package playletser

import (
	"bytes"
	"encoding/json"
	"strings"
)

// UnmarshalJSON 兼容上游 data 为对象、null、空字符串，或二次 JSON 编码的字符串。
func (e *APIEnvelope[T]) UnmarshalJSON(raw []byte) error {
	if e == nil {
		return nil
	}
	raw = bytes.TrimSpace(raw)
	if len(raw) == 0 || bytes.Equal(raw, []byte("null")) {
		return nil
	}
	var aux struct {
		Code int             `json:"code"`
		Msg  string          `json:"msg"`
		Tip  string          `json:"tip"`
		Data json.RawMessage `json:"data"`
	}
	if err := json.Unmarshal(raw, &aux); err != nil {
		return err
	}
	e.Code = aux.Code
	e.Msg = aux.Msg
	e.Tip = aux.Tip
	data, err := unmarshalEnvelopeData[T](aux.Data)
	if err != nil {
		return err
	}
	e.Data = data
	return nil
}

func unmarshalEnvelopeData[T any](raw json.RawMessage) (T, error) {
	var zero T
	raw = bytes.TrimSpace(raw)
	if len(raw) == 0 || bytes.Equal(raw, []byte("null")) {
		return zero, nil
	}
	if raw[0] == '"' {
		var s string
		if err := json.Unmarshal(raw, &s); err != nil {
			return zero, err
		}
		s = strings.TrimSpace(s)
		if s == "" {
			return zero, nil
		}
		inner := bytes.TrimSpace([]byte(s))
		if len(inner) == 0 {
			return zero, nil
		}
		if inner[0] != '{' && inner[0] != '[' {
			return zero, nil
		}
		if err := json.Unmarshal(inner, &zero); err != nil {
			return zero, err
		}
		return zero, nil
	}
	if err := json.Unmarshal(raw, &zero); err != nil {
		return zero, err
	}
	return zero, nil
}