"""Pydantic models for Lambda event validation."""

from __future__ import annotations

from typing import Any, Literal, Optional

from pydantic import BaseModel, ConfigDict, Field

from src.enums import EventType, TargetType


class PaymentAllocationEventMetadata(BaseModel):
    """Metadata section for PaymentAllocationEvent."""

    model_config = ConfigDict(extra='ignore')

    correlation_id: Optional[str] = Field(
        None, description='Correlation ID for tracing'
    )
    target_id: int = Field(..., description='Primary key of target entity')
    target_type: Literal[TargetType.STATEMENT_PERIOD_PAYMENT_ENTITY] = Field(
        ..., description='Entity type (e.g., statement_period_payment_entity)'
    )


class PaymentAllocationEventDetail(BaseModel):
    """Event detail section for PaymentAllocationEvent."""

    model_config = ConfigDict(extra='ignore')

    metadata: PaymentAllocationEventMetadata = Field(..., description='Event metadata')


class PaymentAllocationEvent(BaseModel):
    """EventBridge event for payment allocation (from outbox)."""

    model_config = ConfigDict(extra='ignore', populate_by_name=True)

    detail_type: Literal[EventType.CLOSE_BALANCE_COMPLETED] = Field(
        ...,
        description='Event type',
        alias='detail-type',
    )
    detail: PaymentAllocationEventDetail = Field(..., description='Event details')


class SimplePaymentAllocationEvent(BaseModel):
    """Simple event for manual triggering / testing."""

    statement_period_payment_entity_id: int


def parse_event(raw: dict[str, Any]) -> int:
    """Parse event and return statement_period_payment_entity_id.

    Accepts either an EventBridge envelope (with detail-type/detail) or a
    simple event with just statement_period_payment_entity_id.

    Args:
        raw: Raw event dictionary

    Returns:
        The statement_period_payment_entity_id

    Raises:
        ValidationError: If event structure is invalid for both formats
    """
    if 'detail-type' in raw:
        eb_event = PaymentAllocationEvent(**raw)
        return eb_event.detail.metadata.target_id
    simple_event = SimplePaymentAllocationEvent(**raw)
    return simple_event.statement_period_payment_entity_id