// Copyright 2018 The Hugo Authors. All rights reserved.
//
// 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 commands defines and implements command-line commands and flags
// used by Hugo. Commands and flags are implemented using Cobra.
package commands

import (
	"fmt"
	"regexp"

	"github.com/gohugoio/hugo/config"
	"github.com/spf13/cobra"
)

type flagsToConfigHandler interface {
	flagsToConfig(cfg config.Provider)
}

type cmder interface {
	flagsToConfigHandler
	getCommand() *cobra.Command
}

// commandError is an error used to signal different error situations in command handling.
type commandError struct {
	s         string
	userError bool
}

func (c commandError) Error() string {
	return c.s
}

func (c commandError) isUserError() bool {
	return c.userError
}

func newUserError(a ...interface{}) commandError {
	return commandError{s: fmt.Sprintln(a...), userError: true}
}

func newSystemError(a ...interface{}) commandError {
	return commandError{s: fmt.Sprintln(a...), userError: false}
}

func newSystemErrorF(format string, a ...interface{}) commandError {
	return commandError{s: fmt.Sprintf(format, a...), userError: false}
}

// Catch some of the obvious user errors from Cobra.
// We don't want to show the usage message for every error.
// The below may be to generic. Time will show.
var userErrorRegexp = regexp.MustCompile("argument|flag|shorthand")

func isUserError(err error) bool {
	if cErr, ok := err.(commandError); ok && cErr.isUserError() {
		return true
	}

	return userErrorRegexp.MatchString(err.Error())
}