using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace XP.Common.Database.Helpers
{
    /// <summary>
    /// 通用CRUD SQL构建器（适配SQLite）
    /// </summary>
    public static class SqlBuilderHelper
    {
        /// <summary>
        /// 构建插入SQL
        /// </summary>
        /// <param name="tableName">表名</param>
        /// <param name="columns">列名集合</param>
        /// <returns>插入SQL（参数名：@列名）</returns>
        public static string BuildInsertSql(string tableName, IEnumerable<string> columns)
        {
            if (string.IsNullOrEmpty(tableName)) throw new ArgumentNullException(nameof(tableName));
            var columnList = columns?.ToList() ?? throw new ArgumentNullException(nameof(columns));
            if (columnList.Count == 0) throw new ArgumentException("列名集合不能为空");

            var columnsStr = string.Join(", ", columnList);
            var paramsStr = string.Join(", ", columnList.Select(c => $"@{c}"));
            return $"INSERT INTO {tableName} ({columnsStr}) VALUES ({paramsStr})";
        }

        /// <summary>
        /// 构建更新SQL
        /// </summary>
        /// <param name="tableName">表名</param>
        /// <param name="updateColumns">更新列名</param>
        /// <param name="whereColumns">条件列名（如Id）</param>
        /// <returns>更新SQL</returns>
        public static string BuildUpdateSql(string tableName, IEnumerable<string> updateColumns, IEnumerable<string> whereColumns)
        {
            if (string.IsNullOrEmpty(tableName)) throw new ArgumentNullException(nameof(tableName));
            var updateList = updateColumns?.ToList() ?? throw new ArgumentNullException(nameof(updateColumns));
            var whereList = whereColumns?.ToList() ?? throw new ArgumentNullException(nameof(whereColumns));
            if (updateList.Count == 0) throw new ArgumentException("更新列名集合不能为空");
            if (whereList.Count == 0) throw new ArgumentException("条件列名集合不能为空");

            var updateStr = string.Join(", ", updateList.Select(c => $"{c}=@{c}"));
            var whereStr = string.Join(" AND ", whereList.Select(c => $"{c}=@{c}"));
            return $"UPDATE {tableName} SET {updateStr} WHERE {whereStr}";
        }

        /// <summary>
        /// 构建删除SQL
        /// </summary>
        public static string BuildDeleteSql(string tableName, IEnumerable<string> whereColumns)
        {
            if (string.IsNullOrEmpty(tableName)) throw new ArgumentNullException(nameof(tableName));
            var whereList = whereColumns?.ToList() ?? throw new ArgumentNullException(nameof(whereColumns));
            if (whereList.Count == 0) throw new ArgumentException("条件列名集合不能为空");

            var whereStr = string.Join(" AND ", whereList.Select(c => $"{c}=@{c}"));
            return $"DELETE FROM {tableName} WHERE {whereStr}";
        }

        /// <summary>
        /// 构建查询SQL
        /// </summary>
        public static string BuildSelectSql(string tableName, IEnumerable<string> columns, IEnumerable<string>? whereColumns = null, string orderBy = "")
        {
            if (string.IsNullOrEmpty(tableName)) throw new ArgumentNullException(nameof(tableName));
            var columnList = columns?.ToList() ?? throw new ArgumentNullException(nameof(columns));
            if (columnList.Count == 0) columnList.Add("*");

            var columnsStr = string.Join(", ", columnList);
            var sql = new StringBuilder($"SELECT {columnsStr} FROM {tableName}");

            // 添加WHERE条件
            if (whereColumns != null && whereColumns.Any())
            {
                var whereStr = string.Join(" AND ", whereColumns.Select(c => $"{c}=@{c}"));
                sql.Append($" WHERE {whereStr}");
            }

            // 添加排序
            if (!string.IsNullOrEmpty(orderBy))
            {
                sql.Append($" ORDER BY {orderBy}");
            }

            return sql.ToString();
        }
    }
}