//go:build js && wasm

package wasmruntime

import (
	"strings"
	"testing"

	"kjol/vdom"
)

// The reconciler is wasm-only and needs a DOM, so these do not run under a plain
// `go test ./...` (the native build of this package is an empty placeholder).
// Run them against the minimal DOM in testdata/domexec.js — from kjol/go:
//
//	GOOS=js GOARCH=wasm go test -exec="node testdata/domexec.js" ./wasmruntime

// A Raw() node carries its markup in VNode.HTML and has NO children — the markup
// only exists in the DOM. So when the diff reuses that element for a node that
// has children instead (same tag, same index — e.g. a route change from a page
// with a server-rendered SVG to one without), the new children must not simply be
// appended alongside the surviving markup.
func TestPatchClearsRawHTMLWhenElementIsReused(t *testing.T) {
	root := document.Call("createElement", "div")

	chart := vdom.El("div", vdom.Attr("class", "grid"),
		vdom.El("div", vdom.Attr("class", "cell"), vdom.Raw(`<svg id="bar"></svg>`)),
	)
	patchChildren(root, nil, one(chart))
	if got := root.Get("innerHTML").String(); !strings.Contains(got, `<svg id="bar">`) {
		t.Fatalf("raw HTML was not mounted: %s", got)
	}

	// Same tags at the same indexes, so the diff adopts the DOM rather than
	// replacing it.
	data := vdom.El("div", vdom.Attr("class", "cards"),
		vdom.El("div", vdom.Attr("class", "card"), vdom.Text("gob section")),
	)
	patchChildren(root, one(chart), one(data))

	got := root.Get("innerHTML").String()
	if strings.Contains(got, "svg") {
		t.Errorf("stale raw HTML survived the patch (the chart would follow you to the next page):\n%s", got)
	}
	if !strings.Contains(got, "gob section") {
		t.Errorf("new children were not rendered:\n%s", got)
	}
}

// The reverse transition: an element with real children reused for a Raw() node.
// innerHTML replaces the children wholesale, so nothing may linger.
func TestPatchReplacesChildrenWithRawHTML(t *testing.T) {
	root := document.Call("createElement", "div")

	withKids := vdom.El("div", vdom.El("span", vdom.Text("hello")))
	patchChildren(root, nil, one(withKids))

	withRaw := vdom.El("div", vdom.Raw(`<svg id="pie"></svg>`))
	patchChildren(root, one(withKids), one(withRaw))

	got := root.Get("innerHTML").String()
	if strings.Contains(got, "hello") || strings.Contains(got, "span") {
		t.Errorf("old children survived under raw HTML:\n%s", got)
	}
	if !strings.Contains(got, `<svg id="pie">`) {
		t.Errorf("raw HTML was not applied:\n%s", got)
	}
}

// Raw markup that does not change must be left alone (it is not re-set on every
// render, which would blow away any DOM state inside it).
func TestPatchKeepsUnchangedRawHTML(t *testing.T) {
	root := document.Call("createElement", "div")

	a := vdom.El("div", vdom.Raw(`<svg id="bar"></svg>`))
	patchChildren(root, nil, one(a))
	before := rt(a).dom.Get("childNodes").Index(0)

	b := vdom.El("div", vdom.Raw(`<svg id="bar"></svg>`))
	patchChildren(root, one(a), one(b))

	after := rt(b).dom.Get("childNodes").Index(0)
	if !before.Equal(after) {
		t.Error("unchanged raw HTML was re-parsed instead of being left in place")
	}
}