package orderedmap

import (
	"bytes"
	"encoding/json"
	"sort"
	"sync"
)

type Pair struct {
	key   string
	value interface{}
}

func (kv *Pair) Key() string {
	return kv.key
}

func (kv *Pair) Value() interface{} {
	return kv.value
}

type ByPair struct {
	Pairs    []*Pair
	LessFunc func(a *Pair, j *Pair) bool
}

func (a ByPair) Len() int           { return len(a.Pairs) }
func (a ByPair) Swap(i, j int)      { a.Pairs[i], a.Pairs[j] = a.Pairs[j], a.Pairs[i] }
func (a ByPair) Less(i, j int) bool { return a.LessFunc(a.Pairs[i], a.Pairs[j]) }

type OrderedMap struct {
	keys       []string
	values     map[string]interface{}
	escapeHTML bool
	rwLock     sync.RWMutex
}

func New() *OrderedMap {
	o := OrderedMap{}
	o.keys = []string{}
	o.values = map[string]interface{}{}
	o.escapeHTML = true
	return &o
}

func (o *OrderedMap) SetEscapeHTML(on bool) {
	o.escapeHTML = on
}

func (o *OrderedMap) Get(key string) (interface{}, bool) {
	o.rwLock.RLock()
	defer o.rwLock.RUnlock()
	val, exists := o.values[key]
	return val, exists
}

func (o *OrderedMap) Set(key string, value interface{}) {
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	_, exists := o.values[key]
	if !exists {
		o.keys = append(o.keys, key)
	}
	o.values[key] = value
}

func (o *OrderedMap) LoadOrStore(key string, value interface{}) (interface{}, bool) {
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	_, exists := o.values[key]
	if !exists {
		o.keys = append(o.keys, key)
		o.values[key] = value
		return nil, false
	}
	return o.values[key], true
}

func (o *OrderedMap) Delete(key string) {
	// check key is in use
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	_, ok := o.values[key]
	if !ok {
		return
	}
	// remove from keys
	for i, k := range o.keys {
		if k == key {
			o.keys = append(o.keys[:i], o.keys[i+1:]...)
			break
		}
	}
	// remove from values
	delete(o.values, key)
}

func (o *OrderedMap) Clear() { // delete whole orderdmap
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	for _, key := range o.Keys() {
		o.Delete(key)
	}
}

func (o *OrderedMap) Keys() []string {
	o.rwLock.RLock()
	defer o.rwLock.RUnlock()
	ret := make([]string, len(o.keys))
	for i, v := range o.keys {
		ret[i] = v
	}
	return ret
}

// SortKeys Sort the map keys using your sort func
func (o *OrderedMap) SortKeys(sortFunc func(keys []string)) {
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	sortFunc(o.keys)
}

// Sort Sort the map using your sort func
func (o *OrderedMap) Sort(lessFunc func(a *Pair, b *Pair) bool) {
	o.rwLock.Lock()
	defer o.rwLock.Unlock()
	pairs := make([]*Pair, len(o.keys))
	for i, key := range o.keys {
		pairs[i] = &Pair{key, o.values[key]}
	}

	sort.Sort(ByPair{pairs, lessFunc})

	for i, pair := range pairs {
		o.keys[i] = pair.key
	}
}

func (o *OrderedMap) UnmarshalJSON(b []byte) error {
	o.rwLock.RLock()
	defer o.rwLock.RUnlock()
	if o.values == nil {
		o.values = map[string]interface{}{}
	}
	err := json.Unmarshal(b, &o.values)
	if err != nil {
		return err
	}
	dec := json.NewDecoder(bytes.NewReader(b))
	if _, err = dec.Token(); err != nil { // skip '{'
		return err
	}
	o.keys = make([]string, 0, len(o.values))
	return decodeOrderedMap(dec, o)
}

