package funcs

import (
	"encoding"
	"reflect"
	"sort"
	"strconv"

	"gitee.com/go-better/dev/encoding/jsondoc/encoder/types"
)

func newMapEncoder(t reflect.Type) encoderFunc {
	switch t.Key().Kind() {
	case reflect.String,
		reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
	default:
		if !t.Key().Implements(textMarshalerType) {
			return unsupportedTypeEncoder
		}
	}
	me := mapEncoder{typeEncoder(t.Elem())}
	return me.encode
}

type mapEncoder struct {
	elemEnc encoderFunc
}

func (me mapEncoder) encode(buf *types.Buffer, v reflect.Value, opts types.Options) {
	if v.Len() == 0 {
		typ := v.Type()
		if opts.NotRecursion(typ) {
			v = reflect.MakeMap(typ)
			v.SetMapIndex(reflect.Zero(typ.Key()), reflect.Zero(typ.Elem()))
			opts.AppendConvertedTypeInUpperLayers(typ)
		}
	}
	if v.IsNil() {
		buf.WriteString("null")
		return
	}
	buf.WriteByte('{')
	if v.Len() > 0 {
		opts.WriteCommentIfPresent(buf)
	}

	// Extract and sort the keys.
	keys := v.MapKeys()
	sv := make([]reflectWithString, len(keys))
	for i, v := range keys {
		sv[i].v = v
		if err := sv[i].resolve(); err != nil {
			raiseError(&MarshalerError{v.Type(), err})
		}
	}
	sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s })

	for i, kv := range sv {
		if i > 0 {
			buf.WriteByte(',')
		}
		encodeString(&buf.Buffer, kv.s, opts.EscapeHTML)
		buf.WriteByte(':')
		me.elemEnc(buf, v.MapIndex(kv.v), opts)
	}
	buf.WriteByte('}')
}

type reflectWithString struct {
	v reflect.Value
	s string
}

func (w *reflectWithString) resolve() error {
	if w.v.Kind() == reflect.String {
		w.s = w.v.String()
		return nil
	}
	if tm, ok := w.v.Interface().(encoding.TextMarshaler); ok {
		buf, err := tm.MarshalText()
		w.s = string(buf)
		return err
	}
	switch w.v.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		w.s = strconv.FormatInt(w.v.Int(), 10)
		return nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		w.s = strconv.FormatUint(w.v.Uint(), 10)
		return nil
	}
	panic("unexpected map key type")
}