set -euo pipefail

ROOT="$(cd "$(dirname "$0")/.." && pwd)"

REPO_ROOT="$(cd "$ROOT/.." && pwd)"

TARGET_DIR="${CARGO_TARGET_DIR:-$ROOT/target}"

HELPER_BIN="$TARGET_DIR/release/examples/conformance_helper"

cd "$ROOT"

echo "==> building conformance helper..."

cargo build --release -p oversight-rekor --example conformance_helper >/dev/null

test -x "$HELPER_BIN" || { echo "FAIL: helper not built at $HELPER_BIN"; exit 1; }

PRIV_HEX="1111111111111111111111111111111111111111111111111111111111111111"

PUB_HEX="$(python3 - <<PY

from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey

import sys

priv = bytes.fromhex("$PRIV_HEX")

sk = Ed25519PrivateKey.from_private_bytes(priv)

pk = sk.public_key().public_bytes_raw()

sys.stdout.write(pk.hex())

PY

)"

echo "==> deterministic pub: ${PUB_HEX:0:16}..."

echo "==> [1/4] PAE byte-identity"

PAYLOAD_TYPE="application/vnd.in-toto+json"

PAYLOAD='{"a":1}'

PY_HEX="$(python3 - <<PY

import sys, os

sys.path.insert(0, "$REPO_ROOT")

from oversight_core.rekor import _pae

out = _pae("$PAYLOAD_TYPE", b'$PAYLOAD')

sys.stdout.write(out.hex())

PY

)"

RS_HEX="$(printf '%s' "$PAYLOAD" | "$HELPER_BIN" pae "$PAYLOAD_TYPE")"

if [ "$PY_HEX" != "$RS_HEX" ]; then

    echo "FAIL: PAE drift"

    echo "  py: $PY_HEX"

    echo "  rs: $RS_HEX"

    exit 1

fi

echo "  OK ($PY_HEX)"

echo "==> [2/4] Python signs → Rust verifies"

PY_ENVELOPE="$(python3 - <<PY

import sys, json

sys.path.insert(0, "$REPO_ROOT")

from oversight_core import rekor as R

priv = bytes.fromhex("$PRIV_HEX")

stmt = {"_type": R.STATEMENT_TYPE, "x": 1}

env = R.sign_dsse(stmt, priv)

sys.stdout.write(env.to_json())

PY

)"

RS_VERDICT="$(printf '%s' "$PY_ENVELOPE" | "$HELPER_BIN" verify "$PUB_HEX" || true)"

if [ "$RS_VERDICT" != "ok" ]; then

    echo "FAIL: Rust failed to verify Python-signed envelope (got: '$RS_VERDICT')"

    echo "  envelope: $PY_ENVELOPE"

    exit 1

fi

echo "  OK"

echo "==> [3/4] Rust signs → Python verifies"

STMT='{"_type":"https://in-toto.io/Statement/v1","y":2}'

RS_ENVELOPE="$(printf '%s' "$STMT" | "$HELPER_BIN" sign "$PRIV_HEX")"

PY_VERDICT="$(python3 - <<PY

import sys, json

sys.path.insert(0, "$REPO_ROOT")

from oversight_core import rekor as R

env = R.DSSEEnvelope.from_json('$RS_ENVELOPE')

pub = bytes.fromhex("$PUB_HEX")

print("ok" if R.verify_dsse(env, pub) else "fail")

PY

)"

if [ "$PY_VERDICT" != "ok" ]; then

    echo "FAIL: Python failed to verify Rust-signed envelope (got: '$PY_VERDICT')"

    echo "  envelope: $RS_ENVELOPE"

    exit 1

fi

echo "  OK"

echo "==> [4/4] Canonical payload byte-identity (same key, same statement)"

SAME_STMT='{"_type":"https://in-toto.io/Statement/v1","subject":[{"name":"x","digest":{"sha256":"00"}}]}'

PY_PAYLOAD_HEX="$(python3 - <<PY

import sys, json, base64

sys.path.insert(0, "$REPO_ROOT")

from oversight_core import rekor as R

priv = bytes.fromhex("$PRIV_HEX")

stmt = json.loads('$SAME_STMT')

env = R.sign_dsse(stmt, priv)

sys.stdout.write(base64.b64decode(env.payload_b64).hex())

PY

)"

RS_ENV2="$(printf '%s' "$SAME_STMT" | "$HELPER_BIN" sign "$PRIV_HEX")"

RS_PAYLOAD_HEX="$(printf '%s' "$RS_ENV2" | "$HELPER_BIN" decode_payload | python3 -c "import sys; sys.stdout.write(sys.stdin.buffer.read().hex())")"

if [ "$PY_PAYLOAD_HEX" != "$RS_PAYLOAD_HEX" ]; then

    echo "FAIL: canonical payload drift"

    echo "  py: $PY_PAYLOAD_HEX"

    echo "  rs: $RS_PAYLOAD_HEX"

    exit 1

fi

echo "  OK ($PY_PAYLOAD_HEX)"

echo ""

echo "==> ALL CONFORMANCE CHECKS PASSED - Python ↔ Rust bit-identical (4/4)"