//go:build brlapi && cgo

// Copyright (c) 2026 Storm Dragon
// Authors: Storm Dragon, Angus Kola
// SPDX-License-Identifier: GPL-3.0-or-later

package braille

import (
	"bytes"
	"context"
	"encoding/json"
	"strings"
	"testing"
)

func runVirtualLines(t *testing.T, lines ...string) []VirtualResponse {
	t.Helper()
	var output bytes.Buffer
	if err := RunVirtual(context.Background(), strings.NewReader(strings.Join(lines, "\n")+"\n"), &output); err != nil {
		t.Fatal(err)
	}
	var responses []VirtualResponse
	decoder := json.NewDecoder(&output)
	for decoder.More() {
		var response VirtualResponse
		if err := decoder.Decode(&response); err != nil {
			t.Fatal(err)
		}
		responses = append(responses, response)
	}
	return responses
}

func TestVirtualHelperRendersPansAndRoutes(t *testing.T) {
	responses := runVirtualLines(t,
		`{"frame":{"text":"abcdef","cursor":1,"id":9}}`, // No width yet: nothing rendered.
		`{"width":4}`,
		`{"pan":"right"}`,
		`{"route":1}`,
		`{"pan":"left"}`,
		`{"width":0}`,
		`{"frame":{"text":"x","cursor":-1,"id":10}}`,
	)
	if len(responses) != 4 {
		t.Fatalf("responses = %+v", responses)
	}
	first := responses[0].Cells
	// Computer Braille a=dot1, b=dots12; the cursor on b adds dots 7 and 8.
	if len(first) != 4 || first[0] != 0x01 || first[1] != 0x03|VirtualCursorDots {
		t.Fatalf("first page = %#v", first)
	}
	if second := responses[1].Cells; len(second) != 4 || second[0] == first[0] {
		t.Fatalf("pan right did not change the page: %#v", second)
	}
	if route := responses[2].Route; route == nil || route.ID != 9 || route.Offset != 5 {
		t.Fatalf("route = %+v", route)
	}
	if !equalCells(responses[3].Cells, first) {
		t.Fatalf("pan left did not restore the first page: %#v", responses[3].Cells)
	}
}

func equalCells(a, b []int) bool {
	if len(a) != len(b) {
		return false
	}
	for index := range a {
		if a[index] != b[index] {
			return false
		}
	}
	return true
}

func TestVirtualHelperUsesContractedFrameTable(t *testing.T) {
	responses := runVirtualLines(t, `{"width":8}`,
		`{"frame":{"text":"the cat","cursor":-1,"id":1,"contract":true,"table":"en-ueb-g2.ctb"}}`)
	if len(responses) != 1 || len(responses[0].Cells) != 8 {
		t.Fatalf("responses = %+v", responses)
	}
	// Contraction makes "the" a single cell, so the line fits in fewer cells
	// than its seven characters: the last cell is blank padding.
	if responses[0].Cells[7] != 0 {
		t.Fatalf("contracted output was not shorter: %#v", responses[0].Cells)
	}
}

func TestVirtualHelperRejectsInvalidRequests(t *testing.T) {
	for _, line := range []string{`{"width":5000}`, `{}`, `not json`, `{"pan":"up"}`} {
		var output bytes.Buffer
		if RunVirtual(context.Background(), strings.NewReader(line+"\n"), &output) == nil {
			t.Fatal("invalid request accepted", line)
		}
	}
}