package content

import (
	"testing"
	"testing/fstest"
)

func TestSiteLookupFindsDefaultVariant(t *testing.T) {
	fsys := fstest.MapFS{
		"content/pages/about.md":    {Data: []byte("---\ntitle: About\n---\nhi\n")},
		"content/pages/about.bn.md": {Data: []byte("---\ntitle: পরিচিতি\n---\nহাই\n")},
	}
	bundles, err := Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	site := NewSite(bundles)
	if site.Len() != 2 {
		t.Fatalf("indexed %d bundles, want 2", site.Len())
	}
	b, served, ok := site.Lookup("pages/about", "en")
	if !ok || b.Title != "About" || served != "en" {
		t.Fatalf("Lookup gave %+v %q %v, want the English variant", b, served, ok)
	}
	if _, _, ok := site.Lookup("pages/missing", "en"); ok {
		t.Error("Lookup invented a bundle")
	}
}

func TestLookupFallsBackThroughLanguages(t *testing.T) {
	fsys := fstest.MapFS{
		"content/pages/about.md":    {Data: []byte("---\ntitle: About\n---\n")},
		"content/pages/about.bn.md": {Data: []byte("---\ntitle: পরিচিতি\n---\n")},
		"content/posts/only.bn.md":  {Data: []byte("---\ntitle: শুধু\n---\n")},
		"content/posts/plain.md":    {Data: []byte("---\ntitle: Plain\n---\n")},
	}
	bundles, err := Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	site := NewSite(bundles)
	cases := []struct{ key, want, served string }{
		{"pages/about", "পরিচিতি", "bn"}, // the requested language exists
		{"posts/plain", "Plain", "en"},   // falls back to the default
		{"posts/only", "শুধু", "bn"},     // no default either: any variant beats a 404
	}
	for _, c := range cases {
		b, served, ok := site.Lookup(c.key, "bn")
		if !ok || b.Title != c.want || served != c.served {
			t.Errorf("Lookup(%q, bn) = %q/%q ok=%v, want %q/%q", c.key, b.Title, served, ok, c.want, c.served)
		}
	}
	if got := site.Variants("pages/about"); len(got) != 2 || got[0] != "bn" || got[1] != "en" {
		t.Errorf("Variants = %v, want [bn en]", got)
	}
	if !site.HasLang("bn") || site.HasLang("fr") {
		t.Error("HasLang misreported")
	}
}

func TestURLPrefixesOnlyNonDefaultLanguages(t *testing.T) {
	cases := map[string]string{"en": "/pages/about/", "": "/pages/about/", "bn": "/bn/pages/about/"}
	for lang, want := range cases {
		if got := URL("pages/about", lang); got != want {
			t.Errorf("URL(pages/about, %q) = %q, want %q", lang, got, want)
		}
	}
}

func TestAliasesAreParsedAndIndexed(t *testing.T) {
	fsys := fstest.MapFS{
		"content/posts/new-name.md": {Data: []byte("---\ntitle: New\naliases: [/posts/old-name/, posts/older]\n---\n")},
		"content/pages/single.md":   {Data: []byte("---\ntitle: Single\naliases: pages/one\n---\n")},
	}
	bundles, err := Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	site := NewSite(bundles)
	for alias, want := range map[string]string{
		"posts/old-name": "posts/new-name",
		"posts/older":    "posts/new-name",
		"pages/one":      "pages/single",
	} {
		got, ok := site.Alias(alias)
		if !ok || got != want {
			t.Errorf("Alias(%q) = %q %v, want %q", alias, got, ok, want)
		}
	}
	for _, b := range bundles {
		if _, leaked := b.Extra["aliases"]; leaked {
			t.Error("aliases should be lifted out of Extra, not duplicated")
		}
	}
}

func TestAmbiguousAliasesAreDropped(t *testing.T) {
	fsys := fstest.MapFS{
		"content/pages/real.md": {Data: []byte("---\ntitle: Real\n---\n")},
		"content/pages/a.md":    {Data: []byte("---\ntitle: A\naliases: [pages/real, pages/shared]\n---\n")},
		"content/pages/b.md":    {Data: []byte("---\ntitle: B\naliases: [pages/shared]\n---\n")},
	}
	site := NewSite(mustScan(t, fsys))
	if _, ok := site.Alias("pages/real"); ok {
		t.Error("an alias naming a real bundle must be dropped, not shadow it")
	}
	if _, ok := site.Alias("pages/shared"); ok {
		t.Error("an alias claimed by two bundles must be dropped, not picked arbitrarily")
	}
	if _, _, ok := site.Lookup("pages/real", "en"); !ok {
		t.Error("the real bundle must keep its URL")
	}
}

func mustScan(t *testing.T, fsys fstest.MapFS) []Bundle {
	t.Helper()
	b, err := Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	return b
}

