//go:build browser

// The snippet example as a reader meets it: a line of code in a box no
// wider than the line on a desktop and no wider than the screen on a
// phone, where the line wraps rather than run off the edge, still left
// to right in a right-to-left page; with no script the Copy button is
// gone, the code is selected whole by one click, and the status is a
// live region before it ever speaks.
package check

import (
	"context"
	"fmt"
	"math"
	"testing"
	"time"

	"github.com/chromedp/cdproto/accessibility"
	"github.com/chromedp/cdproto/cdp"
	"github.com/chromedp/cdproto/emulation"
	"github.com/chromedp/chromedp"

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

// snippetExampleDoc is the snippet example's one state as a document,
// its assets flattened beside the page as the sizing mux serves them.
func snippetExampleDoc(t *testing.T) string {
	t.Helper()
	state, ok := manifest(t).Default("snippet")
	if !ok || state == "" {
		t.Fatal("examples.json names no default state for snippet")
	}
	doc, err := example.Document(fiesta.FS(), "snippet", state)
	if err != nil {
		t.Fatal(err)
	}
	return parityLinks(doc)
}

// snippetPages are the example at / and right to left at /rtl.
func snippetPages(t *testing.T) map[string]string {
	t.Helper()
	doc := snippetExampleDoc(t)
	return map[string]string{"/": doc, "/rtl": inArabic(t, doc)}
}

// snippetGeometry is what the layout test reads of the box: its width
// and its container's content width, the code's one-line width (a
// clone of it set on one line), its height and line height, the
// button's width with its inline margins when shown, the box's column
// gap, its paddings and borders, the rect of the code's last character, the document's
// scroll and client widths, and the code's direction.
type snippetGeometry struct {
	Box, BoxLeft, BoxRight, Container             float64
	Line, CodeHeight, LineHeight, Button, Gap     float64
	Chrome                                        float64
	ButtonShown                                   bool
	LastLeft, LastRight, ScrollWidth, ClientWidth float64
	Direction                                     string
}

const snippetGeometryJS = `(() => {
  const box = document.querySelector("[rst-snippet]"), code = box.querySelector("code"),
    b = box.querySelector("[rst-snippet-copy]"), bs = getComputedStyle(box), cs = getComputedStyle(code);
  const parent = box.parentElement, ps = getComputedStyle(parent);
  const clone = code.cloneNode(true);
  clone.style.cssText = "position: absolute; visibility: hidden; white-space: nowrap; inline-size: max-content";
  box.append(clone);
  const line = clone.getBoundingClientRect().width;
  clone.remove();
  const text = code.firstChild, last = document.createRange();
  last.setStart(text, text.length - 1);
  last.setEnd(text, text.length);
  const lr = last.getBoundingClientRect(), r = box.getBoundingClientRect();
  const px = (v) => parseFloat(v) || 0;
  const lh = cs.lineHeight === "normal" ? 1.2 * px(cs.fontSize) : px(cs.lineHeight);
  return JSON.stringify({
    Box: r.width, BoxLeft: r.left, BoxRight: r.right,
    Container: parent.clientWidth - px(ps.paddingLeft) - px(ps.paddingRight),
    Line: line, CodeHeight: code.getBoundingClientRect().height, LineHeight: lh,
    ButtonShown: b.getClientRects().length > 0,
    Button: b.getBoundingClientRect().width + px(getComputedStyle(b).marginLeft) + px(getComputedStyle(b).marginRight),
    Gap: px(bs.columnGap),
    Chrome: px(bs.paddingLeft) + px(bs.paddingRight) + px(bs.borderLeftWidth) + px(bs.borderRightWidth),
    LastLeft: lr.left, LastRight: lr.right,
    ScrollWidth: document.documentElement.scrollWidth, ClientWidth: document.documentElement.clientWidth,
    Direction: cs.direction});
})()`

// TestTheSnippetHugsItsLineAndWrapsOnAPhone: at 1280 the box is as
// wide as the line of code, the Copy button and the box's own gap,
// padding and border, with the code on one line, so a short line does
// not sit in a box the width of the page. At 390 and 320 the box is no
// wider than its container and the code wraps inside it, its last
// character still in the box and the page never wider than the
// screen: the line a reader is told to copy is all on screen. Right to
// left, the code still reads left to right.
func TestTheSnippetHugsItsLineAndWrapsOnAPhone(t *testing.T) {
	rig := sizingRig(t, false, snippetPages(t))
	ctx, cancel := context.WithTimeout(rig.Context(), 60*time.Second)
	defer cancel()
	grantClipboard(t, ctx, rig.Origin)
	for _, w := range []int64{1280, 390, 320} {
		for _, path := range []string{"/", "/rtl"} {
			where := fmt.Sprintf("%s at %d", path, w)
			mustRun(t, ctx, chromedp.EmulateViewport(w, 800), chromedp.Navigate(rig.Origin+path), chromedp.WaitReady("body", chromedp.ByQuery))
			settleUntil(t, ctx, `document.readyState === "complete"`)
			var g snippetGeometry
			at(t, ctx, snippetGeometryJS, &g)
			if !g.ButtonShown {
				t.Fatalf("%s: the Copy button is not shown with a clipboard; the widths below would leave it out", where)
			}
			if g.Direction != "ltr" {
				t.Errorf("%s: the code's direction is %s; code reads left to right in any page", where, g.Direction)
			}
			if w == 1280 {
				want := g.Line + g.Gap + g.Button + g.Chrome
				if math.Abs(g.Box-want) > 2 {
					t.Errorf("%s: the box is %.1fpx wide; want %.1fpx, the line (%.1f), the gap (%.1f), the button (%.1f) and the padding and border (%.1f)", where, g.Box, want, g.Line, g.Gap, g.Button, g.Chrome)
				}
				if g.CodeHeight > 1.5*g.LineHeight {
					t.Errorf("%s: the code is %.1fpx tall, its line %.1fpx; at this width it fits on one line", where, g.CodeHeight, g.LineHeight)
				}
				continue
			}
			if g.Box > g.Container+0.5 {
				t.Errorf("%s: the box is %.1fpx wide in a container of %.1fpx", where, g.Box, g.Container)
			}
			if g.CodeHeight < 1.5*g.LineHeight {
				t.Errorf("%s: the code is %.1fpx tall, its line %.1fpx; a line this long must wrap on a phone", where, g.CodeHeight, g.LineHeight)
			}
			if g.LastLeft < g.BoxLeft-0.5 || g.LastRight > g.BoxRight+0.5 {
				t.Errorf("%s: the code's last character spans %.1f to %.1f, outside the box's %.1f to %.1f", where, g.LastLeft, g.LastRight, g.BoxLeft, g.BoxRight)
			}
			if g.ScrollWidth > g.ClientWidth {
				t.Errorf("%s: the page is %.0fpx wide in a %.0fpx viewport; the code must wrap, not scroll sideways", where, g.ScrollWidth, g.ClientWidth)
			}
		}
	}
}

