using System.Globalization;
using MiniExcelLibs;
using Oms.Application.Dtos.Orders;

namespace Oms.Application.Shared;

/// <summary>
/// 对账件重尺（downstream）Excel 模板与解析。
/// 仅写入下游对账重量，触发应付重算；不改应收。
/// </summary>
public static class OrderDownstreamWeightImportHelper
{
    public const int MaxRows = 2000;

    private static readonly Dictionary<string, string> HeaderAliases = new(StringComparer.OrdinalIgnoreCase)
    {
        ["运单号"] = "WaybillNo",
        ["单号"] = "WaybillNo",
        ["服务商单号"] = "WaybillNo",
        ["WaybillNo"] = "WaybillNo",
        ["waybillNo"] = "WaybillNo",
        ["ServiceNo"] = "WaybillNo",
        ["serviceNo"] = "WaybillNo",
        ["长"] = "Length",
        ["长度"] = "Length",
        ["Length"] = "Length",
        ["length"] = "Length",
        ["宽"] = "Width",
        ["宽度"] = "Width",
        ["Width"] = "Width",
        ["width"] = "Width",
        ["高"] = "Height",
        ["高度"] = "Height",
        ["Height"] = "Height",
        ["height"] = "Height",
        ["实重"] = "ActualWeight",
        ["重量"] = "ActualWeight",
        ["ActualWeight"] = "ActualWeight",
        ["actualWeight"] = "ActualWeight",
        ["Weight"] = "ActualWeight",
        ["weight"] = "ActualWeight",
    };

    public static async Task<byte[]> BuildTemplateBytesAsync()
    {
        var rows = new List<Dictionary<string, object?>>
        {
            new()
            {
                ["运单号"] = "OMS202601010001",
                ["长"] = 30,
                ["宽"] = 20,
                ["高"] = 10,
                ["实重"] = 1.25
            }
        };

        await using var stream = new MemoryStream();
        await MiniExcel.SaveAsAsync(stream, rows);
        return stream.ToArray();
    }

    public static string TemplateFileName => "对账件重尺导入模板.xlsx";

    public static async Task<List<(int RowNumber, OrderDownstreamWeightImportRow Row)>> ParseImportRowsAsync(
        Stream fileStream)
    {
        var rows = await MiniExcel.QueryAsync(fileStream, useHeaderRow: true);
        var result = new List<(int RowNumber, OrderDownstreamWeightImportRow Row)>();
        var rowNumber = 1;

        foreach (var row in rows)
        {
            rowNumber++;
            if (row is not IDictionary<string, object> rowDict)
            {
                continue;
            }

            if (IsEmptyRow(rowDict))
            {
                continue;
            }

            try
            {
                result.Add((rowNumber, ParseRow(rowDict)));
            }
            catch (InvalidOperationException ex)
            {
                result.Add((rowNumber, new OrderDownstreamWeightImportRow
                {
                    WaybillNo = TryPeekWaybillNo(rowDict),
                    ParseError = ex.Message
                }));
            }
        }

        return result;
    }

    public static void ValidateRow(OrderDownstreamWeightImportRow row)
    {
        if (!string.IsNullOrWhiteSpace(row.ParseError))
        {
            throw new InvalidOperationException(row.ParseError);
        }

        if (string.IsNullOrWhiteSpace(row.WaybillNo))
        {
            throw new InvalidOperationException("运单号不能为空");
        }

        row.WaybillNo = row.WaybillNo.Trim();
        if (row.WaybillNo.Length > 64)
        {
            throw new InvalidOperationException("运单号不可超过64个字符");
        }

        if (!row.ActualWeight.HasValue || row.ActualWeight.Value <= 0)
        {
            throw new InvalidOperationException("实重必须大于0");
        }

        ValidateOptionalDimension(row.Length, "长");
        ValidateOptionalDimension(row.Width, "宽");
        ValidateOptionalDimension(row.Height, "高");

        var hasAnyDim = row.Length.HasValue || row.Width.HasValue || row.Height.HasValue;
        var hasAllDim = row.Length.HasValue && row.Width.HasValue && row.Height.HasValue;
        if (hasAnyDim && !hasAllDim)
        {
            throw new InvalidOperationException("长/宽/高需同时填写或全部留空（留空则沿用订单已有尺寸）");
        }
    }

    private static string? TryPeekWaybillNo(IDictionary<string, object> rowDict)
    {
        foreach (var (header, value) in rowDict)
        {
            if (string.IsNullOrWhiteSpace(header))
            {
                continue;
            }

            if (HeaderAliases.TryGetValue(header.Trim(), out var field)
                && string.Equals(field, "WaybillNo", StringComparison.OrdinalIgnoreCase))
            {
                return NormalizeCell(value);
            }
        }

        return null;
    }

    private static void ValidateOptionalDimension(decimal? value, string label)
    {
        if (!value.HasValue)
        {
            return;
        }

        if (value.Value <= 0)
        {
            throw new InvalidOperationException($"{label}必须大于0");
        }
    }

    private static OrderDownstreamWeightImportRow ParseRow(IDictionary<string, object> rowDict)
    {
        var mapped = new Dictionary<string, string?>(StringComparer.OrdinalIgnoreCase);
        foreach (var (header, value) in rowDict)
        {
            if (string.IsNullOrWhiteSpace(header))
            {
                continue;
            }

            if (!HeaderAliases.TryGetValue(header.Trim(), out var field))
            {
                continue;
            }

            mapped[field] = NormalizeCell(value);
        }

        return new OrderDownstreamWeightImportRow
        {
            WaybillNo = mapped.GetValueOrDefault("WaybillNo"),
            Length = ParseDecimal(mapped.GetValueOrDefault("Length")),
            Width = ParseDecimal(mapped.GetValueOrDefault("Width")),
            Height = ParseDecimal(mapped.GetValueOrDefault("Height")),
            ActualWeight = ParseDecimal(mapped.GetValueOrDefault("ActualWeight"))
        };
    }

    private static decimal? ParseDecimal(string? text)
    {
        if (string.IsNullOrWhiteSpace(text))
        {
            return null;
        }

        if (decimal.TryParse(text, NumberStyles.Any, CultureInfo.InvariantCulture, out var value))
        {
            return value;
        }

        if (decimal.TryParse(text, NumberStyles.Any, CultureInfo.GetCultureInfo("zh-CN"), out value))
        {
            return value;
        }

        throw new InvalidOperationException($"数值格式无效：{text}");
    }

    private static string? NormalizeCell(object? value)
    {
        if (value is null)
        {
            return null;
        }

        var text = Convert.ToString(value, CultureInfo.InvariantCulture)?.Trim();
        return string.IsNullOrWhiteSpace(text) ? null : text;
    }

    private static bool IsEmptyRow(IDictionary<string, object> rowDict) =>
        rowDict.Values.All(value => string.IsNullOrWhiteSpace(NormalizeCell(value)));
}

/// <summary>
/// 对账件重尺导入行。
/// </summary>
public sealed class OrderDownstreamWeightImportRow
{
    public string? WaybillNo { get; set; }

    public decimal? Length { get; set; }

    public decimal? Width { get; set; }

    public decimal? Height { get; set; }

    public decimal? ActualWeight { get; set; }

    /// <summary>
    /// Excel 单元格解析错误（校验阶段直接抛出）。
    /// </summary>
    public string? ParseError { get; set; }
}