func decodeOrderedMap(dec *json.Decoder, o *OrderedMap) error {
	hasKey := make(map[string]bool, len(o.values))
	for {
		token, err := dec.Token()
		if err != nil {
			return err
		}
		if delim, ok := token.(json.Delim); ok && delim == '}' {
			return nil
		}
		key := token.(string)
		if hasKey[key] {
			// duplicate key
			for j, k := range o.keys {
				if k == key {
					copy(o.keys[j:], o.keys[j+1:])
					break
				}
			}
			o.keys[len(o.keys)-1] = key
		} else {
			hasKey[key] = true
			o.keys = append(o.keys, key)
		}

		token, err = dec.Token()
		if err != nil {
			return err
		}
		if delim, ok := token.(json.Delim); ok {
			switch delim {
			case '{':
				if values, ok := o.values[key].(map[string]interface{}); ok {
					newMap := &OrderedMap{
						keys:       make([]string, 0, len(values)),
						values:     values,
						escapeHTML: o.escapeHTML,
					}
					if err = decodeOrderedMap(dec, newMap); err != nil {
						return err
					}
					o.values[key] = newMap
				} else if oldMap, ok := o.values[key].(OrderedMap); ok {
					newMap := &OrderedMap{
						keys:       make([]string, 0, len(oldMap.values)),
						values:     oldMap.values,
						escapeHTML: o.escapeHTML,
					}
					if err = decodeOrderedMap(dec, newMap); err != nil {
						return err
					}
					o.values[key] = newMap
				} else if err = decodeOrderedMap(dec, &OrderedMap{}); err != nil {
					return err
				}
			case '[':
				if values, ok := o.values[key].([]interface{}); ok {
					if err = decodeSlice(dec, values, o.escapeHTML); err != nil {
						return err
					}
				} else if err = decodeSlice(dec, []interface{}{}, o.escapeHTML); err != nil {
					return err
				}
			}
		}
	}
}

func decodeSlice(dec *json.Decoder, s []interface{}, escapeHTML bool) error {
	for index := 0; ; index++ {
		token, err := dec.Token()
		if err != nil {
			return err
		}
		if delim, ok := token.(json.Delim); ok {
			switch delim {
			case '{':
				if index < len(s) {
					if values, ok := s[index].(map[string]interface{}); ok {
						newMap := &OrderedMap{
							keys:       make([]string, 0, len(values)),
							values:     values,
							escapeHTML: escapeHTML,
						}
						if err = decodeOrderedMap(dec, newMap); err != nil {
							return err
						}
						s[index] = newMap
					} else if oldMap, ok := s[index].(OrderedMap); ok {
						newMap := &OrderedMap{
							keys:       make([]string, 0, len(oldMap.values)),
							values:     oldMap.values,
							escapeHTML: escapeHTML,
						}
						if err = decodeOrderedMap(dec, newMap); err != nil {
							return err
						}
						s[index] = newMap
					} else if err = decodeOrderedMap(dec, &OrderedMap{}); err != nil {
						return err
					}
				} else if err = decodeOrderedMap(dec, &OrderedMap{}); err != nil {
					return err
				}
			case '[':
				if index < len(s) {
					if values, ok := s[index].([]interface{}); ok {
						if err = decodeSlice(dec, values, escapeHTML); err != nil {
							return err
						}
					} else if err = decodeSlice(dec, []interface{}{}, escapeHTML); err != nil {
						return err
					}
				} else if err = decodeSlice(dec, []interface{}{}, escapeHTML); err != nil {
					return err
				}
			case ']':
				return nil
			}
		}
	}
}

func (o *OrderedMap) MarshalJSON() ([]byte, error) {
	o.rwLock.RLock()
	defer o.rwLock.RUnlock()
	var buf bytes.Buffer
	buf.WriteByte('{')
	encoder := json.NewEncoder(&buf)
	encoder.SetEscapeHTML(o.escapeHTML)
	for i, k := range o.keys {
		if i > 0 {
			buf.WriteByte(',')
		}
		// add key
		if err := encoder.Encode(k); err != nil {
			return nil, err
		}
		buf.WriteByte(':')
		// add value
		if err := encoder.Encode(o.values[k]); err != nil {
			return nil, err
		}
	}
	buf.WriteByte('}')
	return buf.Bytes(), nil
}

/*
The MIT License (MIT)

Copyright (c) 2017 Ian Coleman

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, Subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or Substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/