// Copyright 2021 PingCAP, 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,
// See the License for the specific language governing permissions and
// limitations under the License.

package cli

import (
	"encoding/json"
	"strings"

	"github.com/pingcap/log"
	v2 "github.com/pingcap/tiflow/cdc/api/v2"
	apiv2client "github.com/pingcap/tiflow/pkg/api/v2"
	cmdcontext "github.com/pingcap/tiflow/pkg/cmd/context"
	"github.com/pingcap/tiflow/pkg/cmd/factory"
	"github.com/pingcap/tiflow/pkg/cmd/util"
	putil "github.com/pingcap/tiflow/pkg/util"
	"github.com/r3labs/diff"
	"github.com/spf13/cobra"
	"github.com/spf13/pflag"
	"go.uber.org/zap"
)

// updateChangefeedOptions defines common flags for the `cli changefeed update` command.
type updateChangefeedOptions struct {
	apiV2Client apiv2client.APIV2Interface

	commonChangefeedOptions *changefeedCommonOptions
	changefeedID            string
	namespace               string
}

// newUpdateChangefeedOptions creates new options for the `cli changefeed update` command.
func newUpdateChangefeedOptions(commonChangefeedOptions *changefeedCommonOptions) *updateChangefeedOptions {
	return &updateChangefeedOptions{
		commonChangefeedOptions: commonChangefeedOptions,
	}
}

// addFlags receives a *cobra.Command reference and binds
// flags related to template printing to it.
func (o *updateChangefeedOptions) addFlags(cmd *cobra.Command) {
	o.commonChangefeedOptions.addFlags(cmd)
	cmd.PersistentFlags().StringVarP(&o.namespace, "namespace", "n", "default", "Replication task (changefeed) Namespace")
	cmd.PersistentFlags().StringVarP(&o.changefeedID, "changefeed-id", "c", "", "Replication task (changefeed) ID")
	_ = cmd.MarkPersistentFlagRequired("changefeed-id")
}

func (o *updateChangefeedOptions) getChangefeedConfig(cmd *cobra.Command,
	info *v2.ChangeFeedInfo,
) *v2.ChangefeedConfig {
	replicaConfig := info.Config
	res := &v2.ChangefeedConfig{
		TargetTs:      info.TargetTs,
		SinkURI:       info.SinkURI,
		ReplicaConfig: replicaConfig,
	}
	cmd.Flags().Visit(func(flag *pflag.Flag) {
		switch flag.Name {
		case "upstream-pd":
			res.PDAddrs = strings.Split(o.commonChangefeedOptions.upstreamPDAddrs, ",")
		case "upstream-ca":
			res.CAPath = o.commonChangefeedOptions.upstreamCaPath
		case "upstream-cert":
			res.CertPath = o.commonChangefeedOptions.upstreamCertPath
		case "upstream-key":
			res.KeyPath = o.commonChangefeedOptions.upstreamKeyPath
		}
	})
	return res
}

// complete adapts from the command line args to the data and client required.
func (o *updateChangefeedOptions) complete(f factory.Factory) error {
	apiClient, err := f.APIV2Client()
	if err != nil {
		return err
	}
	o.apiV2Client = apiClient
	return nil
}

// run the `cli changefeed update` command.
func (o *updateChangefeedOptions) run(cmd *cobra.Command) error {
	ctx := cmdcontext.GetDefaultContext()

	old, err := o.apiV2Client.Changefeeds().Get(ctx, o.namespace, o.changefeedID)
	if err != nil {
		return err
	}

	newInfo, err := o.applyChanges(old, cmd)
	if err != nil {
		return err
	}
	// sink uri is not changed, set old to empty to skip diff
	if newInfo.SinkURI == "" {
		old.SinkURI = ""
	}
	changelog, err := diff.Diff(old, newInfo)
	if err != nil {
		return err
	}
	if len(changelog) == 0 {
		cmd.Printf("changefeed config is the same with the old one, do nothing\n")
		return nil
	}
	cmd.Printf("Diff of changefeed config:\n")
	for _, change := range changelog {
		cmd.Printf("%+v\n", change)
	}

	if !o.commonChangefeedOptions.noConfirm {
		cmd.Printf("Could you agree to apply changes above to changefeed [Y/N]\n")
		confirmed := readYOrN(cmd)
		if !confirmed {
			cmd.Printf("No update to changefeed.\n")
			return nil
		}
	}

	changefeedConfig := o.getChangefeedConfig(cmd, newInfo)
	info, err := o.apiV2Client.Changefeeds().Update(ctx, changefeedConfig, o.namespace, o.changefeedID)
	if err != nil {
		return err
	}
	infoStr, err := json.Marshal(info)
	if err != nil {
		return err
	}
	cmd.Printf("Update changefeed config successfully! "+
		"\nID: %s\nInfo: %s\n", o.changefeedID, infoStr)

	return nil
}

// applyChanges applies the new changes to the old changefeed.
func (o *updateChangefeedOptions) applyChanges(oldInfo *v2.ChangeFeedInfo,
	cmd *cobra.Command,
) (*v2.ChangeFeedInfo, error) {
	newInfo, err := oldInfo.Clone()
	if err != nil {
		return nil, err
	}
	newInfo.SinkURI = ""
	cmd.Flags().Visit(func(flag *pflag.Flag) {
		switch flag.Name {
		case "target-ts":
			newInfo.TargetTs = o.commonChangefeedOptions.targetTs
		case "sink-uri":
			newInfo.SinkURI = o.commonChangefeedOptions.sinkURI
		case "config":
			cfg := newInfo.Config.ToInternalReplicaConfig()
			if err = o.commonChangefeedOptions.strictDecodeConfig("TiCDC changefeed", cfg); err != nil {
				log.Error("decode config file error", zap.Error(err))
			}
			newInfo.Config = v2.ToAPIReplicaConfig(cfg)
		case "schema-registry":
			newInfo.Config.Sink.SchemaRegistry = putil.AddressOf(o.commonChangefeedOptions.schemaRegistry)
		case "sort-engine":
		case "sort-dir":
			log.Warn("this flag cannot be updated and will be ignored", zap.String("flagName", flag.Name))
		case "changefeed-id", "no-confirm":
			// Do nothing, these are some flags from the changefeed command,
			// we don't use it to update, but we do use these flags.
		case "pd", "log-level", "key", "cert", "ca", "server":
		// Do nothing, this is a flags from the cli command
		// we don't use it to update, but we do use these flags.
		case "upstream-pd", "upstream-ca", "upstream-cert", "upstream-key":
		default:
			// use this default branch to prevent new added parameter is not added
			log.Warn("unsupported flag, please report a bug", zap.String("flagName", flag.Name))
		}
	})
	if err != nil {
		return nil, err
	}
	return newInfo, nil
}

// newCmdPauseChangefeed creates the `cli changefeed update` command.
func newCmdUpdateChangefeed(f factory.Factory) *cobra.Command {
	commonChangefeedOptions := newChangefeedCommonOptions()
	o := newUpdateChangefeedOptions(commonChangefeedOptions)

	command := &cobra.Command{
		Use:   "update",
		Short: "Update config of an existing replication task (changefeed)",
		Args:  cobra.NoArgs,
		Run: func(cmd *cobra.Command, args []string) {
			util.CheckErr(o.complete(f))
			util.CheckErr(o.run(cmd))
		},
	}

	o.addFlags(command)

	return command
}