package protocol

import (
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/require"
)

func TestEnvelopeRoundTripPreservesMetadata(t *testing.T) {
	now := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
	metadata := Metadata{
		MessageID:     messageID,
		SentAt:        &now,
		ExpiresAt:     &now,
		CorrelationID: commandID,
		CausationID:   deviceID,
	}
	data, err := encodeEnvelope(metadata, map[string]bool{"value": true})
	require.NoError(t, err)

	envelope, err := parseEnvelope(data)
	require.NoError(t, err)
	require.Equal(t, Schema, envelope.Schema)
	require.Equal(t, metadata, envelope.Metadata)
	require.JSONEq(t, `{"value":true}`, string(envelope.Payload))
	require.Equal(t, 5*time.Minute, MeasurementRepeatInterval)
	require.Equal(t, 5*time.Minute, OnlineRepeatInterval)
	require.Equal(t, 15*time.Minute, DeviceContactTimeout)
}

func TestEnvelopeRejectsInvalidWireData(t *testing.T) {
	valid := `{"schema":1,"message_id":"` + messageID + `","payload":{}}`

	testCases := []struct {
		name string
		data string
	}{
		{
			name: "rejects unsupported schema",
			data: strings.Replace(valid, `"schema":1`, `"schema":2`, 1),
		},
		{
			name: "rejects unknown fields",
			data: strings.Replace(valid, `"payload":{}`, `"payload":{},"extra":true`, 1),
		},
		{
			name: "rejects missing payload",
			data: `{"schema":1,"message_id":"` + messageID + `"}`,
		},
		{
			name: "rejects null payload",
			data: strings.Replace(valid, `"payload":{}`, `"payload":null`, 1),
		},
		{
			name: "rejects non-object payload",
			data: strings.Replace(valid, `"payload":{}`, `"payload":[]`, 1),
		},
		{
			name: "rejects missing identity",
			data: `{"schema":1,"payload":{}}`,
		},
		{
			name: "rejects invalid correlation",
			data: strings.Replace(valid, `"payload":{}`, `"payload":{},"correlation_id":"bad"`, 1),
		},
		{
			name: "rejects invalid causation",
			data: strings.Replace(valid, `"payload":{}`, `"payload":{},"causation_id":"bad"`, 1),
		},
		{
			name: "rejects non-UTC time",
			data: strings.Replace(valid, `"payload":{}`, `"payload":{},"sent_at":"2026-01-01T01:00:00+01:00"`, 1),
		},
		{
			name: "rejects invalid expiry",
			data: strings.Replace(valid, `"payload":{}`, `"payload":{},"expires_at":"bad"`, 1),
		},
		{
			name: "rejects trailing JSON",
			data: valid + `{}`,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			_, err := parseEnvelope([]byte(tc.data))
			require.Error(t, err)
		})
	}

	_, err := encodeEnvelope(Metadata{MessageID: "bad"}, map[string]bool{})
	require.Error(t, err)

	_, err = encodeEnvelope(Metadata{MessageID: messageID}, make(chan int))
	require.Error(t, err)

	_, err = encodeEnvelope(Metadata{MessageID: messageID}, []int{1})
	require.Error(t, err)
}