feat(CORE-001D3A): normalize alerts and settings service boundaries

app/services/alerts.py

@@ -2,13 +2,79 @@
 
 from __future__ import annotations
 
+from dataclasses import dataclass
+from decimal import Decimal
 from typing import Mapping
 
 from app.domain.portfolio_math import build_alert_context
+from app.domain.units import decimal_from_float
 from app.models.alerts import AlertEvent, AlertHistoryRepository, AlertStatus
 from app.models.portfolio import PortfolioConfig
 
 
+@dataclass(frozen=True, slots=True)
+class AlertEvaluationInput:
+    ltv_ratio: Decimal
+    spot_price: Decimal
+    updated_at: str
+    warning_threshold: Decimal
+    critical_threshold: Decimal
+    email_alerts_enabled: bool
+
+
+def _decimal_from_boundary_value(value: object, *, field_name: str, default: float = 0.0) -> Decimal:
+    if value is None:
+        return decimal_from_float(float(default))
+    if isinstance(value, bool):
+        raise TypeError(f"{field_name} must be numeric, got bool")
+    if isinstance(value, int):
+        parsed = float(value)
+    elif isinstance(value, float):
+        parsed = value
+    elif isinstance(value, str):
+        stripped = value.strip()
+        if not stripped:
+            parsed = float(default)
+        else:
+            try:
+                parsed = float(stripped)
+            except ValueError as exc:
+                raise ValueError(f"{field_name} must be numeric, got {value!r}") from exc
+    else:
+        raise TypeError(f"{field_name} must be numeric, got {type(value)!r}")
+    return decimal_from_float(float(parsed))
+
+
+def _normalize_alert_evaluation_input(
+    config: PortfolioConfig,
+    portfolio: Mapping[str, object],
+) -> AlertEvaluationInput:
+    return AlertEvaluationInput(
+        ltv_ratio=_decimal_from_boundary_value(
+            portfolio.get("ltv_ratio", 0.0),
+            field_name="portfolio.ltv_ratio",
+        ),
+        spot_price=_decimal_from_boundary_value(
+            portfolio.get("spot_price", 0.0),
+            field_name="portfolio.spot_price",
+        ),
+        updated_at=str(portfolio.get("quote_updated_at", "")),
+        warning_threshold=_decimal_from_boundary_value(
+            config.ltv_warning,
+            field_name="config.ltv_warning",
+        ),
+        critical_threshold=_decimal_from_boundary_value(
+            config.margin_threshold,
+            field_name="config.margin_threshold",
+        ),
+        email_alerts_enabled=bool(config.email_alerts),
+    )
+
+
+def _ratio_text(value: Decimal) -> str:
+    return f"{float(value):.1%}"
+
+
 def build_portfolio_alert_context(
     config: PortfolioConfig,
     *,
@@ -32,20 +98,19 @@ class AlertService:
         self, config: PortfolioConfig, portfolio: Mapping[str, object], *, persist: bool = True
     ) -> AlertStatus:
         history = self.repository.load() if persist else []
-        ltv_ratio = float(portfolio.get("ltv_ratio", 0.0))
-        spot_price = float(portfolio.get("spot_price", 0.0))
-        updated_at = str(portfolio.get("quote_updated_at", ""))
+        evaluation = _normalize_alert_evaluation_input(config, portfolio)
 
-        if ltv_ratio >= float(config.margin_threshold):
+        if evaluation.ltv_ratio >= evaluation.critical_threshold:
             severity = "critical"
             message = (
-                f"Current LTV {ltv_ratio:.1%} is above the critical threshold of "
-                f"{float(config.margin_threshold):.1%}."
+                f"Current LTV {_ratio_text(evaluation.ltv_ratio)} is above the critical threshold of "
+                f"{_ratio_text(evaluation.critical_threshold)}."
             )
-        elif ltv_ratio >= float(config.ltv_warning):
+        elif evaluation.ltv_ratio >= evaluation.warning_threshold:
             severity = "warning"
             message = (
-                f"Current LTV {ltv_ratio:.1%} is above the warning threshold of " f"{float(config.ltv_warning):.1%}."
+                f"Current LTV {_ratio_text(evaluation.ltv_ratio)} is above the warning threshold of "
+                f"{_ratio_text(evaluation.warning_threshold)}."
             )
         else:
             severity = "ok"
@@ -56,12 +121,12 @@ class AlertService:
             event = AlertEvent(
                 severity=severity,
                 message=message,
-                ltv_ratio=ltv_ratio,
-                warning_threshold=float(config.ltv_warning),
-                critical_threshold=float(config.margin_threshold),
-                spot_price=spot_price,
-                updated_at=updated_at,
-                email_alerts_enabled=bool(config.email_alerts),
+                ltv_ratio=float(evaluation.ltv_ratio),
+                warning_threshold=float(evaluation.warning_threshold),
+                critical_threshold=float(evaluation.critical_threshold),
+                spot_price=float(evaluation.spot_price),
+                updated_at=evaluation.updated_at,
+                email_alerts_enabled=evaluation.email_alerts_enabled,
             )
             if persist:
                 if self._should_record(history, event):
@@ -73,10 +138,10 @@ class AlertService:
         return AlertStatus(
             severity=severity,
             message=message,
-            ltv_ratio=ltv_ratio,
-            warning_threshold=float(config.ltv_warning),
-            critical_threshold=float(config.margin_threshold),
-            email_alerts_enabled=bool(config.email_alerts),
+            ltv_ratio=float(evaluation.ltv_ratio),
+            warning_threshold=float(evaluation.warning_threshold),
+            critical_threshold=float(evaluation.critical_threshold),
+            email_alerts_enabled=evaluation.email_alerts_enabled,
             history=(
                 preview_history
                 if not persist