package ui

import (
	"strings"
	"testing"
)

// TestSignatureIsStable guards the wedged-app check: two reads of an unchanged
// screen must produce the same signature, or every screen would look like it
// changed and no wedge could ever be detected.
func TestSignatureIsStable(t *testing.T) {
	h := parseSample(t)
	first := h.Signature("com.android.settings")
	second := h.Signature("com.android.settings")
	if first != second {
		t.Fatalf("signature is not stable:\n%q\n%q", first, second)
	}
	if !strings.Contains(first, "com.android.settings") {
		t.Fatalf("signature %q does not name the foreground package", first)
	}
}

// TestSignatureSeesRealChanges checks the three things a human would call a
// change: different text, a moved element, and a different app in front.
func TestSignatureSeesRealChanges(t *testing.T) {
	h := parseSample(t)
	base := h.Signature("com.android.settings")

	if h.Signature("com.spotify.music") == base {
		t.Fatal("a different foreground package must change the signature")
	}

	renamed, err := parseHierarchy([]byte(strings.Replace(sampleDump, "Connected", "Disconnected", 1)))
	if err != nil {
		t.Fatalf("parseHierarchy: %v", err)
	}
	if renamed.Signature("com.android.settings") == base {
		t.Fatal("different visible text must change the signature")
	}

	moved, err := parseHierarchy([]byte(strings.Replace(sampleDump, "[221,217][453,277]", "[221,300][453,360]", 1)))
	if err != nil {
		t.Fatalf("parseHierarchy: %v", err)
	}
	if moved.Signature("com.android.settings") == base {
		t.Fatal("an element that moved must change the signature")
	}
}

// TestSignatureIgnoresNodeOrder keeps the fingerprint about the screen, not the
// order uiautomator happened to walk it in.
func TestSignatureIgnoresNodeOrder(t *testing.T) {
	a, err := parseHierarchy([]byte(`<hierarchy rotation="0">` +
		`<node index="0" text="Alpha" bounds="[0,0][10,10]"/>` +
		`<node index="1" text="Beta" bounds="[0,10][10,20]"/></hierarchy>`))
	if err != nil {
		t.Fatalf("parseHierarchy: %v", err)
	}
	b, err := parseHierarchy([]byte(`<hierarchy rotation="0">` +
		`<node index="0" text="Beta" bounds="[0,10][10,20]"/>` +
		`<node index="1" text="Alpha" bounds="[0,0][10,10]"/></hierarchy>`))
	if err != nil {
		t.Fatalf("parseHierarchy: %v", err)
	}
	if a.Signature("app.one") != b.Signature("app.one") {
		t.Fatal("node order must not change the signature")
	}
}