money.gno

 1package safe
 2
 3import (
 4	"strconv"
 5	"strings"
 6
 7	"gno.land/p/g19dzk54hhsdc3gllpksuj6gu4a3e6fl8cr6rn4w/minhwa/types/v1"
 8)
 9
10// BpsDenominator is 100% in basis points (EIP-2981, royalty/v0).
11const BpsDenominator = 10000
12
13// BpsOf returns floor(amount * bps / 10000) without ever forming the full
14// product, so it cannot overflow for any amount >= 0 and 0 <= bps <= 10000.
15func BpsOf(amount, bps int64) int64 {
16	if amount < 0 {
17		panic("BpsOf: negative amount")
18	}
19	if bps < 0 || bps > BpsDenominator {
20		panic("BpsOf: bps out of range")
21	}
22	return (amount/BpsDenominator)*bps + (amount%BpsDenominator)*bps/BpsDenominator
23}
24
25// AssertBps panics unless 0 <= bps <= cap.
26func AssertBps(field string, bps, cap int64) {
27	if bps < 0 || bps > cap {
28		panic(field + ": must be between 0 and " + strconv.FormatInt(cap, 10) + " bps")
29	}
30}
31
32// ParsePayees parses "g1…:7000,g1…:3000": 1..max distinct valid addresses,
33// each with a positive share, shares summing to exactly 10000.
34func ParsePayees(field, s string, max int) []types.Payee {
35	if s == "" {
36		panic(field + ": must not be empty")
37	}
38	parts := strings.Split(s, ",")
39	if len(parts) > max {
40		panic(field + ": at most " + strconv.Itoa(max) + " payees")
41	}
42	out := make([]types.Payee, 0, len(parts))
43	var total int64
44	for _, part := range parts {
45		addrStr, bpsStr, ok := strings.Cut(part, ":")
46		if !ok {
47			panic(field + ": expected address:bps, got " + strconv.Quote(part))
48		}
49		addr := address(addrStr)
50		if !addr.IsValid() {
51			panic(field + ": invalid address " + strconv.Quote(addrStr))
52		}
53		bps, err := strconv.ParseInt(bpsStr, 10, 64)
54		if err != nil || bps <= 0 || bps > BpsDenominator {
55			panic(field + ": invalid share " + strconv.Quote(bpsStr))
56		}
57		for _, p := range out {
58			if p.Addr == addr {
59				panic(field + ": duplicate payee " + addrStr)
60			}
61		}
62		total += bps
63		out = append(out, types.Payee{Addr: addr, Bps: bps})
64	}
65	if total != BpsDenominator {
66		panic(field + ": shares must sum to 10000 bps, got " + strconv.FormatInt(total, 10))
67	}
68	return out
69}
70
71// FormatPayees is the inverse of ParsePayees.
72func FormatPayees(ps []types.Payee) string {
73	parts := make([]string, len(ps))
74	for i, p := range ps {
75		parts[i] = p.Addr.String() + ":" + strconv.FormatInt(p.Bps, 10)
76	}
77	return strings.Join(parts, ",")
78}
79
80// SplitByBps divides amount by the payees' shares. The rounding remainder
81// goes to the first payee, so the parts always sum to exactly amount — the
82// property every "no balance left behind" invariant (I-3, I-4) relies on.
83func SplitByBps(amount int64, ps []types.Payee) []int64 {
84	if len(ps) == 0 {
85		panic("SplitByBps: no payees")
86	}
87	out := make([]int64, len(ps))
88	var given int64
89	for i, p := range ps {
90		out[i] = BpsOf(amount, p.Bps)
91		given += out[i]
92	}
93	out[0] += amount - given
94	return out
95}