"""Backend adapter contracts for Memory Gateway v2."""
from __future__ import annotations

from datetime import datetime
from enum import Enum
from typing import Any, Optional
from uuid import uuid4

from pydantic import BaseModel, Field

from .schemas import utc_now
from .schemas_v2 import BackendType, MemoryRefType, OperationStatus


class BackendOperation(str, Enum):
    INGEST_TURN = "ingest_turn"
    COMMIT_SESSION = "commit_session"
    RETRIEVE_CONTEXT = "retrieve_context"
    CREATE_REVIEW_DRAFT = "create_review_draft"


class BackendResultStatus(str, Enum):
    SUCCESS = "success"
    FAILED = "failed"
    SKIPPED = "skipped"
    PENDING = "pending"


class OutboxEventStatus(str, Enum):
    PENDING = "pending"
    PROCESSING = "processing"
    SUCCESS = "success"
    SKIPPED = "skipped"
    FAILED = "failed"
    DEAD_LETTER = "dead_letter"


class BackendWriteResult(BaseModel):
    backend_type: BackendType
    operation: BackendOperation
    status: BackendResultStatus
    native_id: Optional[str] = None
    native_uri: Optional[str] = None
    retryable: bool = False
    error_code: Optional[str] = None
    error_message: Optional[str] = None
    latency_ms: Optional[float] = None
    metadata: dict[str, Any] = Field(default_factory=dict)


class BackendProducedRef(BaseModel):
    ref_type: MemoryRefType
    native_id: Optional[str] = None
    native_uri: Optional[str] = None
    metadata: dict[str, Any] = Field(default_factory=dict)


class BackendCommitResult(BaseModel):
    backend_type: BackendType
    operation: BackendOperation = BackendOperation.COMMIT_SESSION
    status: BackendResultStatus
    native_id: Optional[str] = None
    native_uri: Optional[str] = None
    retryable: bool = False
    error_code: Optional[str] = None
    error_message: Optional[str] = None
    latency_ms: Optional[float] = None
    created_refs: list[str] = Field(default_factory=list)
    refs: list[BackendProducedRef] = Field(default_factory=list)
    metadata: dict[str, Any] = Field(default_factory=dict)


class BackendRetrieveItem(BaseModel):
    text: Optional[str] = None
    source_backend: BackendType
    ref_id: Optional[str] = None
    score: float = 0.0
    memory_type: Optional[str] = None
    metadata: dict[str, Any] = Field(default_factory=dict)


class BackendRetrieveResult(BaseModel):
    backend_type: BackendType
    operation: BackendOperation = BackendOperation.RETRIEVE_CONTEXT
    status: BackendResultStatus
    native_id: Optional[str] = None
    native_uri: Optional[str] = None
    retryable: bool = False
    error_code: Optional[str] = None
    error_message: Optional[str] = None
    latency_ms: Optional[float] = None
    items: list[BackendRetrieveItem] = Field(default_factory=list)
    metadata: dict[str, Any] = Field(default_factory=dict)


class OutboxEvent(BaseModel):
    id: str = Field(default_factory=lambda: f"outbox_{uuid4().hex[:16]}")
    event_type: str
    gateway_id: str
    workspace_id: str
    user_id: str
    agent_id: Optional[str] = None
    session_id: Optional[str] = None
    backend_type: BackendType
    operation: BackendOperation
    payload_ref: Optional[str] = None
    status: OutboxEventStatus = OutboxEventStatus.PENDING
    attempt_count: int = 0
    max_attempts: int = 3
    next_retry_at: Optional[datetime] = None
    last_error: Optional[str] = None
    locked_by: Optional[str] = None
    locked_at: Optional[datetime] = None
    lease_expires_at: Optional[datetime] = None
    metadata: dict[str, Any] = Field(default_factory=dict)
    created_at: datetime = Field(default_factory=utc_now)
    updated_at: datetime = Field(default_factory=utc_now)


class CommitJob(BaseModel):
    job_id: str = Field(default_factory=lambda: f"job_{uuid4().hex[:16]}")
    workspace_id: str
    user_id: str
    agent_id: Optional[str] = None
    session_id: str
    namespace: Optional[str] = None
    status: OperationStatus = OperationStatus.ACCEPTED
    requested_by: Optional[str] = None
    created_refs_count: int = 0
    error_message: Optional[str] = None
    created_at: datetime = Field(default_factory=utc_now)
    updated_at: datetime = Field(default_factory=utc_now)
    started_at: Optional[datetime] = None
    finished_at: Optional[datetime] = None