/*
Copyright 2021 The Dapr Authors
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 retry_test

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

	"github.com/cenkalti/backoff/v4"
	"github.com/stretchr/testify/assert"

	"github.com/dapr/kit/retry"
)

var errRetry = errors.New("Testing")

func TestDecode(t *testing.T) {
	tests := map[string]struct {
		config    interface{}
		overrides func(config *retry.Config)
		err       string
	}{
		"invalid policy type": {
			config: map[string]interface{}{
				"backOffPolicy": "invalid",
			},
			overrides: nil,
			err:       "1 error(s) decoding:\n\n* error decoding 'policy': invalid PolicyType \"invalid\": unexpected back off policy type: invalid",
		},
		"default": {
			config:    map[string]interface{}{},
			overrides: nil,
			err:       "",
		},
		"constant default": {
			config: map[string]interface{}{
				"backOffPolicy": "constant",
			},
			overrides: nil,
			err:       "",
		},
		"constant with duraction": {
			config: map[string]interface{}{
				"backOffPolicy":   "constant",
				"backOffDuration": "10s",
			},
			overrides: func(config *retry.Config) {
				config.Duration = 10 * time.Second
			},
			err: "",
		},
		"exponential default": {
			config: map[string]interface{}{
				"backOffPolicy": "exponential",
			},
			overrides: func(config *retry.Config) {
				config.Policy = retry.PolicyExponential
			},
			err: "",
		},
		"exponential with string settings": {
			config: map[string]interface{}{
				"backOffPolicy":              "exponential",
				"backOffInitialInterval":     "1000", // 1s
				"backOffRandomizationFactor": "1.0",
				"backOffMultiplier":          "2.0",
				"backOffMaxInterval":         "120000",  // 2m
				"backOffMaxElapsedTime":      "1800000", // 30m
			},
			overrides: func(config *retry.Config) {
				config.Policy = retry.PolicyExponential
				config.InitialInterval = 1 * time.Second
				config.RandomizationFactor = 1.0
				config.Multiplier = 2.0
				config.MaxInterval = 2 * time.Minute
				config.MaxElapsedTime = 30 * time.Minute
			},
			err: "",
		},
		"exponential with typed settings": {
			config: map[string]interface{}{
				"backOffPolicy":              "exponential",
				"backOffInitialInterval":     "1000ms", // 1s
				"backOffRandomizationFactor": 1.0,
				"backOffMultiplier":          2.0,
				"backOffMaxInterval":         "120s", // 2m
				"backOffMaxElapsedTime":      "30m",  // 30m
			},
			overrides: func(config *retry.Config) {
				config.Policy = retry.PolicyExponential
				config.InitialInterval = 1 * time.Second
				config.RandomizationFactor = 1.0
				config.Multiplier = 2.0
				config.MaxInterval = 2 * time.Minute
				config.MaxElapsedTime = 30 * time.Minute
			},
			err: "",
		},
		"map[string]string settings": {
			config: map[string]string{
				"backOffPolicy":              "exponential",
				"backOffInitialInterval":     "1000ms", // 1s
				"backOffRandomizationFactor": "1.0",
				"backOffMultiplier":          "2.0",
				"backOffMaxInterval":         "120s", // 2m
				"backOffMaxElapsedTime":      "30m",  // 30m
			},
			overrides: func(config *retry.Config) {
				config.Policy = retry.PolicyExponential
				config.InitialInterval = 1 * time.Second
				config.RandomizationFactor = 1.0
				config.Multiplier = 2.0
				config.MaxInterval = 2 * time.Minute
				config.MaxElapsedTime = 30 * time.Minute
			},
			err: "",
		},
	}

