package handlers_test

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

	"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/delivery"
	"sneak.berlin/go/webhooker/internal/handlers"
	"sneak.berlin/go/webhooker/internal/session"
)

// responseCap is the number of response bytes the event log
// page is allowed to render for one delivery attempt.
const responseCap = handlers.MaxRenderedResponseBytesForTest

// failedAttempt describes the failed delivery every test in
// this file seeds. The values are distinctive so that finding
// them in the rendered page cannot be a coincidence.
const (
	attemptStatusCode = 502
	attemptDurationMS = 1234
	attemptNumber     = 3
	attemptError      = "upstream returned 502 Bad Gateway"
)

// seedFailedDeliveryWithResponse records an event, a failed
// delivery against targetID, and one delivery result carrying
// the given response body. It returns the delivery.
//
// Distinct from seedFailedDelivery in delivery_replay_test.go,
// which seeds an attempt with no response body and returns the
// event as well; these tests need the recorded response.
func seedFailedDeliveryWithResponse(
	t *testing.T,
	dbMgr *database.WebhookDBManager,
	webhookID, targetID, responseBody string,
) *database.Delivery {
	t.Helper()

	webhookDB, err := dbMgr.GetDB(webhookID)
	require.NoError(t, err)

	event := &database.Event{
		WebhookID:   webhookID,
		Method:      http.MethodPost,
		Body:        `{"test":true}`,
		ContentType: contentTypeJSON,
	}

	require.NoError(t, webhookDB.Omit(
		clause.Associations,
	).Create(event).Error)

	dlv := &database.Delivery{
		EventID:  event.ID,
		TargetID: targetID,
		Status:   database.DeliveryStatusFailed,
	}

	require.NoError(t, webhookDB.Omit(
		clause.Associations,
	).Create(dlv).Error)

	result := &database.DeliveryResult{
		DeliveryID:   dlv.ID,
		AttemptNum:   attemptNumber,
		Success:      false,
		StatusCode:   attemptStatusCode,
		ResponseBody: responseBody,
		Error:        attemptError,
		Duration:     attemptDurationMS,
	}

	require.NoError(t, webhookDB.Omit(
		clause.Associations,
	).Create(result).Error)

	return dlv
}

// seedFailureAndRender seeds a failed delivery against a
// target of the given type and config, and returns the
// rendered event log page.
func seedFailureAndRender(
	t *testing.T,
	targetType database.TargetType,
	config, responseBody string,
) string {
	t.Helper()

	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)
	tgt := seedConfiguredTarget(
		t, db, wh.ID, targetType, config,
	)

	seedFailedDeliveryWithResponse(
		t, dbMgr, wh.ID, tgt.ID, responseBody,
	)

	return renderSourceLogsPage(t, h, sess, wh.ID)
}

// TestHandleSourceLogs_RendersFailedAttempt is the regression
// test for the reported gap: a failed delivery used to render
// as the status word alone, so diagnosing it meant opening the
// per-webhook SQLite file by hand.
func TestHandleSourceLogs_RendersFailedAttempt(t *testing.T) {
	t.Parallel()

	body := seedFailureAndRender(
		t,
		database.TargetTypeHTTP,
		`{"url":"https://example.com/hook/abc"}`,
		"upstream exploded",
	)

	assert.Contains(
		t, body, strconv.Itoa(attemptStatusCode),
		"the attempt's status code must reach the page",
	)
	assert.Contains(
		t, body, attemptError,
		"the attempt's error must reach the page",
	)
	assert.Contains(
		t, body, strconv.Itoa(attemptDurationMS),
		"the attempt's duration must reach the page",
	)
	assert.Contains(
		t, body, "Attempt "+strconv.Itoa(attemptNumber),
		"the attempt number must reach the page",
	)
	assert.Contains(
		t, body, "upstream exploded",
		"the attempt's response body must reach the page",
	)
}

// TestHandleSourceLogs_EscapesResponseBody proves the
// response body is treated as the untrusted remote content it
// is. The remote chooses these bytes and the page is rendered
// inside the operator's authenticated origin, where the
// application's own CSP allows inline script from 'self'.
func TestHandleSourceLogs_EscapesResponseBody(t *testing.T) {
	t.Parallel()

	const payload = `<script>alert("xss")</script>`

	body := seedFailureAndRender(
		t,
		database.TargetTypeHTTP,
		`{"url":"https://example.com/hook/abc"}`,
		payload,
	)

	assert.NotContains(t, body, payload)
	assert.NotContains(t, body, "<script>alert")
	assert.Contains(t, body, "alert")
}

