package handlers_test

import (
	"context"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strconv"
	"strings"
	"testing"

	"github.com/go-chi/chi"
	"github.com/google/uuid"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/gorm/clause"
	"sneak.berlin/go/webhooker/internal/database"
	"sneak.berlin/go/webhooker/internal/handlers"
	"sneak.berlin/go/webhooker/internal/session"
)

// paramEventID is the chi URL parameter the body download
// handler reads.
const paramEventID = "eventID"

// otherTestUserID owns webhooks the session user must not be
// able to read.
const otherTestUserID = "other-user-id"

// seedWebhookFor inserts a webhook owned by the given user.
func seedWebhookFor(
	t *testing.T,
	db *database.Database,
	userID string,
) *database.Webhook {
	t.Helper()

	wh := &database.Webhook{
		UserID: userID,
		Name:   "wh-" + userID,
	}

	require.NoError(
		t,
		db.DB().Omit(clause.Associations).Create(wh).Error,
	)

	return wh
}

// fetchEventBody runs the real download handler as the test user
// for the given source and event ids.
func fetchEventBody(
	t *testing.T,
	h *handlers.Handlers,
	sess *session.Session,
	sourceID, eventID string,
) *httptest.ResponseRecorder {
	t.Helper()

	// The path is escaped and the raw id goes in the route
	// context, which is what chi hands a handler: the param is
	// already percent-decoded by the time it is read.
	req := httptest.NewRequestWithContext(
		context.Background(),
		http.MethodGet,
		"/source/"+url.PathEscape(sourceID)+
			"/logs/"+url.PathEscape(eventID)+"/body",
		nil,
	)

	for _, c := range authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	) {
		req.AddCookie(c)
	}

	rctx := chi.NewRouteContext()
	rctx.URLParams.Add(paramSourceID, sourceID)
	rctx.URLParams.Add(paramEventID, eventID)

	req = req.WithContext(
		context.WithValue(
			req.Context(), chi.RouteCtxKey, rctx,
		),
	)

	w := httptest.NewRecorder()
	h.HandleEventBodyDownload().ServeHTTP(w, req)

	return w
}

// TestHandleEventBodyDownload_ServesOversizeBodyInFull is the
// capability the render cap took away: a body far above what the
// event log page will show comes back whole and byte-identical,
// with the headers that keep it from being rendered.
func TestHandleEventBodyDownload_ServesOversizeBodyInFull(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	// Larger than one read chunk as well as the render cap, so
	// the chunked read has to reassemble the body in order and
	// the tail past the last whole chunk is exercised.
	const sentinel = "TAIL-SENTINEL-1f4a9c"

	stored := strings.Repeat("A", 200*1024) +
		strings.Repeat(snowman, 1000) + sentinel

	wh := seedWebhook(t, db)
	evt := seedEventWithBody(t, dbMgr, wh.ID, stored)

	w := fetchEventBody(t, h, sess, wh.ID, evt.ID)

	require.Equal(t, http.StatusOK, w.Code)
	assert.Greater(t, len(stored), bodyCap)
	assert.Equal(t, stored, w.Body.String())
	assert.Equal(
		t, strconv.Itoa(len(stored)),
		w.Header().Get("Content-Length"),
	)
}

// TestHandleEventBodyDownload_HeadersAreNotRenderable pins the
// response headers that stop attacker-supplied bytes executing
// in the operator's own origin. They are a security control, not
// presentation.
func TestHandleEventBodyDownload_HeadersAreNotRenderable(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	evt := seedEventWithBody(t, dbMgr, wh.ID, `{"small":true}`)

	w := fetchEventBody(t, h, sess, wh.ID, evt.ID)

	require.Equal(t, http.StatusOK, w.Code)
	assert.Equal(
		t, "application/octet-stream",
		w.Header().Get("Content-Type"),
	)
	assert.Equal(
		t, "nosniff",
		w.Header().Get("X-Content-Type-Options"),
	)

	disposition := w.Header().Get("Content-Disposition")
	assert.Equal(
		t,
		`attachment; filename="webhooker-event-`+evt.ID+`.bin"`,
		disposition,
	)
}

