share.ts

1	import type { NutBody } from './physics'
2
3	// ── Encoding ───────────────────────────────────────────────────────────────
4	// Settings prefix: "z<nutRadius>" e.g. "z130"
5	// Nuts: "r<radius>c<colorIndex>" e.g. "r130c2"
6	// Gems: "r<radius>g<gemVariant>" e.g. "r80g1"
7	// Balloons: "r<radius>b<colorIndex>" e.g. "r80b3"
8	// Comma-separated after settings: "z130,r130c0,r80g1"
9
10	export interface SharedNut {
11	radius: number
12	colorIndex: number
13	kind: 'nut' \| 'gem' \| 'balloon' \| 'metalnut' \| 'rock' \| 'stressball'
14	gemVariant: number
15	}
16
17	export interface ParsedShare {
18	nuts: SharedNut[]
19	nutRadius: number \| null
20	}
21
22	export function encodeNuts(nuts: NutBody[]): string {
23	return nuts.map(n => {
24	if (n.kind === 'gem') return `r${Math.round(n.radius)}g${n.gemVariant}`
25	if (n.kind === 'balloon') return `r${Math.round(n.radius)}b${n.colorIndex % 7}`
26	if (n.kind === 'metalnut') return `r${Math.round(n.radius)}m${n.colorIndex % 5}`
27	if (n.kind === 'rock') return `r${Math.round(n.radius)}k${n.colorIndex % 4}`
28	if (n.kind === 'stressball') return `r${Math.round(n.radius)}s${n.colorIndex % 6}`
29	return `r${Math.round(n.radius)}c${n.colorIndex % 5}`
30	}).join(',')
31	}
32
33	export function decodeNuts(encoded: string): SharedNut[] \| null {
34	try {
35	if (!encoded) return null
36	return encoded.split(',').map(part => {
37	const gem = part.match(/^r(\d+)g(\d+)$/)
38	if (gem) return { radius: parseInt(gem[1], 10), colorIndex: 0, kind: 'gem' as const, gemVariant: parseInt(gem[2], 10) }
39	const balloon = part.match(/^r(\d+)b(\d+)$/)
40	if (balloon) return { radius: parseInt(balloon[1], 10), colorIndex: parseInt(balloon[2], 10), kind: 'balloon' as const, gemVariant: parseInt(balloon[2], 10) }
41	const metal = part.match(/^r(\d+)m(\d+)$/)
42	if (metal) return { radius: parseInt(metal[1], 10), colorIndex: parseInt(metal[2], 10), kind: 'metalnut' as const, gemVariant: 0 }
43	const rock = part.match(/^r(\d+)k(\d+)$/)
44	if (rock) return { radius: parseInt(rock[1], 10), colorIndex: parseInt(rock[2], 10), kind: 'rock' as const, gemVariant: 0 }
45	const stress = part.match(/^r(\d+)s(\d+)$/)
46	if (stress) return { radius: parseInt(stress[1], 10), colorIndex: parseInt(stress[2], 10), kind: 'stressball' as const, gemVariant: parseInt(stress[2], 10) }
47	const nut = part.match(/^r(\d+)c(\d+)$/)
48	if (nut) return { radius: parseInt(nut[1], 10), colorIndex: parseInt(nut[2], 10), kind: 'nut' as const, gemVariant: 0 }
49	throw new Error('invalid')
50	})
51	} catch {
52	return null
53	}
54	}
55
56	const BASE_URL = 'https://pavelsafronov.gitlab.io/nuts/'
57	const MAX_URL_LENGTH = 1800 // comfortable QR limit at medium error-correction
58
59	/**
60	* Always returns a URL. Encodes the nut size setting first, then fits as many
61	* items as possible within MAX_URL_LENGTH (truncating from the end).
62	*/
63	export function buildShareURL(nuts: NutBody[], nutRadius: number): string {
64	const settingsPart = `z${Math.round(nutRadius)}`
65	const base = `${BASE_URL}#s=${encodeURIComponent(settingsPart)}`
66	// Fit items greedily
67	const parts: string[] = []
68	for (const n of nuts) {
69	const token = n.kind === 'gem'
70	? `r${Math.round(n.radius)}g${n.gemVariant}`
71	: n.kind === 'balloon'
72	? `r${Math.round(n.radius)}b${n.colorIndex % 7}`
73	: n.kind === 'metalnut'
74	? `r${Math.round(n.radius)}m${n.colorIndex % 5}`
75	: n.kind === 'rock'
76	? `r${Math.round(n.radius)}k${n.colorIndex % 4}`
77	: n.kind === 'stressball'
78	? `r${Math.round(n.radius)}s${n.colorIndex % 6}`
79	: `r${Math.round(n.radius)}c${n.colorIndex % 5}`
80	const candidate = base + encodeURIComponent(',' + [...parts, token].join(','))
81	if (candidate.length > MAX_URL_LENGTH) break
82	parts.push(token)
83	}
84	const payload = parts.length > 0
85	? `${settingsPart},${parts.join(',')}`
86	: settingsPart
87	return `${BASE_URL}#s=${encodeURIComponent(payload)}`
88	}
89
90	/** Parse share data from the current URL hash. Returns null if none present. */
91	export function parseShareFromURL(): ParsedShare \| null {
92	const m = location.hash.match(/[#&]s=([^&]*)/)
93	if (!m) return null
94	const raw = decodeURIComponent(m[1])
95	// Clear the hash so refreshing doesn't re-import
96	history.replaceState(null, '', location.pathname + location.search)
97	try {
98	const parts = raw.split(',')
99	let nutRadius: number \| null = null
100	const nutParts: string[] = []
101	for (const part of parts) {
102	const setting = part.match(/^z(\d+)$/)
103	if (setting) { nutRadius = parseInt(setting[1], 10); continue }
104	nutParts.push(part)
105	}
106	const nuts = nutParts.length > 0 ? decodeNuts(nutParts.join(',')) ?? [] : []
107	return { nuts, nutRadius }
108	} catch {
109	return null
110	}
111	}
112
113	/** Place shared nuts/gems into the world with a loose random packing. */
114	export function placeSharedNuts(
115	nuts: SharedNut[],
116	screenW: number,
117	screenH: number,
118	addBody: (x: number, y: number, radius: number, kind: 'nut' \| 'gem' \| 'balloon' \| 'metalnut' \| 'rock' \| 'stressball', gemVariant: number) => void,
119	hasSpace: (x: number, y: number, r: number) => boolean,
120	): void {
121	for (const { radius, colorIndex: _ci, kind, gemVariant } of nuts) {
122	// Attempt random positions until one fits (max 200 tries)
123	const margin = radius * 1.2
124	let placed = false
125	for (let attempt = 0; attempt < 200; attempt++) {
126	const x = margin + Math.random() * (screenW - margin * 2)
127	const y = margin + Math.random() * (screenH - margin * 2)
128	if (hasSpace(x, y, radius)) {
129	addBody(x, y, radius, kind, gemVariant)
130	placed = true
131	break
132	}
133	}
134	if (!placed) {
135	addBody(margin + Math.random() * (screenW - margin * 2), margin, radius, kind, gemVariant)
136	}
137	}
138	}