package pipeline

import (
	"sort"
	"strings"
	"unicode"
)

// miner_palladius.go: the Palladius (Палладий) transliteration syllable table + ru-side name-shape
// detector (WS3 — a Go port of exp16 palladius.py). A ru token that segments cleanly into Palladius
// syllables looks like a transliterated Chinese NAME. The pinyin→Cyrillic table is generated
// deterministically from initials × finals + the documented irregularities (a versioned artifact).
//
// In the ratified DEFAULT-B miner the ru-side name CONFIRMATION sub-channel is OFF (it also needs the
// pymorphy3 is_name_lemma gate to block the «найти»=най+ти false-positive class), so isPalladiusToken is
// not wired into the default-B detector pipeline. It is kept as a deterministic, tested artifact — the
// name-shape signal a future faithful-A variant (with a Go morphology backend) would consume, and the
// pattern P4 transliteration-by-pair seam (§B5).

// palladius initials (声母) → Palladius Cyrillic (palladius.INITIALS).
var palladiusInitials = map[string]string{
	"b": "б", "p": "п", "m": "м", "f": "ф", "d": "д", "t": "т", "n": "н", "l": "л",
	"g": "г", "k": "к", "h": "х", "j": "цз", "q": "ц", "x": "с",
	"zh": "чж", "ch": "ч", "sh": "ш", "r": "ж", "z": "цз", "c": "ц", "s": "с",
}

// palladius finals (韵母) → Palladius Cyrillic (palladius.FINALS). ü is written as v.
var palladiusFinals = map[string]string{
	"a": "а", "o": "о", "e": "э", "ai": "ай", "ei": "эй", "ao": "ао", "ou": "оу",
	"an": "ань", "en": "энь", "ang": "ан", "eng": "эн", "er": "эр", "ong": "ун",
	"i": "и", "ia": "я", "ie": "е", "iao": "яо", "iu": "ю", "ian": "янь",
	"in": "инь", "iang": "ян", "ing": "ин", "iong": "юн",
	"u": "у", "ua": "уа", "uo": "о", "uai": "уай", "ui": "уй", "uan": "уань",
	"un": "унь", "uang": "уан", "ueng": "ун",
	"v": "юй", "ve": "юэ", "van": "юань", "vn": "юнь",
}

// whole zero-initial (y-/w-) syllables (palladius.Y_W).
var palladiusYW = map[string]string{
	"yi": "и", "ya": "я", "ye": "е", "yao": "яо", "you": "ю", "yan": "янь", "yin": "инь",
	"yang": "ян", "ying": "ин", "yong": "юн", "yu": "юй", "yue": "юэ", "yuan": "юань", "yun": "юнь",
	"wu": "у", "wa": "ва", "wo": "во", "wai": "вай", "wei": "вэй", "wan": "вань", "wen": "вэнь",
	"wang": "ван", "weng": "вэн",
}

// retroflex/sibilant + i → -ы/-и class (palladius.SPECIAL_I).
var palladiusSpecialI = map[string]string{
	"zhi": "чжи", "chi": "чи", "shi": "ши", "ri": "жи", "zi": "цзы", "ci": "цы", "si": "сы",
}

var palladiusJQX = map[string]bool{"j": true, "q": true, "x": true}

// palladiusCyrSyllables is the distinct Cyrillic syllable set, longest-first, for greedy segmentation
// (palladius._CYR_SYL). Ties in length never both match a position (distinct strings), so the order
// among equal-length forms is immaterial — sorted (len desc, then value) for a stable artifact.
var palladiusCyrSyllables = buildPalladiusCyrSyllables()

func buildPalladiusCyrSyllables() []string {
	set := map[string]bool{}
	for _, v := range palladiusYW {
		set[v] = true
	}
	for _, v := range palladiusSpecialI {
		set[v] = true
	}
	retroflex := map[string]bool{"zh": true, "ch": true, "sh": true, "r": true, "z": true, "c": true, "s": true}
	for pi, ci := range palladiusInitials {
		for pf, cf := range palladiusFinals {
			// ü finals (written v) are valid only after j/q/x (pinyin writes ü as plain u) or l/n.
			switch pf {
			case "v", "ve", "van", "vn":
				if !palladiusJQX[pi] && pi != "l" && pi != "n" {
					continue
				}
			}
			// skip the retroflex/sibilant + bare i (handled by SPECIAL_I).
			if pf == "i" && retroflex[pi] {
				continue
			}
			set[ci+cf] = true
		}
	}
	out := make([]string, 0, len(set))
	for s := range set {
		if s != "" {
			out = append(out, s)
		}
	}
	sort.Slice(out, func(i, j int) bool {
		if len([]rune(out[i])) != len([]rune(out[j])) {
			return len([]rune(out[i])) > len([]rune(out[j]))
		}
		return out[i] < out[j]
	})
	return out
}

// isPalladiusToken reports whether a ru word segments fully into Palladius syllables (greedy longest-
// match, palladius.is_palladius_token): a high-precision "this looks like a transliterated Chinese name"
// signal. ъ is dropped before segmentation. minSyllables is the minimum syllable count.
func isPalladiusToken(token string, minSyllables int) bool {
	t := strings.ToLower(strings.TrimSpace(token))
	t = strings.ReplaceAll(t, "ъ", "")
	if t == "" || !allCyrillic(t) {
		return false
	}
	tr := []rune(t)
	nSyl := 0
	for i := 0; i < len(tr); {
		matched := false
		for _, s := range palladiusCyrSyllables {
			sr := []rune(s)
			if i+len(sr) <= len(tr) && runesEqual(tr[i:i+len(sr)], sr) {
				i += len(sr)
				nSyl++
				matched = true
				break
			}
		}
		if !matched {
			return false
		}
	}
	return nSyl >= minSyllables
}

// allCyrillic reports whether every rune of s is Cyrillic (palladius._RE_CYR_WORD).
func allCyrillic(s string) bool {
	if s == "" {
		return false
	}
	for _, r := range s {
		if !unicode.Is(unicode.Cyrillic, r) {
			return false
		}
	}
	return true
}