// Copyright 2025 PingCAP, Inc.
//
// Licensed 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 base

import (
	"context"
	"encoding/binary"
	"fmt"
	"math"
)

// Embedder is an interface for embedding providers.
type Embedder interface {
	// CreateEmbeddings generates embeddings for the given texts using the specified model and options.
	// Different implementations requires different options types. Options can be nil if not needed.
	CreateEmbeddings(ctx context.Context, model string, texts []string, opts map[string]any) ([][]float32, error)
}

// DecodeFloat32ArrayBytes decodes bytes of an float32 array in little endian into a float32 slice.
func DecodeFloat32ArrayBytes(item []byte) ([]float32, error) {
	if len(item)%4 != 0 {
		return nil, fmt.Errorf("invalid embedding data")
	}
	dims := len(item) / 4
	embeddings := make([]float32, dims)
	for i := range dims {
		bytes := item[i*4 : (i+1)*4]
		bits := binary.LittleEndian.Uint32(bytes)
		embeddings[i] = math.Float32frombits(bits)
	}
	return embeddings, nil
}