// Tests for feed-identity token and scoring-text construction.
package core

import (
	"strings"
	"testing"
)

func TestFeedSlug(t *testing.T) {
	cases := []struct{ in, want string }{
		{"Marginal Revolution", "marginal-revolution"},
		{"ACM / IEEE", "acm-ieee"},
		{"  Already-Hyphenated  ", "already-hyphenated"},
		{"---", ""},
		{"", ""},
		{"MIT Tech Review #2", "mit-tech-review-2"},
		{"Über Wörter", "ber-w-rter"}, // non-ascii stripped to hyphens
	}
	for _, c := range cases {
		if got := FeedSlug(c.in); got != c.want {
			t.Errorf("FeedSlug(%q) = %q, want %q", c.in, got, c.want)
		}
	}
}

func TestFeedSlugIdempotent(t *testing.T) {
	for _, in := range []string{"Marginal Revolution", "ACM / IEEE", "X---Y", "a b c"} {
		once := FeedSlug(in)
		twice := FeedSlug(once)
		if once != twice {
			t.Errorf("slug not idempotent: %q → %q → %q", in, once, twice)
		}
	}
}

func TestScoringTextIncludesToken(t *testing.T) {
	got := ScoringText("A Title", "Marginal Revolution")
	if !strings.HasSuffix(got, " feed-marginal-revolution") {
		t.Errorf("expected feed-identity token suffix, got %q", got)
	}
}

func TestScoringTextEmptyFeedOmitsToken(t *testing.T) {
	if got := ScoringText("A Title", ""); got != "A Title" {
		t.Errorf("empty feed should yield title only, got %q", got)
	}
	if got := ScoringText("A Title", "   ---   "); got != "A Title" {
		t.Errorf("whitespace-only feed should yield title only, got %q", got)
	}
}

// The feed-identity token must round-trip through Tokenize as a SINGLE token
// (hyphens survive; underscores would fragment). Same feed → shared token;
// different feeds → different tokens.
func TestFeedTokenRoundTripsAsSingleToken(t *testing.T) {
	doc := ScoringText("some title here", "Marginal Revolution")
	toks := Tokenize(doc)
	found := false
	for _, tk := range toks {
		if tk == "feed-marginal-revolution" {
			found = true
			break
		}
	}
	if !found {
		t.Fatalf("feed token not present as a single token in %v", toks)
	}
	// And it must not have fragmented into feed/marginal/revolution.
	for _, bad := range []string{"feed", "marginal", "revolution"} {
		for _, tk := range toks {
			if tk == bad {
				t.Errorf("token fragmented: %q appeared standalone", bad)
			}
		}
	}

	// Same feed → shared token; different feed → different token.
	a := ScoringText("x", "Marginal Revolution")
	b := ScoringText("y", "Marginal Revolution")
	c := ScoringText("z", "Other Blog")
	tokA, tokC := feedToken(t, a), feedToken(t, c)
	if feedToken(t, b) != tokA {
		t.Error("same feed should share the token")
	}
	if tokA == tokC {
		t.Error("different feeds should differ")
	}
}

func feedToken(t *testing.T, doc string) string {
	t.Helper()
	for _, tk := range Tokenize(doc) {
		if strings.HasPrefix(tk, "feed-") {
			return tk
		}
	}
	t.Fatalf("no feed token in %q", doc)
	return ""
}