	for name, tc := range tests {
		t.Run(name, func(t *testing.T) {
			var actual retry.Config
			err := retry.DecodeConfigWithPrefix(&actual, tc.config, "backOff")
			if tc.err != "" {
				if assert.Error(t, err) {
					assert.Equal(t, tc.err, err.Error())
				}
			} else {
				b := actual.NewBackOff()
				config := retry.DefaultConfig()
				if tc.overrides != nil {
					tc.overrides(&config)
				}
				assert.Equal(t, config, actual, "unexpected decoded configuration")
				if actual.Policy == retry.PolicyConstant {
					_, ok := b.(*backoff.ConstantBackOff)
					assert.True(t, ok)
				} else if actual.Policy == retry.PolicyExponential {
					_, ok := b.(*backoff.ExponentialBackOff)
					assert.True(t, ok)
				}
			}
		})
	}
}

func TestRetryNotifyRecoverNoetries(t *testing.T) {
	config := retry.DefaultConfigWithNoRetry()
	config.Duration = 1

	var operationCalls, notifyCalls, recoveryCalls int

	b := config.NewBackOff()
	err := retry.NotifyRecover(func() error {
		operationCalls++

		return errRetry
	}, b, func(err error, d time.Duration) {
		notifyCalls++
	}, func() {
		recoveryCalls++
	})

	assert.Error(t, err)
	assert.Equal(t, errRetry, err)
	assert.Equal(t, 1, operationCalls)
	assert.Equal(t, 0, notifyCalls)
	assert.Equal(t, 0, recoveryCalls)
}

func TestRetryNotifyRecoverMaxRetries(t *testing.T) {
	config := retry.DefaultConfig()
	config.MaxRetries = 3
	config.Duration = 1

	var operationCalls, notifyCalls, recoveryCalls int

	b := config.NewBackOff()
	err := retry.NotifyRecover(func() error {
		operationCalls++

		return errRetry
	}, b, func(err error, d time.Duration) {
		notifyCalls++
	}, func() {
		recoveryCalls++
	})

	assert.Error(t, err)
	assert.Equal(t, errRetry, err)
	assert.Equal(t, 4, operationCalls)
	assert.Equal(t, 1, notifyCalls)
	assert.Equal(t, 0, recoveryCalls)
}

func TestRetryNotifyRecoverRecovery(t *testing.T) {
	config := retry.DefaultConfig()
	config.MaxRetries = 3
	config.Duration = 1

	var operationCalls, notifyCalls, recoveryCalls int

	b := config.NewBackOff()
	err := retry.NotifyRecover(func() error {
		operationCalls++

		if operationCalls >= 2 {
			return nil
		}

		return errRetry
	}, b, func(err error, d time.Duration) {
		notifyCalls++
	}, func() {
		recoveryCalls++
	})

	assert.NoError(t, err)
	assert.Equal(t, 2, operationCalls)
	assert.Equal(t, 1, notifyCalls)
	assert.Equal(t, 1, recoveryCalls)
}

func TestRetryNotifyRecoverCancel(t *testing.T) {
	config := retry.DefaultConfig()
	config.Policy = retry.PolicyConstant
	config.Duration = 1 * time.Minute

	var notifyCalls, recoveryCalls int

	ctx, cancel := context.WithCancel(context.Background())
	b := config.NewBackOffWithContext(ctx)
	errC := make(chan error, 1)
	startedC := make(chan struct{}, 100)

	go func() {
		errC <- retry.NotifyRecover(func() error {
			return errRetry
		}, b, func(err error, d time.Duration) {
			notifyCalls++
			startedC <- struct{}{}
		}, func() {
			recoveryCalls++
		})
	}()

	<-startedC
	cancel()

	err := <-errC
	assert.Error(t, err)
	assert.True(t, errors.Is(err, context.Canceled))
	assert.Equal(t, 1, notifyCalls)
	assert.Equal(t, 0, recoveryCalls)
}

func TestCheckEmptyConfig(t *testing.T) {
	var config retry.Config
	err := retry.DecodeConfig(&config, map[string]interface{}{})
	assert.NoError(t, err)
	defaultConfig := retry.DefaultConfig()
	assert.Equal(t, config, defaultConfig)
}