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

# CASAN H5 — Approval-identity MVP tests (C4 / V20).
#
# Proves that under CASAN_APPROVAL_STRICT=1 a high-risk approval is trusted ONLY
# when a REGISTERED reviewer cryptographically signs THIS request and their role
# is authorized — a plain env-var approver is no longer enough. Also proves the
# default (non-strict) path is unchanged (backward compatible).
#
# Self-contained: generates ephemeral reviewer keypairs into a temp reviewers
# dir and uses the committed reviewers.registry (pubkey filenames match).

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"
REG="$CASAN_GOVERNANCE_ROOT/reviewers.registry"
WORK="$(mktemp -d)"; RV="$WORK/reviewers"; mkdir -p "$RV"
trap 'rm -rf "$WORK"' EXIT

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }
expect_rc() {
  local want="$1" desc="$2"; shift 2
  local got=0
  { "$@" >/dev/null 2>&1; } || got=$?
  [[ "$got" -eq "$want" ]] && pass "$desc (rc=$got)" || fail "$desc (got rc=$got, want $want)"
}

# Ephemeral reviewer keypairs (filenames match reviewers.registry).
for r in ops-owner tech-lead security-lead; do
  openssl genrsa -out "$WORK/$r.priv.pem" 2048 2>/dev/null
  openssl rsa -in "$WORK/$r.priv.pem" -pubout -out "$RV/$r.pub.pem" 2>/dev/null
done
openssl genrsa -out "$WORK/attacker.priv.pem" 2048 2>/dev/null

REQ="$WORK/req.txt"
printf 'deploy to production and run database migration\n' > "$REQ"
OTHER="$WORK/other.txt"
printf 'deploy a different unrelated change to production\n' > "$OTHER"

sign() { bash "$S/approval-sign.sh" "$@" >/dev/null 2>&1; }
# gc <extra-env...> — run governance-check in STRICT mode for a high-risk deploy
gc() {
  env CASAN_APPROVAL_STRICT=1 CASAN_REVIEWERS_FILE="$REG" CASAN_REVIEWERS_DIR="$RV" \
      CASAN_ACTOR=alice CASAN_APPROVAL_DECISION=approve "$@" \
      bash "$S/governance-check.sh" "$REQ" "$WORK/out.txt" deploy
}

echo "===== H5 approval-identity (CASAN_APPROVAL_STRICT=1) ====="

# 1. Valid signed approval by an authorized role -> APPROVED
sign deploy alice "$REQ" ops-owner "$WORK/ops-owner.priv.pem" "$WORK/ops.sig"
OUT="$(gc CASAN_APPROVER=ops-owner CASAN_APPROVAL_SIG="$WORK/ops.sig" 2>/dev/null)"; RC=$?
{ [[ "$RC" -eq 0 ]] && printf '%s' "$OUT" | grep -q "human_approved_signed"; } \
  && pass "valid signed approval by authorized reviewer -> APPROVED" \
  || fail "valid signed approval rejected (rc=$RC out=$OUT)"

# 2. Env-var approver but NO signature -> DENY (the core fix)
expect_rc 2 "env-var approver without signature is denied" \
  gc CASAN_APPROVER=ops-owner

# 3. Registered reviewer, but role not authorized for this action -> DENY
sign deploy alice "$REQ" tech-lead "$WORK/tech-lead.priv.pem" "$WORK/tech.sig"
expect_rc 2 "reviewer whose role is not authorized for deploy is denied" \
  gc CASAN_APPROVER=tech-lead CASAN_APPROVAL_SIG="$WORK/tech.sig"

# 4. Forged signature (attacker key, claims to be ops-owner) -> DENY
sign deploy alice "$REQ" ops-owner "$WORK/attacker.priv.pem" "$WORK/forged.sig"
expect_rc 2 "forged signature (unregistered key) is denied" \
  gc CASAN_APPROVER=ops-owner CASAN_APPROVAL_SIG="$WORK/forged.sig"

# 5. Unregistered approver id -> DENY
sign deploy alice "$REQ" ghost "$WORK/attacker.priv.pem" "$WORK/ghost.sig"
expect_rc 2 "unregistered approver id is denied" \
  gc CASAN_APPROVER=ghost CASAN_APPROVAL_SIG="$WORK/ghost.sig"

