE.SpriteMaterial).opacity = 0;
		(label.material as THREE.SpriteMaterial).opacity = 0;

		this.materializingNodes.push({
			id: node.id,
			frame: 0,
			totalFrames: 30,
			mesh,
			glow,
			label,
			targetScale: 0.5 + node.retention * 2,
		});

		return pos;
	}

	removeNode(id: string) {
		const mesh = this.meshMap.get(id);
		const glow = this.glowMap.get(id);
		const label = this.labelSprites.get(id);
		if (!mesh || !glow || !label) return;

		// Cancel any active materialization
		this.materializingNodes = this.materializingNodes.filter((m) => m.id !== id);

		this.dissolvingNodes.push({
			id,
			frame: 0,
			totalFrames: 60,
			mesh,
			glow,
			label,
			originalScale: mesh.scale.x,
		});
	}

	growNode(id: string, newRetention: number) {
		const mesh = this.meshMap.get(id);
		if (!mesh) return;

		const currentScale = mesh.scale.x;
		const targetScale = 0.5 + newRetention * 2;
		mesh.userData.retention = newRetention;

		this.growingNodes.push({
			id,
			frame: 0,
			totalFrames: 30,
			startScale: currentScale,
			targetScale,
		});
	}

	private createTextSprite(text: string, color: string): THREE.Sprite {
		const canvas = document.createElement('canvas');
		const ctx = canvas.getContext('2d')!;
		canvas.width = 512;
		canvas.height = 64;

		const label = text.length > 40 ? text.slice(0, 37) + '...' : text;

		ctx.clearRect(0, 0, canvas.width, canvas.height);
		ctx.font = 'bold 28px -apple-system, BlinkMacSystemFont, sans-serif';
		ctx.textAlign = 'center';
		ctx.textBaseline = 'middle';
		ctx.shadowColor = 'rgba(0, 0, 0, 0.8)';
		ctx.shadowBlur = 6;
		ctx.shadowOffsetX = 0;
		ctx.shadowOffsetY = 2;
		ctx.fillStyle = color;
		ctx.fillText(label, canvas.width / 2, canvas.height / 2);

		const texture = new THREE.CanvasTexture(canvas);
		texture.needsUpdate = true;

		const mat = new THREE.SpriteMaterial({
			map: texture,
			transparent: true,
			opacity: 0,
			depthTest: false,
			sizeAttenuation: true,
		});

		const sprite = new THREE.Sprite(mat);
		sprite.scale.set(12, 1.5, 1);
		return sprite;
	}

	updatePositions() {
		this.group.children.forEach((child) => {
			if (child.userData.nodeId) {
				const pos = this.positions.get(child.userData.nodeId);
				if (!pos) return;

				if (child.userData.isGlow) {
					child.position.copy(pos);
				} else if (child.userData.isLabel) {
					child.position.copy(pos);
					child.position.y += child.userData.offset;
				} else if (child instanceof THREE.Mesh) {
					child.position.copy(pos);
				}
			}
		});
	}

	animate(time: number, nodes: GraphNode[], camera: THREE.PerspectiveCamera) {
		// Materialization animations — elastic scale-up from 0
		for (let i = this.materializingNodes.length - 1; i >= 0; i--) {
			const mn = this.materializingNodes[i];
			mn.frame++;
			const t = Math.min(mn.frame / mn.totalFrames, 1);
			const scale = easeOutElastic(t);

			// Mesh scales up with elastic spring
			mn.mesh.scale.setScalar(Math.max(0.001, scale));

			// Glow fades in between frames 5-10
			if (mn.frame >= 5) {
				const glowT = Math.min((mn.frame - 5) / 5, 1);
				const glowMat = mn.glow.material as THREE.SpriteMaterial;
				glowMat.opacity = glowT * 0.25;
				const glowSize = mn.targetScale * 4 * scale;
				mn.glow.scale.set(glowSize, glowSize, 1);
			}

			// Label fades in after frame 40 (10 frames after mesh finishes)
			if (mn.frame >= 40) {
				const labelT = Math.min((mn.frame - 40) / 20, 1);
				(mn.label.material as THREE.SpriteMaterial).opacity = labelT * 0.9;
			}

			if (mn.frame >= 60) {
				this.materializingNodes.splice(i, 1);
			}
		}

		// Dissolution animations — easeInBack shrink
		for (let i = this.dissolvingNodes.length - 1; i >= 0; i--) {
			const dn = this.dissolvingNodes[i];
			dn.frame++;
			const t = Math.min(dn.frame / dn.totalFrames, 1);
			const shrink = 1 - easeInBack(t);
			const scale = Math.max(0.001, dn.originalScale * shrink);

			dn.mesh.scale.setScalar(scale);
			const glowScale = scale * 4;
			dn.glow.scale.set(glowScale, glowScale, 1);

