"""
Event models for the reliability framework.
Includes ReliabilityEvent, HealingAction, PolicyCondition, etc.
"""

from pydantic import BaseModel, Field, field_validator, computed_field, ConfigDict
from typing import Optional, List, Literal, Tuple
from enum import Enum
from datetime import datetime, timezone
import hashlib
import re

# Note: The following constants are not used directly in this file,
# but they are kept for potential future extensions or consistency with other modules.
# from agentic_reliability_framework.core.config.constants import (
#     LATENCY_WARNING, LATENCY_CRITICAL, LATENCY_EXTREME,
#     ERROR_RATE_WARNING, ERROR_RATE_HIGH, ERROR_RATE_CRITICAL,
#     CPU_WARNING, CPU_CRITICAL,
#     MEMORY_WARNING, MEMORY_CRITICAL
# )

def validate_component_id(component: str) -> Tuple[bool, str]:
    """
    Validate component ID format (alphanumeric and hyphens only).
    Returns (is_valid, error_message).
    """
    if not isinstance(component, str):
        return False, "Component ID must be a string"
    if not (1 <= len(component) <= 255):
        return False, "Component ID must be 1-255 characters"
    if not re.match(r"^[a-z0-9-]+$", component):
        return False, "Component ID must contain only lowercase letters, numbers, and hyphens"
    return True, ""


class EventSeverity(str, Enum):
    LOW = "low"
    MEDIUM = "medium"
    HIGH = "high"
    CRITICAL = "critical"


class HealingAction(str, Enum):
    RESTART_CONTAINER = "restart_container"
    SCALE_OUT = "scale_out"
    TRAFFIC_SHIFT = "traffic_shift"
    CIRCUIT_BREAKER = "circuit_breaker"
    ROLLBACK = "rollback"
    ALERT_TEAM = "alert_team"
    NO_ACTION = "no_action"


class HealthStatus(str, Enum):
    HEALTHY = "healthy"
    DEGRADED = "degraded"
    UNHEALTHY = "unhealthy"
    UNKNOWN = "unknown"


class PolicyCondition(BaseModel):
    metric: Literal["latency_p99", "error_rate", "cpu_util", "memory_util", "throughput"]
    operator: Literal["gt", "lt", "eq", "gte", "lte"]
    threshold: float = Field(ge=0)
    model_config = ConfigDict(frozen=True)


class ReliabilityEvent(BaseModel):
    timestamp: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
    component: str = Field(min_length=1, max_length=255)
    service_mesh: str = Field(default="default", min_length=1, max_length=100)
    latency_p99: float = Field(ge=0, lt=300000)
    error_rate: float = Field(ge=0, le=1)
    throughput: float = Field(ge=0)
    cpu_util: Optional[float] = Field(default=None, ge=0, le=1)
    memory_util: Optional[float] = Field(default=None, ge=0, le=1)
    revenue_impact: Optional[float] = Field(default=None, ge=0)
    user_impact: Optional[int] = Field(default=None, ge=0)
    upstream_deps: List[str] = Field(default_factory=list)
    downstream_deps: List[str] = Field(default_factory=list)
    severity: EventSeverity = EventSeverity.LOW
    model_config = ConfigDict(frozen=True, validate_assignment=True)

    @field_validator("component")
    @classmethod
    def validate_component_id(cls, v: str) -> str:
        if not re.match(r"^[a-z0-9-]+$", v):
            raise ValueError("Component ID must contain only lowercase letters, numbers, and hyphens")
        return v

    @field_validator("upstream_deps", "downstream_deps")
    @classmethod
    def validate_dependency_format(cls, v: List[str]) -> List[str]:
        for dep in v:
            if not re.match(r"^[a-z0-9-]+$", dep):
                raise ValueError(f"Dependency '{dep}' must contain only lowercase letters, numbers, and hyphens")
        return v

    @computed_field
    @property
    def fingerprint(self) -> str:
        components = [
            self.component,
            self.service_mesh,
            f"{self.latency_p99:.2f}",
            f"{self.error_rate:.4f}",
            f"{self.throughput:.2f}"
        ]
        return hashlib.sha256(":".join(components).encode()).hexdigest()

    def model_post_init(self, __context) -> None:
        circular = set(self.upstream_deps) & set(self.downstream_deps)
        if circular:
            raise ValueError(f"Circular dependencies detected: {circular}")


class HealingPolicy(BaseModel):
    name: str = Field(min_length=1, max_length=255)
    conditions: List[PolicyCondition] = Field(min_length=1)
    actions: List[HealingAction] = Field(min_length=1)
    priority: int = Field(ge=1, le=5, default=3)
    cool_down_seconds: int = Field(ge=0, default=300)
    enabled: bool = Field(default=True)
    max_executions_per_hour: int = Field(ge=1, default=10)
    model_config = ConfigDict(frozen=True)


class AnomalyResult(BaseModel):
    is_anomaly: bool
    confidence: float = Field(ge=0, le=1)
    anomaly_score: float = Field(ge=0, le=1)
    affected_metrics: List[str] = Field(default_factory=list)
    detection_timestamp: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
    model_config = ConfigDict(frozen=True)


class ForecastResult(BaseModel):
    metric: str
    predicted_value: float
    confidence: float = Field(ge=0, le=1)
    trend: Literal["increasing", "decreasing", "stable"]
    time_to_threshold: Optional[float] = Field(default=None)
    risk_level: Literal["low", "medium", "high", "critical"]
    forecast_timestamp: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
    model_config = ConfigDict(frozen=True)