// ------------------------------------------------------------------------
//   Project atila
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  builder.go
//   Created by DEV
//   Modified   21/01/2024
//
//   Copyright 2024 activething.com 
// ------------------------------------------------------------------------
// 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 jjson

import (
	"activething.com/go/gogo/core/opts"
	"activething.com/go/gogo/core/syncs"
	"activething.com/go/gogo/packs"
	"encoding/json"
	"reflect"
	"sort"
	"sync/atomic"
	"time"
)

const(

	maxDeepUncheck 	= 100
)

type (

	Builder 		struct {
		options		Options
		encoder 	*json.Encoder
		dateLayout	string
		scratch 	[64]byte
		state 		*packs.State
	}

)



func AcquireBuilder (options ...opts.OptionFnc[Builder]) *Builder {
	if atomic.CompareAndSwapUint32(&G.sentinel,0,1) {
		G.builderPool = syncs.NewPool[Builder](
			syncs.PoolWithNew[Builder](func() *Builder {
				return &Builder{
					options   : jsonOptionsDefaults,
					state	  : packs.AcquireState(),
					dateLayout: time.RFC822Z,
				}
			}),
		)
	}
	return opts.Apply(G.builderPool.Get(),options...)
}


func ReleaseBuilder (builder *Builder) {
	if builder != nil && atomic.LoadUint32(&G.sentinel) == 1 {
		G.builderPool.Put(builder.reset())
	}
}



func (b *Builder) Any (value any) {

	switch value.(type) {
	default:
		rv := reflect.ValueOf(value)
		switch rv.Kind() {
		case reflect.Struct : b.objPacker(rv)
		case reflect.Map    : b.mapPacker(rv)
		case reflect.Slice  : b.listPacker(rv)
		}
	}
}



func (b *Builder) Map (builder func(packer packs.BuilderMap)) {}




func (b *Builder) reset () *Builder {
	//todo
	b.options = jsonOptionsDefaults
	b.encoder = nil
	b.dateLayout = time.RFC822Z
	b.state.Reset()
	return b
}




func (b *Builder) mapPacker (rv reflect.Value) {
	if rv.IsNil() {
		b.state.Write(G.nullValue)
		return
	}
	if rv.Len() == 0 {
		b.state.Write2Byte('{','}')
		return
	}
	if b.state.Node.Level > maxDeepUncheck {
		p := rv.UnsafePointer()
		if _,ok := b.state.Seen[p]; ok {
			b.state.SetError(packs.G.ErrRedundantPack)
			return
		}
		b.state.Seen[p] = struct{}{}
		defer delete(b.state.Seen,p)
	}


	mi := rv.MapRange()
	if b.options.SortMapKeys() {
		ls := make([]reflectMapElem, rv.Len())
		for i := 0; mi.Next(); i++ {
			ls[i].k = mi.Key()
			ls[i].v = mi.Value()
			if !ls[i].stringifyKey(b.options) {
				b.state.SetError(packs.G.ErrInvalidKey)
				return
			}
		}
		if b.options.SortMapKeys() {
			sort.Slice(ls, func(i, j int) bool { return ls[i].s < ls[j].s })
		}

		b.Map(func(bm packs.BuilderMap) {
			for _, e := range ls {
				bm.ElemAny(e.s, e.v)
				if b.state.Error != nil {
					return
				}
			}
		})
		return
	}

	b.Map(func(bm packs.BuilderMap) {
		for i:=0; mi.Next(); i++ {
			bm.ElemAny(mi.Key(),mi.Value())
			if b.state.Error != nil {
				return
			}
		}
	})

}


func (b *Builder) objPacker (rv reflect.Value) {
	if rv.IsNil() {
		b.state.Write(G.nullValue)
		return
	}
	if rv.Len() == 0 {
		b.state.Write2Byte('{','}')
		return
	}


}


func (b *Builder) listPacker(rv reflect.Value) {
	if rv.IsNil() {
		b.state.Write(G.nullValue)
		return
	}
	if rv.Len() == 0 {
		b.state.Write2Byte('[',']')
		return
	}
	if b.state.Node.Level > maxDeepUncheck {
		p := struct {
			ptr interface{} // always an unsafe.Pointer, but avoids a dependency on package unsafe
			len int
		}{
			ptr: rv.UnsafePointer(), 
			len: rv.Len(),
		}
		if _,ok := b.state.Seen[p]; ok {
			b.state.SetError(packs.G.ErrRedundantPack)
			return
		}
		b.state.Seen[p] = struct{}{}
		defer delete(b.state.Seen,p)
	}

	switch rv.Type().Elem().Kind() {
	case reflect.Int : b._listPacker (rv, func(lb packs.BuilderList, ev reflect.Value) { lb.ItemInt64(int64(ev.Int())) })
	}
}


func (b *Builder) _listPacker (rlist reflect.Value, add func(lb packs.BuilderList, ev reflect.Value)) {
	for i:=0; i< rlist.Len(); i++ {
		add(b,rlist.Index(i))
		if b.state.Error != nil {
			return
		}
	}
}



func stringifyKey(key reflect.Value, ops Options)  (string,bool) {

	return "ss",true
}