using NeonSprawl.Server.Game.Encounters;
using NeonSprawl.Server.Game.Factions;
using NeonSprawl.Server.Game.Items;
using NeonSprawl.Server.Game.Skills;

namespace NeonSprawl.Server.Game.Contracts;

/// <summary>
/// Issue-time economy and reward-bundle validation for contract templates (NEO-150).
/// Mirrors startup catalog gates for defense in depth at <see cref="ContractGeneratorOperations.TryIssue"/>.
/// </summary>
public static class ContractEconomyValidation
{
    /// <summary>
    /// Validates band caps and cross-refs for one template against live registries.
    /// </summary>
    public static bool TryValidateTemplate(
        ContractTemplateRow template,
        IEncounterDefinitionRegistry encounterRegistry,
        IItemDefinitionRegistry itemRegistry,
        ISkillDefinitionRegistry skillRegistry,
        IFactionDefinitionRegistry factionRegistry,
        out string? reasonCode)
    {
        ArgumentNullException.ThrowIfNull(template);
        ArgumentNullException.ThrowIfNull(encounterRegistry);
        ArgumentNullException.ThrowIfNull(itemRegistry);
        ArgumentNullException.ThrowIfNull(skillRegistry);
        ArgumentNullException.ThrowIfNull(factionRegistry);

        reasonCode = null;
        var rowsById = new Dictionary<string, ContractTemplateRow>(StringComparer.Ordinal)
        {
            [template.Id] = template,
        };

        // Band-cap before cross-ref so deny maps to economy_cap_exceeded (startup loader runs cross-ref first).
        if (PrototypeE7M4ContractCatalogRules.TryGetBandCapGateError(rowsById) is not null)
        {
            reasonCode = ContractGeneratorReasonCodes.EconomyCapExceeded;
            return false;
        }

        var knownEncounterIds = encounterRegistry.GetDefinitionsInIdOrder()
            .Select(static d => d.Id)
            .ToHashSet(StringComparer.Ordinal);
        var knownFactionIds = factionRegistry.GetDefinitionsInIdOrder()
            .Select(static d => d.Id)
            .ToHashSet(StringComparer.Ordinal);
        var skillDefsById = skillRegistry.GetDefinitionsInIdOrder()
            .ToDictionary(static d => d.Id, StringComparer.Ordinal);

        if (PrototypeE7M4ContractCatalogRules.TryGetCrossRefError(
                rowsById,
                knownEncounterIds,
                knownFactionIds,
                skillDefsById) is not null)
        {
            reasonCode = ContractGeneratorReasonCodes.InvalidRewardBundle;
            return false;
        }

        return true;
    }
}