// TestHandleSourceLogs_RedactsCredentialEchoedInResponse
// covers the case that makes rendering a response body a
// disclosure question at all: the remote echoes back the
// credential the request carried, and the page would then put
// it on the operator's screen.
func TestHandleSourceLogs_RedactsCredentialEchoedInResponse(
	t *testing.T,
) {
	t.Parallel()

	body := seedFailureAndRender(
		t,
		database.TargetTypeSlack,
		`{"webhookUrl":"`+slackWebhookURL+`"}`,
		"no_service: "+slackWebhookURL,
	)

	assert.NotContains(t, body, slackSecretPath)
	assert.NotContains(t, body, "T00000000")
	assert.NotContains(t, body, "B00000000")
	assert.Contains(t, body, delivery.RedactionMarker)

	// The rest of the response is still shown, or the
	// redaction would have cost the operator the diagnosis.
	assert.Contains(t, body, "no_service")
}

// TestHandleSourceLogs_RedactsCredentialEchoedInError covers
// the same disclosure through the error field. The delivery
// engine masks the URL out of the errors it stores, so this
// holds the read path to the rows written before it did.
func TestHandleSourceLogs_RedactsCredentialEchoedInError(
	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)
	tgt := seedConfiguredTarget(
		t, db, wh.ID,
		database.TargetTypeSlack,
		`{"webhookUrl":"`+slackWebhookURL+`"}`,
	)

	dlv := seedFailedDeliveryWithResponse(t, dbMgr, wh.ID, tgt.ID, "")

	webhookDB, err := dbMgr.GetDB(wh.ID)
	require.NoError(t, err)

	// An unmasked transport error, exactly as Go's HTTP
	// client renders one.
	require.NoError(t, webhookDB.Model(
		&database.DeliveryResult{},
	).Where(
		"delivery_id = ?", dlv.ID,
	).Update(
		"error",
		`Post "`+slackWebhookURL+`": dial tcp: i/o timeout`,
	).Error)

	body := renderSourceLogsPage(t, h, sess, wh.ID)

	assert.NotContains(t, body, slackSecretPath)
	assert.Contains(t, body, delivery.RedactionMarker)
	assert.Contains(t, body, "i/o timeout")
}

// severedPadding is the filler that puts the end of an echoed
// webhook URL five bytes past a cut at the response cap, so
// the cut leaves the workspace ID, the bot ID and all but the
// last few token characters behind.
func severedPadding() string {
	const severedTail = 5

	return strings.Repeat(
		"A", responseCap-len(slackWebhookURL)+severedTail,
	)
}

// TestHandleSourceLogs_RedactsCredentialSeveredByTheEngineCut
// is the regression test for a redactor gated on the SQL cut
// alone. The delivery engine stops reading a response at its
// own cap, which is the same number of bytes this page
// renders, so a row the engine cut is byte-for-byte
// indistinguishable from a complete response and that gate
// never opened on anything the engine writes.
//
// The seeded body is what the engine stores for any remote
// that sends at least that much: exactly responseCap bytes,
// ending in a severed webhook URL.
// TestDeliverHTTP_CutsStoredResponseAtMaxBodyLog in
// internal/delivery pins that this is the size it produces.
func TestHandleSourceLogs_RedactsCredentialSeveredByTheEngineCut(
	t *testing.T,
) {
	t.Parallel()

	sent := severedPadding() + slackWebhookURL +
		strings.Repeat("Z", 128)
	stored := sent[:responseCap]

	require.Len(
		t, stored, responseCap,
		"the engine stores exactly the cap, never more",
	)
	require.Contains(
		t, stored, "T00000000",
		"the severed credential must be in what is seeded",
	)

	body := seedFailureAndRender(
		t,
		database.TargetTypeSlack,
		`{"webhookUrl":"`+slackWebhookURL+`"}`,
		stored,
	)

	assert.NotContains(t, body, "T00000000")
	assert.NotContains(t, body, "B00000000")
	assert.Contains(t, body, delivery.RedactionMarker)
	assert.Contains(
		t, body, "reached the recording limit",
		"a body the engine cut must not be shown as complete",
	)
}

// TestHandleSourceLogs_RedactsCredentialSeveredBySQLCut covers
// the same severing for a row larger than the cap, which is
// SQLite's cut rather than the engine's. The current engine
// writes no such row; rows predating its cap or restored from
// an archive are not bounded by it, which is why the page cuts
// again in SQL and has to redact that cut too.
func TestHandleSourceLogs_RedactsCredentialSeveredBySQLCut(
	t *testing.T,
) {
	t.Parallel()

	stored := severedPadding() + slackWebhookURL +
		strings.Repeat("Z", 128)

	require.Greater(
		t, len(stored), responseCap,
		"the stored body must exceed the cap or nothing is cut",
	)

	body := seedFailureAndRender(
		t,
		database.TargetTypeSlack,
		`{"webhookUrl":"`+slackWebhookURL+`"}`,
		stored,
	)

	assert.NotContains(t, body, "T00000000")
	assert.NotContains(t, body, "B00000000")
	assert.NotContains(
		t, body, slackWebhookURL[:len(slackWebhookURL)-10],
	)
	assert.Contains(t, body, delivery.RedactionMarker)
}

