package handlers_test

import (
	"context"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"github.com/go-chi/chi"
	"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"
)

const (
	deleteTestUserID   = "test-user-id"
	deleteTestUsername = "testuser"

	// paramSourceID and paramTargetID are the chi URL parameter
	// names the deletion handlers read.
	paramSourceID = "sourceID"
	paramTargetID = "targetID"
)

// seedWebhook inserts a webhook owned by the test user and
// returns it.
func seedWebhook(
	t *testing.T,
	db *database.Database,
) *database.Webhook {
	t.Helper()

	wh := &database.Webhook{
		UserID: deleteTestUserID,
		Name:   "delete-me",
	}

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

	return wh
}

// seedTarget inserts a target of the given type for a webhook
// and returns it.
func seedTarget(
	t *testing.T,
	db *database.Database,
	webhookID string,
	targetType database.TargetType,
) *database.Target {
	t.Helper()

	tgt := &database.Target{
		WebhookID: webhookID,
		Name:      "t-" + string(targetType),
		Type:      targetType,
		Active:    true,
	}

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

	return tgt
}

// archivePathFor returns the archive database path the
// delivery engine would use for a webhook: beside the webhook's
// event database in the data directory.
func archivePathFor(
	t *testing.T,
	mgr *database.WebhookDBManager,
	webhookID string,
) string {
	t.Helper()

	return filepath.Join(
		filepath.Dir(mgr.DBPath(webhookID)),
		"archive-"+webhookID+".db",
	)
}

// writeArchivePlaceholder creates a stand-in archive file so a
// test can assert the file survives webhook deletion.
func writeArchivePlaceholder(path string) error {
	return os.WriteFile(path, []byte("archive"), 0o600)
}

// postRequest builds an authenticated POST request carrying the
// given chi URL parameters.
func postRequest(
	path string,
	cookies []*http.Cookie,
	params map[string]string,
) *http.Request {
	req := httptest.NewRequestWithContext(
		context.Background(), http.MethodPost, path, nil,
	)

	for _, c := range cookies {
		req.AddCookie(c)
	}

	rctx := chi.NewRouteContext()
	for k, v := range params {
		rctx.URLParams.Add(k, v)
	}

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

// TestHandleSourceDelete_EvictsArchiveWriter proves that
// deleting a webhook reaches the delivery engine and releases
// the webhook's archive writer, exercised through the real
// deletion handler rather than by calling the evictor directly.
func TestHandleSourceDelete_EvictsArchiveWriter(t *testing.T) {
	t.Parallel()

	var (
		h    *handlers.Handlers
		sess *session.Session
		db   *database.Database
		ev   *recordingEvictor
	)

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

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	seedTarget(t, db, wh.ID, database.TargetTypeDatabase)

	cookies := authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	)

	req := postRequest(
		"/source/"+wh.ID+"/delete",
		cookies,
		map[string]string{paramSourceID: wh.ID},
	)
	w := httptest.NewRecorder()

	h.HandleSourceDelete().ServeHTTP(w, req)

	require.Equal(t, http.StatusSeeOther, w.Code)
	assert.Equal(
		t, []string{wh.ID}, ev.Evicted(),
		"deleting a webhook should evict its archive writer",
	)
}

// TestHandleSourceDelete_KeepsArchiveFile proves that deleting
// a webhook does not remove its archive database file: the
// archive is long-term storage the operator owns.
func TestHandleSourceDelete_KeepsArchiveFile(t *testing.T) {
	t.Parallel()

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

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

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)

	// Place an archive file where the delivery engine would.
	archivePath := archivePathFor(t, mgr, wh.ID)
	require.NoError(
		t,
		writeArchivePlaceholder(archivePath),
	)

	cookies := authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	)

	req := postRequest(
		"/source/"+wh.ID+"/delete",
		cookies,
		map[string]string{paramSourceID: wh.ID},
	)
	w := httptest.NewRecorder()

	h.HandleSourceDelete().ServeHTTP(w, req)

	require.Equal(t, http.StatusSeeOther, w.Code)
	assert.FileExists(
		t, archivePath,
		"webhook deletion must not destroy the archive file",
	)
}

// TestHandleTargetDelete_EvictsWhenLastDatabaseTargetGone
// proves that removing the last database target releases the
// archive writer.
func TestHandleTargetDelete_EvictsWhenLastDatabaseTargetGone(
	t *testing.T,
) {
	t.Parallel()

	var (
		h    *handlers.Handlers
		sess *session.Session
		db   *database.Database
		ev   *recordingEvictor
	)

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

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	tgt := seedTarget(
		t, db, wh.ID, database.TargetTypeDatabase,
	)

	cookies := authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	)

	req := postRequest(
		"/source/"+wh.ID+"/targets/"+tgt.ID+"/delete",
		cookies,
		map[string]string{
			paramSourceID: wh.ID,
			paramTargetID: tgt.ID,
		},
	)
	w := httptest.NewRecorder()

	h.HandleTargetDelete().ServeHTTP(w, req)

	require.Equal(t, http.StatusSeeOther, w.Code)
	assert.Equal(
		t, []string{wh.ID}, ev.Evicted(),
		"removing the last database target should evict",
	)
}

// TestHandleTargetDelete_KeepsWriterWhenDatabaseTargetRemains
// proves that deleting one of several database targets leaves
// the still-needed archive writer alone: the surviving target
// keeps archiving to the same file, so the writer must stay.
func TestHandleTargetDelete_KeepsWriterWhenDatabaseTargetRemains(
	t *testing.T,
) {
	t.Parallel()

	var (
		h    *handlers.Handlers
		sess *session.Session
		db   *database.Database
		ev   *recordingEvictor
	)

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

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	doomed := seedTarget(
		t, db, wh.ID, database.TargetTypeDatabase,
	)
	seedTarget(t, db, wh.ID, database.TargetTypeDatabase)

	cookies := authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	)

	req := postRequest(
		"/source/"+wh.ID+"/targets/"+doomed.ID+"/delete",
		cookies,
		map[string]string{
			paramSourceID: wh.ID,
			paramTargetID: doomed.ID,
		},
	)
	w := httptest.NewRecorder()

	h.HandleTargetDelete().ServeHTTP(w, req)

	require.Equal(t, http.StatusSeeOther, w.Code)
	assert.Empty(
		t, ev.Evicted(),
		"a second database target still needs the writer",
	)
}

// TestHandleTargetDelete_KeepsWriterWhileDatabaseTargetRemains
// proves that deleting an unrelated target type leaves a
// still-needed archive writer alone.
func TestHandleTargetDelete_KeepsWriterWhileDatabaseTargetRemains(
	t *testing.T,
) {
	t.Parallel()

	var (
		h    *handlers.Handlers
		sess *session.Session
		db   *database.Database
		ev   *recordingEvictor
	)

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

	t.Cleanup(app.RequireStop)

	wh := seedWebhook(t, db)
	seedTarget(t, db, wh.ID, database.TargetTypeDatabase)
	other := seedTarget(t, db, wh.ID, database.TargetTypeLog)

	cookies := authenticatedCookies(
		t, sess, deleteTestUserID, deleteTestUsername,
	)

	req := postRequest(
		"/source/"+wh.ID+"/targets/"+other.ID+"/delete",
		cookies,
		map[string]string{
			paramSourceID: wh.ID,
			paramTargetID: other.ID,
		},
	)
	w := httptest.NewRecorder()

	h.HandleTargetDelete().ServeHTTP(w, req)

	require.Equal(t, http.StatusSeeOther, w.Code)
	assert.Empty(
		t, ev.Evicted(),
		"a surviving database target must keep its writer",
	)
}