package tentacle

import (
	"bufio"
	"bytes"
	"errors"
	"io"
	"strings"
	"testing"
)

func TestFramingBoundsAndRequiresNewline(t *testing.T) {
	for _, testCase := range []struct {
		name  string
		input string
		want  error
	}{
		{"valid", strings.Repeat("x", MaxFrameBytes) + "\n", nil},
		{"oversized", strings.Repeat("x", MaxFrameBytes+1) + "\n", ErrLimit},
		{"unterminated", `{}`, io.ErrUnexpectedEOF},
		{"empty", "", io.EOF},
	} {
		t.Run(testCase.name, func(t *testing.T) {
			_, err := read_frame(bufio.NewReaderSize(strings.NewReader(testCase.input), 32))
			if !errors.Is(err, testCase.want) {
				t.Fatalf("got %v, want %v", err, testCase.want)
			}
		})
	}
}

func TestResponseValidation(t *testing.T) {
	for _, valid := range []string{
		`{"jsonrpc":"2.0","id":"1","result":null}`,
		`{"jsonrpc":"2.0","id":"1","result":{"text":"é猫😀é"}}`,
		`{"jsonrpc":"2.0","id":"1","error":{"code":-32601,"message":"Unknown method"}}`,
	} {
		if _, err := decode_response([]byte(valid)); err != nil {
			t.Errorf("valid response rejected: %v", err)
		}
	}
	for _, invalid := range []string{
		`[]`, `null`, `{}`, `{"jsonrpc":"2.0","id":"1"}`,
		`{"jsonrpc":"2.0","id":"1","result":null,"error":null}`,
		`{"jsonrpc":"2.0","id":"1","error":null}`,
		`{"jsonrpc":"2.0","id":1,"result":null}`,
		`{"jsonrpc":"1.0","id":"1","result":null}`,
		`{"jsonrpc":"2.0","id":"1","id":"2","result":null}`,
		`{"jsonrpc":"2.0","id":"1","result":{"x":0,"x":1}}`,
		`{"jsonrpc":"2.0","id":"1","result":null,"extra":1}`,
		`{"jsonrpc":"2.0","id":"1","error":{"message":"missing code"}}`,
		`{"jsonrpc":"2.0","id":"1","error":{"code":null,"message":"null code"}}`,
		`{"jsonrpc":"2.0","id":"1","error":{"code":1,"message":null}}`,
		`{"jsonrpc":"2.0","id":"1","result":"` + string([]byte{0xff}) + `"}`,
		`{"jsonrpc":"2.0","id":"1","result":` + strings.Repeat("[", 40) + "0" + strings.Repeat("]", 40) + `}`,
		`{"jsonrpc":"2.0","id":"1","result":null} {}`,
	} {
		if _, err := decode_response([]byte(invalid)); err == nil {
			t.Errorf("invalid response accepted: %q", invalid)
		}
	}
	if strings.Contains((&RPCError{Code: 1, Message: "private text"}).Error(), "private") {
		t.Fatal("remote text leaked through Error")
	}
}

func FuzzResponseDecoder(f *testing.F) {
	f.Add([]byte(`{"jsonrpc":"2.0","id":"1","result":null}`))
	f.Add([]byte(`{"jsonrpc":"2.0","id":"1","error":{"code":1,"message":"bad"}}`))
	f.Fuzz(func(t *testing.T, data []byte) {
		if len(data) > MaxFrameBytes {
			t.Skip()
		}
		_, _ = decode_response(data)
		_, _ = read_frame(bufio.NewReader(bytes.NewReader(data)))
	})
}

func TestSettingsRegistrationRequiresOneInteractiveCommand(t *testing.T) {
	command := Command{ID: "settings", Title: "Settings", Settings: true, Interaction: true, Presentation: true}
	registration := Registration{Protocol: Version{Major: 1}, Session: "test", Commands: []Command{command}}
	if err := validate_registration(registration, "test"); err != nil {
		t.Fatal(err)
	}
	registration.Commands[0].Interaction = false
	if err := validate_registration(registration, "test"); err == nil {
		t.Fatal("accepted a settings handler without interaction")
	}
	registration.Commands[0] = command
	command.ID = "other-settings"
	registration.Commands = append(registration.Commands, command)
	if err := validate_registration(registration, "test"); err == nil {
		t.Fatal("accepted two settings entry points")
	}
}