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

package common

import (
	"context"
	"sync"

	"github.com/weaviate/weaviate/adapters/repos/db/priorityqueue"
)

type VectorSlice struct {
	Slice []float32
	Mem   []float32
	Buff8 []byte
	Buff  []byte
}

type (
	VectorForID[T float32 | byte | uint64] func(ctx context.Context, id uint64) ([]T, error)
	TempVectorForID                        func(ctx context.Context, id uint64, container *VectorSlice) ([]float32, error)
	MultiVectorForID                       func(ctx context.Context, ids []uint64) ([][]float32, []error)
)

type TempVectorsPool struct {
	pool *sync.Pool
}

func NewTempVectorsPool() *TempVectorsPool {
	return &TempVectorsPool{
		pool: &sync.Pool{
			New: func() interface{} {
				return &VectorSlice{
					Mem:   nil,
					Buff8: make([]byte, 8),
					Buff:  nil,
					Slice: nil,
				}
			},
		},
	}
}

func (pool *TempVectorsPool) Get(capacity int) *VectorSlice {
	container := pool.pool.Get().(*VectorSlice)
	if len(container.Slice) >= capacity {
		container.Slice = container.Mem[:capacity]
	} else {
		container.Mem = make([]float32, capacity)
		container.Slice = container.Mem[:capacity]
	}
	return container
}

func (pool *TempVectorsPool) Put(container *VectorSlice) {
	pool.pool.Put(container)
}

type PqMaxPool struct {
	pool *sync.Pool
}

func NewPqMaxPool(defaultCap int) *PqMaxPool {
	return &PqMaxPool{
		pool: &sync.Pool{
			New: func() interface{} {
				return priorityqueue.NewMax[any](defaultCap)
			},
		},
	}
}

func (pqh *PqMaxPool) GetMax(capacity int) *priorityqueue.Queue[any] {
	pq := pqh.pool.Get().(*priorityqueue.Queue[any])
	if pq.Cap() < capacity {
		pq.ResetCap(capacity)
	} else {
		pq.Reset()
	}

	return pq
}

func (pqh *PqMaxPool) Put(pq *priorityqueue.Queue[any]) {
	pqh.pool.Put(pq)
}