// TestHandleEventBodyDownload_ScriptBodyStaysInert proves a
// stored HTML payload is handed back as an attachment of opaque
// bytes rather than as anything a browser will execute. The
// bytes themselves are unaltered: this route reports what was
// delivered.
func TestHandleEventBodyDownload_ScriptBodyStaysInert(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	const payload = `<html><script>alert(document.cookie)` +
		`</script></html>`

	wh := seedWebhook(t, db)
	evt := seedEventWithBody(t, dbMgr, wh.ID, payload)

	w := fetchEventBody(t, h, sess, wh.ID, evt.ID)

	require.Equal(t, http.StatusOK, w.Code)
	assert.Equal(t, payload, w.Body.String())

	contentType := w.Header().Get("Content-Type")
	assert.Equal(t, "application/octet-stream", contentType)
	assert.NotContains(t, contentType, "html")
	assert.NotContains(t, contentType, "xml")
	assert.NotContains(t, contentType, "javascript")
	assert.Contains(
		t, w.Header().Get("Content-Disposition"), "attachment",
	)
	assert.Equal(
		t, "nosniff",
		w.Header().Get("X-Content-Type-Options"),
	)
}

// TestHandleEventBodyDownload_OtherUsersEvent404s is the
// authorization test the definition of done asks for: an event
// stored under a webhook the session user does not own is not
// readable, and the miss does not distinguish itself from a
// nonexistent one.
func TestHandleEventBodyDownload_OtherUsersEvent404s(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	const theirPayload = "OTHER-USERS-PAYLOAD-8b1d"

	theirs := seedWebhookFor(t, db, otherTestUserID)
	evt := seedEventWithBody(t, dbMgr, theirs.ID, theirPayload)

	w := fetchEventBody(t, h, sess, theirs.ID, evt.ID)

	assert.Equal(t, http.StatusNotFound, w.Code)
	assert.NotContains(t, w.Body.String(), theirPayload)
}

// TestHandleEventBodyDownload_EventOfAnotherWebhook404s pins
// that holding a valid event id is not enough: the event has to
// belong to the webhook in the path. Both webhooks here are the
// session user's and both have event databases, so the
// ownership check cannot be what produces the 404.
//
// What does produce it is the per-webhook database file rather
// than the webhook_id predicate on the query — removing that
// predicate leaves this test green, because the sibling's event
// is in a different file. The test is kept as the behavioural
// guard the route owes; see serveEventBody for which mechanism
// is load-bearing.
func TestHandleEventBodyDownload_EventOfAnotherWebhook404s(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	const other = "BELONGS-TO-THE-OTHER-WEBHOOK-3c7e"

	mine := seedWebhook(t, db)
	seedEventWithBody(t, dbMgr, mine.ID, `{"mine":true}`)

	sibling := seedWebhook(t, db)
	evt := seedEventWithBody(t, dbMgr, sibling.ID, other)

	w := fetchEventBody(t, h, sess, mine.ID, evt.ID)

	assert.Equal(t, http.StatusNotFound, w.Code)
	assert.NotContains(t, w.Body.String(), other)
}

// TestHandleEventBodyDownload_UnknownEvent404s covers the plain
// miss, including an id that is not a uuid at all and so never
// reaches the query or the response header.
func TestHandleEventBodyDownload_UnknownEvent404s(t *testing.T) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	seedEventWithBody(t, dbMgr, wh.ID, `{"mine":true}`)

	for _, id := range []string{
		uuid.New().String(),
		`../../etc/passwd`,
		"not-a-uuid",
		`x"; rm -rf /`,
	} {
		w := fetchEventBody(t, h, sess, wh.ID, id)

		assert.Equal(
			t, http.StatusNotFound, w.Code,
			"event id %q", id,
		)
		assert.Empty(
			t, w.Header().Get("Content-Disposition"),
			"event id %q must not reach a header", id,
		)
	}
}

// TestHandleSourceLogs_TruncationMarkerLinksToDownload proves
// the page tells the reader where the rest of the body is, and
// only when there is a rest to fetch.
func TestHandleSourceLogs_TruncationMarkerLinksToDownload(
	t *testing.T,
) {
	t.Parallel()

	var (
		h     *handlers.Handlers
		sess  *session.Session
		db    *database.Database
		dbMgr *database.WebhookDBManager
	)

	app := newTestApp(t, &h, &sess, &db, &dbMgr)
	app.RequireStart()

	t.Cleanup(app.RequireStop)

	big := seedWebhook(t, db)
	bigEvt := seedEventWithBody(
		t, dbMgr, big.ID, strings.Repeat("A", 4*bodyCap),
	)

	page := renderSourceLogsPage(t, h, sess, big.ID)
	assert.Contains(
		t, page,
		"/source/"+big.ID+"/logs/"+bigEvt.ID+"/body",
	)

	small := seedWebhook(t, db)
	smallEvt := seedEventWithBody(
		t, dbMgr, small.ID, `{"kept":"whole"}`,
	)

	page = renderSourceLogsPage(t, h, sess, small.ID)
	assert.NotContains(
		t, page,
		"/source/"+small.ID+"/logs/"+smallEvt.ID+"/body",
	)
}