namespace NeonSprawl.Server.Game.Combat;

/// <summary>
/// Orchestrates deterministic combat resolution: ability catalog damage + prototype target HP (NEO-81).
/// Cast HTTP wiring: <see cref="AbilityInput.AbilityCastApi"/> (NEO-82).
/// </summary>
public static class CombatOperations
{
    /// <summary>
    /// Resolves one ability against one prototype combat target using catalog damage and the health store.
    /// Defeated targets deny before damage application; zero-damage abilities succeed without mutating HP.
    /// </summary>
    public static CombatResult TryResolve(
        string abilityId,
        string targetId,
        IAbilityDefinitionRegistry abilityRegistry,
        ICombatEntityHealthStore healthStore)
    {
        if (!abilityRegistry.TryNormalizeKnown(abilityId, out var normalizedAbility) ||
            !abilityRegistry.TryGetDefinition(normalizedAbility, out var definition))
        {
            return Deny(CombatReasonCodes.UnknownAbility);
        }

        if (!healthStore.TryGet(targetId, out var snapshot))
        {
            return Deny(CombatReasonCodes.UnknownTarget);
        }

        if (snapshot.Defeated)
        {
            return Deny(CombatReasonCodes.TargetDefeated, snapshot.CurrentHp);
        }

        if (definition.BaseDamage == 0)
        {
            return new CombatResult(
                Success: true,
                ReasonCode: null,
                DamageDealt: 0,
                TargetRemainingHp: snapshot.CurrentHp,
                TargetDefeated: snapshot.Defeated);
        }

        if (!healthStore.TryApplyDamage(targetId, definition.BaseDamage, out var after))
        {
            return Deny(CombatReasonCodes.UnknownTarget);
        }

        return new CombatResult(
            Success: true,
            ReasonCode: null,
            DamageDealt: definition.BaseDamage,
            TargetRemainingHp: after.CurrentHp,
            TargetDefeated: after.Defeated);
    }

    private static CombatResult Deny(string reasonCode, int? targetRemainingHp = null) =>
        new(
            Success: false,
            ReasonCode: reasonCode,
            DamageDealt: 0,
            TargetRemainingHp: targetRemainingHp,
            TargetDefeated: false);
}