package pipeline

import (
	"strings"
	"testing"

	"textmachine/backend/internal/membank"
	"textmachine/backend/internal/store"
)

// TestMinedDeltaSeedCollisions covers both paths of the D39.20 deviation-#1 crash guard: a mined-delta
// term whose UNIQUE key (src, sense, since_ch, until_ch) already exists in the seed must be reported
// (would crash ReplaceGlossary), while a disjoint delta reports nothing. It also asserts a SAME-dst
// duplicate is caught (membank.ApprovedSharedKeyCollisions skips it, so this guard is the one that must fire).
func TestMinedDeltaSeedCollisions(t *testing.T) {
	seed := []store.GlossaryEntry{
		{Src: "元", Dst: "первооснова", Sense: "корень", Status: "approved"},
		{Src: "赤城", Dst: "Чичэн", Status: "approved"},
	}

	// Path A — a mined-delta term duplicating the seed's UNIQUE key (different dst) → loud.
	minedDiff := []store.GlossaryEntry{{Src: "元", Dst: "юань", Sense: "корень", Status: "approved", Source: "mined"}}
	if dups := membank.MinedDeltaSeedCollisions(seed, minedDiff); len(dups) != 1 {
		t.Fatalf("different-dst duplicate: want 1 collision, got %d (%v)", len(dups), dups)
	} else if !strings.Contains(dups[0], "元") {
		t.Fatalf("collision message should name the duplicated src: %q", dups[0])
	}

	// Path A' — a SAME-dst duplicate (membank.ApprovedSharedKeyCollisions skips these; this guard must still fire,
	// since the UNIQUE INSERT crashes regardless of dst).
	minedSame := []store.GlossaryEntry{{Src: "元", Dst: "первооснова", Sense: "корень", Status: "approved", Source: "mined"}}
	if dups := membank.MinedDeltaSeedCollisions(seed, minedSame); len(dups) != 1 {
		t.Fatalf("same-dst duplicate: want 1 collision (the INSERT crashes regardless of dst), got %d", len(dups))
	}

	// Path B — a disjoint delta (a genuinely new term, or the same src in a DIFFERENT spoiler window) →
	// nothing to report; the append is safe.
	minedOK := []store.GlossaryEntry{
		{Src: "春秋蝉", Dst: "Весенне-осенняя цикада", Status: "approved", Source: "mined"},
		{Src: "元", Dst: "юань (валюта)", Sense: "деньги", Status: "approved", Source: "mined"}, // different sense → different UNIQUE key
	}
	if dups := membank.MinedDeltaSeedCollisions(seed, minedOK); len(dups) != 0 {
		t.Fatalf("disjoint delta: want 0 collisions, got %d (%v)", len(dups), dups)
	}
}