using System;
using System.Collections.Generic;

namespace SyncEngine.Access
{
    /// <summary>
    /// Case-insensitive table name → column list for expanding table.* in view SQL.
    /// </summary>
    public sealed class ViewColumnCatalog
    {
        private readonly Dictionary<string, IReadOnlyList<string>> _columns;

        public ViewColumnCatalog(IDictionary<string, IReadOnlyList<string>> columns)
        {
            _columns = new Dictionary<string, IReadOnlyList<string>>(StringComparer.OrdinalIgnoreCase);
            if (columns == null)
            {
                return;
            }

            foreach (var entry in columns)
            {
                _columns[entry.Key] = entry.Value;
            }
        }

        public bool TryGetColumns(string tableName, out IReadOnlyList<string> columns)
        {
            columns = null;
            if (string.IsNullOrWhiteSpace(tableName))
            {
                return false;
            }

            return _columns.TryGetValue(NormalizeTableName(tableName), out columns);
        }

        public static string NormalizeTableName(string tableRef)
        {
            var name = tableRef.Trim();
            if (name.StartsWith("[", StringComparison.Ordinal) && name.EndsWith("]", StringComparison.Ordinal))
            {
                return name.Substring(1, name.Length - 2);
            }

            return name;
        }
    }
}