using GB5Shared.DTO.Framework.Login;
using GB5Shared.QueryExecutor;
using IceImportDAL.DTO.GcmCodeLookup;
using IceImportDAL.Query.GcmCodeLookup;

namespace IceImportDAL.CustomCode.GcmCodeLookup;

// Mirrors GB5Shared/Addon/AddonService.cs's _allowedTables whitelist discipline exactly:
// table names are never taken from uploaded file content, only from server-validated config
// (IceMapDetails.GcmTypeId), and are checked against a fixed whitelist before any query runs.
public class GcmCodeLookupDAL : IGcmCodeLookupDAL
{
    private const int ChunkSize = 2000; // legacy's own safe IN-clause batch size, per the plan

    // MGCM is currently the only registered generic code/define table. Extend this set (never
    // bypass it) if a future genuinely-uniform lookup table needs the same generic dispatch.
    private static readonly HashSet<string> _allowedTables =
        new(StringComparer.OrdinalIgnoreCase) { "MGCM" };

    private readonly IQueryExecutor _qe;

    public GcmCodeLookupDAL(IQueryExecutor qe) => _qe = qe;

    public Task<Dictionary<string, int>> ResolveCodesToIdsAsync(
        int gcmTypeId, IEnumerable<string> codes, LoginDTO login, CancellationToken ct)
        => ResolveAsync(gcmTypeId, codes, GcmCodeLookupQB.RESOLVE_CODES_BY_GCMTYPE, login, ct);

    public Task<Dictionary<string, int>> ResolveNamesToIdsAsync(
        int gcmTypeId, IEnumerable<string> names, LoginDTO login, CancellationToken ct)
        => ResolveAsync(gcmTypeId, names, GcmCodeLookupQB.RESOLVE_NAMES_BY_GCMTYPE, login, ct);

    private async Task<Dictionary<string, int>> ResolveAsync(
        int gcmTypeId, IEnumerable<string> values, string sql, LoginDTO login, CancellationToken ct)
    {
        if (!_allowedTables.Contains("MGCM"))
            throw new InvalidOperationException("MGCM is not a registered lookup table.");

        var distinct = (values ?? Enumerable.Empty<string>())
            .Where(v => !string.IsNullOrWhiteSpace(v))
            .Select(v => v.Trim())
            .Distinct(StringComparer.OrdinalIgnoreCase)
            .ToList();

        var result = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
        if (distinct.Count == 0) return result;

        for (int offset = 0; offset < distinct.Count; offset += ChunkSize)
        {
            var chunk = distinct.Skip(offset).Take(ChunkSize).ToList();
            var rows = await _qe.QueryAsync<GcmLookupRowDTO>(
                login, sql, new { GcmTypeId = gcmTypeId, Values = chunk }, cancellationToken: ct)
                .ConfigureAwait(false);

            foreach (var row in rows)
                result[row.Value] = row.Id;
        }

        return result;
    }
}