// Copyright © 2020 The Knative 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 source

import (
	"fmt"

	"knative.dev/client/pkg/sources"

	"github.com/spf13/cobra"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"knative.dev/client/pkg/commands"
	"knative.dev/client/pkg/commands/flags"
	"knative.dev/client/pkg/commands/source/duck"
	"knative.dev/client/pkg/dynamic"
	knerrors "knative.dev/client/pkg/errors"
)

const (
	sourceListGroup   = "client.knative.dev"
	sourceListVersion = "v1alpha1"
	sourceListKind    = "SourceList"
)

var listExample = `
  # List available eventing sources
  kn source list

  # List PingSource type sources
  kn source list --type=PingSource

  # List PingSource and ApiServerSource types sources
  kn source list --type=PingSource --type=apiserversource`

// NewListCommand defines and processes `kn source list`
func NewListCommand(p *commands.KnParams) *cobra.Command {
	filterFlags := &flags.SourceTypeFilters{}
	listFlags := flags.NewListPrintFlags(ListHandlers)
	listCommand := &cobra.Command{
		Use:     "list",
		Short:   "List event sources",
		Aliases: []string{"ls"},
		Example: listExample,
		RunE: func(cmd *cobra.Command, args []string) error {
			namespace, err := p.GetNamespace(cmd)
			if err != nil {
				return err
			}
			dynamicClient, err := p.NewDynamicClient(namespace)
			if err != nil {
				return err
			}

			var filters dynamic.WithTypes
			for _, filter := range filterFlags.Filters {
				filters = append(filters, dynamic.WithTypeFilter(filter))
			}

			sourceList, err := dynamicClient.ListSources(cmd.Context(), filters...)

			switch {
			case knerrors.IsForbiddenError(err):
				gvks := sources.BuiltInSourcesGVKs()
				if sourceList, err = dynamicClient.ListSourcesUsingGVKs(cmd.Context(), &gvks, filters...); err != nil {
					return knerrors.GetError(err)
				}
			case err != nil:
				return knerrors.GetError(err)
			}

			if sourceList == nil {
				sourceList = &unstructured.UnstructuredList{}
			}
			if !listFlags.GenericPrintFlags.OutputFlagSpecified() && len(sourceList.Items) == 0 {
				fmt.Fprintf(cmd.OutOrStdout(), "No sources found.\n")
				return nil
			}

			if sourceList.GroupVersionKind().Empty() {
				sourceList.SetGroupVersionKind(schema.GroupVersionKind{Group: sourceListGroup, Version: sourceListVersion, Kind: sourceListKind})
			}
			// empty namespace indicates all namespaces flag is specified
			if namespace == "" {
				listFlags.EnsureWithNamespace()
			}
			printer, err := listFlags.ToPrinter()
			if err != nil {
				return nil
			}
			if listFlags.GenericPrintFlags.OutputFlagSpecified() {
				return printer.PrintObj(sourceList, cmd.OutOrStdout())
			}
			// Convert the source list to DuckSourceList only if human readable table printing requested
			sourceDuckList := duck.ToSourceList(sourceList)
			err = printer.PrintObj(sourceDuckList, cmd.OutOrStdout())
			if err != nil {
				return err
			}
			return nil
		},
	}
	commands.AddNamespaceFlags(listCommand.Flags(), true)
	listFlags.AddFlags(listCommand)
	filterFlags.Add(listCommand, "source type")
	return listCommand
}