// Copyright 2015 The Prometheus 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 collector

import (
	"os"
	"strings"
	"testing"
)

func Test_parseTCPStatsError(t *testing.T) {
	tests := []struct {
		name string
		in   string
	}{
		{
			name: "too few fields",
			in:   "sl  local_address\n  0: 00000000:0016",
		},
		{
			name: "missing colon in tx-rx field",
			in: "sl  local_address rem_address   st tx_queue rx_queue\n" +
				" 1: 0F02000A:0016 0202000A:8B6B 01 0000000000000001",
		},
		{
			name: "tx parsing issue",
			in: "sl  local_address rem_address   st tx_queue rx_queue\n" +
				" 1: 0F02000A:0016 0202000A:8B6B 01 0000000x:00000001",
		},
		{
			name: "rx parsing issue",
			in: "sl  local_address rem_address   st tx_queue rx_queue\n" +
				" 1: 0F02000A:0016 0202000A:8B6B 01 00000000:0000000x",
		},
		{
			name: "state parsing issue",
			in: "sl  local_address rem_address   st tx_queue rx_queue\n" +
				" 1: 0F02000A:0016 0202000A:8B6B 0H 00000000:00000001",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if _, err := parseTCPStats(strings.NewReader(tt.in)); err == nil {
				t.Fatal("expected an error, but none occurred")
			}
		})
	}
}

func TestTCPStat(t *testing.T) {

	noFile, _ := os.Open("follow the white rabbit")
	defer noFile.Close()

	if _, err := parseTCPStats(noFile); err == nil {
		t.Fatal("expected an error, but none occurred")
	}

	file, err := os.Open("fixtures/proc/net/tcpstat")
	if err != nil {
		t.Fatal(err)
	}
	defer file.Close()

	tcpStats, err := parseTCPStats(file)
	if err != nil {
		t.Fatal(err)
	}

	if want, got := 1, int(tcpStats[tcpEstablished]); want != got {
		t.Errorf("want tcpstat number of established state %d, got %d", want, got)
	}

	if want, got := 1, int(tcpStats[tcpListen]); want != got {
		t.Errorf("want tcpstat number of listen state %d, got %d", want, got)
	}

	if want, got := 42, int(tcpStats[tcpTxQueuedBytes]); want != got {
		t.Errorf("want tcpstat number of bytes in tx queue %d, got %d", want, got)
	}
	if want, got := 1, int(tcpStats[tcpRxQueuedBytes]); want != got {
		t.Errorf("want tcpstat number of bytes in rx queue %d, got %d", want, got)
	}

}

func Test_getTCPStats(t *testing.T) {
	type args struct {
		statsFile string
	}
	tests := []struct {
		name    string
		args    args
		wantErr bool
	}{
		{
			name:    "file not found",
			args:    args{statsFile: "somewhere over the rainbow"},
			wantErr: true,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			_, err := getTCPStats(tt.args.statsFile)
			if (err != nil) != tt.wantErr {
				t.Errorf("getTCPStats() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			// other cases are covered by TestTCPStat()
		})
	}
}