using System.Text.Json;
using Fake.Application;
using Oms.Domain.OrdersAggregate.Entities;

namespace Oms.Application.Services.Orders.Templates;

/// <summary>
/// 解析模板导入时使用的列映射配置。
/// </summary>
public static class OrderTemplateImportMapping
{
    public static void EnsureTemplateReadyForImport(OrderTemplate template)
    {
        if (!string.Equals(template.Type, "custom", StringComparison.OrdinalIgnoreCase))
        {
            return;
        }

        if (!string.Equals(template.MappingStatus, OrderTemplateMappingStatus.Ready, StringComparison.OrdinalIgnoreCase))
        {
            throw new BusinessException("自定义模板尚未完成字段映射，请先配置并保存映射");
        }

        if (string.IsNullOrWhiteSpace(template.ColumnMappingJson))
        {
            throw new BusinessException("自定义模板映射配置为空");
        }
    }

    public static OrderTemplateColumnMappingDocument Resolve(OrderTemplate template)
    {
        var standardKey = template.StandardTemplateKey
                          ?? template.TemplateKey
                          ?? OrderTemplateKeys.DedicatedSmallParcel;

        if (string.Equals(template.Type, "custom", StringComparison.OrdinalIgnoreCase))
        {
            return Deserialize(template.ColumnMappingJson)
                   ?? throw new BusinessException("自定义模板映射配置无效");
        }

        return BuildStandard(standardKey);
    }

    public static OrderTemplateColumnMappingDocument BuildStandard(string templateKey)
    {
        var fields = OrderTemplateFieldRegistry.GetFields(templateKey);
        return new OrderTemplateColumnMappingDocument
        {
            StandardTemplateKey = templateKey,
            HeaderRowIndex = 1,
            DataStartRowIndex = 2,
            Mappings = fields.Select(field => new OrderTemplateColumnMappingItem
            {
                StandardFieldKey = field.FieldKey,
                SourceColumn = field.Label,
                Required = field.Required
            }).ToList()
        };
    }

    public static OrderTemplateColumnMappingDocument? Deserialize(string? json)
    {
        if (string.IsNullOrWhiteSpace(json))
        {
            return null;
        }

        try
        {
            return JsonSerializer.Deserialize<OrderTemplateColumnMappingDocument>(json);
        }
        catch
        {
            return null;
        }
    }
}