package data

import (
	"bytes"
	"sort"
)

// Data saves slices of bytes referenced by labels.
type Data map[string][]byte

// Finalize returns the final raw data slice and a map of labels with their respective indices.
// It will try to reuse existing data whenever possible.
func (data Data) Finalize() ([]byte, map[string]int32) {
	var (
		final     []byte
		keys      = make([]string, 0, len(data))
		positions = make(map[string]int32, len(data))
	)

	for key := range data {
		keys = append(keys, key)
	}

	sort.SliceStable(keys, func(i, j int) bool {
		return len(data[keys[i]]) > len(data[keys[j]])
	})

	for _, key := range keys {
		raw := data[key]
		position := bytes.Index(final, raw)

		if position != -1 {
			positions[key] = int32(position)
		} else {
			positions[key] = int32(len(final))
			final = append(final, raw...)
		}
	}

	return final, positions
}

func (data Data) Insert(label string, raw []byte) {
	data[label] = raw
}