package bible

import (
	"fmt"
	"regexp"
	"sort"
	"strconv"
	"strings"

	"github.com/lukaszkasprzak/lectio/internal/psalter"
)

// polishToEn maps Polish Biblical abbreviations to the book name accepted by
// the kjv-family tools. Gospels use the short forms (Mat/Mark/Luke/John);
// other books use full names that the tools resolve by unique prefix.
// Ported verbatim from ewangelia.py POLISH_TO_EN.
var polishToEn = map[string]string{
	// Old Testament
	"Rdz": "Genesis", "Wj": "Exodus", "Kpł": "Leviticus", "Lb": "Numbers",
	"Pwt": "Deuteronomy", "Joz": "Joshua", "Sdz": "Judges", "Rt": "Ruth",
	"1 Sm": "1 Samuel", "2 Sm": "2 Samuel", "1 Krl": "1 Kings", "2 Krl": "2 Kings",
	"1 Krn": "1 Chronicles", "2 Krn": "2 Chronicles", "Ezd": "Ezra",
	"Ne": "Nehemiah", "Tb": "Tobit", "Jdt": "Judith", "Est": "Esther",
	"1 Mch": "1 Maccabees", "2 Mch": "2 Maccabees", "Hi": "Job", "Ps": "Psalms",
	"Prz": "Proverbs", "Koh": "Ecclesiastes", "Pnp": "Song of Solomon",
	"Mdr": "Wisdom", "Syr": "Sirach", "Iz": "Isaiah", "Jr": "Jeremiah",
	"Lm": "Lamentations", "Ba": "Baruch", "Ez": "Ezekiel", "Dn": "Daniel",
	"Oz": "Hosea", "Jl": "Joel", "Am": "Amos", "Ab": "Obadiah", "Jon": "Jonah",
	"Mi": "Micah", "Na": "Nahum", "Ha": "Habakkuk", "So": "Zephaniah",
	"Ag": "Haggai", "Za": "Zechariah", "Ml": "Malachi",
	// New Testament
	"Mt": "Mat", "Mk": "Mark", "Łk": "Luke", "J": "John", "Dz": "Acts",
	"Rz": "Romans", "1 Kor": "1 Corinthians", "2 Kor": "2 Corinthians",
	"Ga": "Galatians", "Ef": "Ephesians", "Flp": "Philippians",
	"Kol": "Colossians", "1 Tes": "1 Thessalonians", "2 Tes": "2 Thessalonians",
	"1 Tm": "1 Timothy", "2 Tm": "2 Timothy", "Tt": "Titus", "Flm": "Philemon",
	"Hbr": "Hebrews", "Jk": "James", "1 P": "1 Peter", "2 P": "2 Peter",
	"1 J": "1 John", "2 J": "2 John", "3 J": "3 John", "Jud": "Jude",
	"Ap": "Revelation",
}

var (
	porRe         = regexp.MustCompile(`(?i)^\s*por\.\s*`)
	refrainRe     = regexp.MustCompile(`\s*\(R\.:.*$`)
	wsRe          = regexp.MustCompile(`\s+`)
	iRe           = regexp.MustCompile(`\s+i\s+`)
	dashRe        = regexp.MustCompile(`\s*[-–—]\s*`)
	verseLetterRe = regexp.MustCompile(`(\d)[a-c]\b`)
	psalmRestRe   = regexp.MustCompile(`(\d+)(?:\s*\((\d+)\))?(.*)$`)
	digitsRe      = regexp.MustCompile(`\d+`)
)

// polishBookKeys holds the POLISH_TO_EN keys sorted longest-first, matching
// the Python `sorted(POLISH_TO_EN, key=len, reverse=True)` traversal order.
var polishBookKeys = sortedPolishBookKeys()

func sortedPolishBookKeys() []string {
	keys := make([]string, 0, len(polishToEn))
	for k := range polishToEn {
		keys = append(keys, k)
	}
	sort.SliceStable(keys, func(i, j int) bool { return len(keys[i]) > len(keys[j]) })
	return keys
}

// psalmRef maps the psalm citation body ("63 (62), 2. 3-4. ...") to the target Psalter.
func psalmRef(rest, system string) string {
	m := psalmRestRe.FindStringSubmatch(rest)
	if m == nil {
		return rest
	}
	heb, _ := strconv.Atoi(m[1])
	tail := m[3]
	if system == "vulgate" {
		ch := m[1]
		if m[2] != "" {
			ch = m[2]
		}
		return ch + tail
	}
	if system == "drb" {
		tail = digitsRe.ReplaceAllStringFunc(tail, func(s string) string {
			n, _ := strconv.Atoi(s)
			return strconv.Itoa(psalter.DrbVerse(heb, n))
		})
	}
	return strconv.Itoa(heb) + tail
}

// ToEnglishRef converts a Polish citation to kjv-tool style: "Mt 7, 1-5" -> "Mat 7:1-5".
//
// Handles the extra apparatus of non-gospel readings: a leading "por." (compare)
// marker, a trailing "(R.: ...)" responsorial refrain, and psalm versification.
// system selects the target Psalter: "vulgate" (vul/grb/wuj) uses the citation's
// Vulgate chapter (62 of "63 (62)"); "drb" uses the Hebrew chapter (63) with the
// DRB title-fold verse shift; other values use the Hebrew chapter unshifted.
func ToEnglishRef(plRef, system string) (string, error) {
	plRef = porRe.ReplaceAllString(plRef, "")     // 'compare' marker
	plRef = refrainRe.ReplaceAllString(plRef, "") // responsorial refrain
	plRef = wsRe.ReplaceAllString(strings.TrimSpace(plRef), " ")

	var book string
	found := false
	for _, k := range polishBookKeys {
		if plRef == k || strings.HasPrefix(plRef, k+" ") {
			book = k
			found = true
			break
		}
	}
	if !found {
		return "", fmt.Errorf("unknown book in reference: %q", plRef)
	}

	rest := strings.TrimSpace(plRef[len(book):])
	if polishToEn[book] == "Psalms" {
		rest = psalmRef(rest, system)
	}
	rest = strings.ReplaceAll(rest, ", ", ":")        // chapter/verse separator
	rest = strings.ReplaceAll(rest, ". ", ",")        // disjoint verse groups
	rest = iRe.ReplaceAllString(rest, ",")            // Polish 'and'
	rest = dashRe.ReplaceAllString(rest, "-")         // normalise ranges
	rest = verseLetterRe.ReplaceAllString(rest, "$1") // drop verse-part letters (15a -> 15)
	rest = strings.ReplaceAll(rest, " ", "")

	return strings.TrimSpace(fmt.Sprintf("%s %s", polishToEn[book], rest)), nil
}