#!/usr/bin/env python3
"""Regression guard for the EGG LIMIT hard rule.

Run after any change to meal-history.json, inventory.json, or the daily job,
and before sending a regenerated day's email:

  python3 scripts/verify_eggs.py

Checks the EGG LIMIT contract against the persisted rules in inventory.json:
  - No single meal may exceed diet.egg_rules.max_per_meal (default 4).
  - No day may have more than diet.egg_rules.max_meals_per_day_with_eggs
    (default 1) meals containing eggs — i.e. the other meal must be egg-free.

Exits non-zero on violation so it can gate a send or a CI-style check.
"""
import json
import os
import sys

HERE = os.path.dirname(os.path.abspath(__file__))
SKILL_DIR = os.path.dirname(HERE)


def load(name):
    with open(os.path.join(SKILL_DIR, name)) as f:
        return json.load(f)


def main():
    inv = load("inventory.json")
    hist = load("meal-history.json")

    rules = inv.get("diet", {}).get("egg_rules", {})
    max_per_meal = rules.get("max_per_meal", 4)
    max_egg_meals = rules.get("max_meals_per_day_with_eggs", 1)

    violations = []
    by_date = {}
    for e in hist.get("entries", []):
        eggs = next((i["qty"] for i in e["items"] if i["name"].lower() == "eggs"), 0)
        by_date.setdefault(e["date"], []).append((e["meal"], e.get("name", ""), eggs))

    for date, meals in by_date.items():
        for meal, name, eggs in meals:
            if eggs > max_per_meal:
                violations.append(
                    f"{date} {meal} ('{name}'): {eggs} eggs > max {max_per_meal}/meal")
        egg_meal_count = sum(1 for _, _, eggs in meals if eggs > 0)
        if egg_meal_count > max_egg_meals:
            violations.append(
                f"{date}: {egg_meal_count} egg-containing meals > max {max_egg_meals}/day "
                f"(other meal must be egg-free)")

    # Also confirm the inventory metadata carries the cap.
    if not rules:
        violations.append("inventory.json missing diet.egg_rules — egg cap not enforced at the data level")

    if violations:
        print("FAIL: egg-limit violations found:")
        for v in violations:
            print(f"  - {v}")
        sys.exit(1)
    print(f"PASS: egg limit OK (max {max_per_meal}/meal, max {max_egg_meals} egg-meal/day) "
          f"across {len(by_date)} day(s).")


if __name__ == "__main__":
    main()