package app

import (
	"strings"
	"testing"
)

func TestViewportRendererShiftsCursor(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(120, 40))
	got := string(vr.Render([]byte("\x1b[H")))
	if got != "\x1b[2;1H" {
		t.Fatalf("CUP home: got %q", got)
	}
}

func TestViewportRendererSwallowsAltScreenToggles(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(120, 40))
	got := string(vr.Render([]byte("a\x1b[?1049hb\x1b[?1049lc")))
	if got != "abc" {
		t.Fatalf("alt-screen toggles: got %q", got)
	}
}

func TestViewportRendererClearScreenIsViewportOnly(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(20, 5))
	got := string(vr.Render([]byte("\x1b[2J")))
	if strings.Contains(got, "\x1b[2J") {
		t.Fatalf("host clear-screen leaked through: %q", got)
	}
	if strings.Count(got, "                    ") != 3 {
		t.Fatalf("clear rows: got %q", got)
	}
	if !strings.Contains(got, "\x1b[2;1H") || !strings.Contains(got, "\x1b[4;1H") {
		t.Fatalf("clear did not target viewport rows: %q", got)
	}
}

func TestViewportRendererClearLineUsesEraseChars(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(20, 5))
	got := string(vr.Render([]byte("\x1b[K")))
	if strings.Contains(got, "\x1b[K") {
		t.Fatalf("host clear-line leaked through: %q", got)
	}
	if got != "\x1b[20X" {
		t.Fatalf("clear-line: got %q want ECH", got)
	}
}

func TestViewportRendererClearLineStopsAtViewportRight(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(20, 5))
	got := string(vr.Render([]byte("\x1b[10G\x1b[K")))
	if !strings.HasSuffix(got, "\x1b[11X") {
		t.Fatalf("clear-line from col 10 should erase 11 cells: %q", got)
	}
}

func TestViewportRendererTracksPrintableCursor(t *testing.T) {
	vr := newViewportRenderer(newTerminalLayout(20, 5))
	got := string(vr.Render([]byte("hello\x1b[K")))
	if !strings.HasSuffix(got, "\x1b[15X") {
		t.Fatalf("clear-line after five chars should erase 15 cells: %q", got)
	}
}