package main

import (
	"fmt"
	"io"
	"os"
	"reflect"
	"strconv"
	"strings"
	"sync"
)

type IJceStruct interface{}

const head = "// Code generated by structs_parser; DO NOT EDIT.\npackage jce\n"

func Main_() {
	w, err := os.Create("%s")
	if err != nil {
		panic(err)
	}
	w.WriteString(head)
	// structs_parser: fill area
	err = w.Close()
	if err != nil {
		panic(err)
	}
}

func writeObject(w io.Writer, v reflect.Value, tag byte, name string) {
	k := v.Kind()
	if k == reflect.Map {
		switch v.Interface().(type) {
		case map[string]string:
			w.Write([]byte(fmt.Sprintf("\tw.writeMapStrStr(pkt.%s, %d)\n", name, tag)))
		case map[string][]byte:
			w.Write([]byte(fmt.Sprintf("\tw.writeMapStrBytes(pkt.%s, %d)\n", name, tag)))
		case map[string]map[string][]byte:
			w.Write([]byte(fmt.Sprintf("\tw.writeMapStrMapStrBytes(pkt.%s, %d)\n", name, tag)))
		default:
			w.Write([]byte(fmt.Sprintf("\tw.writeMap(pkt.%s, %d)\n", name, tag)))
		}
		return
	}
	if k == reflect.Slice {
		switch v.Interface().(type) {
		case []byte:
			w.Write([]byte(fmt.Sprintf("\tw.WriteBytes(pkt.%s, %d)\n", name, tag)))
		case []int64:
			w.Write([]byte(fmt.Sprintf("\tw.WriteInt64Slice(pkt.%s, %d)\n", name, tag)))
		case [][]byte:
			w.Write([]byte(fmt.Sprintf("\tw.WriteBytesSlice(pkt.%s, %d)\n", name, tag)))
		default:
			writeJceStructSlice(w, tag, name)
		}
		return
	}
	switch k {
	case reflect.Uint8, reflect.Int8:
		w.Write([]byte(fmt.Sprintf("\tw.WriteByte(pkt.%s, %d)\n", name, tag)))
	case reflect.Uint16, reflect.Int16:
		w.Write([]byte(fmt.Sprintf("\tw.WriteInt16(pkt.%s, %d)\n", name, tag)))
	case reflect.Uint32, reflect.Int32:
		w.Write([]byte(fmt.Sprintf("\tw.WriteInt32(pkt.%s, %d)\n", name, tag)))
	case reflect.Uint64, reflect.Int64:
		w.Write([]byte(fmt.Sprintf("\tw.WriteInt64(pkt.%s, %d)\n", name, tag)))
	case reflect.Int, reflect.Uint:
		w.Write([]byte(fmt.Sprintf("\tw.WriteInt64(int64(pkt.%s), %d)\n", name, tag)))
	case reflect.String:
		w.Write([]byte(fmt.Sprintf("\tw.WriteString(pkt.%s, %d)\n", name, tag)))
	default:
		switch v.Interface().(type) {
		case float32:
			w.Write([]byte(fmt.Sprintf("\tw.WriteFloat32(pkt.%s, %d)\n", name, tag)))
		case float64:
			w.Write([]byte(fmt.Sprintf("\tw.WriteFloat64(pkt.%s, %d)\n", name, tag)))
		case IJceStruct:
			w.Write([]byte(fmt.Sprintf("\tw.writeHead(10, %d)\n", tag)))
			w.Write([]byte(fmt.Sprintf("\tw.buf.Write(pkt.%s.ToBytes())\n", name)))
			w.Write([]byte("\tw.writeHead(11, 0)\n"))
		}
	}
}

type decoder struct {
	index int
	id    int
	name  string
}

var decoderCache = sync.Map{}

// writeJceStructRaw 写入 Jce 结构体
func writeJceStructRaw(w io.Writer, s interface{}) {
	t := reflect.TypeOf(s)
	if t.Kind() != reflect.Ptr {
		return
	}
	t = t.Elem()
	v := reflect.ValueOf(s).Elem()
	var jceDec []decoder
	dec, ok := decoderCache.Load(t)
	if ok { // 从缓存中加载
		jceDec = dec.([]decoder)
	} else { // 初次反射
		jceDec = make([]decoder, 0, t.NumField())
		for i := 0; i < t.NumField(); i++ {
			field := t.Field(i)
			strId := field.Tag.Get("jceId")
			if strId == "" {
				continue
			}
			id, err := strconv.Atoi(strId)
			if err != nil {
				continue
			}
			jceDec = append(jceDec, decoder{
				index: i,
				id:    id,
				name:  field.Name,
			})
		}
		decoderCache.Store(t, jceDec) // 存入缓存
	}
	for _, dec := range jceDec {
		obj := v.Field(dec.index)
		writeObject(w, obj, byte(dec.id), dec.name)
	}
}

func writeJceStructSlice(w io.Writer, tag byte, name string) {
	w.Write([]byte(fmt.Sprintf("\tw.writeHead(9, %d)\n", tag)))
	w.Write([]byte(fmt.Sprintf("\tif len(pkt.%s) == 0 {\n", name)))
	w.Write([]byte("\t\tw.writeHead(12, 0) // w.WriteInt32(0, 0)\n"))
	w.Write([]byte("\t} else {\n"))
	w.Write([]byte(fmt.Sprintf("\t\tw.WriteInt32(int32(len(pkt.%s)), 0)\n", name)))
	w.Write([]byte(fmt.Sprintf("\t\tfor _, i := range pkt.%s {\n", name)))
	w.Write([]byte("\t\t\tw.buf.Write(i.ToBytes())\n"))
	w.Write([]byte("\t\t}\n"))
	w.Write([]byte("\t}\n"))
}

func WriteJceStruct(w io.Writer, s IJceStruct) {
	w.Write([]byte(fmt.Sprintf("\nfunc (pkt %s) ToBytes() []byte {\n", strings.ReplaceAll(reflect.TypeOf(s).String(), "main.", ""))))
	w.Write([]byte("\tw := NewJceWriter()\n"))
	writeJceStructRaw(w, s)
	w.Write([]byte("\treturn w.Bytes()\n"))
	w.Write([]byte("}\n"))
}