package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"sort"
	"strings"
)

func main() {
	files, err := ioutil.ReadDir("./texts/")
	if err != nil {
		log.Fatal(err)
	}

	// runtime saving space for texts (seperated by space)
	textMap := make(map[string][]string)

	// go through all files and build data
	for _, f := range files {
		// read specific file
		tmpText, err := ioutil.ReadFile("./texts/" + f.Name())
		if err != nil {
			log.Fatal(err)
		}

		// convert to single words and save with filename
		textMap[f.Name()] = strings.Split(string(tmpText), " ")
	}

	// runtime variable for evaluation with format: word - number of occurrences
	evaluation := make(map[string]int)

	// go through list of words for each text and look for matches
	for file, words := range textMap {
		for _, f := range files {
			// only compare with not equal texts
			if f.Name() != file {
				// for each word in the original text (outer loop words from textMap)
				for _, w := range words {
					// check with each work from other text (inner loop words from comparing text)
					for _, w2 := range textMap[f.Name()] {
						// finally check if equal
						if w == w2 {
							// add to evaluation
							evaluation[w]++
						}
					}
				}
			}
		}
	}

	// convert to sortable format, do sorting and finally output result
	type kv struct {
		Key   string
		Value int
	}

	var ss []kv
	for k, v := range evaluation {
		ss = append(ss, kv{k, v})
	}

	sort.Slice(ss, func(i, j int) bool {
		return ss[i].Value > ss[j].Value
	})

	for _, kv := range ss {
		fmt.Printf("%s, %d\n", kv.Key, kv.Value)
	}

}