"""Deterministic goal rewrite rules for controller-level recovery.

Rules map goal substrings → safe fallback goals.
Applied exactly once after a first-run failure.
If no rule matches, recovery is skipped and the run terminates as failed.

Rules (pattern → replacement):
  "deny bash"        → "inspect project"  (security block → harmless read)
  "deny rm"          → "inspect project"
  "deny curl"        → "inspect project"
  "forbidden"        → "inspect project"
  "bad template"     → "inspect project"  (template logic error → harmless read)
  "retry execution"  → "inspect project"  (flaky step exhausted → harmless read)

Goals with no matching rule (e.g. "test traversal", "test absolute path"):
  → no rewrite → recovery_skipped → final_status=failed
"""
from __future__ import annotations

from typing import Optional

# Each entry: (substring_to_match_in_lower_goal, replacement_goal)
_RULES: list[tuple[str, str]] = [
    ("deny bash",       "inspect project"),
    ("deny rm",         "inspect project"),
    ("deny curl",       "inspect project"),
    ("forbidden",       "inspect project"),
    ("bad template",    "inspect project"),
    ("retry execution", "inspect project"),
]


def try_rewrite(goal: str) -> Optional[str]:
    """Return a replacement goal if a rewrite rule matches, else None."""
    lower = goal.lower()
    for pattern, replacement in _RULES:
        if pattern in lower:
            return replacement
    return None


def explain(goal: str) -> str:
    """Return a human-readable reason for the rewrite, or 'no rule' if none."""
    lower = goal.lower()
    for pattern, replacement in _RULES:
        if pattern in lower:
            return f"matched rule '{pattern}' → '{replacement}'"
    return "no rewrite rule for this goal"