package auth

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/go-chi/chi/v5"
	"github.com/google/uuid"
)

// newWebTicketHandler wires a Handler with BOTH the public routes (via
// RegisterRoutes) and the auth-required /auth/web-ticket route, mirroring how
// main.go mounts them in two separate groups (public vs RequireAuth).
func newWebTicketHandler(t *testing.T, cfg ServiceConfig) (*Service, http.Handler) {
	t.Helper()
	svc, _, _ := newService(t, cfg)
	h := NewHandler(svc)
	r := chi.NewRouter()
	h.RegisterRoutes(r) // public: includes /auth/web-ticket/exchange
	r.Group(func(protected chi.Router) {
		protected.Use(RequireAuth(svc.tokens))
		protected.Post("/auth/web-ticket", h.WebTicket)
	})
	return svc, r
}

// issueAccessToken mints a real, valid access token for a fresh user id/uuid
// pair — bypassing full register/login, since the ticket flow only cares that
// RequireAuth's middleware injects a valid uid/uuid into the request context.
func issueAccessToken(t *testing.T, svc *Service) (accessToken string, userID int64, userUUID string) {
	t.Helper()
	userID = 42
	userUUID = uuid.NewString()
	pair, _, err := svc.tokens.IssueWithJTI(context.Background(), userID, userUUID)
	if err != nil {
		t.Fatalf("issue access token: %v", err)
	}
	return pair.AccessToken, userID, userUUID
}

func doAuthed(t *testing.T, h http.Handler, method, path, token string, body interface{}) *httptest.ResponseRecorder {
	t.Helper()
	var buf bytes.Buffer
	if body != nil {
		_ = json.NewEncoder(&buf).Encode(body)
	}
	req := httptest.NewRequest(method, path, &buf)
	req.RemoteAddr = "203.0.113.5:1234"
	if token != "" {
		req.Header.Set("Authorization", "Bearer "+token)
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	return rec
}

// TestWebTicket_IssueAndExchange covers the full happy path: an authed app
// mints a ticket, the (unauthenticated) web side exchanges it for a token
// pair shaped exactly like a normal /auth/login response.
func TestWebTicket_IssueAndExchange(t *testing.T) {
	svc, h := newWebTicketHandler(t, ServiceConfig{})
	token, wantUID, wantUUID := issueAccessToken(t, svc)

	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket", token, nil)
	if rec.Code != http.StatusOK {
		t.Fatalf("issue status = %d, body %s", rec.Code, rec.Body)
	}
	var issued webTicketResponse
	if err := json.Unmarshal(rec.Body.Bytes(), &issued); err != nil {
		t.Fatalf("decode issue response: %v", err)
	}
	if issued.Ticket == "" {
		t.Fatal("empty ticket")
	}
	if issued.ExpiresIn != 60 {
		t.Fatalf("expires_in = %d, want 60", issued.ExpiresIn)
	}

	rec = doAuthed(t, h, http.MethodPost, "/auth/web-ticket/exchange", "",
		map[string]any{"ticket": issued.Ticket, "device": map[string]string{"platform": "web"}})
	if rec.Code != http.StatusOK {
		t.Fatalf("exchange status = %d, body %s", rec.Code, rec.Body)
	}
	var pair tokenPairResponse
	if err := json.Unmarshal(rec.Body.Bytes(), &pair); err != nil {
		t.Fatalf("decode exchange response: %v", err)
	}
	if pair.AccessToken == "" || pair.RefreshToken == "" || pair.ExpiresIn != 900 {
		t.Fatalf("bad token pair: %+v", pair)
	}

	// The exchanged access token must authenticate as the SAME user the app
	// ticket was issued for.
	claims, err := svc.tokens.ParseAccess(pair.AccessToken)
	if err != nil {
		t.Fatalf("parse exchanged access token: %v", err)
	}
	if claims.UID != wantUID || claims.Subject != wantUUID {
		t.Fatalf("exchanged token identifies uid=%d uuid=%s, want uid=%d uuid=%s",
			claims.UID, claims.Subject, wantUID, wantUUID)
	}
}

// TestWebTicket_SingleUse_ReplayRejected: a second exchange of the same
// ticket (replay) must fail 401, even though the first succeeded.
func TestWebTicket_SingleUse_ReplayRejected(t *testing.T) {
	svc, h := newWebTicketHandler(t, ServiceConfig{})
	token, _, _ := issueAccessToken(t, svc)

	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket", token, nil)
	var issued webTicketResponse
	_ = json.Unmarshal(rec.Body.Bytes(), &issued)

	rec = doAuthed(t, h, http.MethodPost, "/auth/web-ticket/exchange", "",
		map[string]any{"ticket": issued.Ticket})
	if rec.Code != http.StatusOK {
		t.Fatalf("first exchange should succeed, got %d: %s", rec.Code, rec.Body)
	}

	rec = doAuthed(t, h, http.MethodPost, "/auth/web-ticket/exchange", "",
		map[string]any{"ticket": issued.Ticket})
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("replayed exchange status = %d, want 401 (body %s)", rec.Code, rec.Body)
	}
}

// TestWebTicket_Expired_Rejected simulates TTL expiry the same way the rest of
// this package does (service_test.go TestService_CodeExpired): delete the
// Redis key directly rather than fast-forwarding a clock.
func TestWebTicket_Expired_Rejected(t *testing.T) {
	svc, h := newWebTicketHandler(t, ServiceConfig{})
	token, _, _ := issueAccessToken(t, svc)

	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket", token, nil)
	var issued webTicketResponse
	_ = json.Unmarshal(rec.Body.Bytes(), &issued)

	svc.rdb.Del(context.Background(), webTicketKey(issued.Ticket))

	rec = doAuthed(t, h, http.MethodPost, "/auth/web-ticket/exchange", "",
		map[string]any{"ticket": issued.Ticket})
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("expired ticket exchange status = %d, want 401 (body %s)", rec.Code, rec.Body)
	}
}

// TestWebTicket_Bogus_Rejected: a made-up ticket that was never issued.
func TestWebTicket_Bogus_Rejected(t *testing.T) {
	_, h := newWebTicketHandler(t, ServiceConfig{})
	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket/exchange", "",
		map[string]any{"ticket": "not-a-real-ticket"})
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("bogus ticket exchange status = %d, want 401 (body %s)", rec.Code, rec.Body)
	}
}

// TestWebTicket_RequiresAuth: minting a ticket without a bearer token is
// rejected by RequireAuth before it ever reaches the handler.
func TestWebTicket_RequiresAuth(t *testing.T) {
	_, h := newWebTicketHandler(t, ServiceConfig{})
	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket", "", nil)
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("unauthenticated issue status = %d, want 401", rec.Code)
	}
}

// TestWebTicket_RateLimited: a second ticket request within the same second
// for the same user is rejected 429 (rebuff-abuse backstop; the endpoint
// already requires login).
func TestWebTicket_RateLimited(t *testing.T) {
	svc, h := newWebTicketHandler(t, ServiceConfig{})
	token, _, _ := issueAccessToken(t, svc)

	rec := doAuthed(t, h, http.MethodPost, "/auth/web-ticket", token, nil)
	if rec.Code != http.StatusOK {
		t.Fatalf("first issue status = %d, body %s", rec.Code, rec.Body)
	}
	rec = doAuthed(t, h, http.MethodPost, "/auth/web-ticket", token, nil)
	if rec.Code != http.StatusTooManyRequests {
		t.Fatalf("second issue status = %d, want 429 (body %s)", rec.Code, rec.Body)
	}
}