using System.Globalization;
using System.Threading;
using Microsoft.Extensions.Logging;
using SqlSugar;

namespace Admin.NET.Plugin.AiDOP.Service.S8.Rules;

/// <summary>
/// S8-SQL-EVALUATOR-GUARD-P2-1：S8 三类 SQL evaluator 公共防护工具。
/// 承载：
///   1) AIDOP_S8_EVALUATOR_COMMAND_TIMEOUT_SECONDS / AIDOP_S8_EVALUATOR_MAX_ROWS env 解析（含默认值与下限保护，解析失败单次 warn）；
///   2) ApplyCommandTimeout：在 evaluator 独立 SqlSugarScope 上显式设置 Ado.CommandTimeOut；
///   3) EnsureRowCountWithinLimit：检查返回行数，超限抛 S8RuleEvaluatorException(result_too_many_rows)。
/// 不承载业务规则判断；不访问数据库；不修改 rule；不写业务数据明细；不读取 rule.Expression / dataSource.Endpoint / rule.ParamsJson。
/// </summary>
internal static class S8EvaluatorGuard
{
    public const int DefaultCommandTimeoutSeconds = 60;
    public const int MinCommandTimeoutSeconds = 5;
    public const int DefaultMaxRows = 1000;
    public const int MinMaxRows = 1;

    public const string EnvCommandTimeoutSeconds = "AIDOP_S8_EVALUATOR_COMMAND_TIMEOUT_SECONDS";
    public const string EnvMaxRows = "AIDOP_S8_EVALUATOR_MAX_ROWS";

    // 单进程内 AIDOP_S8_EVALUATOR_* 解析失败 warn 仅输出一次，避免日志刷屏。
    // 与 S8WatchSchedulerJob._firstParseFailLogged 同形（Interlocked.Exchange 单次锚点）。
    private static int _firstParseFailLogged;

    public static int ResolveCommandTimeoutSeconds(ILogger? logger = null) =>
        ResolveIntFromEnv(EnvCommandTimeoutSeconds, DefaultCommandTimeoutSeconds, MinCommandTimeoutSeconds, logger);

    public static int ResolveMaxRows(ILogger? logger = null) =>
        ResolveIntFromEnv(EnvMaxRows, DefaultMaxRows, MinMaxRows, logger);

    public static void ApplyCommandTimeout(SqlSugarScope scope, int seconds)
    {
        scope.Ado.CommandTimeOut = seconds;
    }

    /// <summary>
    /// 检查 evaluator SQL 返回行数；超限抛 S8RuleEvaluatorException(result_too_many_rows)。
    /// 异常 message 仅含 ruleType / ruleCode / 实际行数 / 上限值，禁止携带 SQL 全文、连接串、ParamsJson、返回行内容。
    /// </summary>
    public static void EnsureRowCountWithinLimit(int actualRows, int maxRows, string ruleType, string ruleCode)
    {
        if (actualRows > maxRows)
        {
            throw new S8RuleEvaluatorException(
                "result_too_many_rows",
                $"{ruleType} 规则 {ruleCode} 返回 {actualRows} 行，超过安全上限 {maxRows}，请缩小规则条件或拆分规则");
        }
    }

    private static int ResolveIntFromEnv(string envName, int defaultValue, int minValue, ILogger? logger)
    {
        var raw = Environment.GetEnvironmentVariable(envName);
        if (string.IsNullOrWhiteSpace(raw)) return defaultValue;
        if (int.TryParse(raw.Trim(), NumberStyles.Integer, CultureInfo.InvariantCulture, out var v) && v >= minValue)
            return v;
        if (Interlocked.Exchange(ref _firstParseFailLogged, 1) == 0 && logger != null)
        {
            logger.LogWarning(
                "s8_evaluator_guard_env_invalid env={Env} fallback={Fallback}",
                envName, defaultValue);
        }
        return defaultValue;
    }
}