package token

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"slices"
	"sort"
	"strings"
	"testing"
	"time"

	"atcr.io/pkg/auth"
)

// accessNames returns the repository names in the token, sorted, so an
// assertion does not depend on parameter ordering.
func accessNames(access []auth.AccessEntry) []string {
	names := make([]string, 0, len(access))
	for _, entry := range access {
		names = append(names, entry.Name)
	}
	sort.Strings(names)
	return names
}

// scopeTestHandler wires an issuer, a device store and a device secret together
// so each test drives a real authenticated request.
func scopeTestHandler(t *testing.T) (*Handler, string) {
	t.Helper()
	issuer, err := NewIssuer(getSharedTestKey(t), "atcr.io", "registry", 5*time.Minute)
	if err != nil {
		t.Fatalf("NewIssuer() error = %v", err)
	}
	deviceStore, database := setupTestDeviceStore(t)
	secret := createTestDevice(t, deviceStore, database, "did:plc:alice123", "alice.bsky.social")
	return NewHandler(issuer, deviceStore), secret
}

// getAccess runs the GET form with a pre-built raw query and returns the access
// list from the issued JWT.
func getAccess(t *testing.T, rawQuery string) []auth.AccessEntry {
	t.Helper()
	h, secret := scopeTestHandler(t)
	req := httptest.NewRequest(http.MethodGet, "/auth/token?"+rawQuery, nil)
	req.SetBasicAuth("alice", secret)
	w := httptest.NewRecorder()
	h.ServeHTTP(w, req)
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d. Body: %s", w.Code, w.Body.String())
	}
	return ExtractAccess(decodeToken(t, w))
}

// The defect: the handler read only the first ?scope= value, so a client asking
// for two repositories was issued a token covering one and got a 401 on the
// other. The Docker token spec allows the parameter to repeat, and clients use
// it. This test fails before the fix with exactly one entry.
func TestHandler_Scope_RepeatedParamsYieldAllEntries(t *testing.T) {
	access := getAccess(t,
		"service=registry"+
			"&scope=repository:alice.bsky.social/first:pull"+
			"&scope=repository:alice.bsky.social/second:pull")

	want := []string{"alice.bsky.social/first", "alice.bsky.social/second"}
	if got := accessNames(access); !slices.Equal(got, want) {
		t.Fatalf("repeated scope params dropped entries: got %v, want %v (full access %+v)", got, want, access)
	}
	for _, entry := range access {
		if !slices.Equal(entry.Actions, []string{"pull"}) {
			t.Errorf("entry %q: expected actions [pull], got %v", entry.Name, entry.Actions)
		}
	}
}

// Both forms in one request: a repeated parameter where one of the values is
// itself space-separated. Flattening has to happen in both dimensions.
func TestHandler_Scope_MixedRepeatedAndSpaceSeparated(t *testing.T) {
	access := getAccess(t,
		"service=registry"+
			"&scope="+url.QueryEscape("repository:alice.bsky.social/first:pull repository:alice.bsky.social/second:pull")+
			"&scope=repository:alice.bsky.social/third:pull")

	want := []string{"alice.bsky.social/first", "alice.bsky.social/second", "alice.bsky.social/third"}
	if got := accessNames(access); !slices.Equal(got, want) {
		t.Fatalf("mixed scope forms lost entries: got %v, want %v", got, want)
	}
}

// Regression guard: the space-separated form is what works today and must keep
// working byte for byte.
func TestHandler_Scope_SingleSpaceSeparatedValueStillWorks(t *testing.T) {
	access := getAccess(t,
		"service=registry"+
			"&scope="+url.QueryEscape("repository:alice.bsky.social/first:pull,push repository:alice.bsky.social/second:pull"))

	want := []string{"alice.bsky.social/first", "alice.bsky.social/second"}
	if got := accessNames(access); !slices.Equal(got, want) {
		t.Fatalf("space-separated scope regressed: got %v, want %v", got, want)
	}
	for _, entry := range access {
		if entry.Name == "alice.bsky.social/first" && !slices.Equal(entry.Actions, []string{"pull", "push"}) {
			t.Errorf("expected actions [pull push] to survive, got %v", entry.Actions)
		}
	}
}

// An empty scope value must contribute nothing: ParseScope would reject a bare
// "" as a malformed scope if it ever reached it, and a bogus entry in the token
// is worse than none.
func TestHandler_Scope_EmptyValuesAreIgnored(t *testing.T) {
	access := getAccess(t, "service=registry&scope=&scope=&scope="+url.QueryEscape("   "))
	if len(access) != 0 {
		t.Fatalf("expected empty scope params to yield no access entries, got %+v", access)
	}

