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

# CASAN Plan-17 Track 5 — Meta-loop (self-improving loop policy).
#
# Proves:
#   * propose is dry-run (emits proposals, writes nothing to the CP store),
#   * apply enforces Separation of Duties (proposer == approver -> DENY),
#   * apply requires an approval (no approval -> DENY),
#   * a loosen proposal above the org hard cap is refused (17.19),
#   * an approved loosen is applied via the governed store AND actually changes the
#     governor's effective ceiling (governed override is real, not paper),
#   * rollback via the governed store reverts the governor's behaviour,
#   * the CP audit chain stays intact,
#   * no repo / home pollution (sandboxed state, store, keys).
#
# Deterministic; hermetic; dev profile keeps the backward-compatible approval gate.

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
PROJECT_ROOT="$CASAN_APP_ROOT"
BIN="$CASAN_HARNESS_ROOT/scripts/bash"
META="$BIN/loop-metaloop.py"
GOV="$BIN/loop-governor.py"
CPS="$BIN/control-plane-settings.py"
POLICY="$CASAN_HARNESS_ROOT/config/loop-policy.yaml"

WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT
export CASAN_LOOP_STATE_ROOT="$WORK/state"
export CASAN_LOOP_POLICY_FILE="$POLICY"
export CASAN_CP_STORE_FILE="$WORK/cp/settings.json"   # sandbox governed store
export CASAN_CP_KEY_DIR="$WORK/keys"                  # sandbox signing keys (not ~)

PASS=0; FAIL=0
pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }

gov_rc() {
  # gov_rc <step> [profile]; returns governor rc (0 continue, 3 halt)
  local step="$1" prof="${2:-dev}"
  python3 "$GOV" check --run-id metarun --step "$step" --profile "$prof" >/dev/null 2>&1
  echo $?
}

echo "===== Plan-17 T5: Meta-loop ====="

# crafted trace: a run that halted on budget at step 100 + an OSCILLATING verdict
cat > "$WORK/trace.jsonl" <<'JSON'
{"iteration":{"run_id":"r","step":10,"gate_verdict":"PASS","decision":"CONTINUE","progress":0.1}}
{"iteration":{"run_id":"r","step":100,"gate_verdict":"OSCILLATING","decision":"HALT","progress":0.1}}
JSON

# 1) propose (dry-run)
OUT="$(python3 "$META" propose --loop-trace "$WORK/trace.jsonl" 2>/dev/null)"
grep -q '"id": "P-LOOSEN-STEPS"' <<<"$OUT" && pass "propose emits P-LOOSEN-STEPS" || fail "no loosen proposal"
grep -q '"value": 110' <<<"$OUT" && pass "loosen value = max_step+10 (110)" || fail "wrong loosen value"
echo "$OUT" > "$WORK/props.json"
[[ ! -f "$CASAN_CP_STORE_FILE" ]] && pass "propose wrote nothing to CP store (dry-run)" || fail "propose polluted CP store"

# baseline: dev default max_steps=50 -> step 60 HALTs (no override yet)
[[ "$(gov_rc 60 dev)" -eq 3 ]] && pass "baseline governor HALTs step 60 (dev max_steps 50)" || fail "baseline governor wrong"

# 2) SoD violation: proposer == approver -> DENY
python3 "$META" apply --proposals "$WORK/props.json" --id P-LOOSEN-STEPS \
  --proposer alice --approver alice --approval tok >/dev/null 2>&1
[[ "$?" -eq 3 ]] && pass "SoD violation refused" || fail "SoD not enforced"

# 3) missing approval -> DENY
python3 "$META" apply --proposals "$WORK/props.json" --id P-LOOSEN-STEPS \
  --proposer alice --approver bob >/dev/null 2>&1
[[ "$?" -eq 3 ]] && pass "apply without approval refused" || fail "approval not required"

# 4) loosen beyond org ceiling (200) -> DENY
cat > "$WORK/props-big.json" <<'JSON'
{"proposals":[{"id":"P-BIG","key":"loop.max_steps","value":999,"direction":"loosen","security_sensitive":true,"source_trust":"untrusted","reason":"too big"}]}
JSON
OUT="$(python3 "$META" apply --proposals "$WORK/props-big.json" --id P-BIG \
  --proposer alice --approver bob --approval tok 2>/dev/null)"; rc=$?
[[ "$rc" -eq 3 ]] && pass "loosen above org ceiling refused (rc=3)" || fail "org ceiling not enforced (rc=$rc)"
grep -q '"reason": "exceeds_org_ceiling"' <<<"$OUT" && pass "reason exceeds_org_ceiling" || fail "wrong org-ceiling reason"

# 5) valid approved loosen -> APPLIED + governor now honours 110
OUT="$(python3 "$META" apply --proposals "$WORK/props.json" --id P-LOOSEN-STEPS \
  --proposer alice --approver bob --approval tok 2>/dev/null)"; rc=$?
[[ "$rc" -eq 0 ]] && pass "approved loosen APPLIED (rc=0)" || fail "approved loosen failed (rc=$rc)"
grep -q '"decision": "APPLIED"' <<<"$OUT" && pass "APPLIED decision" || fail "no APPLIED decision"
[[ "$(gov_rc 60 dev)" -eq 0 ]] && pass "governor now CONTINUEs step 60 (override 110 in effect)" || fail "governed override not applied to governor"

# 6) rollback reverts governor behaviour: set a tighter 90, prove HALT@100, rollback -> 110 -> CONTINUE@100
cat > "$WORK/props-90.json" <<'JSON'
{"proposals":[{"id":"P-90","key":"loop.max_steps","value":90,"direction":"tighten","security_sensitive":false,"source_trust":"untrusted","reason":"tighten"}]}
JSON
python3 "$META" apply --proposals "$WORK/props-90.json" --id P-90 \
  --proposer alice --approver bob --approval tok >/dev/null 2>&1
[[ "$(gov_rc 100 dev)" -eq 3 ]] && pass "after set 90, governor HALTs step 100" || fail "tighten not applied"
python3 "$CPS" rollback loop.max_steps --actor bob --reason "revert" >/dev/null 2>&1
[[ "$(gov_rc 100 dev)" -eq 0 ]] && pass "after rollback to 110, governor CONTINUEs step 100" || fail "rollback did not revert governor"

# 7) CP audit chain intact
python3 "$CPS" verify-audit >/dev/null 2>&1 && pass "CP audit chain intact after meta-loop applies" || fail "CP audit chain broken"

# 8) no repo pollution (state + default CP store + home keys untouched)
POLLUTED=0
[[ -d "$CASAN_STATE_ROOT/state" && -n "$(ls -A "$CASAN_STATE_ROOT/state" 2>/dev/null)" ]] && POLLUTED=1
[[ -f "$CASAN_STATE_ROOT/level5/control-plane-settings.json" ]] && POLLUTED=1
[[ "$POLLUTED" -eq 0 ]] && pass "no repo pollution (state / default CP store clean)" || fail "repo polluted"

echo ""
echo "===== T5 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
[[ "$FAIL" -eq 0 ]] || exit 1