using IceImportDAL.DTO.IceImportPipeline;

namespace IceImportBLL.FieldResolvers;

// ValueType = 5 (Name -> Id lookup). See CodeToIdLookupResolver — identical dispatch, distinct
// dictionary slice populated by IEntityLookupService for Name-based lookups.
public class NameToIdLookupResolver : IIceFieldValueResolver
{
    public int ValueType => 5;

    public Task<FieldResolutionResult> ResolveAsync(FieldResolutionContext ctx, CancellationToken ct)
    {
        var fieldName = ctx.DetailConfig.IceMapDetailsSourceFieldName?.Trim().ToUpperInvariant();
        string? raw = null;
        if (!string.IsNullOrEmpty(fieldName) && ctx.SourceRow.Table.Columns.Contains(fieldName))
            raw = ctx.SourceRow[fieldName]?.ToString()?.Trim();
        else if (ctx.DetailConfig.IceMapDetailsIsOptional == 0)
            // Optional field whose source column isn't present in this file — fall back to the
            // configured default name, then resolve it through the same Name -> Id lookup below.
            raw = ctx.DetailConfig.IceMapDetailsOptionalFiledValue?.Trim();

        if (string.IsNullOrEmpty(raw))
            return Task.FromResult(FieldResolutionResult.Ok(null));

        if (ctx.Lookups.TryGetValue(ctx.DetailConfig.EntityId, out var byName) &&
            byName.TryGetValue(raw, out var id))
            return Task.FromResult(FieldResolutionResult.Ok(id));

        // Error, not Warning — an unresolved Name -> Id lookup means this field would otherwise be
        // committed with a null/invalid FK (e.g. GcmTypeId), so the whole row must be rejected
        // rather than silently saved with bad data.
        var error = new IceImportFieldErrorDTO
        {
            RowNumber = ctx.RowNumber,
            EntityCode = ctx.DetailConfig.EntityCode ?? string.Empty,
            FieldName = ctx.DetailConfig.IceMapDetailsSourceFieldName ?? fieldName ?? string.Empty,
            Message = $"Name '{raw}' could not be resolved to an existing {ctx.DetailConfig.EntityCode ?? "record"}.",
            Severity = IceImportSeverity.Error,
            Value = raw
        };
        return Task.FromResult(FieldResolutionResult.WithWarning(null, error));
    }
}