package httpapi_test

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

	"github.com/urpi/go-bananas/internal/auth"
	"github.com/urpi/go-bananas/internal/config"
	"github.com/urpi/go-bananas/internal/domain"
	"github.com/urpi/go-bananas/internal/httpapi"
	"github.com/urpi/go-bananas/internal/logging"
	"github.com/urpi/go-bananas/internal/store"
)

// devUser is the account the dev bypass authenticates as. Dev mode is the only
// fixture available without minting a real session cookie: Authenticate reads the
// session or the dev bypass and never consults the login resolver, so a stub
// resolver would simply never run.
const devUser = "dev-user=person@example.test"

// withDevUser appends the dev bypass parameter to a path.
func withDevUser(path string) string {
	separator := "?"
	if strings.Contains(path, "?") {
		separator = "&"
	}
	return path + separator + devUser
}

// preferenceRouter builds a router that authenticates every caller through the dev
// bypass, against a real store so the migration runs.
func preferenceRouter(t *testing.T) (http.Handler, *store.Store) {
	t.Helper()

	st, err := store.Open(context.Background(), store.Options{Path: ":memory:"})
	if err != nil {
		t.Fatalf("open store: %v", err)
	}
	t.Cleanup(func() { _ = st.Close() })

	cfg := testConfig(t)
	cfg.AuthMode = config.AuthModeDev
	cfg.DevFallbackRole = string(domain.RoleViewer)
	cfg.SessionSecure = false

	authenticator, err := auth.New(cfg, nil, nil)
	if err != nil {
		t.Fatalf("new authenticator: %v", err)
	}

	return httpapi.NewRouter(httpapi.Deps{
		Config:        cfg,
		Store:         st,
		Cache:         httpapi.NewThemeCache(),
		Authenticator: authenticator,
		Log:           logging.New(logging.Options{Level: "error", Writer: io.Discard}),
		Version:       "test",
		RuntimeDefaults: func() (string, domain.Appearance) {
			return "", ""
		},
	}), st
}

func putJSON(t *testing.T, h http.Handler, path string, body any) *httptest.ResponseRecorder {
	t.Helper()
	encoded, err := json.Marshal(body)
	if err != nil {
		t.Fatalf("encode body: %v", err)
	}
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequestWithContext(t.Context(), http.MethodPut, path, bytes.NewReader(encoded)))
	return rec
}

func deleteRequest(t *testing.T, h http.Handler, path string) *httptest.ResponseRecorder {
	t.Helper()
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequestWithContext(t.Context(), http.MethodDelete, path, nil))
	return rec
}

// seedPublishedTheme inserts a published theme, since a preference may only name
// one that runtime consumers can load.
func seedPublishedTheme(t *testing.T, st *store.Store, slug string) {
	t.Helper()
	ctx := context.Background()
	theme := &domain.Theme{
		Slug: slug, Name: slug, Status: domain.StatusDraft, DefaultAppearance: domain.AppearanceLight,
		Tokens: domain.TokenDoc{},
	}
	if err := st.Create(ctx, theme, ""); err != nil {
		t.Fatalf("create theme: %v", err)
	}
	published := domain.StatusPublished
	if _, err := st.Update(ctx, slug, store.UpdateFields{Status: &published}); err != nil {
		t.Fatalf("publish theme: %v", err)
	}
}

func decodeBody[T any](t *testing.T, rec *httptest.ResponseRecorder) T {
	t.Helper()
	var value T
	if err := json.Unmarshal(rec.Body.Bytes(), &value); err != nil {
		t.Fatalf("decode %q: %v", rec.Body.String(), err)
	}
	return value
}

func TestPreferencesEndpointRoundTrip(t *testing.T) {
	router, st := preferenceRouter(t)
	seedPublishedTheme(t, st, "midnight")

	// An account that has never chosen reads as empty.
	got := decodeBody[domain.UserPreferences](t, get(t, router, withDevUser("/api/v1/me/preferences")))
	if got.SelectedTheme != "" {
		t.Fatalf("initial = %+v, want empty", got)
	}

	rec := putJSON(t, router, withDevUser("/api/v1/me/preferences"), domain.UserPreferences{
		SelectedTheme: "midnight", SelectedAppearance: domain.AppearanceDark,
	})
	if rec.Code != http.StatusOK {
		t.Fatalf("put = %d, want 200: %s", rec.Code, rec.Body.String())
	}
	if echoed := decodeBody[domain.UserPreferences](t, rec); echoed.SelectedTheme != "midnight" ||
		echoed.SelectedAppearance != domain.AppearanceDark {
		t.Fatalf("echoed = %+v", echoed)
	}

