from datetime import datetime

class ThresholdMonitor:
    def __init__(self, fp_rate_alert_threshold: float = 0.001):
        self.decisions = []
        self.confirmed_fp = 0
        self.auto_merge_count = 0
        self.fp_rate_alert_threshold = fp_rate_alert_threshold

    def record_decision(self, decision: ERDecision, probability: float):
        self.decisions.append({
            "decision": decision,
            "probability": probability,
            "timestamp": datetime.utcnow()
        })
        if decision == ERDecision.AUTO_MERGE:
            self.auto_merge_count += 1

    def record_confirmed_false_positive(self):
        self.confirmed_fp += 1

    @property
    def false_positive_rate(self) -> float:
        if self.auto_merge_count == 0:
            return 0.0
        return self.confirmed_fp / self.auto_merge_count

    def is_alert(self) -> bool:
        return self.false_positive_rate > self.fp_rate_alert_threshold