package bible

import (
	"regexp"
	"strconv"
	"strings"
)

var refRe = regexp.MustCompile(`^(.*?)\s+(\d+):(.+)$`)

// SplitRef splits a ref whose verse list mixes single verses and ranges into
// one ref per group (the kjv tools reject a mixed list in a single query).
func SplitRef(ref string) []string {
	m := refRe.FindStringSubmatch(ref)
	if m == nil {
		return []string{ref}
	}
	book, chap, verses := m[1], m[2], m[3]
	if !strings.Contains(verses, ",") {
		return []string{ref}
	}
	var out []string
	for _, g := range strings.Split(verses, ",") {
		g = strings.TrimSpace(g)
		if g == "" {
			continue
		}
		if strings.Contains(g, ":") {
			out = append(out, book+" "+g)
		} else {
			out = append(out, book+" "+chap+":"+g)
		}
	}
	return out
}

// Lookup resolves an English-style reference against a version, returning the
// matched verses (in order) and the sub-refs the corpus had no entry for.
func Lookup(version, ref string) ([]Verse, []string) {
	var verses []Verse
	var missing []string
	for _, part := range SplitRef(ref) {
		m := refRe.FindStringSubmatch(part)
		if m == nil {
			missing = append(missing, part)
			continue
		}
		book, ok := ResolveBook(m[1])
		if !ok {
			missing = append(missing, part)
			continue
		}
		chap, _ := strconv.Atoi(m[2])
		from, to := verseRange(m[3])
		found := false
		for _, v := range Verses(version, book, chap) {
			if v.Verse >= from && v.Verse <= to {
				verses = append(verses, v)
				found = true
			}
		}
		if !found {
			missing = append(missing, part)
		}
	}
	return verses, missing
}

func verseRange(s string) (int, int) {
	s = strings.TrimSpace(s)
	if i := strings.IndexAny(s, "-–—"); i >= 0 {
		from, _ := strconv.Atoi(strings.TrimSpace(s[:i]))
		to, _ := strconv.Atoi(strings.TrimSpace(s[i+1:]))
		return from, to
	}
	n, _ := strconv.Atoi(s)
	return n, n
}