package api

import (
	"encoding/json"
	"errors"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"testing"

	"git.dcrubro.com/dcrubro/hammy-backend/internal/apikey"
	"git.dcrubro.com/dcrubro/hammy-backend/internal/ratelimit"
)

func testRouter(t *testing.T, ready func() error) http.Handler {
	t.Helper()

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	rt := &Router{
		Auth: &Authenticator{
			Keys:    &fakeStore{rec: activeRecord()},
			Limiter: ratelimit.NewMemory(),
			Logger:  logger,
		},
		Logger:  logger,
		Version: "test",
		Ready:   ready,
	}

	return rt.Handler()
}

func TestHealthzNeedsNoKey(t *testing.T) {
	h := testRouter(t, nil)

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/healthz", nil))

	if w.Code != http.StatusOK {
		t.Fatalf("status %d, want 200", w.Code)
	}

	if id := w.Header().Get("X-Request-Id"); id == "" {
		t.Error("no X-Request-Id on the response")
	}
}

// Liveness must not depend on Postgres. If it did, a database blip would get
// the process killed by its supervisor and turn a wobble into an outage.
func TestHealthzIgnoresDependencies(t *testing.T) {
	h := testRouter(t, func() error { return errors.New("postgres down") })

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/healthz", nil))

	if w.Code != http.StatusOK {
		t.Errorf("healthz status %d with a failing dependency, want 200", w.Code)
	}
}

func TestReadyzReflectsDependencies(t *testing.T) {
	h := testRouter(t, func() error { return errors.New("postgres down") })

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/readyz", nil))

	if w.Code != http.StatusServiceUnavailable {
		t.Errorf("readyz status %d, want 503", w.Code)
	}

	ok := testRouter(t, func() error { return nil })
	w = httptest.NewRecorder()
	ok.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/readyz", nil))

	if w.Code != http.StatusOK {
		t.Errorf("healthy readyz status %d, want 200", w.Code)
	}
}

func TestV1RequiresKey(t *testing.T) {
	h := testRouter(t, nil)

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/v1/whoami", nil))

	if w.Code != http.StatusUnauthorized {
		t.Fatalf("status %d, want 401", w.Code)
	}
}

func TestWhoamiEndToEnd(t *testing.T) {
	h := testRouter(t, nil)

	g, err := apikey.Generate(apikey.Live)
	if err != nil {
		t.Fatal(err)
	}

	r := httptest.NewRequest(http.MethodGet, "/v1/whoami", nil)
	r.Header.Set("Authorization", "Bearer "+g.Plaintext)

	w := httptest.NewRecorder()
	h.ServeHTTP(w, r)

	if w.Code != http.StatusOK {
		t.Fatalf("status %d: %s", w.Code, w.Body.String())
	}

	var got struct {
		KeyID   int64    `json:"key_id"`
		OwnerID int64    `json:"owner_id"`
		Scopes  []string `json:"scopes"`
	}

	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
		t.Fatal(err)
	}

	if got.KeyID != 42 || got.OwnerID != 7 {
		t.Errorf("principal not propagated: %+v", got)
	}
}

func TestScopeEnforcedOnRoute(t *testing.T) {
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	rec := activeRecord()
	rec.Scopes = []string{ScopeLogbook} // deliberately not reference

	rt := &Router{
		Auth: &Authenticator{
			Keys:    &fakeStore{rec: rec},
			Limiter: ratelimit.NewMemory(),
			Logger:  logger,
		},
		Logger: logger,
	}

	g, _ := apikey.Generate(apikey.Live)

	r := httptest.NewRequest(http.MethodGet, "/v1/reference/ping", nil)
	r.Header.Set("Authorization", "Bearer "+g.Plaintext)

	w := httptest.NewRecorder()
	rt.Handler().ServeHTTP(w, r)

	if w.Code != http.StatusForbidden {
		t.Errorf("status %d, want 403", w.Code)
	}
}

func TestUnknownPathIsJSON404(t *testing.T) {
	h := testRouter(t, nil)

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/nope", nil))

	if w.Code != http.StatusNotFound {
		t.Fatalf("status %d, want 404", w.Code)
	}

	if ct := w.Header().Get("Content-Type"); ct[:16] != "application/json" {
		t.Errorf("Content-Type %q, want JSON so clients can parse errors uniformly", ct)
	}
}

// A wrong method on a real path must 405, not 404.
func TestMethodMismatch(t *testing.T) {
	h := testRouter(t, nil)

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodPost, "/healthz", nil))

	if w.Code != http.StatusMethodNotAllowed {
		t.Errorf("status %d, want 405", w.Code)
	}
}

// A panicking handler must produce a 500, not kill the process.
func TestRecoveryMiddleware(t *testing.T) {
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	boom := http.HandlerFunc(func(http.ResponseWriter, *http.Request) {
		panic("kaboom")
	})

	h := Chain(boom, WithRequestID, WithRecovery(logger))

	w := httptest.NewRecorder()
	h.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/x", nil))

	if w.Code != http.StatusInternalServerError {
		t.Fatalf("status %d, want 500", w.Code)
	}

	if got := bodyCode(t, w); got != CodeInternal {
		t.Errorf("code %q, want %q", got, CodeInternal)
	}
}

func TestRequestIDHonoursInbound(t *testing.T) {
	h := Chain(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if got := RequestIDFrom(r.Context()); got != "abc123" {
			t.Errorf("request id %q, want abc123", got)
		}
	}), WithRequestID)

	r := httptest.NewRequest(http.MethodGet, "/", nil)
	r.Header.Set("X-Request-Id", "abc123")

	h.ServeHTTP(httptest.NewRecorder(), r)
}