package directstream

import (
	"bytes"
	"errors"
	"testing"
)

func TestDecodeControlFrame(t *testing.T) {
	frame, err := DecodeControlFrame([]byte(`{"type":"authenticate","ticket":"ticket-value"}`))
	if err != nil {
		t.Fatalf("DecodeControlFrame() error = %v", err)
	}
	if frame.Type != ControlAuthenticate || frame.Ticket != "ticket-value" {
		t.Fatalf("DecodeControlFrame() = %#v", frame)
	}
}

func TestDecodeControlFrameRejectsAmbiguousOrOversizedInput(t *testing.T) {
	tests := []struct {
		name    string
		payload []byte
	}{
		{name: "empty", payload: nil},
		{name: "unknown field", payload: []byte(`{"type":"writer.request","extra":true}`)},
		{name: "multiple values", payload: []byte(`{"type":"writer.request"}{"type":"writer.release"}`)},
		{name: "unknown type", payload: []byte(`{"type":"shell.execute"}`)},
		{name: "missing ticket", payload: []byte(`{"type":"authenticate"}`)},
		{name: "ticket on writer request", payload: []byte(`{"type":"writer.request","ticket":"unexpected"}`)},
		{name: "oversized", payload: bytes.Repeat([]byte{'x'}, MaxControlFrameBytes+1)},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			if _, err := DecodeControlFrame(test.payload); !errors.Is(err, ErrInvalidControlFrame) {
				t.Fatalf("DecodeControlFrame() error = %v, want ErrInvalidControlFrame", err)
			}
		})
	}
}

func TestValidateClientDataRequiresAuthenticatedWriterAndBoundedPayload(t *testing.T) {
	if err := ValidateClientData(AccessWriter, false, []byte{0x3a}); !errors.Is(err, ErrStreamUnauthenticated) {
		t.Fatalf("ValidateClientData(unauthenticated) error = %v", err)
	}
	if err := ValidateClientData(AccessViewer, true, []byte{0x3a}); !errors.Is(err, ErrWriterRequired) {
		t.Fatalf("ValidateClientData(viewer) error = %v", err)
	}
	if err := ValidateClientData(AccessWriter, true, nil); !errors.Is(err, ErrInvalidDataFrame) {
		t.Fatalf("ValidateClientData(empty) error = %v", err)
	}
	if err := ValidateClientData(AccessWriter, true, bytes.Repeat([]byte{0x3a}, MaxDataFrameBytes+1)); !errors.Is(err, ErrInvalidDataFrame) {
		t.Fatalf("ValidateClientData(oversized) error = %v", err)
	}
	if err := ValidateClientData(AccessWriter, true, []byte{0x00, 0x3a, 0xff}); err != nil {
		t.Fatalf("ValidateClientData(valid binary) error = %v", err)
	}
}

func TestValidateChannelAndAccess(t *testing.T) {
	for _, channel := range []string{"CH01", "CH24", "CH25", "CH48"} {
		if err := ValidateChannel(channel); err != nil {
			t.Fatalf("ValidateChannel(%q) error = %v", channel, err)
		}
	}
	for _, channel := range []string{"", "CH00", "CH49", "ttyWCH4", "ch01"} {
		if err := ValidateChannel(channel); err == nil {
			t.Fatalf("ValidateChannel(%q) error = nil", channel)
		}
	}
	for _, access := range []string{AccessViewer, AccessWriter} {
		if err := ValidateAccess(access); err != nil {
			t.Fatalf("ValidateAccess(%q) error = %v", access, err)
		}
	}
}