/*
 * MinIO Cloud Storage, (C) 2019 MinIO, Inc.
 *
 * 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 madmin

import (
	"bufio"
	"bytes"
	"encoding/base64"
	"fmt"
	"strings"

	"github.com/minio/minio/pkg/color"
)

// KVS each sub-system key, value
type KVS map[string]string

// Targets sub-system targets
type Targets map[string]map[string]KVS

const (
	commentKey = "comment"
)

// Count - returns total numbers of target
func (t Targets) Count() int {
	var count int
	for _, targetKV := range t {
		for range targetKV {
			count++
		}
	}
	return count
}

func (t Targets) String() string {
	var s strings.Builder
	count := t.Count()
	for subSys, targetKV := range t {
		for target, kv := range targetKV {
			count--
			c := kv[commentKey]
			data, err := base64.RawStdEncoding.DecodeString(c)
			if err == nil {
				c = string(data)
			}
			for _, c1 := range strings.Split(c, KvNewline) {
				if c1 == "" {
					continue
				}
				s.WriteString(color.YellowBold(KvComment))
				s.WriteString(KvSpaceSeparator)
				s.WriteString(color.BlueBold(strings.TrimSpace(c1)))
				s.WriteString(KvNewline)
			}
			s.WriteString(subSys)
			if target != Default {
				s.WriteString(SubSystemSeparator)
				s.WriteString(target)
			}
			s.WriteString(KvSpaceSeparator)
			for k, v := range kv {
				// Comment is already printed, do not print it here.
				if k == commentKey {
					continue
				}
				s.WriteString(k)
				s.WriteString(KvSeparator)
				s.WriteString(KvDoubleQuote)
				s.WriteString(v)
				s.WriteString(KvDoubleQuote)
				s.WriteString(KvSpaceSeparator)
			}
			if (len(t) > 1 || len(targetKV) > 1) && count > 0 {
				s.WriteString(KvNewline)
				s.WriteString(KvNewline)
			}
		}
	}
	return s.String()
}

// Constant separators
const (
	SubSystemSeparator = `:`
	KvSeparator        = `=`
	KvSpaceSeparator   = ` `
	KvComment          = `#`
	KvNewline          = "\n"
	KvDoubleQuote      = `"`
	KvSingleQuote      = `'`

	Default = `_`
)

// This function is needed, to trim off single or double quotes, creeping into the values.
func sanitizeValue(v string) string {
	v = strings.TrimSuffix(strings.TrimPrefix(strings.TrimSpace(v), KvDoubleQuote), KvDoubleQuote)
	return strings.TrimSuffix(strings.TrimPrefix(v, KvSingleQuote), KvSingleQuote)
}

func convertTargets(s string, targets Targets) error {
	inputs := strings.SplitN(s, KvSpaceSeparator, 2)
	if len(inputs) <= 1 {
		return fmt.Errorf("invalid number of arguments '%s'", s)
	}
	subSystemValue := strings.SplitN(inputs[0], SubSystemSeparator, 2)
	if len(subSystemValue) == 0 {
		return fmt.Errorf("invalid number of arguments %s", s)
	}
	var kvs = KVS{}
	var prevK string
	for _, v := range strings.Fields(inputs[1]) {
		kv := strings.SplitN(v, KvSeparator, 2)
		if len(kv) == 0 {
			continue
		}
		if len(kv) == 1 && prevK != "" {
			kvs[prevK] = strings.Join([]string{kvs[prevK], sanitizeValue(kv[0])}, KvSpaceSeparator)
			continue
		}
		if len(kv) == 1 {
			return fmt.Errorf("value for key '%s' cannot be empty", kv[0])
		}
		prevK = kv[0]
		kvs[kv[0]] = sanitizeValue(kv[1])
	}

	_, ok := targets[subSystemValue[0]]
	if !ok {
		targets[subSystemValue[0]] = map[string]KVS{}
	}
	if len(subSystemValue) == 2 {
		targets[subSystemValue[0]][subSystemValue[1]] = kvs
	} else {
		targets[subSystemValue[0]][Default] = kvs
	}
	return nil
}

// ParseSubSysTarget - parse sub-system target
func ParseSubSysTarget(buf []byte) (Targets, error) {
	targets := make(map[string]map[string]KVS)
	bio := bufio.NewScanner(bytes.NewReader(buf))
	for bio.Scan() {
		if err := convertTargets(bio.Text(), targets); err != nil {
			return nil, err
		}
	}
	if err := bio.Err(); err != nil {
		return nil, err
	}
	return targets, nil
}