// Copyright 2024 The etcd 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 logutil

import (
	"bytes"
	"encoding/json"
	"regexp"
	"slices"
	"testing"

	"github.com/stretchr/testify/require"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

type commonLogFields struct {
	Level     string `json:"level"`
	Timestamp string `json:"ts"`
	Message   string `json:"msg"`
}

const (
	fractionSecondsPrecision = 6 // MicroSeconds
)

func TestEncodeTimePrecisionToMicroSeconds(t *testing.T) {
	buf := bytes.NewBuffer(nil)
	syncer := zapcore.AddSync(buf)
	zc := zapcore.NewCore(
		zapcore.NewJSONEncoder(DefaultZapLoggerConfig.EncoderConfig),
		syncer,
		zap.NewAtomicLevelAt(zap.InfoLevel),
	)

	lg := zap.New(zc)
	lg.Info("TestZapLog")
	fields := commonLogFields{}
	require.NoError(t, json.Unmarshal(buf.Bytes(), &fields))
	// example 1: 2024-06-06T23:37:21.948385Z
	// example 2 with zone offset: 2024-06-06T16:16:44.176778-0700
	regex := `\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.(\d+)(Z|[+-]\d{4})`
	re := regexp.MustCompile(regex)
	matches := re.FindStringSubmatch(fields.Timestamp)
	require.Len(t, matches, 3)
	require.Lenf(t, matches[1], fractionSecondsPrecision, "unexpected timestamp %s", fields.Timestamp)
}

func TestMergeOutputPaths(t *testing.T) {
	tests := []struct {
		name string
		cfg  zap.Config
		want zap.Config
	}{
		{
			name: "OutputPaths /dev/null",
			cfg: zap.Config{
				OutputPaths:      []string{"c", "/dev/null"},
				ErrorOutputPaths: []string{"c", "a", "a", "b"},
			},
			want: zap.Config{
				OutputPaths:      []string{"/dev/null"},
				ErrorOutputPaths: []string{"a", "b", "c"},
			},
		},
		{
			name: "ErrorOutputPaths /dev/null",
			cfg: zap.Config{
				OutputPaths:      []string{"c", "a", "a", "b"},
				ErrorOutputPaths: []string{"/dev/null", "c"},
			},
			want: zap.Config{
				OutputPaths:      []string{"a", "b", "c"},
				ErrorOutputPaths: []string{"/dev/null"},
			},
		},
		{
			name: "empty slice",
			cfg: zap.Config{
				OutputPaths:      []string{},
				ErrorOutputPaths: []string{"c", "a", "a", "b"},
			},
			want: zap.Config{
				OutputPaths:      []string{},
				ErrorOutputPaths: []string{"a", "b", "c"},
			},
		},
		{
			name: "nil slice",
			cfg: zap.Config{
				OutputPaths:      []string{"c", "a", "a", "b"},
				ErrorOutputPaths: nil,
			},
			want: zap.Config{
				OutputPaths:      []string{"a", "b", "c"},
				ErrorOutputPaths: []string{},
			},
		},
		{
			name: "normal",
			cfg: zap.Config{
				OutputPaths:      []string{"c", "a", "a", "b"},
				ErrorOutputPaths: []string{"c", "a", "a", "b"},
			},
			want: zap.Config{
				OutputPaths:      []string{"a", "b", "c"},
				ErrorOutputPaths: []string{"a", "b", "c"},
			},
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			outputPaths := slices.Clone(tt.cfg.OutputPaths)
			errorOutputPaths := slices.Clone(tt.cfg.ErrorOutputPaths)

			require.Equal(t, tt.want, MergeOutputPaths(tt.cfg))

			// ensure the OutputPaths and ErrorOutputPaths have not been modified
			require.Equal(t, outputPaths, tt.cfg.OutputPaths)
			require.Equal(t, errorOutputPaths, tt.cfg.ErrorOutputPaths)
		})
	}
}