// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package config

import (
	"fmt"
	"os"
	"strings"

	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

const fileMode = os.FileMode(0644)

// NewZapLogger builds and returns a new
// Zap logger for this logging configuration
func (cfg *Logger) NewZapLogger() (*zap.Logger, error) {
	levelKey := cfg.LevelKey
	if levelKey == "" {
		levelKey = "level"
	}

	encodeConfig := zapcore.EncoderConfig{
		TimeKey:        "ts",
		LevelKey:       levelKey,
		NameKey:        "logger",
		CallerKey:      "", // we use our own caller, check common/log/logger.go
		MessageKey:     "msg",
		StacktraceKey:  "stacktrace",
		LineEnding:     zapcore.DefaultLineEnding,
		EncodeLevel:    zapcore.LowercaseLevelEncoder,
		EncodeTime:     zapcore.ISO8601TimeEncoder,
		EncodeDuration: zapcore.SecondsDurationEncoder,
		EncodeCaller:   nil,
	}

	outputPath := "stderr"
	if len(cfg.OutputFile) > 0 {
		outputPath = cfg.OutputFile
		if cfg.Stdout {
			outputPath = "stdout"
		}
	}

	encoding := "json"
	if cfg.Encoding != "" {
		if cfg.Encoding == "json" || cfg.Encoding == "console" {
			encoding = cfg.Encoding
		} else {
			return nil, fmt.Errorf("invalid encoding for log, only supporting json or console")
		}
	}

	config := zap.Config{
		Level:            zap.NewAtomicLevelAt(parseZapLevel(cfg.Level)),
		Development:      false,
		Sampling:         nil, // consider exposing this to config for our external customer
		Encoding:         encoding,
		EncoderConfig:    encodeConfig,
		OutputPaths:      []string{outputPath},
		ErrorOutputPaths: []string{outputPath},
	}
	return config.Build()
}

func parseZapLevel(level string) zapcore.Level {
	switch strings.ToLower(level) {
	case "debug":
		return zap.DebugLevel
	case "info":
		return zap.InfoLevel
	case "warn":
		return zap.WarnLevel
	case "error":
		return zap.ErrorLevel
	case "fatal":
		return zap.FatalLevel
	default:
		return zap.InfoLevel
	}
}
