//go:build brlapi && cgo

package braille

import (
	"bytes"
	"reflect"
	"testing"
)

// These feasibility checks use real liblouis translation and the helper's
// viewport, but never construct or open a BrlAPI backend. The two viewports
// model independently owned local and remote sessions, not a session API.
func TestVirtualBrailleIndependentWidthsAndRouting(t *testing.T) {
	frame := Frame{ID: 11, Text: "the cat", Cursor: -1, Contract: true,
		Table: "en-us-g2.ctb", WordWrap: true, Dots: []byte{0, 0x40, 0, 0, 0, 0, 0}}
	local, remote := viewport{width: 8}, viewport{width: 4}
	for _, v := range []*viewport{&local, &remote} {
		if err := v.setFrame(frame); err != nil {
			t.Fatal(err)
		}
	}
	localCells, err := local.rawCells(0xc0)
	if err != nil || !bytes.Equal(localCells, []byte{0x6e, 0, 9, 1, 0x1e, 0, 0, 0}) {
		t.Fatalf("local=%x error=%v", localCells, err)
	}
	remoteCells, err := remote.rawCells(0xc0)
	if err != nil || !bytes.Equal(remoteCells, []byte{0x6e, 0, 0, 0}) {
		t.Fatalf("wrapped remote=%x error=%v", remoteCells, err)
	}
	if route, ok := remote.route(RouteBase + 1); !ok || route != (RoutingEvent{ID: 11, Offset: 3}) {
		t.Fatalf("contracted route=%+v ok=%v", route, ok)
	}
	if _, ok := remote.route(RouteBase + 2); ok {
		t.Fatal("wrapped padding routed into hidden text")
	}
	if !remote.pan(PanRight) {
		t.Fatal("remote did not pan")
	}
	panned, err := remote.rawCells(0xc0)
	if err != nil || !bytes.Equal(panned, []byte{9, 1, 0x1e, 0}) {
		t.Fatalf("panned=%x error=%v", panned, err)
	}
	if route, ok := remote.route(RouteBase); !ok || route != (RoutingEvent{ID: 11, Offset: 4}) {
		t.Fatalf("panned route=%+v ok=%v", route, ok)
	}
	if !remote.pan(PanLeft) {
		t.Fatal("remote did not pan back")
	}
	restored, err := remote.rawCells(0xc0)
	if err != nil || !bytes.Equal(restored, remoteCells) {
		t.Fatalf("restored=%x error=%v", restored, err)
	}
	// A new width gets fresh state. No physical geometry is changed and no
	// old pan offset or routing map is carried across the replacement.
	remote = viewport{width: 2}
	frame.ID = 12
	if err := remote.setFrame(frame); err != nil {
		t.Fatal(err)
	}
	if route, ok := remote.route(RouteBase); !ok || route.ID != 12 {
		t.Fatal("replacement retained an old frame identity")
	}
	unchanged, err := local.rawCells(0xc0)
	if err != nil || !bytes.Equal(unchanged, localCells) || local.offset != 0 || local.width != 8 || local.id != 11 {
		t.Fatal("remote pan/resize altered local viewport")
	}
}

func TestVirtualBrailleCursorUsesTranslatedPosition(t *testing.T) {
	v := viewport{width: 4}
	if err := v.setFrame(Frame{Text: "the cat", Cursor: 4, Contract: true, Table: "en-us-g2.ctb"}); err != nil {
		t.Fatal(err)
	}
	cells, err := v.rawCells(0xc0)
	if err != nil || !bytes.Equal(cells, []byte{0x2e, 0, 0xc9, 1}) {
		t.Fatalf("translated cursor=%x error=%v", cells, err)
	}
	if !v.pan(PanRight) {
		t.Fatal("did not pan past cursor")
	}
	cells, err = v.rawCells(0xc0)
	if err != nil || !bytes.Equal(cells, []byte{0x1e, 0, 0, 0}) {
		t.Fatalf("hidden cursor=%x error=%v", cells, err)
	}
	if err := v.setFrame(Frame{ID: 14, Text: "the cat", Cursor: 7, Contract: true, Table: "en-us-g2.ctb"}); err != nil {
		t.Fatal(err)
	}
	cells, err = v.rawCells(0xc0)
	if err != nil || !bytes.Equal(cells, []byte{0x1e, 0xc0, 0, 0}) {
		t.Fatalf("end cursor=%x error=%v", cells, err)
	}
	if route, ok := v.route(RouteBase + 1); !ok || route != (RoutingEvent{ID: 14, Offset: 7}) {
		t.Fatalf("end route=%+v ok=%v", route, ok)
	}
}

func TestVirtualBrailleExplicitComputerTableAndFailure(t *testing.T) {
	v := viewport{width: 4}
	// Contract selects the helper's liblouis path; the table determines whether
	// it contracts. A future virtual-helper API must resolve this distinction.
	if err := v.setFrame(Frame{ID: 15, Text: "cat", Cursor: -1, Contract: true, Table: "en-us-comp8.ctb"}); err != nil {
		t.Fatal(err)
	}
	cells, err := v.rawCells(0)
	if err != nil || !bytes.Equal(cells, []byte{9, 1, 0x1e, 0}) {
		t.Fatalf("computer table=%x error=%v", cells, err)
	}
	before := v
	if err := v.setFrame(Frame{Text: "cat", Cursor: -1, Contract: true, Table: "missing-remote-test-table.ctb"}); err == nil {
		t.Fatal("missing table accepted")
	}
	if !reflect.DeepEqual(v, before) {
		t.Fatal("failed translation replaced a valid viewport")
	}
}