// Copyright 2017 Istio 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 cmd

import (
	"context"
	"sync"

	ot "github.com/opentracing/opentracing-go"
	"github.com/opentracing/opentracing-go/ext"
	"github.com/spf13/cobra"
	"golang.org/x/time/rate"

	mixerpb "istio.io/api/mixer/v1"
	"istio.io/istio/mixer/cmd/shared"
)

func reportCmd(rootArgs *rootArgs, printf, fatalf shared.FormatFn) *cobra.Command {
	return &cobra.Command{
		Use:   "report",
		Short: "Invokes Mixer's Report API to generate telemetry.",
		Long: "The Report method is used to produce telemetry. Mixer\n" +
			"expects a set of attributes as input, which it uses, along with\n" +
			"its configuration, to determine which adapters to invoke and with\n" +
			"which parameters in order to output the telemetry.",
		Args: cobra.ExactArgs(0),
		Run: func(cmd *cobra.Command, args []string) {
			report(rootArgs, printf, fatalf)
		}}
}

func report(rootArgs *rootArgs, printf, fatalf shared.FormatFn) {
	var attrs *mixerpb.CompressedAttributes
	var dw []string
	var err error

	if attrs, dw, err = parseAttributes(rootArgs); err != nil {
		fatalf("%v", err)
	}

	var cs *clientState
	if cs, err = createAPIClient(rootArgs.mixerAddress, rootArgs.tracingOptions); err != nil {
		fatalf("Unable to establish connection to %s: %v", rootArgs.mixerAddress, err)
	}
	defer deleteAPIClient(cs)

	span, ctx := ot.StartSpanFromContext(context.Background(), "mixc Report", ext.SpanKindRPCClient)

	var rl *rate.Limiter
	if rootArgs.rate > 0 {
		rl = rate.NewLimiter(rate.Limit(rootArgs.rate), rootArgs.rate)
	}
	if rootArgs.concurrency < 1 {
		fatalf("concurrency has to be at least 1")
	}
	var wg sync.WaitGroup
	wg.Add(rootArgs.concurrency)
	for c := 0; c < rootArgs.concurrency; c++ {
		go func() {
			defer wg.Done()
			for i := 0; i < rootArgs.repeat; i += rootArgs.reportBatchSize {
				bs := rootArgs.reportBatchSize
				if bs > rootArgs.repeat-i {
					bs = rootArgs.repeat - i
				}
				ca := []mixerpb.CompressedAttributes{}
				for s := 0; s < bs; s++ {
					ca = append(ca, *attrs)
				}
				request := mixerpb.ReportRequest{
					Attributes:   ca,
					DefaultWords: dw,
				}
				if rl != nil {
					_ = rl.Wait(context.Background())
				}
				_, err := cs.client.Report(ctx, &request)

				if rootArgs.printResponse {
					printf("Report RPC returned %s", decodeError(err))
				}
			}
		}()
	}
	wg.Wait()
	span.Finish()
}
