package backend

import (
	"context"
	"fmt"
	"sync"

	config "github.com/go-skynet/LocalAI/api/config"
	"github.com/go-skynet/LocalAI/api/options"
	"github.com/go-skynet/LocalAI/pkg/grpc"
	model "github.com/go-skynet/LocalAI/pkg/model"
	bert "github.com/go-skynet/go-bert.cpp"
)

func ModelEmbedding(s string, tokens []int, loader *model.ModelLoader, c config.Config, o *options.Option) (func() ([]float32, error), error) {
	if !c.Embeddings {
		return nil, fmt.Errorf("endpoint disabled for this model by API configuration")
	}

	modelFile := c.Model

	grpcOpts := gRPCModelOpts(c)

	var inferenceModel interface{}
	var err error

	opts := []model.Option{
		model.WithLoadGRPCOpts(grpcOpts),
		model.WithThreads(uint32(c.Threads)),
		model.WithAssetDir(o.AssetsDestination),
		model.WithModelFile(modelFile),
	}

	if c.Backend == "" {
		inferenceModel, err = loader.GreedyLoader(opts...)
	} else {
		opts = append(opts, model.WithBackendString(c.Backend))
		inferenceModel, err = loader.BackendLoader(opts...)
	}
	if err != nil {
		return nil, err
	}

	var fn func() ([]float32, error)
	switch model := inferenceModel.(type) {
	case *grpc.Client:
		fn = func() ([]float32, error) {
			predictOptions := gRPCPredictOpts(c, loader.ModelPath)
			if len(tokens) > 0 {
				embeds := []int32{}

				for _, t := range tokens {
					embeds = append(embeds, int32(t))
				}
				predictOptions.EmbeddingTokens = embeds

				res, err := model.Embeddings(context.TODO(), predictOptions)
				if err != nil {
					return nil, err
				}

				return res.Embeddings, nil
			}
			predictOptions.Embeddings = s

			res, err := model.Embeddings(context.TODO(), predictOptions)
			if err != nil {
				return nil, err
			}

			return res.Embeddings, nil
		}

	// bert embeddings
	case *bert.Bert:
		fn = func() ([]float32, error) {
			if len(tokens) > 0 {
				return model.TokenEmbeddings(tokens, bert.SetThreads(c.Threads))
			}
			return model.Embeddings(s, bert.SetThreads(c.Threads))
		}
	default:
		fn = func() ([]float32, error) {
			return nil, fmt.Errorf("embeddings not supported by the backend")
		}
	}

	return func() ([]float32, error) {
		// This is still needed, see: https://github.com/ggerganov/llama.cpp/discussions/784
		l := Lock(modelFile)
		defer l.Unlock()

		embeds, err := fn()
		if err != nil {
			return embeds, err
		}
		// Remove trailing 0s
		for i := len(embeds) - 1; i >= 0; i-- {
			if embeds[i] == 0.0 {
				embeds = embeds[:i]
			} else {
				break
			}
		}
		return embeds, nil
	}, nil
}