Move all the code to a lib folder

lib/parser/language.go

@@ -0,0 +1,66 @@
+package parser
+
+import (
+	"io/ioutil"
+	"strings"
+
+	"github.com/meskio/epubgo"
+	"github.com/rainycape/cld2"
+)
+
+func GuessLang(epub *epubgo.Epub, orig_langs []string) []string {
+	spine, err := epub.Spine()
+	if err != nil {
+		return orig_langs
+	}
+
+	var err_spine error
+	err_spine = nil
+	langs := []string{}
+	for err_spine == nil {
+		html, err := spine.Open()
+		err_spine = spine.Next()
+		if err != nil {
+			continue
+		}
+		defer html.Close()
+
+		buff, err := ioutil.ReadAll(html)
+		if err != nil {
+			continue
+		}
+		langs = append(langs, cld2.Detect(string(buff)))
+	}
+
+	lang := commonLang(langs)
+	if lang != "un" && differentLang(lang, orig_langs) {
+		return []string{lang}
+	}
+	return orig_langs
+}
+
+func commonLang(langs []string) string {
+	count := map[string]int{}
+	for _, l := range langs {
+		count[l]++
+	}
+
+	lang := "un"
+	maxcount := 0
+	for l, c := range count {
+		if c > maxcount && l != "un" {
+			lang = l
+			maxcount = c
+		}
+	}
+	return lang
+}
+
+func differentLang(lang string, orig_langs []string) bool {
+	orig_lang := "un"
+	if len(orig_langs) > 0 && len(orig_langs) >= 2 {
+		orig_lang = strings.ToLower(orig_langs[0][0:2])
+	}
+
+	return orig_lang != lang
+}