// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.

package commands

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"reflect"
	"strings"

	"github.com/pkg/errors"
	"github.com/spf13/cobra"

	"github.com/mattermost/mattermost-server/mlog"
	"github.com/mattermost/mattermost-server/model"
	"github.com/mattermost/mattermost-server/utils"
)

var ConfigCmd = &cobra.Command{
	Use:   "config",
	Short: "Configuration",
}

var ValidateConfigCmd = &cobra.Command{
	Use:   "validate",
	Short: "Validate config file",
	Long:  "If the config file is valid, this command will output a success message and have a zero exit code. If it is invalid, this command will output an error and have a non-zero exit code.",
	RunE:  configValidateCmdF,
}

var ConfigSubpathCmd = &cobra.Command{
	Use:   "subpath",
	Short: "Update client asset loading to use the configured subpath",
	Long:  "Update the hard-coded production client asset paths to take into account Mattermost running on a subpath.",
	Example: `  config subpath
  config subpath --path /mattermost
  config subpath --path /`,
	RunE: configSubpathCmdF,
}

var ConfigGetCmd = &cobra.Command{
	Use:     "get",
	Short:   "Get config setting",
	Long:    "Gets the value of a config setting by its name in dot notation.",
	Example: `config get SqlSettings.DriverName`,
	Args:    cobra.ExactArgs(1),
	RunE:    configGetCmdF,
}

func init() {
	ConfigSubpathCmd.Flags().String("path", "", "Optional subpath; defaults to value in SiteURL")

	ConfigCmd.AddCommand(
		ValidateConfigCmd,
		ConfigSubpathCmd,
		ConfigGetCmd,
	)
	RootCmd.AddCommand(ConfigCmd)
}

func configValidateCmdF(command *cobra.Command, args []string) error {
	utils.TranslationsPreInit()
	model.AppErrorInit(utils.T)
	filePath, err := command.Flags().GetString("config")
	if err != nil {
		return err
	}

	filePath = utils.FindConfigFile(filePath)

	file, err := os.Open(filePath)
	if err != nil {
		return err
	}

	decoder := json.NewDecoder(file)
	config := model.Config{}
	err = decoder.Decode(&config)
	if err != nil {
		return err
	}

	if _, err := file.Stat(); err != nil {
		return err
	}

	if err := config.IsValid(); err != nil {
		return errors.New(utils.T(err.Id))
	}

	CommandPrettyPrintln("The document is valid")
	return nil
}

func configSubpathCmdF(command *cobra.Command, args []string) error {
	a, err := InitDBCommandContextCobra(command)
	if err != nil {
		return err
	}
	defer a.Shutdown()

	path, err := command.Flags().GetString("path")
	if err != nil {
		return errors.Wrap(err, "failed reading path")
	}

	if path == "" {
		return utils.UpdateAssetsSubpathFromConfig(a.Config())
	}

	if err := utils.UpdateAssetsSubpath(path); err != nil {
		return errors.Wrap(err, "failed to update assets subpath")
	}

	return nil
}

func configGetCmdF(command *cobra.Command, args []string) error {
	app, err := InitDBCommandContextCobra(command)
	if err != nil {
		return err
	}
	defer app.Shutdown()

	// create the model for config
	// Note: app.Config() returns a pointer, make appropriate changes
	config := app.Config()

	// get the print config setting and any error if there is
	out, err := printConfigValues(configToMap(*config), strings.Split(args[0], "."), args[0])
	if err != nil {
		return err
	}

	fmt.Printf("%s", out)

	return nil
}

// printConfigValues function prints out the value of the configSettings working recursively or
// gives an error if config setting is not in the file.
func printConfigValues(configMap map[string]interface{}, configSetting []string, name string) (string, error) {

	res, ok := configMap[configSetting[0]]
	if !ok {
		return "", fmt.Errorf("%s configuration setting is not in the file", name)
	}
	value := reflect.ValueOf(res)
	switch value.Kind() {
	case reflect.Map:
		if len(configSetting) == 1 {
			return printMap(value, 0), nil
		}
		return printConfigValues(res.(map[string]interface{}), configSetting[1:], name)
	default:
		if len(configSetting) == 1 {
			return fmt.Sprintf("%s: \"%v\"\n", name, res), nil
		}
		return "", fmt.Errorf("%s configuration setting is not in the file", name)
	}
}

// printMap takes a reflect.Value and return a string, recursively if its a map with the given tab settings.
func printMap(value reflect.Value, tabVal int) string {

	// our output buffer
	out := &bytes.Buffer{}

	for _, key := range value.MapKeys() {
		val := value.MapIndex(key)
		if newVal, ok := val.Interface().(map[string]interface{}); !ok {
			fmt.Fprintf(out, "%s", strings.Repeat("\t", tabVal))
			fmt.Fprintf(out, "%v: \"%v\"\n", key.Interface(), val.Interface())
		} else {
			fmt.Fprintf(out, "%s", strings.Repeat("\t", tabVal))
			fmt.Fprintf(out, "%v:\n", key.Interface())
			// going one level in, increase the tab
			tabVal++
			fmt.Fprintf(out, "%s", printMap(reflect.ValueOf(newVal), tabVal))
			// coming back one level, decrease the tab
			tabVal--
		}
	}

	return out.String()

}

// configToMap converts our config into a map
func configToMap(s interface{}) map[string]interface{} {
	return structToMap(s)
}

// structToMap converts a struct into a map
func structToMap(t interface{}) map[string]interface{} {
	defer func() {
		if r := recover(); r != nil {
			mlog.Error(fmt.Sprintf("Panicked in structToMap. This should never happen. %v", r))
		}
	}()

	val := reflect.ValueOf(t)

	if val.Kind() != reflect.Struct {
		return nil
	}

	out := map[string]interface{}{}

	for i := 0; i < val.NumField(); i++ {
		field := val.Field(i)

		var value interface{}

		switch field.Kind() {
		case reflect.Struct:
			value = structToMap(field.Interface())
		case reflect.Ptr:
			indirectType := field.Elem()

			if indirectType.Kind() == reflect.Struct {
				value = structToMap(indirectType.Interface())
			} else {
				value = indirectType.Interface()
			}
		default:
			value = field.Interface()
		}

		out[val.Type().Field(i).Name] = value
	}
	return out
}