package pipeline

import (
	"sort"
	"strings"
)

// miner_alias.go: alias tier-1 clustering (WS3 — a Go port of exp16 alias.py, DEFAULT-B). Precision-safe
// PROP-layer rules over a set of src surfaces:
//
//	R1 surface containment    X ⊂ Y, |X|≥2 → 'extension' edge (方源 ⊂ 古月方源), COMPOSITIONAL guard
//	                          (古月+族长 = a phrase, not an alias) blocks the clan↔title chaining
//	R2 surname anchor+compose shared surname → FAMILY supercluster (NOT identity)
//	R4 NEGATIVE hard-blocks (checked FIRST): (ii) different confirmed gender; (iii/v) different approved
//	   dst → different entities EVEN under containment (族长⊂四代族长, 古月⊂古月方源); (i) same surname +
//	   different given names → family, not identity; (iv) co-presence in one source sentence → not identity
//
// The R3 "shared ru rendering → identity" edge is OMITTED in default B (it needs the pymorphy3-backed
// dst-variant lemmas, which the ratified default drops). Precision is measured entity-level (B³, §A5).

// aliasParticle is the trailing-particle set that marks a boundary FRAGMENT (alias.PARTICLE): a candidate
// = a known surface + one of these is 方源在/方源心, not an entity.
var aliasParticle = buildRuneSet2("的了在是和就也都不心面前后上下今少多大小与之其")

// aliasSurface is one src surface with the seed metadata the rules read (alias.Surface, minus the
// default-B-dropped dst_lemmas).
type aliasSurface struct {
	src         string // normalized src surface
	gender      string
	approvedDst string
	typ         string
}

// aliasEdge is one proposed edge between two surfaces.
type aliasEdge struct {
	a, b string
	rule string
	kind string
}

// isFragment reports whether src is a known surface + a trailing particle (alias.frag): a boundary
// artifact, not an independent entity. seedSurfaces is the normalized seed src/alias set.
func isFragment(src string, seedSurfaces map[string]bool) bool {
	r := []rune(src)
	if len(r) < 2 {
		return false
	}
	return seedSurfaces[string(r[:len(r)-1])] && aliasParticle[r[len(r)-1]]
}

// cooccurSameSentence reports whether a and b appear in one source sentence anywhere (alias.
// cooccur_same_sentence: split on 。！？\n).
func cooccurSameSentence(chunks []MinerChunk, aNorm, bNorm string) bool {
	for _, c := range chunks {
		for _, sent := range splitMinerSentences(c.NSource) {
			if strings.Contains(sent, aNorm) && strings.Contains(sent, bNorm) {
				return true
			}
		}
	}
	return false
}

func splitMinerSentences(s string) []string {
	return strings.FieldsFunc(s, func(r rune) bool {
		return r == '。' || r == '！' || r == '？' || r == '\n'
	})
}

