// ------------------------------------------------------------------------
//   Project atila
//   Active Thing (activething.com) git.activething.com/go
//
//   File name  rpacker_object.go
//   Created by DEV
//   Modified   07/02/2024
//
//   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 pjson

import (
	"activething.com/go/gogo/core/bins"
	"activething.com/go/gogo/packs"
	"reflect"
	"sort"
)

type (

	rObject 		struct {
		fields 		rFieldList
		nameIndex	map[string]int
	}
)



func newRObject(rtype reflect.Type) *rObject {
	cur := rFieldList{}
	nxt := rFieldList{{ rtype: rtype}}

	var fls rFieldList
	var cnt, nxCnt map[reflect.Type]int
	vis := map[reflect.Type]bool{}
	nms := bins.NewBuffer()

	for len(nxt) > 0 {
		cur,nxt = nxt,cur[:0]

		for _,f := range cur {
			if vis[f.rtype] {
				continue
			}
			vis[f.rtype]=true

			for i:=0; i<f.rtype.NumField(); i++ {
				sf := f.rtype.Field(i)
				if sf.Anonymous {
					tp := sf.Type
					if tp.Kind() == reflect.Pointer {
						tp = tp.Elem()
					}
					if !sf.IsExported() && tp.Kind() != reflect.Struct {
						continue
					}
				} else if !sf.IsExported() {
					continue
				}
				nm,fg :=packs.TagPacksFlags(sf.Tag)
				if nm == "-" || fg.Omit() {
					continue
				}
				if !packs.CheckTag(nm) {
					nm = ""
				}
				index:=make([]int,len(f.index)+1)
				copy(index,f.index)
				index[len(f.index)] = i

				ft := sf.Type
				if ft.Name() == "" && ft.Kind() == reflect.Pointer {
					ft = ft.Elem()
				}

				if fg.String() && !fg.Quote() {
					switch ft.Kind() {
					case	reflect.Bool,
							reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
							reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
							reflect.Float32, reflect.Float64,
							reflect.String:
							fg = fg|packs.FlagQuote
					}
				}

				if nm != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
					tged := nm != ""
					if nm == "" {
						nm = sf.Name
					}
					of := rObjectField {
						name  	: nm,
						isTagged: tged,
						index   : index,
						rtype   : ft,
						flags   : fg,
					}
					of.nameB = []byte(of.name)
					of.foldFn= packs.GetFoldFunc(of.nameB)

					// Build nameEscHTML and nameNonEsc ahead of time.
					nms.Reset()
					nms.WriteByte('"')
					nms.WriteHTMLScape(of.nameB)
					nms.Write2Byte('"',':')
					of.nameS = nms.String()
					of.nameU = `"` + of.name + `":`

					fls = append(fls,of)
					if cnt[f.rtype] > 1 {
						fls = append(fls,fls[len(fls)-1])
					}
					continue
				}

				nxCnt[ft]++
				if nxCnt[ft] == 1 {
					nxt = append(nxt,rObjectField{ name: ft.Name(), index: index, rtype: ft})
				}

			}
		}

	}

	sort.Slice(fls,func(i,j int) bool {
		ls := fls
		if ls[i].name != ls[j].name {
			return ls[i].name < ls[j].name
		}
		if len(ls[i].index) != len(ls[j].index) {
			return len(ls[i].index) < len(ls[j].index)
		}
		if ls[i].isTagged != ls[j].isTagged {
			return ls[i].isTagged
		}
		return rFieldIndexList(ls).Less(i, j)
	})

	out := fls[:0]
	for ad,i :=0,0; i< len(fls); i += ad {
		fi := fls[i]
		nm := fi.name
		for ad=1; i+ad <len(fls); ad++ {
			fj := fls[i+ad]
			if fj.name != nm {
				break
			}
		}
		if ad == 1 {
			out = append(out,fi)
			continue
		}
		do,ok := fls[i:i+ad].dominant()
		if ok {
			out = append(out,do)
		}
	}

	fls = out
	sort.Sort(rFieldIndexList(fls))

	for i:= range fls {
		f := &fls[i]
		f.packerFn = rTypePacker(f.typeByIndex(rtype))
	}
	nmIdx := make(map[string]int,len(fls))
	for i,fd := range fls {
		nmIdx[fd.name]=i
	}
	return &rObject{
		fields: fls,
		nameIndex: nmIdx,
	}
}



func (o rObject) pack (s *packs.State, v reflect.Value, f packs.Flags) {
	nx := byte('{')
FieldLoop:
	for i:= range o.fields {
		fd := &o.fields[i]

		fv := v
		for _,i := range fd.index {
			if fv.Kind() == reflect.Pointer {
				if fv.IsNil() {
					continue FieldLoop
				}
				fv = fv.Elem()
			}
			fv = fv.Field(i)
		}
		if fd.flags.OmitEmpty() && isEmptyValue(v) {
			continue
		}
		s.WriteByte(nx)
		nx = ','
		if fd.flags.EscapeHTML() {
			s.WriteString(fd.nameS)
		} else {
			s.WriteString(fd.nameU)
		}
		fd.packerFn(s,fv, fd.flags|f)
	}
	if nx == '{' {
		s.Write2Byte('{','}')
	} else {
		s.WriteByte('}')
	}

}



func isEmptyValue(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
		return v.Len() == 0
	case reflect.Bool:
		return !v.Bool()
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return v.Int() == 0
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		return v.Uint() == 0
	case reflect.Float32, reflect.Float64:
		return v.Float() == 0
	case reflect.Interface, reflect.Pointer:
		return v.IsNil()
	}
	return false
}