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

namespace ExcelHelper.Utils;
public class Excel2Prompt
{
    /// <summary>
    /// 将excel数据转化为Ai可读的Prompt格式
    /// </summary>
    /// <param name="excelData"></param>
    /// <param name="columns"></param>
    /// <param name="startCell">A</param>
    /// <returns></returns>
    public static string ConverterToPrompt(IEnumerable<dynamic> excelData, IEnumerable<string> columns, string startCell)
    {
        /*
        示例:
            - Column '系统单号' (Excel Column A)
                - Type: object
                - Unique values: 30462
                - Sample values: ['103526033584143963', '103526050570323185', '103525904231101189']
                - Missing values: 8278

            - Column '参考号' (Excel Column B)
                - Type: object
                - Unique values: 11911
                - Sample values: ['200012590592083', '200012844542760', '200012745140484']
                - Missing values: 26899

            - Column '状态' (Excel Column C)
                - Type: object
                - Unique values: 8
                - Sample values: ['待审核发货', '待审核发货', '待审核发货']
                - Missing values: 7007
        */
        var prompts = new List<string>();
        prompts.Add("This Excel file contains the following columns:");
        var dataList = excelData.ToList();

        // 解析 startCell，获取起始列的索引
        int startColumnIndex = GetColumnIndexFromCell(startCell);

        int columnIndex = startColumnIndex;
        foreach (var column in columns)
        {
            columnIndex++;
            string columnLetter = GetExcelColumnName(columnIndex);

            var columnData = dataList.Select(row =>
            {
                var rowDict = (IDictionary<string, object>)row;
                return rowDict.ContainsKey(column) ? rowDict[column] : null;
            }).ToList();

            var nonNullData = columnData.Where(value => value != null).ToList();
            var missingValues = columnData.Count - nonNullData.Count;
            var uniqueValues = nonNullData.Distinct().Count();
            var sampleValues = nonNullData.Take(3).Select(value => value.ToString().Replace("\n", " ")).ToArray();

            // 自动识别数据类型
            var dataType = GetColumnDataType(nonNullData);

            var prompt = $"- Column '{column.Replace("\n", " ")}' (Excel Column {columnLetter})" +
                         $"    - Type: {dataType}" +
                         $"    - Sample values: ['{string.Join("', '", sampleValues)}']";
            prompts.Add(prompt);
        }

        return string.Join(Environment.NewLine + Environment.NewLine, prompts);
    }

    private static int GetColumnIndexFromCell(string cell)
    {
        // 提取列部分
        string columnPart = new string(cell.Where(char.IsLetter).ToArray());
        int columnIndex = 0;
        int factor = 1;

        for (int i = columnPart.Length - 1; i >= 0; i--)
        {
            columnIndex += (columnPart[i] - 'A' + 1) * factor;
            factor *= 26;
        }
        // 最终结果需要包含StartCell
        return columnIndex - 1;
    }

    private static string GetExcelColumnName(int columnNumber)
    {
        int dividend = columnNumber;
        string columnName = string.Empty;

        while (dividend > 0)
        {
            int modulo = (dividend - 1) % 26;
            columnName = Convert.ToChar(65 + modulo) + columnName;
            dividend = (dividend - modulo) / 26;
        }

        return columnName;
    }

    private static string GetColumnDataType(List<object> data)
    {
        var isInt = true;
        var isLong = true;
        var isDouble = true;
        var isDateTime = true;
        var isBool = true;

        foreach (var item in data)
        {
            var str = item.ToString();

            // 检查数据类型
            if (!int.TryParse(str, out _))
            {
                isInt = false;
            }
            if (!long.TryParse(str, out _))
            {
                isLong = false;
            }
            if (!double.TryParse(str, out _))
            {
                isDouble = false;
            }
            if (!DateTime.TryParse(str, out _))
            {
                isDateTime = false;
            }
            if (!bool.TryParse(str, out _))
            {
                isBool = false;
            }
        }

        return true switch
        {
            bool _ when isInt => "int",
            bool _ when isLong => "int64",
            bool _ when isDouble => "double",
            bool _ when isDateTime => "datetime",
            bool _ when isBool => "bool",
            _ => "string",
        };
    }

}