// Copyright 2024 Redpanda Data, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package aws

import (
	"context"
	"errors"
	"testing"
	"time"

	"github.com/aws/aws-sdk-go-v2/service/lambda"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/redpanda-data/benthos/v4/public/service"
)

type mockLambda struct {
	fn func(*lambda.InvokeInput) (*lambda.InvokeOutput, error)
}

func (m *mockLambda) Invoke(ctx context.Context, in *lambda.InvokeInput, opts ...func(*lambda.Options)) (*lambda.InvokeOutput, error) {
	return m.fn(in)
}

func TestLambdaErrors(t *testing.T) {
	mock := &mockLambda{
		fn: func(ii *lambda.InvokeInput) (*lambda.InvokeOutput, error) {
			require.Equal(t, "foofn", *ii.FunctionName)
			return nil, errors.New("meow " + string(ii.Payload))
		},
	}

	p, err := newLambdaProc(mock, false, "foofn", 3, "", time.Second, service.MockResources())
	require.NoError(t, err)

	bCtx := context.Background()
	inBatch := service.MessageBatch{
		service.NewMessage([]byte("foo")),
		service.NewMessage([]byte("bar")),
		service.NewMessage([]byte("baz")),
	}

	outBatches, err := p.ProcessBatch(bCtx, inBatch)
	require.NoError(t, err)

	require.Len(t, outBatches, 1)
	require.Len(t, outBatches[0], 3)

	assert.EqualError(t, outBatches[0][0].GetError(), "meow foo")
	assert.EqualError(t, outBatches[0][1].GetError(), "meow bar")
	assert.EqualError(t, outBatches[0][2].GetError(), "meow baz")

	p, err = newLambdaProc(mock, true, "foofn", 3, "", time.Second, service.MockResources())
	require.NoError(t, err)

	outBatches, err = p.ProcessBatch(bCtx, inBatch)
	require.NoError(t, err)

	require.Len(t, outBatches, 1)
	require.Len(t, outBatches[0], 3)

	assert.EqualError(t, outBatches[0][0].GetError(), "meow foo")
	assert.EqualError(t, outBatches[0][1].GetError(), "meow bar")
	assert.EqualError(t, outBatches[0][2].GetError(), "meow baz")
}

func TestLambdaMutations(t *testing.T) {
	mock := &mockLambda{
		fn: func(ii *lambda.InvokeInput) (*lambda.InvokeOutput, error) {
			require.Equal(t, "foofn", *ii.FunctionName)
			return &lambda.InvokeOutput{
				Payload: []byte("meow " + string(ii.Payload)),
			}, nil
		},
	}

	p, err := newLambdaProc(mock, false, "foofn", 3, "", time.Second, service.MockResources())
	require.NoError(t, err)

	bCtx := context.Background()
	inBatch := service.MessageBatch{
		service.NewMessage([]byte("foo")),
		service.NewMessage([]byte("bar")),
		service.NewMessage([]byte("baz")),
	}

	outBatches, err := p.ProcessBatch(bCtx, inBatch.Copy())
	require.NoError(t, err)

	require.Len(t, outBatches, 1)
	require.Len(t, outBatches[0], 3)

	b, _ := outBatches[0][0].AsBytes()
	assert.Equal(t, "meow foo", string(b))
	b, _ = outBatches[0][1].AsBytes()
	assert.Equal(t, "meow bar", string(b))
	b, _ = outBatches[0][2].AsBytes()
	assert.Equal(t, "meow baz", string(b))

	// Ensure origin didn't change
	b, _ = inBatch[0].AsBytes()
	assert.Equal(t, "foo", string(b))
	b, _ = inBatch[1].AsBytes()
	assert.Equal(t, "bar", string(b))
	b, _ = inBatch[2].AsBytes()
	assert.Equal(t, "baz", string(b))

	p, err = newLambdaProc(mock, true, "foofn", 3, "", time.Second, service.MockResources())
	require.NoError(t, err)

	outBatches, err = p.ProcessBatch(bCtx, inBatch.Copy())
	require.NoError(t, err)

	require.Len(t, outBatches, 1)
	require.Len(t, outBatches[0], 3)

	b, _ = outBatches[0][0].AsBytes()
	assert.Equal(t, "meow foo", string(b))
	b, _ = outBatches[0][1].AsBytes()
	assert.Equal(t, "meow bar", string(b))
	b, _ = outBatches[0][2].AsBytes()
	assert.Equal(t, "meow baz", string(b))

	// Ensure origin didn't change
	b, _ = inBatch[0].AsBytes()
	assert.Equal(t, "foo", string(b))
	b, _ = inBatch[1].AsBytes()
	assert.Equal(t, "bar", string(b))
	b, _ = inBatch[2].AsBytes()
	assert.Equal(t, "baz", string(b))
}