"""会话资源域 Router。

提供渠道会话管理的 6 个 HTTP 端点，全部由 ``get_admin_user`` 守门，仅管理员
可访问。Router 不含任何业务逻辑，仅做协议翻译：将 HTTP 请求参数组装为契约层
命令/参数，调用 ``use_cases.session_management`` 的类型化方法走控制面管道，
再通过 ``raiseOnControlFailure`` 转译失败、``serialize_control_data`` 序列化
成功结果（模板 A）。

端点清单：
    - GET    /sessions                       SES-QUERY-01  列出渠道会话
    - POST   /sessions/batch-close           SES-BATCH-CLOSE-01 批量关闭会话
    - GET    /sessions/{session_id}          SES-QUERY-02  查询会话详情
    - POST   /sessions/{session_id}/merge    SES-05        合并会话（FR-07）
    - POST   /sessions/{session_id}/transfer SES-13        转移会话所有者（FR-26）
    - POST   /sessions/{session_id}/close    SES-CLOSE-01  关闭会话
    - GET    /sessions/{session_id}/messages SES-MSG-01    查询会话消息流
    - GET    /sessions/{session_id}/stats    SES-STATS-01  查询会话统计指标
"""

from __future__ import annotations

from typing import Any

from fastapi import APIRouter, Depends, Query, Request
from pydantic import BaseModel, ConfigDict, Field

from yuxi.channels.contract.dtos.channel import ChannelType
from yuxi.channels.contract.dtos.conversation import MergeConversationCmd
from yuxi.channels.contract.dtos.session import (
    BatchCloseSessionsCmd,
    CloseSessionCmd,
    OwnerTransferCmd,
)
from yuxi.storage.postgres.models_business import User

from server.routers.channels import (
    build_operator,
    get_channel_use_cases,
    raiseOnControlFailure,
    serialize_control_data,
)
from server.utils.auth_middleware import get_admin_user

session_router = APIRouter(tags=["channels-session"])


class MergeSessionRequest(BaseModel):
    """合并会话请求体。``target_conversation_id`` 由路径参数提供，不在 body 中。"""

    model_config = ConfigDict(frozen=True)

    source_conversation_id: str = Field(..., min_length=1, description="源会话 ID（被合并方）")
    reason: str = Field(default="", max_length=512, description="合并原因（审计用）")


class TransferOwnerRequest(BaseModel):
    """转移所有者请求体。``conversation_id`` 由路径参数提供，不在 body 中。"""

    model_config = ConfigDict(frozen=True)

    new_owner_id: str = Field(..., min_length=1, description="新所有者对端 ID")


class CloseSessionRequest(BaseModel):
    """关闭会话请求体。``session_id`` 由路径参数提供，不在 body 中。"""

    model_config = ConfigDict(frozen=True)

    reason: str | None = Field(default=None, max_length=512, description="关闭原因（审计用）")


class BatchCloseSessionsRequest(BaseModel):
    """批量关闭会话请求体（SES-BATCH-CLOSE-01）。

    ``session_ids`` 与 ``filter`` 二者不可同时为空（由 dispatch handler 校验）。
    """

    model_config = ConfigDict(frozen=True)

    session_ids: list[str] | None = Field(
        default=None,
        description="显式会话 ID 列表（与 filter 二选一）",
    )
    filter: dict[str, Any] | None = Field(
        default=None,
        description="筛选条件（含 channel_type / inactive_before / status）",
    )
    max_count: int = Field(default=100, ge=1, le=1000, description="单次最大关闭数")
    reason: str | None = Field(default=None, max_length=512, description="关闭原因（审计用）")


@session_router.get("/sessions", response_model=dict)
async def list_sessions(
    request: Request,
    channel_type: ChannelType | None = Query(default=None, description="按渠道类型过滤，留空跨渠道查询"),
    peer_id: str | None = Query(default=None, description="按对端 ID 模糊匹配"),
    limit: int = Query(default=100, ge=1, le=1000, description="分页大小"),
    offset: int = Query(default=0, ge=0, description="分页偏移"),
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """列出渠道会话（运维排查用例，SES-QUERY-01）。

    供管理员排查"用户消息未到达"等运维问题。``channel_type`` 留空时跨渠道查询；
    ``peer_id`` 提供时按对端 ID 模糊匹配。对应控制面操作 ``session/list``。
    """
    operator = build_operator(current_user, request)
    result = await use_cases.session_management.listSessions(
        channel_type=channel_type,
        limit=limit,
        operator=operator,
        offset=offset,
        peer_id=peer_id,
    )
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.post("/sessions/batch-close", response_model=dict)
async def batch_close_sessions(
    payload: BatchCloseSessionsRequest,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """批量关闭渠道会话（SES-BATCH-CLOSE-01）。

    支持 ``session_ids`` 显式列表与 ``filter`` 筛选条件两种模式（二者不可
    同时空，由 dispatch handler 校验）。逐条独立事务复用单条 ``closeSession``
    逻辑（模式 D，部分成功语义），单条失败不回滚已成功条目。对应控制面
    操作 ``session/batch_close``。