// TestHandleSourceLogs_RedactsForSoftDeletedTarget covers a
// target an operator has deleted. The row is only soft deleted
// and its deliveries survive in the per-webhook database, so
// its redactor has to survive with it or every response body
// it ever recorded renders unredacted.
func TestHandleSourceLogs_RedactsForSoftDeletedTarget(
	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)
	tgt := seedConfiguredTarget(
		t, db, wh.ID,
		database.TargetTypeSlack,
		`{"webhookUrl":"`+slackWebhookURL+`"}`,
	)

	seedFailedDeliveryWithResponse(
		t, dbMgr, wh.ID, tgt.ID,
		"no_service: "+slackWebhookURL,
	)

	require.NoError(t, db.DB().Delete(tgt).Error)

	body := renderSourceLogsPage(t, h, sess, wh.ID)

	assert.NotContains(t, body, slackSecretPath)
	assert.NotContains(t, body, "T00000000")
	assert.Contains(t, body, delivery.RedactionMarker)
	assert.Contains(t, body, "no_service")
}

// TestHandleSourceLogs_BoundsRenderedAttempts pins the ceiling
// on how many of one delivery's attempts reach the page, and
// that what it drops is counted rather than hidden.
func TestHandleSourceLogs_BoundsRenderedAttempts(t *testing.T) {
	t.Parallel()

	const extraAttempts = 7

	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)
	tgt := seedConfiguredTarget(
		t, db, wh.ID, database.TargetTypeLog, "",
	)

	dlv := seedFailedDeliveryWithResponse(t, dbMgr, wh.ID, tgt.ID, "")

	webhookDB, err := dbMgr.GetDB(wh.ID)
	require.NoError(t, err)

	total := handlers.MaxRenderedAttemptsForTest + extraAttempts

	// seedFailedDeliveryWithResponse already recorded one attempt.
	for i := range total - 1 {
		require.NoError(t, webhookDB.Omit(
			clause.Associations,
		).Create(&database.DeliveryResult{
			DeliveryID: dlv.ID,
			AttemptNum: attemptNumber + 1 + i,
			Error:      attemptError,
		}).Error)
	}

	views := h.LoadEventLogViewsForTest(
		httptest.NewRecorder(), *wh, 1,
	)
	require.Len(t, views, 1)
	require.Len(t, views[0].Deliveries, 1)

	dv := views[0].Deliveries[0]

	assert.Equal(t, total, dv.AttemptCount)
	assert.Len(
		t, dv.Results, handlers.MaxRenderedAttemptsForTest,
	)
	assert.Equal(t, extraAttempts, dv.AttemptsOmitted)

	page := renderSourceLogsPage(t, h, sess, wh.ID)

	assert.Contains(t, page, "attempts omitted")
	assert.Contains(
		t, page, strconv.Itoa(total)+" attempts",
		"the header must count every recorded attempt",
	)
}

// TestHandleSourceLogs_BoundsOversizeResponse proves the
// rendered page is bounded by the response cap rather than by
// the stored response size. The cut happens in SQLite, so the
// oversized value never becomes a Go string; this asserts the
// observable consequence, that neither the page nor the
// projection carries the tail.
func TestHandleSourceLogs_BoundsOversizeResponse(t *testing.T) {
	t.Parallel()

	const tail = "QQRESPONSETAILQQ"

	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)
	tgt := seedConfiguredTarget(
		t, db, wh.ID, database.TargetTypeLog, "",
	)

	stored := strings.Repeat("A", responseCap*4) + tail
	seedFailedDeliveryWithResponse(t, dbMgr, wh.ID, tgt.ID, stored)

	views := h.LoadEventLogViewsForTest(
		httptest.NewRecorder(), *wh, 1,
	)
	require.Len(t, views, 1)
	require.Len(t, views[0].Deliveries, 1)
	require.Len(t, views[0].Deliveries[0].Results, 1)

	attempt := views[0].Deliveries[0].Results[0]

	assert.LessOrEqual(
		t, len(attempt.ResponseBody), responseCap,
	)
	assert.Equal(
		t, int64(len(stored)), attempt.ResponseBytes,
	)
	assert.True(t, attempt.ResponseTruncated)

	page := renderSourceLogsPage(t, h, sess, wh.ID)

	assert.NotContains(t, page, tail)
	assert.Contains(
		t, page, "Response truncated for display",
	)
}