// proposeAliasEdges applies the tier-1 rules over the surfaces, returning identity, family and weak
// edges (alias.propose_edges, default B). seedSurfaces is the normalized seed src/alias set (the R1
// entity-vs-fragment guard). Deterministic: surfaces are iterated in a fixed sorted order.
func proposeAliasEdges(surfaces map[string]aliasSurface, chunks []MinerChunk, seedSurfaces map[string]bool) (ident, family, weak []aliasEdge) {
	keys := make([]string, 0, len(surfaces))
	for k := range surfaces {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for i := 0; i < len(keys); i++ {
		for j := i + 1; j < len(keys); j++ {
			a, b := surfaces[keys[i]], surfaces[keys[j]]
			// R4-ii different confirmed gender (hidden never blocks).
			if a.gender != "" && b.gender != "" && a.gender != b.gender && a.gender != "hidden" && b.gender != "hidden" {
				continue
			}
			// R4-iii/v different approved dst → different entities, even under containment.
			if a.approvedDst != "" && b.approvedDst != "" && normalizeSourceKey(a.approvedDst) != normalizeSourceKey(b.approvedDst) {
				continue
			}
			surA, surB := isSurnameStart([]rune(a.src)), isSurnameStart([]rune(b.src))
			// R1 containment → extension edge (same entity, fuller vs shorter surface).
			if runeLen(a.src) >= 2 && runeLen(b.src) >= 2 && a.src != b.src && (strings.Contains(b.src, a.src) || strings.Contains(a.src, b.src)) {
				short, long := a, b
				if runeLen(b.src) < runeLen(a.src) {
					short, long = b, a
				}
				shortIsEntity := short.typ != "" || seedSurfaces[short.src]
				rest := containmentRest(short.src, long.src)
				restEnt, restKnown := surfaces[rest]
				compositional := rest != "" && seedSurfaces[rest] &&
					(!restKnown || restEnt.typ == "title" || restEnt.typ == "place" || restEnt.typ == "term")
				switch {
				case compositional:
					weak = append(weak, aliasEdge{a.src, b.src, "R1-compositional", "phrase_not_alias"})
				case shortIsEntity:
					ident = append(ident, aliasEdge{a.src, b.src, "R1", "extension"})
				default:
					weak = append(weak, aliasEdge{a.src, b.src, "R1-fragment?", "containment_weak"})
				}
				continue
			}
			// R2 surname anchor → family (NOT identity).
			if surA != "" && surB != "" && surA == surB && a.src != b.src {
				givenA := trimRunePrefix(a.src, surA)
				givenB := trimRunePrefix(b.src, surB)
				if givenA != givenB && givenA != "" && givenB != "" { // R4-i different given names → family only
					if cooccurSameSentence(chunks, a.src, b.src) {
						family = append(family, aliasEdge{a.src, b.src, "R2+R4iv", "family_copresent"})
					} else {
						family = append(family, aliasEdge{a.src, b.src, "R2", "family"})
					}
					continue
				}
			}
			// R3 (shared ru rendering → identity) is OMITTED in default B.
		}
	}
	return ident, family, weak
}

// containmentRest is alias.py's rest = long[len(short):] if long.startswith(short) else long[:-len(short)]
// (by character). short is contained in long.
func containmentRest(short, long string) string {
	sr, lr := []rune(short), []rune(long)
	if len(sr) > len(lr) {
		return ""
	}
	if runesEqual(lr[:len(sr)], sr) {
		return string(lr[len(sr):])
	}
	return string(lr[:len(lr)-len(sr)])
}

// trimRunePrefix removes the leading prefix (a surname) from src, by character.
func trimRunePrefix(src, prefix string) string {
	sr, pr := []rune(src), []rune(prefix)
	if len(pr) <= len(sr) && runesEqual(sr[:len(pr)], pr) {
		return string(sr[len(pr):])
	}
	return src
}

// clusterAlias runs union-find over the identity edges and returns clusters of size > 1, each sorted
// (alias.cluster). allSurfaces bounds the universe.
func clusterAlias(ident []aliasEdge, allSurfaces []string) [][]string {
	parent := make(map[string]string, len(allSurfaces))
	for _, s := range allSurfaces {
		parent[s] = s
	}
	var find func(string) string
	find = func(x string) string {
		for parent[x] != x {
			parent[x] = parent[parent[x]]
			x = parent[x]
		}
		return x
	}
	for _, e := range ident {
		if _, ok := parent[e.a]; ok {
			if _, ok := parent[e.b]; ok {
				parent[find(e.a)] = find(e.b)
			}
		}
	}
	groups := map[string][]string{}
	for _, s := range allSurfaces {
		r := find(s)
		groups[r] = append(groups[r], s)
	}
	var out [][]string
	roots := make([]string, 0, len(groups))
	for r := range groups {
		roots = append(roots, r)
	}
	sort.Strings(roots)
	for _, r := range roots {
		if len(groups[r]) > 1 {
			g := append([]string(nil), groups[r]...)
			sort.Strings(g)
			out = append(out, g)
		}
	}
	return out
}