    静态路径先于 ``/sessions/{session_id}`` 声明，避免被动态参数捕获。
    """
    operator = build_operator(current_user, request)
    cmd = BatchCloseSessionsCmd(
        operator=operator,
        session_ids=tuple(payload.session_ids) if payload.session_ids else (),
        filter=payload.filter,
        max_count=payload.max_count,
        reason=payload.reason,
    )
    result = await use_cases.session_management.batchCloseSessions(cmd)
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.get("/sessions/{session_id}", response_model=dict)
async def get_session(
    session_id: str,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """按 session_id 查询渠道会话详情（SES-QUERY-02）。

    供管理员审批 mergeSession 前核对源/目标会话信息。软删除的会话返回 404。
    对应控制面操作 ``session/get``。
    """
    operator = build_operator(current_user, request)
    result = await use_cases.session_management.getSession(
        session_id=session_id,
        operator=operator,
    )
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.post("/sessions/{session_id}/merge", response_model=dict)
async def merge_session(
    session_id: str,
    payload: MergeSessionRequest,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """合并会话（FR-07，SES-05）。

    将源会话合并至目标会话（路径 ``session_id``），迁移消息并软删除源会话。
    受 ``merge_strategy_enabled`` 配置策略门控制，falsy 时返回 422。
    对应控制面操作 ``session/merge``。

    协议翻译：路径参数 ``session_id`` → ``MergeConversationCmd.target_conversation_id``。
    """
    operator = build_operator(current_user, request)
    cmd = MergeConversationCmd(
        source_conversation_id=payload.source_conversation_id,
        target_conversation_id=session_id,
        operator=operator,
        reason=payload.reason,
    )
    result = await use_cases.session_management.mergeSession(cmd)
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.post("/sessions/{session_id}/transfer", response_model=dict)
async def transfer_session_owner(
    session_id: str,
    payload: TransferOwnerRequest,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """转移会话所有者（FR-26，SES-13）。

    将会话（路径 ``session_id``）所有者从当前对端转移至新对端，纯 DB 写入，
    加入控制面管道事务。审计日志由 AuditStage 在 SHARED 事务中统一写入（fail-closed）。
    对应控制面操作 ``session/transfer_owner``。

    协议翻译：路径参数 ``session_id`` → ``OwnerTransferCmd.conversation_id``。
    """
    operator = build_operator(current_user, request)
    cmd = OwnerTransferCmd(
        conversation_id=session_id,
        new_owner_id=payload.new_owner_id,
        operator=operator,
    )
    result = await use_cases.session_management.transferSessionOwner(cmd)
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.post("/sessions/{session_id}/close", response_model=dict)
async def close_session(
    session_id: str,
    payload: CloseSessionRequest,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """关闭渠道会话（SES-CLOSE-01）。

    主动关闭指定会话，停止接收新消息。已关闭会话不可重新激活。
    对应控制面操作 ``session/close``。

    协议翻译：路径参数 ``session_id`` → ``CloseSessionCmd.session_id``。
    """
    operator = build_operator(current_user, request)
    cmd = CloseSessionCmd(
        session_id=session_id,
        reason=payload.reason,
        operator=operator,
    )
    result = await use_cases.session_management.closeSession(cmd)
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.get("/sessions/{session_id}/messages", response_model=dict)
async def list_session_messages(
    session_id: str,
    request: Request,
    limit: int = Query(default=50, ge=1, le=200, description="分页大小"),
    offset: int = Query(default=0, ge=0, description="分页偏移"),
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """查询会话消息流（SES-MSG-01）。

    按时间顺序列出会话内的消息，支持分页。
    对应控制面操作 ``session/list_messages``。
    """
    operator = build_operator(current_user, request)
    result = await use_cases.session_management.listSessionMessages(
        session_id=session_id,
        limit=limit,
        offset=offset,
        operator=operator,
    )
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}


@session_router.get("/sessions/{session_id}/stats", response_model=dict)
async def get_session_stats(
    session_id: str,
    request: Request,
    use_cases=Depends(get_channel_use_cases),
    current_user: User = Depends(get_admin_user),
) -> dict[str, Any]:
    """查询单会话统计指标（SES-STATS-01）。

    按 ``session_id`` 查询会话的统计指标（消息计数、首响时间、平均响应、
    会话时长等），由 dispatch handler 组合 ConversationPort 消息查询计算。
    对应控制面操作 ``session/stats``。

    协议翻译：路径参数 ``session_id`` 直接传入
    ``getSessionStats(session_id=..., operator=...)``。
    """
    operator = build_operator(current_user, request)
    result = await use_cases.session_management.getSessionStats(
        session_id=session_id,
        operator=operator,
    )
    raiseOnControlFailure(result)
    return {"success": True, "data": serialize_control_data(result.data)}