package analyse

import (
	"bufio"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
)

var (
	stopWords map[string]string
	idfFreq   map[string]float64
	medianIdf float64
)

func init() {
	idfFreq = make(map[string]float64)
	stopWords = map[string]string{
		"the": "the", "of": "of", "is": "is", "and": "and", "to": "to", "in": "in", "that": "that", "we": "we", "for": "for", "an": "an", "are": "are", "by": "bye", "be": "be", "as": "as", "on": "on", "with": "with", "can": "can", "if": "of", "from": "from", "which": "which", "you": "you", "it": "it", "this": "this", "then": "then", "at": "at", "have": "have", "all": "all", "not": "not", "one": "one", "has": "has", "or": "or",
	}
}

func SetIdf(idfFilePath string) error {
	if !filepath.IsAbs(idfFilePath) {
		pwd, err := os.Getwd()
		if err != nil {
			return err
		}
		idfFilePath = filepath.Clean(filepath.Join(pwd, idfFilePath))
	}
	idfFile, err := os.Open(idfFilePath)
	if err != nil {
		return err
	}
	scanner := bufio.NewScanner(idfFile)
	freqs := make([]float64, 0)
	for scanner.Scan() {
		line := scanner.Text()
		words := strings.Split(line, " ")
		word, freqStr := words[0], words[1]
		freq, err := strconv.ParseFloat(freqStr, 64)
		if err != nil {
			continue
		}
		idfFreq[word] = freq
		freqs = append(freqs, freq)
	}
	if err := scanner.Err(); err != nil {
		return err
	}
	sort.Float64s(freqs)
	medianIdf = freqs[len(freqs)/2]
	return nil
}

func SetStopWords(stopWordsFilePath string) error {
	if !filepath.IsAbs(stopWordsFilePath) {
		pwd, err := os.Getwd()
		if err != nil {
			return err
		}
		stopWordsFilePath = filepath.Clean(filepath.Join(pwd, stopWordsFilePath))
	}
	stopWordsFile, err := os.Open(stopWordsFilePath)
	if err != nil {
		return err
	}
	scanner := bufio.NewScanner(stopWordsFile)
	for scanner.Scan() {
		stopWord := scanner.Text()
		stopWord = strings.TrimSpace(stopWord)
		stopWords[stopWord] = stopWord
	}
	if err := scanner.Err(); err != nil {
		return err
	}
	return nil
}