// seriesFS is a series joined structurally: the landing bundle plus four chapters nested under it, two
// carrying order and two not, and one outsider that must never join.
func seriesFS() fstest.MapFS {
	return fstest.MapFS{
		"content/comics/the-long-monsoon/_index.md":        {Data: []byte("---\ntitle: The Long Monsoon\n---\n")},
		"content/comics/the-long-monsoon/first-rain.md":    {Data: []byte("---\ntitle: First Rain\norder: 10\n---\n")},
		"content/comics/the-long-monsoon/the-flood.md":     {Data: []byte("---\ntitle: The Flood\norder: 20\n---\n")},
		"content/comics/the-long-monsoon/appendix-a.md":    {Data: []byte("---\ntitle: Appendix A\n---\n")},
		"content/comics/the-long-monsoon/appendix-b.bn.md": {Data: []byte("---\ntitle: পরিশিষ্ট খ\n---\n")},
		"content/comics/the-long-monsoon/appendix-b.md":    {Data: []byte("---\ntitle: Appendix B\n---\n")},
		"content/comics/elsewhere.md":                      {Data: []byte("---\ntitle: Elsewhere\n---\n")},
	}
}

func TestSequenceMembershipIsStructural(t *testing.T) {
	site := NewSite(mustScan(t, seriesFS()))
	seq, ok := site.Sequence("comics/the-long-monsoon/the-flood", "en")
	if !ok {
		t.Fatal("a bundle nested under a landing bundle is a member (ADR-0033)")
	}
	if seq.Series.Title != "The Long Monsoon" {
		t.Errorf("series = %q, want the enclosing landing bundle", seq.Series.Title)
	}
	var titles []string
	for _, m := range seq.Members {
		titles = append(titles, m.Title)
	}
	want := []string{"First Rain", "The Flood", "Appendix A", "Appendix B"}
	if len(titles) != len(want) {
		t.Fatalf("members = %v, want %v", titles, want)
	}
	for i := range want {
		if titles[i] != want[i] {
			t.Fatalf("members = %v, want %v — ordered first, then by name", titles, want)
		}
	}
	if seq.Index != 2 {
		t.Errorf("index = %d, want 2", seq.Index)
	}
	if _, ok := site.Sequence("comics/elsewhere", "en"); ok {
		t.Error("a bundle beside the series is not in it")
	}
}

func TestSequenceOnTheLandingPageListsItsMembers(t *testing.T) {
	site := NewSite(mustScan(t, seriesFS()))
	seq, ok := site.Sequence("comics/the-long-monsoon", "en")
	if !ok {
		t.Fatal("a bundle with bundles nested under it is a series landing page")
	}
	if seq.Index != 0 {
		t.Errorf("index = %d, want 0: the landing page holds no position in its own series", seq.Index)
	}
	if len(seq.Members) != 4 {
		t.Errorf("members = %d, want 4", len(seq.Members))
	}
}

func TestSequenceMembersFollowTheLanguageFallback(t *testing.T) {
	site := NewSite(mustScan(t, seriesFS()))
	seq, ok := site.Sequence("comics/the-long-monsoon/the-flood", "bn")
	if !ok {
		t.Fatal("the series must resolve in every language")
	}
	if len(seq.Members) != 4 {
		t.Fatalf("members = %d, want 4: a chapter missing in Bengali still holds its place", len(seq.Members))
	}
	if got := seq.Members[3].Title; got != "পরিশিষ্ট খ" {
		t.Errorf("last member = %q, want the Bengali variant where one exists", got)
	}
	if got := seq.Members[1].Title; got != "The Flood" {
		t.Errorf("member without a Bengali variant = %q, want the English fallback", got)
	}
}

func TestNestedSeriesReportsItsOwnMembers(t *testing.T) {
	fsys := seriesFS()
	fsys["content/comics/_index.md"] = &fstest.MapFile{Data: []byte("---\ntitle: Comics\n---\n")}
	site := NewSite(mustScan(t, fsys))
	seq, ok := site.Sequence("comics/the-long-monsoon", "en")
	if !ok {
		t.Fatal("still a series")
	}
	if len(seq.Members) != 4 || seq.Series.Title != "The Long Monsoon" {
		t.Errorf("a landing page inside another series reports its own members, got %d under %q",
			len(seq.Members), seq.Series.Title)
	}
	// The outsider's nearest bundle ancestor is now the section landing, so it joins that sequence.
	seq, ok = site.Sequence("comics/elsewhere", "en")
	if !ok || seq.Series.Title != "Comics" {
		t.Errorf("nearest ancestor should win, got %q ok=%v", seq.Series.Title, ok)
	}
}

func TestQueryFiltersByTagAndSection(t *testing.T) {
	fsys := fstest.MapFS{
		"content/posts/a.md":   {Data: []byte("---\ntitle: A\ndate: 2026-01-03\ntags: [Monsoon, prose]\n---\n")},
		"content/posts/b.md":   {Data: []byte("---\ntitle: B\ndate: 2026-01-02\ntags: [prose]\n---\n")},
		"content/comics/c.md":  {Data: []byte("---\ntitle: C\ndate: 2026-01-01\ntags: [monsoon]\n---\n")},
		"content/writing/d.md": {Data: []byte("---\ntitle: D\n---\n")},
	}
	site := NewSite(mustScan(t, fsys))
	got := func(q Query) []string {
		var titles []string
		for _, b := range site.Run(q) {
			titles = append(titles, b.Title)
		}
		return titles
	}
	if titles := got(Query{Tag: "monsoon", Lang: "en"}); len(titles) != 2 || titles[0] != "A" || titles[1] != "C" {
		t.Errorf("global tag query = %v, want [A C] — a tag spans sections and case does not matter", titles)
	}
	if titles := got(Query{Section: "posts", Tag: "monsoon", Lang: "en"}); len(titles) != 1 || titles[0] != "A" {
		t.Errorf("section-narrowed tag query = %v, want [A]", titles)
	}
	if titles := got(Query{Tag: "nothing", Lang: "en"}); titles != nil {
		t.Errorf("unknown tag = %v, want none", titles)
	}
}