"""审计日志模块路由。

提供审计日志的查询、统计和导出功能。
记录系统中所有重要操作的详细信息，支持按操作类型、资源、操作人和时间范围筛选。
"""
import uuid
import csv
import io
from datetime import datetime
from fastapi import APIRouter, Depends, HTTPException, Request, Query
from fastapi.responses import StreamingResponse
from sqlalchemy import select, func, and_
from sqlalchemy.ext.asyncio import AsyncSession
from database import get_db
from models import AuditLog
from schemas import AuditLogOut, AuditLogPage
from dependencies import get_current_user

router = APIRouter(prefix="/api/audit", tags=["audit"])


@router.get("/logs", response_model=AuditLogPage)
async def list_logs(
    request: Request,
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    action: str | None = Query(None),
    resource: str | None = Query(None),
    operator_id: uuid.UUID | None = Query(None),
    date_from: datetime | None = Query(None),
    date_to: datetime | None = Query(None),
    db: AsyncSession = Depends(get_db),
):
    """分页查询审计日志列表，支持多条件筛选。

    Args:
        request: HTTP 请求对象。
        page: 页码，从 1 开始。
        page_size: 每页数量，最大 100。
        action: 可选的操作类型筛选条件。
        resource: 可选的资源类型筛选条件。
        operator_id: 可选的操作人 ID 筛选条件。
        date_from: 可选的起始时间筛选条件。
        date_to: 可选的结束时间筛选条件。
        db: 异步数据库会话。

    Returns:
        AuditLogPage: 分页的审计日志响应数据。
    """
    conditions = []
    if action:
        conditions.append(AuditLog.action == action)
    if resource:
        conditions.append(AuditLog.resource == resource)
    if operator_id:
        conditions.append(AuditLog.operator_id == operator_id)
    if date_from:
        conditions.append(AuditLog.created_at >= date_from)
    if date_to:
        conditions.append(AuditLog.created_at <= date_to)

    where = and_(*conditions) if conditions else None  # 组合所有筛选条件

    # 查询总数
    count_q = select(func.count(AuditLog.id))
    if where is not None:
        count_q = count_q.where(where)
    total_result = await db.execute(count_q)
    total = total_result.scalar() or 0

    # 分页查询
    q = select(AuditLog).order_by(AuditLog.created_at.desc())
    if where is not None:
        q = q.where(where)
    q = q.offset((page - 1) * page_size).limit(page_size)
    result = await db.execute(q)
    logs = result.scalars().all()

    return AuditLogPage(
        items=[AuditLogOut.model_validate(log, from_attributes=True) for log in logs],
        total=total,
        page=page,
        page_size=page_size,
    )


@router.get("/actions")
async def list_action_types(request: Request, db: AsyncSession = Depends(get_db)):
    """获取所有操作类型及其出现次数统计。

    Args:
        request: HTTP 请求对象。
        db: 异步数据库会话。

    Returns:
        dict: 包含操作类型统计列表的响应数据。
    """
    result = await db.execute(
        select(AuditLog.action, func.count(AuditLog.id)).group_by(AuditLog.action)
    )
    return {
        "code": 200,
        "data": [{"action": r[0], "count": r[1]} for r in result.all()],
    }


@router.get("/stats")
async def audit_stats(request: Request, db: AsyncSession = Depends(get_db)):
    """获取审计日志的统计摘要，包括总数、今日数量和 TOP 排行。

    Args:
        request: HTTP 请求对象。
        db: 异步数据库会话。

    Returns:
        dict: 包含审计统计摘要的响应数据。
    """
    total_result = await db.execute(select(func.count(AuditLog.id)))
    total = total_result.scalar() or 0

    today_start = datetime.utcnow().replace(hour=0, minute=0, second=0, microsecond=0)  # 今日零点
    today_result = await db.execute(
        select(func.count(AuditLog.id)).where(AuditLog.created_at >= today_start)
    )
    today = today_result.scalar() or 0

    # 最常见的操作类型 TOP 10
    top_result = await db.execute(
        select(AuditLog.action, func.count(AuditLog.id))
        .group_by(AuditLog.action)
        .order_by(func.count(AuditLog.id).desc())
        .limit(10)
    )
    top_actions = [{"action": r[0], "count": r[1]} for r in top_result.all()]

    # 最常见的资源类型 TOP 10
    top_resources = await db.execute(
        select(AuditLog.resource, func.count(AuditLog.id))
        .group_by(AuditLog.resource)
        .order_by(func.count(AuditLog.id).desc())
        .limit(10)
    )
    top_resources_list = [{"resource": r[0], "count": r[1]} for r in top_resources.all()]

    return {
        "code": 200,
        "data": {
            "total": total,
            "today": today,
            "top_actions": top_actions,
            "top_resources": top_resources_list,
        },
    }


@router.get("/export")
async def export_logs(
    request: Request,
    date_from: datetime | None = Query(None),
    date_to: datetime | None = Query(None),
    db: AsyncSession = Depends(get_db),
):
    """导出审计日志为 CSV 文件。

    Args:
        request: HTTP 请求对象。
        date_from: 可选的起始时间筛选条件。
        date_to: 可选的结束时间筛选条件。
        db: 异步数据库会话。

    Returns:
        StreamingResponse: CSV 格式的文件流响应。
    """
    conditions = []
    if date_from:
        conditions.append(AuditLog.created_at >= date_from)
    if date_to:
        conditions.append(AuditLog.created_at <= date_to)

    q = select(AuditLog).order_by(AuditLog.created_at.desc())
    if conditions:
        q = q.where(and_(*conditions))
    q = q.limit(10000)  # 最多导出 10000 条
    result = await db.execute(q)
    logs = result.scalars().all()

    output = io.StringIO()
    writer = csv.writer(output)
    writer.writerow(["ID", "操作时间", "操作人ID", "操作", "资源", "资源ID", "详情", "IP地址"])  # CSV 表头
    for log in logs:
        writer.writerow([
            str(log.id),
            log.created_at.isoformat() if log.created_at else "",
            str(log.operator_id) if log.operator_id else "",
            log.action,
            log.resource or "",
            log.resource_id or "",
            str(log.detail)[:500] if log.detail else "",
            log.ip_address or "",
        ])
    output.seek(0)

    return StreamingResponse(
        iter([output.getvalue()]),
        media_type="text/csv",
        headers={"Content-Disposition": f"attachment; filename=audit_logs_{datetime.utcnow().strftime('%Y%m%d_%H%M%S')}.csv"},
    )