// id, title, and content are text fields.
// num in image is the image number, such as the frame number (optional).
// emb in image is the image embedding data; image = [image1_emb, image2_emb, image3_emb, ..., imagen_emb].

PUT /image_embeddings
{
  "mappings": {
    "properties": {
      "id": {
        "type": "keyword"
        },
      "title": {
        "type": "text"
        },
      "content": {
        "type": "text"
        },
      "image": {
        "type": "nested",
        "properties": {
          "num": {"type": "keyword"},
          "emb": {
              "type": "dense_vector",
              "dims": 5,
              "index_options": {
                "type": "int8_hnsw"  
              },
              "similarity": "cosine"
          }
        }
      }
    }
  }
}

POST /image_embeddings/_doc/1
{
  "id": "book_001",
  "title": "Sunny day",
  "content": "On this windy day, I tried to hold your hand",
  "image": [
    {"num": "0", "emb": [0.1,0.2,0.3,0.4,0.5]},
    {"num": "1", "emb": [0.6,0.7,0.8,0.9,1.0]},
    {"num": "2", "emb": [0.2,0.3,0.4,0.5,0.6]}
  ]
}

POST /image_embeddings/_doc/2
{
  "id": "book_002",
  "title": "Heading north",
  "content": "Heading north, I tried to hold your hand",
  "image": [
    {"num": "0", "emb": [0.1,0.2,0.3,0.4,0.5]},
    {"num": "1", "emb": [0.6,0.7,0.8,0.9,1.0]}
  ]
}

POST /image_embeddings/_doc/3
{
  "id": "book_003",
  "title": " Nunchaku",
  "content": "Heng Heng Ha Hei",
  "image": [
    {"num": "0", "emb": [0.1,0.2,0.3,0.4,0.5]},
    {"num": "1", "emb": [0.6,0.7,0.8,0.9,1.0]},
    {"num": "2", "emb": [0.1,0.2,0.3,0.4,0.5]},
    {"num": "3", "emb": [0.6,0.7,0.8,0.9,1.0]},
    {"num": "4", "emb": [0.1,0.2,0.3,0.4,0.5]},
    {"num": "5", "emb": [0.6,0.7,0.8,0.9,1.0]}
  ]
}

GET book-index/_search
{
  "retriever": {
    "rrf": {
      "retrievers": [
        {
          "retriever": {
            "knn": {
              "field": "image.emb",
              "query_vector": [0.1, 0.2, 0.3,0.4,0.5],
              "k": 5,
              "num_candidates": 50
            }
          },
          "weight": 0.8
        },
        {
          "retriever": {
            "standard": {
              "query": {
                "match": {
                  "title": "Sunny day"
                }
              }
            }
          },
          "weight": 0.2
        }
      ],
      "rank_window_size": 50,
      "rank_constant": 20        
    }
  }
}