// statusInTheTree says whether the element sel finds is a status node
// in the accessibility tree: a live region that is not in the tree
// when its first message arrives may never be announced.
func statusInTheTree(t *testing.T, ctx context.Context, sel string) bool {
	t.Helper()
	var nodes []*cdp.Node
	mustRun(t, ctx, chromedp.Nodes(sel, &nodes, chromedp.ByQuery))
	// Read loosely: cdproto's Node refuses an ignored reason it has no
	// constant for (Chromium's "uninteresting"), and this needs only
	// the role, the ignored flag and the DOM node.
	var tree struct {
		Nodes []struct {
			Ignored bool `json:"ignored"`
			Role    *struct {
				Value any `json:"value"`
			} `json:"role"`
			BackendDOMNodeID cdp.BackendNodeID `json:"backendDOMNodeId"`
		} `json:"nodes"`
	}
	mustRun(t, ctx, accessibility.Enable(), chromedp.ActionFunc(func(ctx context.Context) error {
		return cdp.Execute(ctx, accessibility.CommandGetFullAXTree, accessibility.GetFullAXTree(), &tree)
	}))
	if len(tree.Nodes) == 0 {
		t.Fatal("the accessibility tree came back empty; the read is broken, not the status")
	}
	for _, n := range tree.Nodes {
		if n.BackendDOMNodeID == nodes[0].BackendNodeID {
			return !n.Ignored && n.Role != nil && n.Role.Value == "status"
		}
	}
	return false
}

// TestTheSnippetWithNoScript: with scripts off there is no Copy
// button to press and do nothing; the code is selected whole by one
// click or tap (user-select: all), so it can still be copied by hand;
// and the empty status takes no room, though it is a status node in
// the accessibility tree, clipped rather than display: none.
func TestTheSnippetWithNoScript(t *testing.T) {
	rig := sizingRig(t, false, snippetPages(t))
	ctx, cancel := context.WithTimeout(rig.Context(), 60*time.Second)
	defer cancel()
	mustRun(t, ctx, emulation.SetScriptExecutionDisabled(true))
	for _, path := range []string{"/", "/rtl"} {
		mustRun(t, ctx, chromedp.EmulateViewport(1280, 800), chromedp.Navigate(rig.Origin+path), chromedp.WaitReady("body", chromedp.ByQuery))
		var r struct {
			Ran, Shown               bool
			Width, Height            float64
			UserSelect, WebkitSelect string
		}
		at(t, ctx, `(() => {
		  const box = document.querySelector("[rst-snippet]"), s = box.querySelector("[rst-snippet-status]").getBoundingClientRect(),
		    cs = getComputedStyle(box.querySelector("code"));
		  return JSON.stringify({Ran: window.fiestaCopy === true, Shown: box.querySelector("[rst-snippet-copy]").getClientRects().length > 0,
		    Width: s.width, Height: s.height, UserSelect: cs.userSelect, WebkitSelect: cs.webkitUserSelect}); })()`, &r)
		if r.Ran {
			t.Fatalf("%s: copy.js ran with scripts off; this leg is not the page a reader with no script gets", path)
		}
		if r.Shown {
			t.Errorf("%s: with no script the Copy button is displayed; it could only do nothing", path)
		}
		if r.Width > 1 || r.Height > 1 {
			t.Errorf("%s: the empty status is %.1f by %.1f; while it has nothing to say it takes no room", path, r.Width, r.Height)
		}
		if r.UserSelect != "all" && r.WebkitSelect != "all" {
			t.Errorf("%s: the code's user-select is %q (-webkit- %q); want all, so one click selects the whole line to copy by hand", path, r.UserSelect, r.WebkitSelect)
		}
		if !statusInTheTree(t, ctx, "[rst-snippet-status]") {
			t.Errorf("%s: the empty status is not a status node in the accessibility tree", path)
		}
	}
}

// TestTheSnippetExampleCopies: the gallery's own snippet document takes
// driveCopy's journey, so what the gallery shows is markup copy.js
// works on, with the example's own strings.
func TestTheSnippetExampleCopies(t *testing.T) {
	rig := sizingRig(t, false, snippetPages(t))
	ctx, cancel := context.WithTimeout(rig.Context(), 60*time.Second)
	defer cancel()
	driveCopy(t, ctx, rig.Origin, "/")
	rig.Screen("body", "the snippet example after two copies")
}