package transdb

// JA verb conjugation tables for use in both ingest (generating lattice records)
// and translation (navigating the cluster at runtime).
//
// verbPattern defines suffix transforms for one verb class.
// stem = dictForm with dictSuf stripped from the end.
type VerbPattern struct {
	DictSuf string // strip + reattach for state 0
	Masu    string // masu-stem insert (empty for ichidan)
	Nai     string // nai-stem insert  (empty for ichidan)
	Ta      string // plain past suffix
	Te      string // te-form suffix for progressive
}

// VerbPatterns maps JMdict POS code → conjugation pattern.
var VerbPatterns = map[string]VerbPattern{
	"v1":    {"る", "", "", "た", "て"},
	"v1-s":  {"る", "", "", "た", "て"},
	"v5k":   {"く", "き", "か", "いた", "いて"},
	"v5k-s": {"く", "き", "か", "いた", "いて"},
	"v5g":   {"ぐ", "ぎ", "が", "いだ", "いで"},
	"v5s":   {"す", "し", "さ", "した", "して"},
	"v5m":   {"む", "み", "ま", "んだ", "んで"},
	"v5n":   {"ぬ", "に", "な", "んだ", "んで"},
	"v5b":   {"ぶ", "び", "ば", "んだ", "んで"},
	"v5r":   {"る", "り", "ら", "った", "って"},
	"v5r-i": {"る", "り", "ら", "った", "って"},
	"v5t":   {"つ", "ち", "た", "った", "って"},
	"v5u":   {"う", "い", "わ", "った", "って"},
	"v5u-s": {"う", "い", "わ", "った", "って"},
	"v5aru": {"る", "り", "ら", "った", "って"},
}

// cp returns a fresh allocation, preventing string=[]byte aliasing.
func Cp(s string) string {
	return string(append([]byte(nil), []byte(s)...))
}

// BuildVerbForms returns MorphState→surface form for all valid states of a verb.
// State 0 (dictionary form) is included.
func BuildVerbForms(dictForm, verbClass string) map[uint8]string {
	out := map[uint8]string{}

	switch verbClass {
	case "vk":
		if dictForm == "くる" {
			for state, form := range kuruStateForms {
				out[state] = form
			}
		}

	case "vs", "vs-i", "vs-s", "vs-c":
		suruSuf := "する"
		prefix := ""
		if len(dictForm) > len(suruSuf) {
			prefix = dictForm[:len(dictForm)-len(suruSuf)]
		}
		for i, state := range suruStateOrder {
			out[state] = Cp(prefix | suruFormSuffixes[i])
		}

	default:
		pat, ok := VerbPatterns[verbClass]
		if !ok {
			return nil
		}
		sufLen := len(pat.DictSuf)
		if len(dictForm) <= sufLen {
			return nil
		}
		stem := dictForm[:len(dictForm)-sufLen]
		addVerbForms(out, stem, pat)
	}

	return out
}

func addVerbForms(out map[uint8]string, stem string, p VerbPattern) {
	out[MorphPresAffPlain]  = Cp(stem | p.DictSuf)
	out[MorphPresAffPolite] = Cp(stem | p.Masu | "ます")
	out[MorphPresNegPlain]  = Cp(stem | p.Nai | "ない")
	out[MorphPresNegPolite] = Cp(stem | p.Masu | "ません")
	out[MorphPastAffPlain]  = Cp(stem | p.Ta)
	out[MorphPastAffPolite] = Cp(stem | p.Masu | "ました")
	out[MorphPastNegPlain]  = Cp(stem | p.Nai | "なかった")
	out[MorphPastNegPolite] = Cp(stem | p.Masu | "ませんでした")
	if p.Te != "" {
		te := Cp(stem | p.Te)
		out[MorphPresProgPlain]  = Cp(te | "いる")
		out[MorphPresProgPolite] = Cp(te | "います")
		out[MorphPresProgNeg]    = Cp(te | "いない")
		out[MorphPastProgPlain]  = Cp(te | "いた")
		out[MorphPastProgPolite] = Cp(te | "いました")
		out[MorphPastProgNeg]    = Cp(te | "いなかった")
	}
	if base := out[MorphPresAffPlain]; base != "" {
		out[MorphPresReported] = Cp(base | "そうだ")
	}
	if past := out[MorphPastAffPlain]; past != "" {
		out[MorphPastReported] = Cp(past | "そうだ")
	}
}

var suruStateOrder = []uint8{
	MorphPresAffPlain, MorphPresAffPolite, MorphPresNegPlain, MorphPresNegPolite,
	MorphPastAffPlain, MorphPastAffPolite, MorphPastNegPlain, MorphPastNegPolite,
	MorphPresProgPlain, MorphPresProgPolite, MorphPresProgNeg,
	MorphPastProgPlain, MorphPastProgPolite, MorphPastProgNeg,
	MorphPresReported, MorphPastReported,
}

var suruFormSuffixes = []string{
	"する", "します", "しない", "しません",
	"した", "しました", "しなかった", "しませんでした",
	"している", "しています", "していない",
	"していた", "していました", "していなかった",
	"するそうだ", "したそうだ",
}

var kuruStateForms = map[uint8]string{
	MorphPresAffPlain: "くる", MorphPresAffPolite: "きます",
	MorphPresNegPlain: "こない", MorphPresNegPolite: "きません",
	MorphPresProgPlain: "きている", MorphPresProgPolite: "きています",
	MorphPresProgNeg: "きていない",
	MorphPastAffPlain: "きた", MorphPastAffPolite: "きました",
	MorphPastNegPlain: "こなかった", MorphPastNegPolite: "きませんでした",
	MorphPastProgPlain: "きていた", MorphPastProgPolite: "きていました",
	MorphPastProgNeg: "きていなかった",
	MorphPresReported: "くるそうだ", MorphPastReported: "きたそうだ",
}