escrow.gno

  1package escrow
  2
  3import (
  4	"chain"
  5	"errors"
  6	"strconv"
  7	"strings"
  8
  9	"gno.land/p/nym-moultest123/kit/ui/v0"
 10	"gno.land/p/nym-moultest123/md/v0"
 11	"gno.land/p/nt/avl/v0"
 12)
 13
 14// State constants for a deal's lifecycle.
 15const (
 16	StateOpen     = "Open"
 17	StateSettled  = "Settled"
 18	StateCanceled = "Canceled"
 19)
 20
 21// Deal is a 2-party escrow record. Accounting only: no funds move,
 22// this tracks agreement and mutual confirmation between two parties.
 23type Deal struct {
 24	ID           int
 25	Creator      address
 26	Counterparty address
 27	Terms        string
 28	State        string
 29	CreatorOK    bool
 30	CounterOK    bool
 31}
 32
 33var (
 34	deals  = avl.NewTree() // id (string) -> *Deal
 35	nextID int
 36)
 37
 38var (
 39	errNotFound   = errors.New("escrow: deal not found")
 40	errNotParty   = errors.New("escrow: caller is not a party to this deal")
 41	errNotOpen    = errors.New("escrow: deal is not open")
 42	errNotCreator = errors.New("escrow: only the creator can cancel")
 43	errBadAddr    = errors.New("escrow: invalid counterparty address")
 44	errSelfDeal   = errors.New("escrow: counterparty must differ from creator")
 45)
 46
 47// Create opens a new escrow deal between the caller (creator) and the
 48// given counterparty, governed by a free-form terms string. Returns the
 49// new deal id. Panics on invalid input (cross-realm abort).
 50func Create(cur realm, counterparty address, terms string) int {
 51	if !cur.IsCurrent() {
 52		panic("escrow: spoofed realm")
 53	}
 54	if !counterparty.IsValid() {
 55		panic(errBadAddr)
 56	}
 57	creator := cur.Previous().Address()
 58	if counterparty == creator {
 59		panic(errSelfDeal)
 60	}
 61
 62	id := nextID
 63	nextID++
 64
 65	d := &Deal{
 66		ID:           id,
 67		Creator:      creator,
 68		Counterparty: counterparty,
 69		Terms:        terms,
 70		State:        StateOpen,
 71	}
 72	deals.Set(strconv.Itoa(id), d)
 73
 74	chain.Emit("Created", "id", strconv.Itoa(id),
 75		"creator", creator.String(), "counterparty", counterparty.String())
 76	return id
 77}
 78
 79// Confirm records confirmation by whichever party is calling. Once both
 80// parties have confirmed, the deal transitions to Settled.
 81func Confirm(cur realm, id int) {
 82	if !cur.IsCurrent() {
 83		panic("escrow: spoofed realm")
 84	}
 85	d := mustGet(id)
 86	if d.State != StateOpen {
 87		panic(errNotOpen)
 88	}
 89	caller := cur.Previous().Address()
 90
 91	switch caller {
 92	case d.Creator:
 93		d.CreatorOK = true
 94	case d.Counterparty:
 95		d.CounterOK = true
 96	default:
 97		panic(errNotParty)
 98	}
 99
100	chain.Emit("Confirmed", "id", strconv.Itoa(id), "party", caller.String())
101
102	if d.CreatorOK && d.CounterOK {
103		d.State = StateSettled
104		chain.Emit("Settled", "id", strconv.Itoa(id))
105	}
106}
107
108// Cancel voids an open deal. Only the creator may cancel, and only
109// before the deal has settled.
110func Cancel(cur realm, id int) {
111	if !cur.IsCurrent() {
112		panic("escrow: spoofed realm")
113	}
114	d := mustGet(id)
115	if d.State != StateOpen {
116		panic(errNotOpen)
117	}
118	caller := cur.Previous().Address()
119	if caller != d.Creator {
120		panic(errNotCreator)
121	}
122	d.State = StateCanceled
123	chain.Emit("Canceled", "id", strconv.Itoa(id))
124}
125
126func mustGet(id int) *Deal {
127	v := deals.Get(strconv.Itoa(id))
128	if v == nil {
129		panic(errNotFound)
130	}
131	return v.(*Deal)
132}
133
134// Render lists all escrow deals with their parties, terms, and state.
135// When path is a numeric id, renders just that deal.
136func Render(path string) string {
137	path = strings.TrimSpace(strings.Trim(path, "/"))
138	if path != "" {
139		if id, err := strconv.Atoi(path); err == nil {
140			v := deals.Get(strconv.Itoa(id))
141			if v == nil {
142				return "# Escrow\n\nDeal " + md.InlineCode(path) + " not found.\n"
143			}
144			return renderOne(v.(*Deal))
145		}
146	}
147
148	var b strings.Builder
149	b.WriteString("# Escrow\n\n")
150	b.WriteString("2-party escrow deals (accounting only — no funds move).\n\n")
151
152	if deals.Size() == 0 {
153		b.WriteString("_No deals yet._\n")
154		return b.String()
155	}
156
157	b.WriteString("| ID | Creator | Counterparty | State | Confirmations | Terms |\n")
158	b.WriteString("|----|---------|--------------|-------|---------------|-------|\n")
159	deals.Iterate("", "", func(_ string, v interface{}) bool {
160		d := v.(*Deal)
161		b.WriteString("| " + strconv.Itoa(d.ID) +
162			" | " + ui.Addr(d.Creator) +
163			" | " + ui.Addr(d.Counterparty) +
164			" | " + d.State +
165			" | " + confs(d) +
166			" | " + ui.Cell(d.Terms) + " |\n")
167		return false
168	})
169	return b.String()
170}
171
172func renderOne(d *Deal) string {
173	var b strings.Builder
174	b.WriteString("# Escrow Deal #" + strconv.Itoa(d.ID) + "\n\n")
175	b.WriteString("- **State:** " + d.State + "\n")
176	b.WriteString("- **Creator:** " + d.Creator.String() + " (" + yn(d.CreatorOK) + ")\n")
177	b.WriteString("- **Counterparty:** " + d.Counterparty.String() + " (" + yn(d.CounterOK) + ")\n")
178	b.WriteString("- **Terms:** " + ui.Inline(d.Terms) + "\n")
179	return b.String()
180}
181
182func confs(d *Deal) string {
183	n := 0
184	if d.CreatorOK {
185		n++
186	}
187	if d.CounterOK {
188		n++
189	}
190	return strconv.Itoa(n) + "/2"
191}
192
193func yn(b bool) string {
194	if b {
195		return "confirmed"
196	}
197	return "pending"
198}