# descro

A decentralized escrow protocol on Solana for physical goods trading. Fully permissionless and resolver-agnostic — any wallet or program that implements the resolver interface can adjudicate disputes.

## Overview

```
APPLICATION LAYER
  Central Platform (own resolver, KYC, normal UX)
  Decentralized Clients (raw protocol access, free resolver choice)
        │
PROTOCOL LAYER
  ┌─────────────────┐     ┌──────────────────────┐
  │  Escrow Program │────▶│  Resolver Registry   │
  │   (descro)      │ CPI │  (descro_ext_res.)   │
  └─────────────────┘     └──────────────────────┘
```

The protocol only defines the interface. Any resolver that implements it is compatible — from a single authority wallet to a jury DAO voting contract.

## Programs

| Program | ID |
|---|---|
| `descro` | `DjVR4EuYV6USMJFfsGZwhZ3y8rtWsmG8EvDY96GTqqi3` |
| `descro_ext_resolvers` | `GwUPAKs3HHzCpj8uhet4NAnxk9GWNwfrYbpihu5DyFp` |

### Escrow Program (`descro`)

Holds trade state and SOL. Two PDAs per escrow:

- **EscrowAccount** `["escrow", seller_pubkey, escrow_id_le_bytes]` — trade state
- **Vault** `["vault", escrow_account_pubkey]` — system-owned, holds SOL only

**Instruction flow:**

```
create_escrow (seller)
  └─▶ deposit (buyer)
        ├─▶ complete (buyer)          → SOL released to seller
        └─▶ dispute (buyer | seller)
              └─▶ resolve (resolver)  → SOL released to winner
cancel (seller, only from AwaitingDeposit)
```

The `dispute_resolver` field in the escrow can be any pubkey — a wallet signing directly or a program calling `resolve()` via CPI. The check is identical either way.

**Emergency resolve:** After 14 days in `Disputed` state with no resolution, either party can call `emergency_resolve` to unlock funds.

### Resolver Registry (`descro_ext_resolvers`)

An on-chain directory for resolvers. Resolvers register with metadata (name, type, fee, URI); resolution stats are auto-incremented by the escrow program via CPI and cannot be manipulated externally.

`update_stats` is callable only by the escrow program — enforced via an `["escrow_authority"]` PDA that only the escrow program can sign for.

Resolver types: `CentralAuthority`, `JuryDAO`, `MAD`, `Algorithmic`, `Multisig`

## Repository Structure

```
programs/
├── descro/                    — Escrow Program (Rust/Anchor)
└── descro_ext_resolvers/      — Resolver Registry (Rust/Anchor)
sdk/                           — @descro/sdk TypeScript client
├── src/
│   ├── idl/                   — Anchor-generated IDL JSON
│   ├── escrow.ts              — EscrowClient (instruction builders + fetchers)
│   ├── registry.ts            — RegistryClient
│   ├── listener.ts            — WebSocket subscriptions
│   ├── pda.ts                 — PDA derivation helpers
│   ├── types.ts               — TypeScript types matching on-chain state
│   └── index.ts               — Re-exports + DescroSdk convenience class
app/                           — Next.js + Tamagui playground
├── src/app/                   — App Router pages + providers
├── src/components/            — EscrowDetail, ResolverPanel, …
└── src/hooks/                 — useEscrows, useEscrowDetail
```

## Getting Started

### Prerequisites

- Rust + `cargo-build-sbf`
- Solana CLI
- Node.js + Yarn

### Build

Programs must be built in order — the escrow program depends on the registry:

```bash
cargo build-sbf --manifest-path programs/descro_ext_resolvers/Cargo.toml
cargo build-sbf --manifest-path programs/descro/Cargo.toml
```

Install JS dependencies from the repo root:

```bash
yarn install
```

### Test

Tests load the compiled `.so` files via `include_bytes!`, so programs must be built first:

```bash
cargo test --manifest-path programs/descro/Cargo.toml
cargo test --manifest-path programs/descro_ext_resolvers/Cargo.toml
```

Run a single test:

```bash
cargo test --manifest-path programs/descro/Cargo.toml -- test_create_escrow
cargo test --manifest-path programs/descro/Cargo.toml --test test_resolve
```

### App (dev server)

```bash
yarn workspace descro-app run dev
```

## SDK Usage

The SDK is consumed as raw TypeScript via `transpilePackages` in the Next.js config — no build step needed.

```ts
import { DescroSdk } from "@descro/sdk";

const sdk = new DescroSdk(provider);

// Create escrow
await sdk.escrow.createEscrow({ amount, disputeResolver, escrowId });

// Fetch all escrows for a seller
const escrows = await sdk.escrow.fetchEscrowsBySeller(sellerPubkey);

// Subscribe to state changes
sdk.listener.onEscrowUpdate(escrowPubkey, (account) => { ... });
```

## Security Properties

| Property | Mechanism |
|---|---|
| Nobody can take SOL without consent | Network enforces signature requirement at protocol level |
| Vault can only be drained by the escrow program | Vault owner = system_program, only accessible via `invoke_signed` with correct seeds |
| Wrong resolver cannot call `resolve()` | `require!(signer.key() == escrow.dispute_resolver)` |
| PDAs cannot be spoofed | Program verifies seeds on-chain for every instruction |
| Registry stats cannot be manipulated | `update_stats` only callable via CPI from the escrow program |

## Architecture Notes

- **Anchor 1.0.x:** `UncheckedAccount<'info>` with `/// CHECK:` doc comments; `#[derive(InitSpace)]` + `#[max_len(N)]` for strings.
- **`@coral-xyz/anchor@0.32.x`:** Use `new Program(idl, provider)` — the IDL's `address` field provides the program ID. The 3-argument form is broken in 0.32.x.
- **Yarn workspaces:** `nodeLinker: node-modules` (not PnP) — required for Next.js Turbopack compatibility.
- **LiteSVM tests:** each `tests/common/mod.rs` provides `setup()`, PDA helpers, `send()`/`try_send()`, `ix_*` builders, and `read_*` deserializers. `test_resolve_with_registry.rs` loads both `.so` files to test the full CPI flow.