package web

import (
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"testing/fstest"

	"khosra/internal/content"
	"khosra/internal/render"
)

func slugHandler(t *testing.T, fsys fstest.MapFS) http.Handler {
	t.Helper()
	bundles, err := content.Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	r, err := render.New(nil, content.Settings{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	return Handler(content.NewSite(bundles), r, fsys, nil, content.Settings{})
}

func TestASlugRenamesTheAddressInEveryLanguage(t *testing.T) {
	h := slugHandler(t, fstest.MapFS{
		"content/posts/hello-world.md":    {Data: []byte("---\ntitle: Hello\nslug: ekti-post\n---\nEnglish.\n")},
		"content/posts/hello-world.bn.md": {Data: []byte("---\ntitle: একটি পোস্ট\n---\nবাংলা।\n")},
	})
	for _, path := range []string{"/posts/ekti-post/", "/bn/posts/ekti-post/"} {
		rec := httptest.NewRecorder()
		h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, path, nil))
		if rec.Code != http.StatusOK {
			t.Errorf("GET %s = %d, want 200 — a slug renames every language (ADR-0035)", path, rec.Code)
		}
	}
	// The old path is gone: the engine serves the new one only, and an author who wants both writes an alias.
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/posts/hello-world/", nil))
	if rec.Code != http.StatusNotFound {
		t.Errorf("the derived path = %d, want 404", rec.Code)
	}
	// Canonical and hreflang must name the new address, not the key.
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/bn/posts/ekti-post/", nil))
	body := rec.Body.String()
	if !strings.Contains(body, `rel="canonical" href="/bn/posts/ekti-post/"`) {
		t.Errorf("canonical should name the served address:\n%s", body)
	}
	if strings.Contains(body, "hello-world") {
		t.Errorf("nothing the engine emits should still say hello-world:\n%s", body)
	}
}

func TestAnAliasCanKeepTheOldPathWorking(t *testing.T) {
	h := slugHandler(t, fstest.MapFS{
		"content/posts/hello-world.md": {Data: []byte("---\ntitle: Hello\nslug: ekti-post\naliases: [posts/hello-world]\n---\nx\n")},
	})
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/posts/hello-world/", nil))
	if rec.Code != http.StatusMovedPermanently {
		t.Fatalf("got %d, want 301 — this is how a rename keeps its promise (ADR-0008)", rec.Code)
	}
	if loc := rec.Header().Get("Location"); loc != "/posts/ekti-post/" {
		t.Errorf("Location = %q, want the new address", loc)
	}
}

func TestListingsAndSitemapsUseTheSluggedAddress(t *testing.T) {
	fsys := fstest.MapFS{
		"content/posts/hello-world.md": {Data: []byte("---\ntitle: Hello\ndate: 2026-03-01\nslug: ekti-post\n---\nx\n")},
		"content/posts/plain.md":       {Data: []byte("---\ntitle: Plain\ndate: 2026-02-01\n---\nx\n")},
	}
	bundles, err := content.Scan(fsys)
	if err != nil {
		t.Fatal(err)
	}
	settings := content.Settings{Base: "https://khosra.example"}
	r, err := render.New(nil, settings, nil)
	if err != nil {
		t.Fatal(err)
	}
	h := Handler(content.NewSite(bundles), r, fsys, nil, settings)

	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/posts/", nil))
	if body := rec.Body.String(); !strings.Contains(body, `href="/posts/ekti-post/"`) || strings.Contains(body, "hello-world") {
		t.Errorf("a listing must link the address, not the key:\n%s", body)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/sitemap.xml", nil))
	if body := rec.Body.String(); !strings.Contains(body, "/posts/ekti-post/") || strings.Contains(body, "hello-world") {
		t.Errorf("a sitemap that disagrees with what is served is worse than none:\n%s", body)
	}
}

func TestAmbiguousOrCollidingSlugsAreDropped(t *testing.T) {
	// Both cases keep the derived path rather than picking a winner, the same rule aliases follow.
	h := slugHandler(t, fstest.MapFS{
		// Variants disagree.
		"content/posts/a.md":    {Data: []byte("---\ntitle: A\nslug: one\n---\nx\n")},
		"content/posts/a.bn.md": {Data: []byte("---\ntitle: ক\nslug: two\n---\nx\n")},
		// Slug lands on a bundle that already exists.
		"content/posts/b.md":     {Data: []byte("---\ntitle: B\nslug: taken\n---\nx\n")},
		"content/posts/taken.md": {Data: []byte("---\ntitle: Taken\n---\nx\n")},
	})
	for path, want := range map[string]int{
		"/posts/a/":     http.StatusOK,       // kept its derived path
		"/posts/one/":   http.StatusNotFound, // neither declared slug won
		"/posts/two/":   http.StatusNotFound,
		"/posts/b/":     http.StatusOK,
		"/posts/taken/": http.StatusOK, // the bundle already there keeps its URL
	} {
		rec := httptest.NewRecorder()
		h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, path, nil))
		if rec.Code != want {
			t.Errorf("GET %s = %d, want %d", path, rec.Code, want)
		}
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/posts/taken/", nil))
	if body := rec.Body.String(); !strings.Contains(body, "<h1>Taken</h1>") {
		t.Errorf("the bundle already there must still be the one served:\n%s", body)
	}
}

func TestASeriesSurvivesItsLandingBeingSlugged(t *testing.T) {
	// The reason a slug does not touch the key: membership is the directory (ADR-0033), so renaming the
	// landing page's address must not orphan its chapters.
	h := slugHandler(t, fstest.MapFS{
		"content/comics/the-long-monsoon/_index.md":     {Data: []byte("---\ntitle: The Long Monsoon\nslug: monsoon\n---\nx\n")},
		"content/comics/the-long-monsoon/first-rain.md": {Data: []byte("---\ntitle: First Rain\norder: 10\n---\nx\n")},
		"content/comics/the-long-monsoon/the-flood.md":  {Data: []byte("---\ntitle: The Flood\norder: 20\n---\nx\n")},
	})
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/comics/monsoon/", nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("the landing page = %d, want 200 at its new address", rec.Code)
	}
	body := rec.Body.String()
	for _, want := range []string{"First Rain", "The Flood"} {
		if !strings.Contains(body, want) {
			t.Errorf("the archive lost %q — a slug must not orphan a series:\n%s", want, body)
		}
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/comics/the-long-monsoon/the-flood/", nil))
	if rec.Code != http.StatusOK {
		t.Errorf("a chapter = %d, want 200: chapters keep their own addresses", rec.Code)
	}
	if body := rec.Body.String(); !strings.Contains(body, `href="/comics/monsoon/"`) {
		t.Errorf("the chapter should link its series at the slugged address:\n%s", body)
	}
}