# 6. Replay: a signature bound to a DIFFERENT request cannot approve this one
sign deploy alice "$OTHER" ops-owner "$WORK/ops-owner.priv.pem" "$WORK/replay.sig"
expect_rc 2 "signature bound to another request cannot be replayed" \
  gc CASAN_APPROVER=ops-owner CASAN_APPROVAL_SIG="$WORK/replay.sig"

# 7. Separation of duties still enforced even with a valid signature
sign deploy ops-owner "$REQ" ops-owner "$WORK/ops-owner.priv.pem" "$WORK/sod.sig"
expect_rc 2 "self-approval denied even with a valid signature (SoD)" \
  env CASAN_APPROVAL_STRICT=1 CASAN_REVIEWERS_FILE="$REG" CASAN_REVIEWERS_DIR="$RV" \
      CASAN_ACTOR=ops-owner CASAN_APPROVAL_DECISION=approve \
      CASAN_APPROVER=ops-owner CASAN_APPROVAL_SIG="$WORK/sod.sig" \
      bash "$S/governance-check.sh" "$REQ" "$WORK/out.txt" deploy

# 8. Backward compatibility: default (non-strict) env approval still works
expect_rc 0 "non-strict env approval unchanged (backward compatible)" \
  env CASAN_ACTOR=alice CASAN_APPROVAL_DECISION=approve CASAN_APPROVER=bob \
      bash "$S/governance-check.sh" "$REQ" "$WORK/out.txt" deploy

echo "===== H5 OIDC approval via mock IdP JWT (CASAN_APPROVAL_STRICT=1) ====="
openssl genrsa -out "$WORK/idp.priv.pem" 2048 2>/dev/null
openssl rsa -in "$WORK/idp.priv.pem" -pubout -out "$WORK/idp.pub.pem" 2>/dev/null
openssl genrsa -out "$WORK/fake-idp.priv.pem" 2048 2>/dev/null

mint_jwt() {
  python3 "$S/approval-jwt-mint.py" --key "$1" --sub "$2" --role "$3" \
    --action deploy --actor alice --input "$REQ" --exp-offset "$4"
}

# 9. Valid IdP-signed JWT by an authorized role -> APPROVED
OIDC_JWT="$(mint_jwt "$WORK/idp.priv.pem" oidc-ops ops 300)"
OUT="$(gc CASAN_APPROVER=oidc-ops CASAN_APPROVAL_JWT="$OIDC_JWT" CASAN_IDP_PUBLIC_KEY="$WORK/idp.pub.pem" 2>/dev/null)"; RC=$?
{ [[ "$RC" -eq 0 ]] && printf '%s' "$OUT" | grep -q "human_approved_oidc"; } \
  && pass "valid IdP JWT by authorized role -> APPROVED" \
  || fail "valid IdP JWT rejected (rc=$RC out=$OUT)"

# 10. Expired JWT -> DENY
EXPIRED_JWT="$(mint_jwt "$WORK/idp.priv.pem" oidc-ops ops -60)"
expect_rc 2 "expired IdP JWT is denied" \
  gc CASAN_APPROVER=oidc-ops CASAN_APPROVAL_JWT="$EXPIRED_JWT" CASAN_IDP_PUBLIC_KEY="$WORK/idp.pub.pem"

# 11. Role not authorized for deploy -> DENY
WRONG_ROLE_JWT="$(mint_jwt "$WORK/idp.priv.pem" oidc-tech tech_lead 300)"
expect_rc 2 "IdP JWT with unauthorized role is denied" \
  gc CASAN_APPROVER=oidc-tech CASAN_APPROVAL_JWT="$WRONG_ROLE_JWT" CASAN_IDP_PUBLIC_KEY="$WORK/idp.pub.pem"

# 12. JWT signed by a different key than the trusted IdP pubkey -> DENY
FORGED_JWT="$(mint_jwt "$WORK/fake-idp.priv.pem" oidc-ops ops 300)"
expect_rc 2 "JWT with forged IdP signature is denied" \
  gc CASAN_APPROVER=oidc-ops CASAN_APPROVAL_JWT="$FORGED_JWT" CASAN_IDP_PUBLIC_KEY="$WORK/idp.pub.pem"

echo ""
echo "===== H5 APPROVAL-IDENTITY SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1