"""系统管理接口（契约1.23），对齐 Java 版 SystemController。

资源监控（实时/趋势/进程）、存储占用、转换器状态、一键体检、
系统信息、运行参数、运行日志、维护操作（预览缓存清理/强制下线）。
查询类只读；维护操作记审计。全部要求系统管理权限（manage_system），
运行日志并入日志审计权限（manage_audit_log，单开窗口查看原始日志）。
"""

from __future__ import annotations

from flask import request, send_file

from dms.api.v1.blueprint import api_v1
from dms.common.enums import AuditAction, AuditTarget
from dms.common.errors import (
    InvalidArgumentError,
    ResourceNotFoundError,
    UserSelfProtectionError,
)
from dms.common.response import serialize_id, success_response
from dms.extensions import db
from dms.models import User
from dms.security.auth_context import get_auth_context
from dms.security.decorators import (
    audit_log_required,
    bearer_auth_required,
    system_management_required,
)
from dms.services.audit_service import business_audit
from dms.services.system_management_service import (
    clear_preview_cache,
    converter_status,
    current_metrics,
    health_check,
    log_file_path,
    metric_history,
    process_metrics,
    read_log_tail,
    runtime_config,
    storage_usage,
    system_info,
)


def _positive_int(value: str | None, default: int, maximum: int) -> int:
    if value is None or not value.strip():
        return default
    try:
        number = int(value.strip())
    except ValueError as exc:
        raise InvalidArgumentError("参数必须是整数") from exc
    if number < 1 or number > maximum:
        raise InvalidArgumentError(f"参数取值范围为 1~{maximum}")
    return number


@api_v1.get("/system/metrics/current")
@bearer_auth_required
@system_management_required
def system_metrics_current():
    return success_response(current_metrics())


@api_v1.get("/system/metrics/history")
@bearer_auth_required
@system_management_required
def system_metrics_history():
    hours = _positive_int(request.args.get("hours"), default=24, maximum=720)
    return success_response(metric_history(hours))


@api_v1.get("/system/process")
@bearer_auth_required
@system_management_required
def system_process():
    return success_response(process_metrics())


@api_v1.get("/system/storage-usage")
@bearer_auth_required
@system_management_required
def system_storage_usage():
    return success_response({"entries": storage_usage()})


@api_v1.get("/system/converter")
@bearer_auth_required
@system_management_required
def system_converter():
    return success_response(converter_status())


@api_v1.get("/system/health")
@bearer_auth_required
@system_management_required
def system_health():
    return success_response({"items": health_check()})


@api_v1.get("/system/info")
@bearer_auth_required
@system_management_required
def system_information():
    return success_response(system_info())


@api_v1.get("/system/runtime-config")
@bearer_auth_required
@system_management_required
def system_runtime_config():
    return success_response({"entries": runtime_config()})


@api_v1.get("/system/logs")
@bearer_auth_required
@system_management_required
def system_logs():
    lines = _positive_int(request.args.get("lines"), default=500, maximum=5000)
    level = (request.args.get("level") or "").strip() or None
    return success_response(read_log_tail(lines=lines, level=level))


@api_v1.get("/system/logs/download")
@bearer_auth_required
@audit_log_required
def system_logs_download():
    """原始运行日志文件下载（日志审计页签单开窗口查看）。"""
    path = log_file_path()
    if path is None or not path.is_file():
        raise ResourceNotFoundError("运行日志文件未启用或不存在")
    return send_file(
        path,
        mimetype="text/plain",
        as_attachment=True,
        download_name=path.name,
    )


@api_v1.post("/system/maintenance/preview-cache")
@bearer_auth_required
@system_management_required
def system_clear_preview_cache():
    """清空预览缓存（可重建），记 PREVIEW_CACHE_CLEAR 审计。"""
    result = clear_preview_cache()
    db.session.add(
        business_audit(
            action=AuditAction.PREVIEW_CACHE_CLEAR,
            target=AuditTarget.SYSTEM,
            target_id=0,
            target_name="preview",
            detail=result,
        )
    )
    db.session.commit()
    return success_response(result)


@api_v1.post("/system/users/<user_id>/force-offline")
@bearer_auth_required
@system_management_required
def system_force_offline(user_id: str):
    """强制下线：auth_version + 1 使目标用户全部访问令牌立即失效。"""
    from dms.services.user_service import parse_string_id

    numeric_id = parse_string_id(user_id, name="userId")
    if numeric_id is None:
        raise InvalidArgumentError("userId不能为空")
    if get_auth_context().user_id == numeric_id:
        raise UserSelfProtectionError("不能强制自己下线")
    user = db.session.get(User, numeric_id)
    if user is None or user.is_deleted:
        raise ResourceNotFoundError("用户不存在")
    user.auth_version += 1
    db.session.add(
        business_audit(
            action=AuditAction.FORCE_OFFLINE,
            target=AuditTarget.USER,
            target_id=user.id,
            target_name=user.username,
            detail={"authVersion": user.auth_version},
        )
    )
    db.session.commit()
    return success_response(
        {
            "userId": serialize_id(user.id),
            "username": user.username,
            "authVersion": user.auth_version,
        }
    )