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

# CASAN Plan-16 SEC-10 (M-05) — non-spoofable agent identity.
#
# tool-registry-gate least-privilege trusted CASAN_AGENT (a plain env var anyone can
# set → privilege spoofing). In enforced mode the caller must present a signed token
# proving it is that agent (bound to agent id + run id). Proves:
#   * dev mode still trusts CASAN_AGENT (backward compatible),
#   * enforced mode denies an env-only claim (no token),
#   * a valid token is accepted,
#   * a forged token (unregistered key) is denied,
#   * a token minted for a different run is denied (no replay).
#
# Self-contained: ephemeral agent keypair + temp registry.

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$CASAN_APP_ROOT"
S="$CASAN_HARNESS_ROOT/scripts/bash"
GATE="$S/tool-registry-gate.sh"
WORK="$(mktemp -d)"
trap 'git -C "$PROJECT_ROOT" checkout -- .specify/logs/ 2>/dev/null; rm -rf "$WORK"' EXIT

AK="$WORK/agents"; mkdir -p "$AK"
openssl genrsa -out "$WORK/rm.priv" 2048 2>/dev/null
openssl rsa -in "$WORK/rm.priv" -pubout -out "$AK/release-manager.pub.pem" 2>/dev/null
openssl genrsa -out "$WORK/atk.priv" 2048 2>/dev/null
printf 'agent release-manager release-manager.pub.pem\n' > "$WORK/reg"

export CASAN_AGENT_REGISTRY="$WORK/reg" CASAN_AGENT_KEYS_DIR="$AK" CASAN_RUN_ID=run-sec10
export CASAN_IDEMPOTENCY_KEY=k   # deploy is side-effecting + idempotency-required

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }
rc_of() { set +e; "$@" >/dev/null 2>&1; echo $?; set -e 2>/dev/null || true; }

echo "===== Plan-16 SEC-10: non-spoofable agent identity ====="

# Dev (default): CASAN_AGENT is trusted (backward compatible).
[[ "$(rc_of env CASAN_AGENT=release-manager bash "$GATE" deploy)" -eq 0 ]] \
  && pass "dev mode: authorized CASAN_AGENT approved (backward compatible)" \
  || fail "dev-mode agent authz broke"

# Enforced: env-only claim (no token) is denied.
[[ "$(rc_of env CASAN_IDENTITY_STRICT=1 CASAN_AGENT=release-manager bash "$GATE" deploy)" -ne 0 ]] \
  && pass "enforced: env-only agent claim DENIED (spoof blocked)" \
  || fail "enforced mode trusted a bare CASAN_AGENT env"

# Enforced: a valid signed token is accepted.
bash "$S/agent-identity-sign.sh" release-manager run-sec10 "$WORK/rm.priv" "$WORK/rm.sig" >/dev/null 2>&1
[[ "$(rc_of env CASAN_IDENTITY_STRICT=1 CASAN_AGENT=release-manager CASAN_AGENT_SIG="$WORK/rm.sig" bash "$GATE" deploy)" -eq 0 ]] \
  && pass "enforced: valid signed agent token ACCEPTED" \
  || fail "enforced mode rejected a valid agent token"

# Enforced: a forged token (attacker key claiming to be release-manager) is denied.
bash "$S/agent-identity-sign.sh" release-manager run-sec10 "$WORK/atk.priv" "$WORK/forged.sig" >/dev/null 2>&1
[[ "$(rc_of env CASAN_IDENTITY_STRICT=1 CASAN_AGENT=release-manager CASAN_AGENT_SIG="$WORK/forged.sig" bash "$GATE" deploy)" -ne 0 ]] \
  && pass "enforced: forged agent token DENIED" \
  || fail "enforced mode accepted a forged agent token"

# Enforced: a token minted for a DIFFERENT run cannot be replayed.
bash "$S/agent-identity-sign.sh" release-manager other-run "$WORK/rm.priv" "$WORK/replay.sig" >/dev/null 2>&1
[[ "$(rc_of env CASAN_IDENTITY_STRICT=1 CASAN_AGENT=release-manager CASAN_AGENT_SIG="$WORK/replay.sig" bash "$GATE" deploy)" -ne 0 ]] \
  && pass "enforced: token bound to another run DENIED (no replay)" \
  || fail "enforced mode allowed a cross-run token replay"

echo ""
echo "===== SEC-10 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1