namespace MiaoYu.Core.CodeGenerator.Services;

/// <summary>
/// 表结构缓存服务实现
/// </summary>
[Component]
public class TableSchemaCache : ITableSchemaCache, IScopedDependency
{
    private readonly IMemoryCache _memoryCache;
    private readonly DataSourceManager _dataSourceManager;
    private readonly ILogger<TableSchemaCache> _logger;

    private const string CACHE_KEY = "CodeGenerator:AllTables";
    private static readonly TimeSpan CACHE_DURATION = TimeSpan.FromMinutes(20);

    public TableSchemaCache(
        IMemoryCache memoryCache,
        DataSourceManager dataSourceManager,
        ILogger<TableSchemaCache> logger)
    {
        _memoryCache = memoryCache;
        _dataSourceManager = dataSourceManager;
        _logger = logger;
    }

    /// <summary>
    /// 获取所有表信息（从缓存或数据库）
    /// </summary>
    public List<DbTableInfo> GetAllTables()
    {
        return _memoryCache.GetOrCreate(CACHE_KEY, entry =>
        {
            entry.SlidingExpiration = CACHE_DURATION;
            
            _logger.LogInformation("缓存未命中，从数据库查询表结构信息");
            
            var tables = _dataSourceManager.GetAllTables();
            
            _logger.LogInformation("成功加载 {Count} 个表到缓存", tables.Count);
            
            return tables;
        }) ?? new List<DbTableInfo>();
    }

    /// <summary>
    /// 刷新缓存
    /// </summary>
    public void RefreshCache()
    {
        _logger.LogInformation("手动刷新表结构缓存");
        
        _memoryCache.Remove(CACHE_KEY);
        
        // 重新加载
        GetAllTables();
    }

    /// <summary>
    /// 清除缓存
    /// </summary>
    public void ClearCache()
    {
        _logger.LogInformation("清除表结构缓存");
        _memoryCache.Remove(CACHE_KEY);
    }

    /// <summary>
    /// 根据数据库和表名获取表信息
    /// </summary>
    public DbTableInfo? GetTable(string databaseKey, string tableName)
    {
        var allTables = GetAllTables();
        
        return allTables.FirstOrDefault(t => 
            t.DataBase?.Equals(databaseKey, StringComparison.OrdinalIgnoreCase) == true &&
            t.Name?.Equals(tableName, StringComparison.OrdinalIgnoreCase) == true);
    }
}