using System.Reflection;
using GB5Shared.DTO.Framework.Login;
using IceImportDAL.DTO.IceImportPipeline;

namespace IceImportBLL.FieldResolvers;

// ValueType = 2 (Global System Value). Reflects LoginDTO by property name, modeled on
// GB5Shared.GB5Library.Qualifier.DbEnrichExecutor.GetFromData's reflection style — deliberately
// NOT a giant if/else chain of string comparisons the way legacy did.
//
// Design decision: legacy's short field names (OU/Period/Store/PartyBranch/WorkDate/Role) don't
// match LoginDTO's actual property names 1:1 (confirmed by reading LoginDTO.cs), so a small alias
// map translates the legacy IceMapDetailsSourceFieldName into the real LoginDTO property before
// reflecting. Any IceMapDetailsSourceFieldName that already matches a LoginDTO property name
// directly (case-insensitive) also works without an alias entry.
public class GlobalSystemValueResolver : IIceFieldValueResolver
{
    public int ValueType => 2;

    private static readonly Dictionary<string, string> _legacyAliases =
        new(StringComparer.OrdinalIgnoreCase)
        {
            ["OU"] = nameof(LoginDTO.WorkOUId),
            ["Period"] = nameof(LoginDTO.WorkPeriodId),
            ["Store"] = nameof(LoginDTO.WorkStoreId),
            ["PartyBranch"] = nameof(LoginDTO.WorkPartyBranchId),
            ["WorkDate"] = nameof(LoginDTO.WorkDate),
            ["Role"] = nameof(LoginDTO.RoleId),
        };

    public Task<FieldResolutionResult> ResolveAsync(FieldResolutionContext ctx, CancellationToken ct)
    {
        var name = ctx.DetailConfig.IceMapDetailsSourceFieldName?.Trim() ?? string.Empty;
        var propertyName = _legacyAliases.TryGetValue(name, out var mapped) ? mapped : name;

        var prop = typeof(LoginDTO).GetProperty(
            propertyName, BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase);

        if (prop is null)
        {
            var warning = new IceImportFieldErrorDTO
            {
                RowNumber = ctx.RowNumber,
                EntityCode = ctx.DetailConfig.EntityCode ?? string.Empty,
                FieldName = ctx.DetailConfig.DestinationMemberMemberName ?? name,
                Message = $"'{name}' does not resolve to any LoginDTO property for a Global System Value field.",
                Severity = IceImportSeverity.Warning
            };
            return Task.FromResult(FieldResolutionResult.WithWarning(null, warning));
        }

        return Task.FromResult(FieldResolutionResult.Ok(prop.GetValue(ctx.Login)));
    }
}