/*
Copyright 2016 The Kubernetes 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 federation

import (
	"bytes"
	"fmt"
	"strings"
)

type AuthFile struct {
	Lines []*AuthFileLine
}

type AuthFileLine struct {
	User   string
	Secret string
	Role   string
}

func ParseAuthFile(data []byte) (*AuthFile, error) {
	parsed := &AuthFile{}
	for _, line := range strings.Split(string(data), "\n") {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}
		parsedLine, err := ParseAuthFileLine(line)
		if err != nil {
			return nil, err
		}
		parsed.Lines = append(parsed.Lines, parsedLine)
	}
	return parsed, nil
}

func (a *AuthFile) FindUser(user string) *AuthFileLine {
	for _, line := range a.Lines {
		if line.User == user {
			return line
		}
	}
	return nil
}

func (a *AuthFile) Add(line *AuthFileLine) error {
	existing := a.FindUser(line.User)
	if existing != nil {
		return fmt.Errorf("user %q already exists in file", line.User)
	}
	a.Lines = append(a.Lines, line)
	return nil
}

func (a *AuthFile) Encode() string {
	var b bytes.Buffer

	for _, line := range a.Lines {
		b.WriteString(fmt.Sprintf("%s,%s,%s\n", line.Secret, line.User, line.Role))
	}
	return b.String()
}

func ParseAuthFileLine(line string) (*AuthFileLine, error) {
	tokens := strings.Split(line, ",")
	if len(tokens) != 3 {
		return nil, fmt.Errorf("unexpected line: expected exactly 3 tokens, found %d", len(tokens))
	}
	parsed := &AuthFileLine{
		Secret: tokens[0],
		User:   tokens[1],
		Role:   tokens[2],
	}
	return parsed, nil
}