from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import StreamingResponse
from sqlalchemy.orm import Session
from typing import Optional
from datetime import datetime
import csv
import io

from app.core.database import get_db
from app.core.security import get_current_user
from app.models.auth import User
from app.services.audit_service import AuditService

router = APIRouter(
    prefix="/audit",
    tags=["审计日志"],
    dependencies=[Depends(get_current_user)],
)


@router.get("/logs", summary="查询审计日志")
def get_audit_logs(
    user_id: Optional[int] = None,
    username: Optional[str] = None,
    action: Optional[str] = None,
    resource_type: Optional[str] = None,
    status: Optional[str] = None,
    start_time: Optional[datetime] = None,
    end_time: Optional[datetime] = None,
    skip: int = Query(0, ge=0),
    limit: int = Query(50, ge=1, le=500),
    # 当前用户必须是 admin 或 super_admin 才能看审计
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    # 角色检查：super_admin / admin 可以看所有人的，operator/viewer 只能看自己的
    if current_user.role not in ("super_admin", "admin"):
        user_id = current_user.id

    total, items = AuditService.get_logs(
        db,
        user_id=user_id,
        username=username,
        action=action,
        resource_type=resource_type,
        status=status,
        start_time=start_time,
        end_time=end_time,
        skip=skip,
        limit=limit,
    )

    serialized = []
    for log in items:
        serialized.append({
            "id": log.id,
            "user_id": log.user_id,
            "username": log.username,
            "action": log.action,
            "resource_type": log.resource_type,
            "resource_id": log.resource_id,
            "resource_name": log.resource_name,
            "method": log.method,
            "path": log.path,
            "ip_address": log.ip_address,
            "user_agent": log.user_agent,
            "status": log.status,
            "detail": log.detail,
            "created_at": log.created_at.isoformat() if log.created_at else None,
        })

    return {"total": total, "items": serialized}


@router.get("/logs/export", summary="导出审计日志为 CSV")
def export_audit_logs(
    user_id: Optional[int] = None,
    username: Optional[str] = None,
    action: Optional[str] = None,
    resource_type: Optional[str] = None,
    status: Optional[str] = None,
    start_time: Optional[datetime] = None,
    end_time: Optional[datetime] = None,
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    """导出 CSV 流。admin/super_admin 看全部；operator/viewer 仅能导出自己的。"""
    if current_user.role not in ("super_admin", "admin"):
        user_id = current_user.id

    # 导出上限 50000 行，避免一次拉太多 OOM
    total, items = AuditService.get_logs(
        db,
        user_id=user_id,
        username=username,
        action=action,
        resource_type=resource_type,
        status=status,
        start_time=start_time,
        end_time=end_time,
        skip=0,
        limit=50000,
    )

    output = io.StringIO()
    # 写入 UTF-8 BOM 让 Excel 直接打开不乱码
    output.write("\ufeff")
    writer = csv.writer(output)
    writer.writerow([
        "ID", "时间", "用户", "操作", "资源类型", "资源ID", "资源名称",
        "HTTP方法", "路径", "客户端IP", "状态", "详情"
    ])
    for log in items:
        writer.writerow([
            log.id,
            log.created_at.isoformat() if log.created_at else "",
            log.username or "",
            log.action or "",
            log.resource_type or "",
            log.resource_id or "",
            log.resource_name or "",
            log.method or "",
            log.path or "",
            log.ip_address or "",
            log.status or "",
            (log.detail or "").replace("\n", " ")[:500],
        ])

    output.seek(0)
    filename = f"audit_logs_{datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
    return StreamingResponse(
        iter([output.getvalue()]),
        media_type="text/csv; charset=utf-8",
        headers={"Content-Disposition": f'attachment; filename="{filename}"'},
    )


@router.get("/stats", summary="审计日志统计")
def get_audit_stats(
    current_user: User = Depends(get_current_user),
    db: Session = Depends(get_db),
):
    if current_user.role not in ("super_admin", "admin"):
        # operator/viewer 只能看自己的简单计数
        from app.models.audit import AuditLog
        from sqlalchemy import func
        my_count = db.query(func.count(AuditLog.id)).filter(AuditLog.user_id == current_user.id).scalar()
        return {"recent_24h": 0, "by_action_24h": {}, "my_total": int(my_count or 0)}

    return AuditService.get_stats(db)


@router.get("/actions", summary="获取所有审计操作类型（用于前端过滤下拉框）")
def get_action_types():
    """硬编码返回常用 action 列表，避免每次都查 DB"""
    from app.services.audit_service import AuditAction
    actions = []
    for name in dir(AuditAction):
        if name.startswith("_") or name.isupper() and not name.startswith("__"):
            continue
        val = getattr(AuditAction, name, None)
        if isinstance(val, str):
            actions.append({"code": val, "name": name})
    return actions