	// An empty value alongside a real one must not disturb the real one.
	access = getAccess(t, "service=registry&scope=&scope=repository:alice.bsky.social/first:pull")
	if got := accessNames(access); !slices.Equal(got, []string{"alice.bsky.social/first"}) {
		t.Fatalf("an empty scope param disturbed the real one: got %v", got)
	}
}

// The same scope string twice cannot mean more than once, so it collapses.
// Duplicates are dropped rather than merged: merging entries that name one
// repository with different action sets would union them, and nothing on this
// path is allowed to widen.
func TestHandler_Scope_ExactDuplicatesCollapse(t *testing.T) {
	access := getAccess(t,
		"service=registry"+
			"&scope=repository:alice.bsky.social/first:pull"+
			"&scope=repository:alice.bsky.social/first:pull")

	if len(access) != 1 {
		t.Fatalf("expected the duplicate scope to collapse to one entry, got %+v", access)
	}
	if !slices.Equal(access[0].Actions, []string{"pull"}) {
		t.Errorf("a duplicate must not widen the actions, got %v", access[0].Actions)
	}
}

// The POST form (the OAuth2 token spec containerd and Docker try first) reads
// its scope from the form body, and r.PostFormValue has the same first-value
// trap as r.URL.Query().Get.
func TestHandler_Scope_PostFormRepeatedValues(t *testing.T) {
	h, secret := scopeTestHandler(t)

	form := url.Values{}
	form.Set("grant_type", "password")
	form.Set("username", "alice")
	form.Set("password", secret)
	form.Set("service", "registry")
	form["scope"] = []string{
		"repository:alice.bsky.social/first:pull",
		"repository:alice.bsky.social/second:pull repository:alice.bsky.social/third:pull",
		"",
	}

	req := httptest.NewRequest(http.MethodPost, "/auth/token", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	w := httptest.NewRecorder()
	h.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200 on the POST form, got %d. Body: %s", w.Code, w.Body.String())
	}
	want := []string{"alice.bsky.social/first", "alice.bsky.social/second", "alice.bsky.social/third"}
	if got := accessNames(ExtractAccess(decodeToken(t, w))); !slices.Equal(got, want) {
		t.Fatalf("POST form dropped scope entries: got %v, want %v", got, want)
	}
}

// More entries now reach the anonymous gate, which is the point: the gate has
// to keep deciding per entry. Public survives, private is dropped.
func TestHandler_Scope_RepeatedParamsAnonymousGateStillNarrows(t *testing.T) {
	gate := &stubAnonymousAuthorizer{public: []string{"alice.test/public-app"}}
	h := newGateTestHandler(t, gate)

	w := anonymousGet(t, h,
		"service=registry"+
			"&scope=repository:alice.test/public-app:pull"+
			"&scope=repository:bob.test/private-app:pull,push")
	if w.Code != http.StatusOK {
		t.Fatalf("expected 200 when one repeated entry is public, got %d. Body: %s", w.Code, w.Body.String())
	}

	access := ExtractAccess(decodeToken(t, w))
	if got := accessNames(access); !slices.Equal(got, []string{"alice.test/public-app"}) {
		t.Fatalf("expected only the public entry to survive, got %v", got)
	}
	if !slices.Equal(access[0].Actions, []string{"pull"}) {
		t.Errorf("anonymous token must carry pull and nothing else, got %v", access[0].Actions)
	}
	// Both entries have to reach the gate now, not just the first one.
	if len(gate.saw) != 2 {
		t.Errorf("expected the gate to see both repeated entries, saw %+v", gate.saw)
	}
}

// Nothing grantable across every repeated entry must still challenge rather
// than mint a token the registry would refuse.
func TestHandler_Scope_RepeatedParamsAllPrivateStillChallenges(t *testing.T) {
	gate := &stubAnonymousAuthorizer{} // nothing is public
	h := newGateTestHandler(t, gate)

	w := anonymousGet(t, h,
		"service=registry"+
			"&scope=repository:alice.test/private-one:pull"+
			"&scope=repository:bob.test/private-two:pull")
	if w.Code != http.StatusUnauthorized {
		t.Fatalf("expected 401 when no repeated entry is grantable, got %d. Body: %s", w.Code, w.Body.String())
	}
	if w.Header().Get("WWW-Authenticate") == "" {
		t.Error("expected a WWW-Authenticate challenge so docker prompts for credentials")
	}
	if strings.Contains(w.Body.String(), `"token"`) {
		t.Errorf("expected no token in the challenge body, got %q", w.Body.String())
	}
}