using GB5Shared.DTO.Ice;
using GB5Shared.DTO.Framework.Login;
using IceImportDAL.DTO.IceImportPipeline;

namespace IceImportBLL.Validators;

// IceMapDetailsIsOptional == 1 (mandatory) fields must have a non-null/non-empty resolved value.
// IsOptional == 0 is optional — its resolver already falls back to IceMapDetailsOptionalFiledValue
// when the source column is absent, so an empty resolved value there is never an error.
//
// ValueType 0/3/4/5 (Source/Expression/CodeToId/NameToId — the types that read a real source
// column) are deliberately EXCLUDED here: their "required and not provided" check is done in
// IceImportPipeline.MapAndTransformAsync against the RAW Excel cell (IceMapDetailsSourceFieldName),
// not against the resolved/coerced row.Fields value — a failed date coercion or an unresolved
// Code/Name lookup must surface as its own distinct warning, never get mislabeled as "missing" just
// because resolution happened to produce null for some other reason.
//
// ValueType 8/9 (Fixed/Global Value During Update) are ALSO excluded here — IceImportPipeline
// already flags them with a distinct "not supported" Error for Insert-mode runs (isUpdateMode
// false; CommitImport is the only Insert entry point), so checking them again here would just
// double up on the same finding. ValueType 1/2 (their Insert-time counterparts) get the identical
// "not supported" treatment from IceImportPipeline, but ONLY for Update-mode runs (isUpdateMode
// true; IceImport/Update is the only Update entry point) — for Insert-mode runs 1/2 remain valid,
// so THIS validator is still what catches a mandatory Fixed/Global field configured with nothing to
// resolve (e.g. an empty IceMapDetailsSourceFieldName) during Insert. What's left in scope here —
// 1 (Fixed), 2 (Global), 6 (ParentIdAssigning), 7 (AutoNumberAssigning) — never read Excel at all,
// so checking their resolved value is the only meaningful "required" check available for them.
//
// The object/List CONTAINER marker row (e.g. "EmployeeAddon", DestinationMemberDataType==5 AND
// IceMapDetailsAddonFields empty) is also excluded: IceImportPipeline only fills
// row.Fields[ListMemberName] for it at Commit time, never during MapAndTransform/Validate, so an
// empty resolved value there is structural, not a data problem. DestinationMemberDataType==5 alone
// cannot distinguish "the container" from "an addon field routed through the same shared placeholder
// member" (see IceImportPipeline's identical check), hence the IceMapDetailsAddonFields condition.
public class RequiredFieldValidator : IRowValidator
{
    public string Key => "REQUIRED_FIELD";

    private static readonly HashSet<short> PipelineHandledValueTypes = new() { 0, 3, 4, 5, 8, 9 };

    public Task<List<IceImportFieldErrorDTO>> ValidateAsync(
        MappedEntityRowDTO row, IceMapDTO mapDefinition, ParsedImportDataSetDTO parsedData, LoginDTO login, CancellationToken ct)
    {
        var errors = new List<IceImportFieldErrorDTO>();

        var requiredFields = mapDefinition.IceMapDetailsArray
            .Where(d => d.DestinationMemberEntityId == row.EntityId &&
                        d.IceMapDetailsIsOptional == 1 &&
                        !(d.DestinationMemberDataType == 5 && string.IsNullOrWhiteSpace(d.IceMapDetailsAddonFields)) &&
                        !PipelineHandledValueTypes.Contains(d.IceMapDetailsValueType));

        foreach (var detail in requiredFields)
        {
            var fieldName = detail.DestinationMemberMemberName;
            if (string.IsNullOrEmpty(fieldName)) continue;

            var hasValue = row.Fields.TryGetValue(fieldName, out var value) &&
                           value is not null &&
                           !(value is string s && string.IsNullOrWhiteSpace(s));

            if (!hasValue)
            {
                errors.Add(new IceImportFieldErrorDTO
                {
                    RowNumber = row.RowNumber,
                    EntityCode = row.EntityCode,
                    FieldName = fieldName,
                    Message = $"'{fieldName}' is required and was not provided.",
                    Severity = IceImportSeverity.Error
                });
            }
        }

        return Task.FromResult(errors);
    }
}