	got = decodeBody[domain.UserPreferences](t, get(t, router, withDevUser("/api/v1/me/preferences")))
	if got.SelectedTheme != "midnight" || got.SelectedAppearance != domain.AppearanceDark {
		t.Fatalf("read back = %+v", got)
	}

	if rec := deleteRequest(t, router, withDevUser("/api/v1/me/preferences")); rec.Code != http.StatusOK {
		t.Fatalf("delete = %d, want 200: %s", rec.Code, rec.Body.String())
	}
	got = decodeBody[domain.UserPreferences](t, get(t, router, withDevUser("/api/v1/me/preferences")))
	if got.SelectedTheme != "" {
		t.Fatalf("after reset = %+v, want empty", got)
	}
}

func TestPreferencesRejectAnUnusableTheme(t *testing.T) {
	router, st := preferenceRouter(t)
	seedPublishedTheme(t, st, "midnight")

	for name, body := range map[string]domain.UserPreferences{
		"unknown theme": {SelectedTheme: "no-such-theme"},
		"bad slug":      {SelectedTheme: "Not A Slug"},
		"bad appearance": {
			SelectedTheme: "midnight", SelectedAppearance: "sepia",
		},
	} {
		t.Run(name, func(t *testing.T) {
			rec := putJSON(t, router, withDevUser("/api/v1/me/preferences"), body)
			// A malformed preference is the caller's mistake, so a 400 rather than
			// the 500 an unwrapped validation error would produce.
			if rec.Code != http.StatusBadRequest {
				t.Fatalf("put = %d, want 400: %s", rec.Code, rec.Body.String())
			}
		})
	}
}

// TestSessionCarriesPreferences is what lets the UI preselect a theme from the same
// round trip that establishes who the caller is.
func TestSessionCarriesPreferences(t *testing.T) {
	router, st := preferenceRouter(t)
	seedPublishedTheme(t, st, "midnight")

	if rec := putJSON(t, router, withDevUser("/api/v1/me/preferences"), domain.UserPreferences{
		SelectedTheme: "midnight", SelectedAppearance: domain.AppearanceLight,
	}); rec.Code != http.StatusOK {
		t.Fatalf("put = %d: %s", rec.Code, rec.Body.String())
	}

	rec := get(t, router, withDevUser("/api/v1/auth/me"))
	if rec.Code != http.StatusOK {
		t.Fatalf("me = %d: %s", rec.Code, rec.Body.String())
	}
	var payload struct {
		Authenticated bool                       `json:"authenticated"`
		Preferences   domain.UserPreferences     `json:"preferences"`
		Identity      *domain.Identity           `json:"identity"`
		Extra         map[string]json.RawMessage `json:"-"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode session: %v", err)
	}
	if !payload.Authenticated || payload.Identity == nil {
		t.Fatalf("session = %+v, want an authenticated caller", payload)
	}
	if payload.Preferences.SelectedTheme != "midnight" ||
		payload.Preferences.SelectedAppearance != domain.AppearanceLight {
		t.Fatalf("session preferences = %+v", payload.Preferences)
	}
}

// TestAnonymousSessionOmitsPreferences keeps the unauthenticated response free of
// anything about a person, since that endpoint is reachable without a session.
func TestAnonymousSessionOmitsPreferences(t *testing.T) {
	router := newUnauthenticatedRouter(t)
	rec := get(t, router, withDevUser("/api/v1/auth/me"))
	if rec.Code != http.StatusOK {
		t.Fatalf("me = %d: %s", rec.Code, rec.Body.String())
	}
	var payload map[string]json.RawMessage
	if err := json.Unmarshal(rec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode session: %v", err)
	}
	if _, present := payload["preferences"]; present {
		t.Error("an anonymous session must not carry preferences")
	}
}

func TestPreferencesRequireASession(t *testing.T) {
	router := newUnauthenticatedRouter(t)
	if rec := get(t, router, withDevUser("/api/v1/me/preferences")); rec.Code != http.StatusUnauthorized {
		t.Fatalf("get = %d, want 401", rec.Code)
	}
	rec := putJSON(t, router, withDevUser("/api/v1/me/preferences"), domain.UserPreferences{})
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("put = %d, want 401: %s", rec.Code, rec.Body.String())
	}
}