package conftool

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"gitee.com/thincats/conftool/helper"
	"github.com/pkg/errors"
	"github.com/spf13/pflag"
	"github.com/spf13/viper"
)

func addConfigFileSupport(sv *viper.Viper, configDir string, filename string) error {
	const errHeader = "parse config file"
	configDir, err := filepath.Abs(configDir)
	if err != nil {
		return errors.Wrap(err, errHeader)
	}

	if filename == "" {
		return errors.Errorf("%s: config filename is empty", errHeader)
	}

	ext := strings.TrimPrefix(filepath.Ext(filename), ".")
	if ext == "" {
		ext = "yaml" // 默认读取yaml文件
	}

	// 文件名不带后缀
	file := filepath.Base(filename)
	sv.SetConfigName(file)
	sv.AddConfigPath(configDir) // config dir
	sv.SetConfigType(ext)
	err = sv.ReadInConfig()

	if err != nil {
		return errors.Wrap(err, errHeader)
	}
	return nil
}

func addEnvSupport(sv *viper.Viper, envPrefix string) error {
	// tell viper to load env variables
	sv.AutomaticEnv()
	sv.SetEnvPrefix(envPrefix)
	sv.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	return nil
}

func addCommandLineSupport(sv *viper.Viper, config interface{}, args []string) error {
	const errHeader = "parse command line"
	flags := pflag.NewFlagSet("", pflag.ContinueOnError)

	flattenConfigTypes, err := helper.FlattenStructReflectType(config)
	if err != nil {
		return errors.Wrap(err, errHeader)
	}

	flattenConfigTags, err := helper.FlattenStructFieldTag(config, "cli")
	if err != nil {
		return errors.Wrap(err, errHeader)
	}

	for k, v := range flattenConfigTypes {
		cliTag := flattenConfigTags[k]

		// only bind flag if tag cli set
		if cliTag != "-" && cliTag != "" {
			tagParser, err := helper.NewTagParser(cliTag)
			if err != nil {
				return errors.WithMessage(err, errHeader+": tag `cli`")
			}

			key := helper.LowerFirstInDotString(k)
			helper.AddFlag(flags, key, v, tagParser.QueryByKey("usage"))
		}
	}

	// Parse command-line first
	err = flags.Parse(args)
	if err != nil {
		return errors.Wrap(err, errHeader)
	}

	sv.BindPFlags(flags)

	return nil
}

func exitIfError(err error) {
	// if help error, not print stack
	if !IsHelpError(err) {
		fmt.Printf("%+v\n", err)
	}
	os.Exit(1)
}