//go:build browser

package calendartest

import (
	"context"
	"io"
	"log/slog"
	"net"
	"net/http"
	"net/url"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"
	"testing"
	"time"

	calendar "amadan.net/oficina/calendar/internal/calendar"
)

// TestViewSwitchingHoldsStillInARealBrowser is Paul's "views jumping"
// complaint as a gate: switching Day, Week, Month and Agenda, and stepping
// each with Previous and Next, moves none of the page's controls and
// shifts no layout, at 1440 and 390 wide. Each hop is a full document
// load, so no single-page CLS figure sees the jump; the node script
// compares boxes across documents. See test/browser/views.mjs.
func TestViewSwitchingHoldsStillInARealBrowser(t *testing.T) {
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("listen: %v", err)
	}
	origin := "http://" + ln.Addr().String()
	app, err := calendar.New(calendar.Config{
		DBPath: filepath.Join(t.TempDir(), "calendar.db"),
		Env:    "development",
		Origin: origin,
		Logger: slog.New(slog.NewTextHandler(io.Discard, nil)),
	})
	if err != nil {
		t.Fatalf("calendar.New: %v", err)
	}
	t.Cleanup(func() { app.Close() })
	srv := &http.Server{Handler: app.Handler()}
	go func() { _ = srv.Serve(ln) }()
	t.Cleanup(func() { _ = srv.Close() })

	session := signInOverHTTP(t, app, origin, "someone@example.com")
	client := &http.Client{CheckRedirect: func(*http.Request, []*http.Request) error { return http.ErrUseLastResponse }}
	do := func(method, path string, form url.Values) *http.Response {
		t.Helper()
		var body io.Reader
		if form != nil {
			body = strings.NewReader(form.Encode())
		}
		req, _ := http.NewRequest(method, origin+path, body)
		if form != nil {
			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
			req.Header.Set("Origin", origin)
		}
		req.AddCookie(session)
		res, err := client.Do(req)
		if err != nil {
			t.Fatal(err)
		}
		return res
	}
	res := do("GET", "/events/new", nil)
	page, _ := io.ReadAll(res.Body)
	res.Body.Close()
	m := regexp.MustCompile(`<option value="(\d+)"[^>]*\bselected\b`).FindSubmatch(page)
	if m == nil {
		t.Fatal("no default calendar on the create form")
	}
	// Content in every view, including an all-day event (it adds a row
	// in Day and Week) and a busy day (Month's "+N more").
	for _, v := range []url.Values{
		{"title": {"Team offsite"}, "all_day": {"1"}, "start": {"2026-09-23"}, "end": {"2026-09-24"}, "kind": {"commitment"}},
		{"title": {"Design review"}, "start": {"2026-09-24T10:00"}, "end": {"2026-09-24T11:00"}, "kind": {"meeting"}},
		{"title": {"Lunch with Ana"}, "start": {"2026-09-24T13:00"}, "end": {"2026-09-24T14:00"}, "kind": {"commitment"}},
		{"title": {"Planning"}, "start": {"2026-09-22T15:00"}, "end": {"2026-09-22T17:00"}, "kind": {"meeting"}},
		{"title": {"Standup"}, "start": {"2026-09-24T09:30"}, "end": {"2026-09-24T09:45"}, "kind": {"meeting"}},
		{"title": {"Dentist"}, "start": {"2026-09-24T16:00"}, "end": {"2026-09-24T16:30"}, "kind": {"commitment"}},
	} {
		v.Set("calendar_id", string(m[1]))
		v.Set("status", "confirmed")
		v.Set("repeat", "none")
		res := do("POST", "/events", v)
		res.Body.Close()
		if res.StatusCode != http.StatusSeeOther {
			t.Fatalf("create %q: status %d", v.Get("title"), res.StatusCode)
		}
	}

	ctx, cancel := context.WithTimeout(context.Background(), 4*time.Minute)
	defer cancel()
	cmd := exec.CommandContext(ctx, "node", "test/browser/views.mjs", origin, session.Name, session.Value)
	cmd.Dir = repoRootForBrowser(t)
	out, err := cmd.CombinedOutput()
	t.Logf("node:\n%s", out)
	if err != nil {
		t.Fatalf("the browser checks failed: %v", err)
	}
}