//go:build browser

package check

import (
	"context"
	"net/http"
	"strings"
	"testing"
	"time"

	"github.com/chromedp/chromedp"

	"amadan.net/rastrillo/fiesta"
	"amadan.net/rastrillo/fiesta/example"
	"amadan.net/rastrillo/fiesta/internal/harness"
)

// The seam between datetime.js and calendar.js is one name on the
// window, fiestaCalendar, looked up at enhance time. Nothing breaks
// loudly if it moves: the button quietly falls back to the browser's
// own picker, which is the control the overlay replaced. This drive
// holds the rename end to end, and driveCalendarOpen is its body,
// standalone so the release build's tests can run it against the
// stripped scripts on a rig of their own built from calendarPages.

// calendarPages is the drive's two pages: "/" is field-date's default
// state, from the manifest, on the shared fixture page, which links
// calendar.js and datetime.js; "/nocal" is the same page with
// calendar.js's tag left out, so the button has only the native
// picker to fall back to.
func calendarPages(t *testing.T) map[string]string {
	t.Helper()
	m, err := example.Load(fiesta.FS())
	if err != nil {
		t.Fatal(err)
	}
	state, ok := m.Default("field-date")
	if !ok {
		t.Fatal("the manifest has no field-date example")
	}
	markup, err := example.Markup(fiesta.FS(), "field-date", state)
	if err != nil {
		t.Fatal(err)
	}
	if !strings.Contains(markup, "data-rst-date") {
		t.Fatalf("field-date's default state %q is not an armed date field:\n%s", state, markup)
	}
	with := sizingDoc("calendar", markup)
	const tag = `<script defer src="/calendar.js"></script>`
	without := strings.Replace(with, tag, "", 1)
	if without == with {
		t.Fatalf("the fixture page does not link %s; the fallback leg has nothing to leave out", tag)
	}
	return map[string]string{"/": with, "/nocal": without}
}

// calendarOpening is what the page says once the button is pressed.
type calendarOpening struct {
	Seam     bool   // window.fiestaCalendar is a function
	Haspopup string // the button's aria-haspopup, "" for none
	Dialogs  int    // [role=dialog] elements on the page
	Grids    int    // [role=grid] inside the dialog
	Cells    int    // [role=gridcell] inside the dialog
	Heads    int    // [role=columnheader] inside the dialog
}

const calendarOpeningJS = `JSON.stringify({
  Seam: typeof window.fiestaCalendar === "function",
  Haspopup: document.querySelector('[rst-dtp-pick]')?.getAttribute('aria-haspopup') ?? '',
  Dialogs: document.querySelectorAll('[role="dialog"]').length,
  Grids: document.querySelectorAll('[role="dialog"] [role="grid"]').length,
  Cells: document.querySelectorAll('[role="dialog"] [role="gridcell"]').length,
  Heads: document.querySelectorAll('[role="dialog"] [role="columnheader"]').length
})`

// driveCalendarOpen is TestTheCalendarOpensThroughFiestaCalendar's
// body, on whatever rig serves calendarPages: with calendar.js on the
// page, pressing the calendar button opens a dialog holding a month
// grid of forty-two days under seven column headers; with it left
// out, the button is the plain fallback to the native picker, with no
// popup of its own and no dialog on the page after a press.
func driveCalendarOpen(t *testing.T, rig *harness.Rig) {
	t.Helper()
	ctx, cancel := context.WithTimeout(rig.Context(), 120*time.Second)
	defer cancel()

	mustRun(t, ctx, chromedp.Navigate(rig.Origin+"/"), chromedp.WaitVisible(`input[role="combobox"]`, chromedp.ByQuery))
	var before calendarOpening
	at(t, ctx, calendarOpeningJS, &before)
	if !before.Seam {
		t.Fatal("calendar.js is on the page, but window.fiestaCalendar is not a function; datetime.js has no grid to ask for")
	}
	if before.Haspopup != "dialog" {
		t.Errorf("with calendar.js, the button's aria-haspopup is %q, want dialog", before.Haspopup)
	}
	mustRun(t, ctx, chromedp.Click(`[rst-dtp-pick]`, chromedp.ByQuery),
		chromedp.WaitVisible(`[role="dialog"] [role="gridcell"]`, chromedp.ByQuery))
	var opened calendarOpening
	at(t, ctx, calendarOpeningJS, &opened)
	if opened.Dialogs != 1 || opened.Grids != 1 || opened.Cells != 42 || opened.Heads != 7 {
		t.Errorf("after the press: %d dialogs, %d grids, %d cells, %d headers; want 1, 1, 42, 7", opened.Dialogs, opened.Grids, opened.Cells, opened.Heads)
	}
	rig.Screen("body", "the calendar open through fiestaCalendar")

	mustRun(t, ctx, chromedp.Navigate(rig.Origin+"/nocal"), chromedp.WaitVisible(`input[role="combobox"]`, chromedp.ByQuery))
	var fallback calendarOpening
	at(t, ctx, calendarOpeningJS, &fallback)
	if fallback.Seam {
		t.Fatal("/nocal still has window.fiestaCalendar; the fallback leg is not running without calendar.js")
	}
	if fallback.Haspopup != "" {
		t.Errorf("without calendar.js, the button's aria-haspopup is %q, want none: it hands over to the browser's own panel", fallback.Haspopup)
	}
	// The press reaches native.showPicker(), the browser's own panel,
	// and that is the only thing it reaches: a counting spy stands in
	// for the method (the handler calls it synchronously, so there is
	// nothing to wait for), and the page draws no dialog of its own. A
	// handler that returned early would leave the count at zero.
	mustRun(t, ctx, chromedp.Evaluate(`(() => { window.__fiestaPicked = 0; HTMLInputElement.prototype.showPicker = function () { window.__fiestaPicked++; }; return true; })()`, nil))
	mustRun(t, ctx, chromedp.Click(`[rst-dtp-pick]`, chromedp.ByQuery))
	var picked int
	mustRun(t, ctx, chromedp.Evaluate(`window.__fiestaPicked`, &picked))
	if picked != 1 {
		t.Errorf("without calendar.js, the press called showPicker %d times; want once, the fallback to the native picker", picked)
	}
	var pressed calendarOpening
	at(t, ctx, calendarOpeningJS, &pressed)
	if pressed.Dialogs != 0 || pressed.Cells != 0 {
		t.Errorf("without calendar.js, the press drew %d dialogs with %d cells; want none", pressed.Dialogs, pressed.Cells)
	}
}

// TestTheCalendarOpensThroughFiestaCalendar: see driveCalendarOpen.
func TestTheCalendarOpensThroughFiestaCalendar(t *testing.T) {
	pages := calendarPages(t)
	rig := harness.New(t, func(string) http.Handler { return sizingMux(t, pages) })
	driveCalendarOpen(t, rig)
}