namespace NeonSprawl.Server.Game.Encounters;

/// <summary>Maps <c>GET /game/world/encounter-definitions</c> (NEO-103).</summary>
public static class EncounterDefinitionsWorldApi
{
    public static WebApplication MapEncounterDefinitionsWorldApi(this WebApplication app)
    {
        app.MapGet(
            "/game/world/encounter-definitions",
            (IEncounterDefinitionRegistry encounterRegistry, IRewardTableDefinitionRegistry rewardTableRegistry) =>
            {
                var defs = encounterRegistry.GetDefinitionsInIdOrder();
                var encounters = new List<EncounterDefinitionJson>(defs.Count);
                foreach (var d in defs)
                {
                    if (!rewardTableRegistry.TryGetDefinition(d.RewardTableId, out var rewardTable) ||
                        rewardTable is null)
                    {
                        throw new InvalidOperationException(
                            $"Encounter definition '{d.Id}' references reward table '{d.RewardTableId}' that is not in the loaded catalog.");
                    }

                    encounters.Add(
                        new EncounterDefinitionJson
                        {
                            Id = d.Id,
                            DisplayName = d.DisplayName,
                            CompletionCriteria = new EncounterCompletionCriteriaJson
                            {
                                Kind = d.CompletionCriteriaKind,
                            },
                            RequiredNpcInstanceIds = d.RequiredNpcInstanceIds,
                            RewardTable = MapRewardTable(rewardTable),
                        });
                }

                return Results.Json(
                    new EncounterDefinitionsListResponse
                    {
                        SchemaVersion = EncounterDefinitionsListResponse.CurrentSchemaVersion,
                        Encounters = encounters,
                    });
            });

        return app;
    }

    private static EncounterRewardTableJson MapRewardTable(RewardTableDefRow rewardTable)
    {
        var grants = new List<EncounterRewardGrantJson>(rewardTable.FixedGrants.Count);
        foreach (var grant in rewardTable.FixedGrants)
        {
            grants.Add(
                new EncounterRewardGrantJson
                {
                    ItemId = grant.ItemId,
                    Quantity = grant.Quantity,
                });
        }

        return new EncounterRewardTableJson
        {
            Id = rewardTable.Id,
            DisplayName = rewardTable.DisplayName,
            FixedGrants = grants,
        };
    }
}