// Assets/_Project/Scripts/Gameplay/Draft/BuilderSpellUpgradeDraftOption.cs
using UnityEngine;
using TD.Core;
using TD.Gameplay.BuilderSpells;

namespace TD.Gameplay.Draft
{
    /// <summary>
    /// Draft choice — "upgrade a builder spell you already have". Replaces
    /// <see cref="BaseKind"/> with <see cref="UpgradedKind"/> in the player's
    /// <see cref="PlayerSpellLoadout"/>, in place — the upgraded spell keeps the same hotkey
    /// slot the base spell occupied.
    /// </summary>
    /// <remarks>
    /// Mirrors <see cref="BuilderSpellDraftOption"/>, but swaps rather than adds (so it doesn't
    /// consume a slot). Only offered while the player currently has <see cref="BaseKind"/>
    /// granted — once taken, <see cref="BaseKind"/> is removed, which automatically makes this
    /// option (and any sibling upgrade branching off the same base) invalid for future drafts.
    /// </remarks>
    [CreateAssetMenu(fileName = "BuilderSpellUpgradeOption",
                      menuName = "TD/Draft/Builder Spell Upgrade Option")]
    public class BuilderSpellUpgradeDraftOption : DraftOption
    {
        [Header("Payload")]
        [Tooltip("The builder spell this option upgrades from.")]
        public BuilderSpellKind BaseKind;

        [Tooltip("The builder spell this option upgrades to.")]
        public BuilderSpellKind UpgradedKind;

        public override bool IsValidFor(ulong clientId)
        {
            var loadout = PlayerSpellLoadout.GetForClient(clientId);
            return loadout != null && loadout.PlayerHasSpell(BaseKind);
        }

        public override bool ServerApply(ulong clientId)
        {
            var loadout = PlayerSpellLoadout.GetForClient(clientId);
            return loadout != null && loadout.ServerUpgradeSpell(BaseKind, UpgradedKind);
        }

        /// <summary>Inherits the upgraded spell's icon (resolved from the pool by
        /// <see cref="UpgradedKind"/>) unless this option assigns an override.</summary>
        public override Sprite ResolveIcon()
        {
            if (Icon != null) return Icon;
            var def = BuilderSpellPool.Instance != null ? BuilderSpellPool.Instance.Get(UpgradedKind) : null;
            return def != null ? def.Icon : null;
        }
    }
}