cli.sh

#!/usr/bin/env bash
set -euo pipefail

###############################################################################
# cli.sh — Coin Smith: PSBT transaction builder CLI
#
# Usage:
#   ./cli.sh <fixture.json>
#
# Workflow:
#   1. Read the fixture JSON (UTXOs, payments, change template, fee rate)
#   2. Select coins (inputs) to fund the payments
#   3. Compute fee, change, and construct outputs
#   4. Build an unsigned PSBT (BIP-174)
#   5. Write JSON report to out/<fixture_name>.json
#   6. Exit 0 on success, 1 on error
#
# On error, writes { "ok": false, "error": { "code": "...", "message": "..." } }
# to the output file and exits 1.
###############################################################################

error_json() {
  local code="$1"
  local message="$2"
  printf '{"ok":false,"error":{"code":"%s","message":"%s"}}\n' "$code" "$message"
}

if [[ $# -lt 1 ]]; then
  error_json "INVALID_ARGS" "Usage: cli.sh <fixture.json>"
  echo "Error: No fixture file provided" >&2
  exit 1
fi

FIXTURE="$1"

if [[ ! -f "$FIXTURE" ]]; then
  error_json "FILE_NOT_FOUND" "Fixture file not found: $FIXTURE"
  echo "Error: Fixture file not found: $FIXTURE" >&2
  exit 1
fi

# Create output directory
mkdir -p out

# Derive output filename from fixture basename
# e.g. fixtures/basic_change_p2wpkh.json → out/basic_change_p2wpkh.json
FIXTURE_NAME="$(basename "$FIXTURE")"
OUTPUT_FILE="out/$FIXTURE_NAME"

# TODO: Implement your PSBT builder here
#   1. Read fixture JSON (network, utxos, payments, change, fee_rate_sat_vb, rbf, locktime, …)
#   2. Validate inputs defensively (reject malformed fixtures with structured errors)
#   3. Select coins (UTXOs) to cover payments + estimated fee
#   4. Determine change output (skip if dust; handle fee/change interaction)
#   5. Set nSequence and nLockTime per RBF / locktime rules
#   6. Build unsigned PSBT (BIP-174) with witness_utxo / non_witness_utxo metadata
#   7. Emit warnings (HIGH_FEE, DUST_CHANGE, SEND_ALL, RBF_SIGNALING, …)
#   8. Write JSON report to $OUTPUT_FILE
#
# Example:
#   python builder.py "$FIXTURE" "$OUTPUT_FILE"
#   node builder.js "$FIXTURE" "$OUTPUT_FILE"
#   cargo run -- "$FIXTURE" "$OUTPUT_FILE"

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
exec "$SCRIPT_DIR/coinsmith-cli" "$FIXTURE" "$OUTPUT_FILE"