package wristband

import (
	"encoding/json"
	"errors"
	"net/http"
	"net/url"
	"testing"
)

// TestPairwiseSubjects pins D-15: the sector rules, ErrSectorRequired,
// stable random subjects per (user, sector), the same sub in the id_token
// and at userinfo, and a 500 when a pairwise client has no usable sector.
func TestPairwiseSubjects(t *testing.T) {
	for _, tc := range []struct {
		name   string
		client *OIDCClientRecord
		want   string
		err    error
	}{
		{"empty type is public", &OIDCClientRecord{RedirectURIs: []string{"https://a.example.test/cb"}}, "", nil},
		{"public", &OIDCClientRecord{SubjectType: SubjectTypePublic, SectorIdentifier: "ignored.example.test"}, "", nil},
		{"pairwise sector identifier wins and is trimmed", &OIDCClientRecord{SubjectType: SubjectTypePairwise, SectorIdentifier: "  sector.example.test\t", RedirectURIs: []string{"https://a.example.test/cb", "https://b.example.test/cb"}}, "sector.example.test", nil},
		{"pairwise single host, lowercased", &OIDCClientRecord{SubjectType: SubjectTypePairwise, RedirectURIs: []string{"https://RP.Example.test/a", "https://rp.example.test:8443/b"}}, "rp.example.test", nil},
		{"pairwise mixed hosts", &OIDCClientRecord{SubjectType: SubjectTypePairwise, RedirectURIs: []string{"https://a.example.test/cb", "https://b.example.test/cb"}}, "", ErrSectorRequired},
		{"pairwise without redirect URIs", &OIDCClientRecord{SubjectType: SubjectTypePairwise}, "", ErrSectorRequired},
		{"pairwise with a blank sector and a relative URI", &OIDCClientRecord{SubjectType: SubjectTypePairwise, SectorIdentifier: "  ", RedirectURIs: []string{"/cb"}}, "", ErrSectorRequired},
		{"pairwise with an unparsable URI", &OIDCClientRecord{SubjectType: SubjectTypePairwise, RedirectURIs: []string{"https://a.example.test/cb", "http://[::1"}}, "", ErrSectorRequired},
	} {
		got, err := SubjectSector(tc.client)
		if got != tc.want || !errors.Is(err, tc.err) || (tc.err == nil && err != nil) {
			t.Errorf("%s: SubjectSector = %q, %v; want %q, %v", tc.name, got, err, tc.want, tc.err)
		}
	}
	if _, err := SubjectSector(&OIDCClientRecord{SubjectType: "ppid"}); err == nil || errors.Is(err, ErrSectorRequired) {
		t.Fatalf("unknown subject type = %v", err)
	}
	if _, err := SubjectSector(nil); err == nil {
		t.Fatal("a nil client must be refused")
	}

	f := newOIDCFixture(t, testOIDCIssuer, nil)
	a := f.backend.addClient(OIDCClientRecord{ClientID: "oas_pw_a", Kind: ClientKindOIDC, RedirectURIs: []string{"https://a.example.test/cb"}, Scopes: []string{"openid"}, IsActive: true, SubjectType: SubjectTypePairwise}, testOIDCSecret)
	a2 := f.backend.addClient(OIDCClientRecord{ClientID: "oas_pw_a2", Kind: ClientKindOIDC, RedirectURIs: []string{"https://a.example.test/other"}, Scopes: []string{"openid"}, IsActive: true, SubjectType: SubjectTypePairwise}, testOIDCSecret)
	sector := f.backend.addClient(OIDCClientRecord{ClientID: "oas_pw_s", Kind: ClientKindOIDC, RedirectURIs: []string{"https://c.example.test/cb"}, Scopes: []string{"openid"}, IsActive: true, SubjectType: SubjectTypePairwise, SectorIdentifier: "a.example.test"}, testOIDCSecret)
	b := f.backend.addClient(OIDCClientRecord{ClientID: "oas_pw_b", Kind: ClientKindOIDC, RedirectURIs: []string{"https://b.example.test/cb"}, Scopes: []string{"openid"}, IsActive: true, SubjectType: SubjectTypePairwise}, testOIDCSecret)

	f.backend.setIdentity(8, map[string]any{"name": "Bea Example"})
	subs := func(c *OIDCClientRecord, user uint) (string, string) {
		t.Helper()
		tok := decodeToken(t, f.exchange(c, testOIDCSecret, f.obtainCode(t, c, user, "openid"), oidcTestVerifier))
		var info map[string]any
		if err := json.Unmarshal(f.userinfo(tok.AccessToken).Body.Bytes(), &info); err != nil {
			t.Fatal(err)
		}
		idSub, _ := f.parseIDToken(t, tok.IDToken)["sub"].(string)
		return idSub, info["sub"].(string)
	}
	subA, infoA := subs(a, 7)
	subA2, _ := subs(a2, 7)
	subS, _ := subs(sector, 7)
	subB, infoB := subs(b, 7)
	subPub, _ := subs(f.client, 7)
	subA8, _ := subs(a, 8)
	if subA != infoA || subB != infoB {
		t.Fatalf("userinfo sub differs from the id_token sub: %s/%s %s/%s", subA, infoA, subB, infoB)
	}
	if subA != subA2 || subA != subS {
		t.Fatalf("one sector must give one sub: %s %s %s", subA, subA2, subS)
	}
	if subA == subB || subA == subPub || subB == subPub || subA == subA8 {
		t.Fatalf("subs must differ per sector and per user: a=%s b=%s public=%s a(8)=%s", subA, subB, subPub, subA8)
	}
	for _, s := range []string{subA, subB, subPub, subA8} {
		if !uuidV4.MatchString(s) {
			t.Fatalf("sub %q is not a random UUIDv4", s)
		}
	}
	if again, _ := subs(a, 7); again != subA {
		t.Fatalf("pairwise sub changed: %s then %s", subA, again)
	}
	if f.backend.subject(7, "a.example.test") != subA || f.backend.subject(7, "") != subPub {
		t.Fatal("subjects are not stored per (user, sector)")
	}

	// A pairwise client whose redirect URIs span hosts without a sector
	// identifier fails at resume (500); an administrator must set one.
	mixed := f.backend.addClient(OIDCClientRecord{ClientID: "oas_pw_mixed", Kind: ClientKindOIDC, RedirectURIs: []string{"https://a.example.test/cb", "https://b.example.test/cb"}, Scopes: []string{"openid"}, IsActive: true, SubjectType: SubjectTypePairwise}, testOIDCSecret)
	f.host.signIn(7)
	rec := f.startAndResume(t, oidcAuthorizeParams(f, func(q url.Values) {
		q.Set("client_id", mixed.ClientID)
		q.Set("redirect_uri", mixed.RedirectURIs[0])
		q.Set("scope", "openid")
	}))
	if rec.Code != http.StatusInternalServerError || rec.Body.Len() != 0 {
		t.Fatalf("resume for a client without a sector = %d %q", rec.Code, rec.Body.String())
	}
}