// 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 index

import "strconv"

const (
	ivfNlistKey = `nlist`
	ivfPQMKey   = `m`
	ivfPQNbits  = `nbits`
)

var _ Index = ivfFlatIndex{}

type ivfFlatIndex struct {
	baseIndex

	nlist int
}

func (idx ivfFlatIndex) Params() map[string]string {
	return map[string]string{
		MetricTypeKey: string(idx.metricType),
		IndexTypeKey:  string(IvfFlat),
		ivfNlistKey:   strconv.Itoa(idx.nlist),
	}
}

func NewIvfFlatIndex(metricType MetricType, nlist int) Index {
	return ivfFlatIndex{
		baseIndex: baseIndex{
			metricType: metricType,
			indexType:  IvfFlat,
		},

		nlist: nlist,
	}
}

type ivfPQIndex struct {
	baseIndex

	nlist int
	m     int
	nbits int
}

func (idx ivfPQIndex) Params() map[string]string {
	return map[string]string{
		MetricTypeKey: string(idx.metricType),
		IndexTypeKey:  string(IvfPQ),
		ivfNlistKey:   strconv.Itoa(idx.nlist),
		ivfPQMKey:     strconv.Itoa(idx.m),
		ivfPQNbits:    strconv.Itoa(idx.nbits),
	}
}

func NewIvfPQIndex(metricType MetricType, nlist int, m int, nbits int) Index {
	return ivfPQIndex{
		baseIndex: baseIndex{
			metricType: metricType,
			indexType:  IvfPQ,
		},

		nlist: nlist,
		m:     m,
		nbits: nbits,
	}
}

type ivfSQ8Index struct {
	baseIndex

	nlist int
}

func (idx ivfSQ8Index) Params() map[string]string {
	return map[string]string{
		MetricTypeKey: string(idx.metricType),
		IndexTypeKey:  string(IvfSQ8),
		ivfNlistKey:   strconv.Itoa(idx.nlist),
	}
}

func NewIvfSQ8Index(metricType MetricType, nlist int) Index {
	return ivfPQIndex{
		baseIndex: baseIndex{
			metricType: metricType,
			indexType:  IvfSQ8,
		},

		nlist: nlist,
	}
}