			// Fade opacity
			const mat = dn.mesh.material as THREE.MeshStandardMaterial;
			mat.opacity *= 0.97;
			(dn.glow.material as THREE.SpriteMaterial).opacity *= 0.95;
			(dn.label.material as THREE.SpriteMaterial).opacity *= 0.93;

			if (dn.frame >= dn.totalFrames) {
				// Clean up
				this.group.remove(dn.mesh);
				this.group.remove(dn.glow);
				this.group.remove(dn.label);
				dn.mesh.geometry.dispose();
				(dn.mesh.material as THREE.Material).dispose();
				(dn.glow.material as THREE.SpriteMaterial).map?.dispose();
				(dn.glow.material as THREE.Material).dispose();
				(dn.label.material as THREE.SpriteMaterial).map?.dispose();
				(dn.label.material as THREE.Material).dispose();

				this.meshMap.delete(dn.id);
				this.glowMap.delete(dn.id);
				this.labelSprites.delete(dn.id);
				this.positions.delete(dn.id);

				this.dissolvingNodes.splice(i, 1);
			}
		}

		// Growth animations — smooth scale transition for promoted nodes
		for (let i = this.growingNodes.length - 1; i >= 0; i--) {
			const gn = this.growingNodes[i];
			gn.frame++;
			const t = Math.min(gn.frame / gn.totalFrames, 1);
			const scale = gn.startScale + (gn.targetScale - gn.startScale) * easeOutElastic(t);

			const mesh = this.meshMap.get(gn.id);
			if (mesh) mesh.scale.setScalar(scale);

			const glow = this.glowMap.get(gn.id);
			if (glow) {
				const glowSize = scale * 4;
				glow.scale.set(glowSize, glowSize, 1);
			}

			if (gn.frame >= gn.totalFrames) {
				this.growingNodes.splice(i, 1);
			}
		}

		// Node breathing (skip nodes being animated)
		const animatingIds = new Set([
			...this.materializingNodes.map((m) => m.id),
			...this.dissolvingNodes.map((d) => d.id),
			...this.growingNodes.map((g) => g.id),
		]);

		this.meshMap.forEach((mesh, id) => {
			if (animatingIds.has(id)) return;
			const node = nodes.find((n) => n.id === id);
			if (!node) return;
			const breathe =
				1 + Math.sin(time * 1.5 + nodes.indexOf(node) * 0.5) * 0.15 * node.retention;
			mesh.scale.setScalar(breathe);

			const mat = mesh.material as THREE.MeshStandardMaterial;
			if (id === this.hoveredNode) {
				mat.emissiveIntensity = 1.0;
			} else if (id === this.selectedNode) {
				mat.emissiveIntensity = 0.8;
			} else {
				const baseIntensity = 0.3 + node.retention * 0.5;
				const breatheIntensity =
					baseIntensity + Math.sin(time * (0.8 + node.retention * 0.7)) * 0.1 * node.retention;
				mat.emissiveIntensity = breatheIntensity;
			}
		});

		// Distance-based label visibility
		this.labelSprites.forEach((sprite, id) => {
			if (animatingIds.has(id)) return;
			const pos = this.positions.get(id);
			if (!pos) return;
			const dist = camera.position.distanceTo(pos);
			const mat = sprite.material as THREE.SpriteMaterial;
			const targetOpacity =
				id === this.hoveredNode || id === this.selectedNode
					? 1.0
					: dist < 40
						? 0.9
						: dist < 80
							? 0.9 * (1 - (dist - 40) / 40)
							: 0;
			mat.opacity += (targetOpacity - mat.opacity) * 0.1;
		});
	}

	getMeshes(): THREE.Mesh[] {
		return Array.from(this.meshMap.values());
	}

	dispose() {
		this.group.traverse((obj) => {
			if (obj instanceof THREE.Mesh) {
				obj.geometry?.dispose();
				(obj.material as THREE.Material)?.dispose();
			} else if (obj instanceof THREE.Sprite) {
				(obj.material as THREE.SpriteMaterial)?.map?.dispose();
				(obj.material as THREE.Material)?.dispose();
			}
		});
		this.materializingNodes = [];
		this.dissolvingNodes = [];
		this.growingNodes = [];
	}
}