/*
 * # Licensed to the LF AI & Data foundation under one
 * # or more contributor license agreements. See the NOTICE file
 * # distributed with this work for additional information
 * # regarding copyright ownership. The ASF licenses this file
 * # to you under the Apache License, Version 2.0 (the
 * # "License"); you may not use this file except in compliance
 * # with the License. You may obtain a copy of the License at
 * #
 * #     http://www.apache.org/licenses/LICENSE-2.0
 * #
 * # Unless required by applicable law or agreed to in writing, software
 * # distributed under the License is distributed on an "AS IS" BASIS,
 * # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * # See the License for the specific language governing permissions and
 * # limitations under the License.
 */

package function

import (
	"fmt"
	"os"
	"strings"

	"github.com/milvus-io/milvus-proto/go-api/v2/schemapb"
	"github.com/milvus-io/milvus/internal/util/function/models/cohere"
	"github.com/milvus-io/milvus/pkg/v2/util/typeutil"
)

type CohereEmbeddingProvider struct {
	fieldDim int64

	client    *cohere.CohereEmbedding
	modelName string
	truncate  string

	maxBatch   int
	timeoutSec int64
}

func createCohereEmbeddingClient(apiKey string, url string) (*cohere.CohereEmbedding, error) {
	if apiKey == "" {
		apiKey = os.Getenv(cohereAIAKEnvStr)
	}
	if apiKey == "" {
		return nil, fmt.Errorf("Missing credentials. Please pass `api_key`, or configure the %s environment variable in the Milvus service.", cohereAIAKEnvStr)
	}

	if url == "" {
		url = "https://api.cohere.com/v2/embed"
	}

	c := cohere.NewCohereEmbeddingClient(apiKey, url)
	return c, nil
}

func NewCohereEmbeddingProvider(fieldSchema *schemapb.FieldSchema, functionSchema *schemapb.FunctionSchema) (*CohereEmbeddingProvider, error) {
	fieldDim, err := typeutil.GetDim(fieldSchema)
	if err != nil {
		return nil, err
	}
	var apiKey, url, modelName string
	truncate := "END"
	for _, param := range functionSchema.Params {
		switch strings.ToLower(param.Key) {
		case modelNameParamKey:
			modelName = param.Value
		case apiKeyParamKey:
			apiKey = param.Value
		case embeddingURLParamKey:
			url = param.Value
		case truncateParamKey:
			if param.Value != "NONE" && param.Value != "START" && param.Value != "END" {
				return nil, fmt.Errorf("Illegal parameters, %s only supports [NONE, START, END]", truncateParamKey)
			}
			truncate = param.Value
		default:
		}
	}

	if modelName != embedEnglishV30 && modelName != embedMultilingualV30 && modelName != embedEnglishLightV30 && modelName != embedMultilingualLightV30 && modelName != embedEnglishV20 && modelName != embedEnglishLightV20 && modelName != embedMultilingualV20 {
		return nil, fmt.Errorf("Unsupported model: %s, only support [%s, %s, %s, %s, %s, %s, %s]",
			modelName, embedEnglishV30, embedMultilingualV30, embedEnglishLightV30, embedMultilingualLightV30, embedEnglishV20, embedEnglishLightV20, embedMultilingualV20)
	}

	c, err := createCohereEmbeddingClient(apiKey, url)
	if err != nil {
		return nil, err
	}

	provider := CohereEmbeddingProvider{
		client:     c,
		fieldDim:   fieldDim,
		modelName:  modelName,
		truncate:   truncate,
		maxBatch:   96,
		timeoutSec: 30,
	}
	return &provider, nil
}

func (provider *CohereEmbeddingProvider) MaxBatch() int {
	return 5 * provider.maxBatch
}

func (provider *CohereEmbeddingProvider) FieldDim() int64 {
	return provider.fieldDim
}

// Specifies the type of input passed to the model. Required for embedding models v3 and higher.
func (provider *CohereEmbeddingProvider) getInputType(mode TextEmbeddingMode) string {
	if provider.modelName == embedEnglishV20 || provider.modelName == embedEnglishLightV20 || provider.modelName == embedMultilingualV20 {
		return ""
	}
	if mode == InsertMode {
		return "search_document" // Used for embeddings stored in a vector database for search use-cases.
	}
	return "search_query" // Used for embeddings of search queries run against a vector DB to find relevant documents.
}

func (provider *CohereEmbeddingProvider) CallEmbedding(texts []string, mode TextEmbeddingMode) ([][]float32, error) {
	numRows := len(texts)
	inputType := provider.getInputType(mode)
	data := make([][]float32, 0, numRows)
	for i := 0; i < numRows; i += provider.maxBatch {
		end := i + provider.maxBatch
		if end > numRows {
			end = numRows
		}
		resp, err := provider.client.Embedding(provider.modelName, texts[i:end], inputType, "float", provider.truncate, provider.timeoutSec)
		if err != nil {
			return nil, err
		}
		if end-i != len(resp.Embeddings.Float) {
			return nil, fmt.Errorf("Get embedding failed. The number of texts and embeddings does not match text:[%d], embedding:[%d]", end-i, len(resp.Embeddings.Float))
		}
		for _, embedding := range resp.Embeddings.Float {
			if len(embedding) != int(provider.fieldDim) {
				return nil, fmt.Errorf("The required embedding dim is [%d], but the embedding obtained from the model is [%d]",
					provider.fieldDim, len(embedding))
			}
		}
		data = append(data, resp.Embeddings.Float...)
	}
	return data, nil
}