import { TriggerAction, type ISdk } from "iii-sdk";
import { KV } from "../state/schema.js";
import { StateKV } from "../state/kv.js";
import { deleteImage, touchImage } from "../utils/image-store.js";
import { withKeyedLock } from "../state/keyed-mutex.js";

export async function getImageRefCount(kv: StateKV, filePath: string): Promise<number> {
  const count = await kv.get<number>(KV.imageRefs, filePath);
  return count ? Number(count) : 0;
}

export async function incrementImageRef(kv: StateKV, filePath: string): Promise<void> {
  return withKeyedLock(`imgRef:${filePath}`, async () => {
    const current = await getImageRefCount(kv, filePath);
    await kv.set(KV.imageRefs, filePath, current + 1);
    await touchImage(filePath);
  });
}

export async function decrementImageRef(kv: StateKV, sdk: ISdk, filePath: string): Promise<void> {
  return withKeyedLock(`imgRef:${filePath}`, async () => {
    const current = await getImageRefCount(kv, filePath);
    if (current <= 1) {
      await kv.delete(KV.imageEmbeddings, filePath);
      await kv.delete(KV.imageRefs, filePath);
      const { deletedBytes } = await deleteImage(filePath);
      if (deletedBytes > 0) {
        sdk.trigger({
          function_id: "mem::disk-size-delta",
          payload: { deltaBytes: -deletedBytes },
          action: TriggerAction.Void(),
        });
      }
    } else {
      await kv.set(KV.imageRefs, filePath, current - 1);
    }
  });
}