//                           _       _
// __      _____  __ ___   ___  __ _| |_ ___
// \ \ /\ / / _ \/ _` \ \ / / |/ _` | __/ _ \
//  \ V  V /  __/ (_| |\ V /| | (_| | ||  __/
//   \_/\_/ \___|\__,_| \_/ |_|\__,_|\__\___|
//
//  Copyright © 2016 - 2024 Weaviate B.V. All rights reserved.
//
//  CONTACT: hello@weaviate.io
//

package vectorizer

import (
	"context"

	"github.com/pkg/errors"

	"github.com/go-openapi/strfmt"
	"github.com/weaviate/weaviate/entities/models"
	"github.com/weaviate/weaviate/entities/moduletools"
	"github.com/weaviate/weaviate/modules/multi2vec-clip/ent"
	libvectorizer "github.com/weaviate/weaviate/usecases/vectorizer"
)

type Vectorizer struct {
	client Client
}

func New(client Client) *Vectorizer {
	return &Vectorizer{
		client: client,
	}
}

type Client interface {
	Vectorize(ctx context.Context,
		texts, images []string) (*ent.VectorizationResult, error)
}

type ClassSettings interface {
	ImageField(property string) bool
	ImageFieldsWeights() ([]float32, error)
	TextField(property string) bool
	TextFieldsWeights() ([]float32, error)
}

func (v *Vectorizer) Object(ctx context.Context, object *models.Object,
	objDiff *moduletools.ObjectDiff, settings ClassSettings,
) error {
	vec, err := v.object(ctx, object.ID, object.Properties, objDiff, settings)
	if err != nil {
		return err
	}

	object.Vector = vec
	return nil
}

func (v *Vectorizer) VectorizeImage(ctx context.Context, image string) ([]float32, error) {
	res, err := v.client.Vectorize(ctx, []string{}, []string{image})
	if err != nil {
		return nil, err
	}
	if len(res.ImageVectors) != 1 {
		return nil, errors.New("empty vector")
	}

	return res.ImageVectors[0], nil
}

func (v *Vectorizer) object(ctx context.Context, id strfmt.UUID,
	schema interface{}, objDiff *moduletools.ObjectDiff, ichek ClassSettings,
) ([]float32, error) {
	vectorize := objDiff == nil || objDiff.GetVec() == nil

	// vectorize image and text
	texts := []string{}
	images := []string{}
	if schema != nil {
		for prop, value := range schema.(map[string]interface{}) {
			if ichek.ImageField(prop) {
				valueString, ok := value.(string)
				if ok {
					images = append(images, valueString)
					vectorize = vectorize || (objDiff != nil && objDiff.IsChangedProp(prop))
				}
			}
			if ichek.TextField(prop) {
				valueString, ok := value.(string)
				if ok {
					texts = append(texts, valueString)
					vectorize = vectorize || (objDiff != nil && objDiff.IsChangedProp(prop))
				}
			}
			valueArr, ok := value.([]interface{})
			if ok {
				for _, value := range valueArr {
					valueString, ok := value.(string)
					if ok {
						texts = append(texts, valueString)
						vectorize = vectorize || (objDiff != nil && objDiff.IsChangedProp(prop))
					}
				}
			}
		}
	}

	// no property was changed, old vector can be used
	if !vectorize {
		return objDiff.GetVec(), nil
	}

	vectors := [][]float32{}
	if len(texts) > 0 || len(images) > 0 {
		res, err := v.client.Vectorize(ctx, texts, images)
		if err != nil {
			return nil, err
		}
		vectors = append(vectors, res.TextVectors...)
		vectors = append(vectors, res.ImageVectors...)
	}
	weights, err := v.getWeights(ichek)
	if err != nil {
		return nil, err
	}

	return libvectorizer.CombineVectorsWithWeights(vectors, weights), nil
}

func (v *Vectorizer) getWeights(ichek ClassSettings) ([]float32, error) {
	weights := []float32{}
	textFieldsWeights, err := ichek.TextFieldsWeights()
	if err != nil {
		return nil, err
	}
	imageFieldsWeights, err := ichek.ImageFieldsWeights()
	if err != nil {
		return nil, err
	}

	weights = append(weights, textFieldsWeights...)
	weights = append(weights, imageFieldsWeights...)

	normalizedWeights := v.normalizeWeights(weights)

	return normalizedWeights, nil
}

func (v *Vectorizer) normalizeWeights(weights []float32) []float32 {
	if len(weights) > 0 {
		var denominator float32
		for i := range weights {
			denominator += weights[i]
		}
		normalizer := 1 / denominator
		normalized := make([]float32, len(weights))
		for i := range weights {
			normalized[i] = weights[i] * normalizer
		}
		return normalized
	}
	return nil
}