bazaarflux/src/main/java/me/lethunderhawk/custom/item/abstraction/migration/MigrationService.java

package me.lethunderhawk.custom.item.abstraction.migration;

import me.lethunderhawk.custom.item.abstraction.definition.ItemDefinition;
import me.lethunderhawk.custom.item.abstraction.instance.ItemInstance;
import me.lethunderhawk.custom.item.abstraction.instance.ItemInstanceReader;
import me.lethunderhawk.custom.item.abstraction.registry.CustomItemRegistry;
import me.lethunderhawk.custom.item.abstraction.visual.ItemRenderer;
import org.bukkit.entity.Player;
import org.bukkit.inventory.ItemStack;

public final class MigrationService {

    /**
     * Migrates a single stack.
     * Returns the migrated stack or the original if no migration was needed.
     */
    public ItemStack migrate(ItemStack original) {
        if (original == null) return null;

        ItemInstance current = ItemInstanceReader.read(original);
        if (current == null) return original;

        ItemDefinition latest = CustomItemRegistry.get(current.itemId());
        if (latest == null) {

            return original;
        }
        if (current.version() == latest.getVersion()) {
            return original;
        }

        // --- Ensure correct material ---
        ItemStack stack = original;
        if (!latest.getVisual().isHead()
                && stack.getType() != latest.getVisual().getMaterial()) {
            stack = stack.withType(latest.getVisual().getMaterial());
        }

        // --- Create migrated instance ---
        ItemInstance migrated = new ItemInstance(latest);
        migrated.data().putAll(current.data());
        migrated.setVersion(latest.getVersion());

        // --- Render ---
        ItemRenderer.renderInto(stack, migrated);

        return stack;
    }

    public void migratePlayer(Player player) {
        ItemStack[] contents = player.getInventory().getContents();
        boolean changed = false;

        for (int i = 0; i < contents.length; i++) {
            ItemStack item = contents[i];
            if (item == null || item.isEmpty()) continue;

            ItemInstance before = ItemInstanceReader.read(item);
            if (before == null) continue;
            int oldVersion = before.version();

            ItemStack migrated = migrate(item);
            contents[i] = migrated;

            ItemInstance after = ItemInstanceReader.read(migrated);
            if (after != null && after.version() != oldVersion) {
                player.sendMessage(
                        "Migrated " + after.itemId() +
                                " from v" + oldVersion +
                                " to v" + after.version()
                );
                changed = true;
            }
        }

        if (changed) {
            player.getInventory().setContents(contents);
            player.updateInventory();
        }
    }
}