package skate

import (
	"index/suffixarray"
	"regexp"
	"strings"
)

var (
	patNonWordDomain       = regexp.MustCompile(`(https?:\/\/)([^\w]*)(.*)`)
	patRepeatedHttpSlashes = regexp.MustCompile(`(https?:\/\/)(\/)*(.*)`)
	patHttpDOI             = regexp.MustCompile(`(https?:\/\/)(10[.][0-9]{1,8}\/.*)`)
	patAccessedOn          = regexp.MustCompile(`(?iU)(.*)[.;,]?(abgerufen|acces-sed|últimoacesso|updated|ac-cessed|zugegriffen|diunduh|adresinden|sayfasındanulaşıl|accessedon|consultéle|consultad|diaksestanggal|diaksespadatanggal|diakses|dateofaccess|lastaccessed|acesso|acessado|accessoem|accessed|recibido|accessedat|доступ-свободный|датаобращения|pageconsulté|indirme|downloadedfrom).*$`)
	patFileExtraSuffix     = regexp.MustCompile(`(?i)(http.*[.](pdf\+html|zip|pdf|html|doc|docx|rar))([^?]*)$`)
)

// SanitizeURL applies various cleanup rules on URLs as found in references.
// Returns an empty string when no URL could be constructed. Still, many
// results will not be a URL after all.  XXX: Sometimes a URL contains other
// identifying information, like:
// http://agingmind.utdallas.edu/facedb/view/neutral-faces.doi:10.3758/BF03206543.
// http://10.3386/w20634https://doi.org/10.3386/w20634
func SanitizeURL(s string) string {
	var (
		// seems to only be about 15% of total time spent
		index   = suffixarray.New([]byte(s))
		indices = index.Lookup([]byte("http"), -1)
	)
	if !strings.HasPrefix(s, "http") && !strings.HasPrefix(s, "ftp") {
		s = sanitizeRaw(s, index)
		if s == "" {
			return s
		}
	}
	if len(indices) > 1 {
		s = s[0:indices[1]] // only use the first
		s = strings.TrimRight(s, ":")
		s = strings.TrimRight(s, ";")
	}
	// http://!!!:
	// http://!
	// http://"
	s = patNonWordDomain.ReplaceAllString(s, `$1$3`)
	// http:///en.m.wikipedia.org/ChenLong
	s = patRepeatedHttpSlashes.ReplaceAllString(s, `$1$3`)
	// http://10.1113/jphysiol.2002.026047
	s = patHttpDOI.ReplaceAllString(s, `https://doi.org/$2`)
	// .diaksestanggal27-03-2017.10.30Wib
	// accessedon15
	// .Accessed
	// Acessoem:10/09/2012
	// .Acesso:11Abr
	if patAccessedOn.MatchString(s) {
		s = patAccessedOn.ReplaceAllString(s, `$1`)
	}
	// http://140.120.197.173/Ecology/Download/Timing-MSChart.zipJournalofInsectScience
	if patFileExtraSuffix.MatchString(s) {
		s = patFileExtraSuffix.ReplaceAllString(s, `$1`)
	}
	return s
}

func sanitizeRaw(s string, index *suffixarray.Index) string {
	if len(s) < 4 {
		return ""
	}
	if !strings.Contains(s, ".") {
		return ""
	}
	indices := index.Lookup([]byte("www."), 1)
	if len(indices) > 0 {
		s = "http://" + s[indices[0]:]
	} else {
		s = "http://" + s
	}
	return s
	// Re-trievedfrom
}