package hmm

import (
	"sort"
)

// CountNSort consumes a stream of strings, calculates counts of occurances in
// the stream. After the stream is closed it sorts the unique keys by frequency
// and returns it as a Results.
func CountNSort(in <-chan string) Results {
	res := map[string]int{}

	for i := range in {
		res[i]++
	}

	r := Results{}
	for k, v := range res {
		r = append(r, Result{k, v})
	}

	sort.Sort(r)

	return r
}

// Result encodes a frequency for seen string.
type Result struct {
	Key   string
	Count int
}

// Results exists to sort a slice of Result
type Results []Result

func (r Results) Len() int           { return len(r) }
func (r Results) Swap(i, j int)      { r[i], r[j] = r[j], r[i] }
func (r Results) Less(i, j int) bool { return r[i].Count < r[j].Count }