package configser

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

// UnmarshalJSON 兼容 seoNavInfo 为空字符串，以及 dhKeyworld 为字符串/数组。
func (s *SeoNavInfo) UnmarshalJSON(raw []byte) error {
	if s == nil {
		return nil
	}
	raw = bytes.TrimSpace(raw)
	if len(raw) == 0 || bytes.Equal(raw, []byte("null")) {
		return nil
	}
	if raw[0] == '"' {
		var encoded string
		if err := json.Unmarshal(raw, &encoded); err != nil {
			return err
		}
		encoded = strings.TrimSpace(encoded)
		if encoded == "" {
			return nil
		}
		inner := bytes.TrimSpace([]byte(encoded))
		if len(inner) == 0 || inner[0] != '{' {
			return nil
		}
		return s.UnmarshalJSON(inner)
	}
	var aux struct {
		DhTitle       string          `json:"dhTitle"`
		DhDescription string          `json:"dhDescription"`
		DhSiteName    string          `json:"dhSiteName"`
		DhKeyworld    json.RawMessage `json:"dhKeyworld"`
		Keywords      json.RawMessage `json:"keywords"`
	}
	if err := json.Unmarshal(raw, &aux); err != nil {
		return err
	}
	s.DhTitle = strings.TrimSpace(aux.DhTitle)
	s.DhDescription = strings.TrimSpace(aux.DhDescription)
	s.DhSiteName = strings.TrimSpace(aux.DhSiteName)
	s.DhKeyworld = decodeNavKeywords(aux.DhKeyworld, aux.Keywords)
	return nil
}

func decodeNavKeywords(values ...json.RawMessage) []string {
	for _, raw := range values {
		raw = bytes.TrimSpace(raw)
		if len(raw) == 0 || bytes.Equal(raw, []byte("null")) {
			continue
		}
		if raw[0] == '[' {
			var list []string
			if err := json.Unmarshal(raw, &list); err != nil {
				continue
			}
			out := make([]string, 0, len(list))
			for _, item := range list {
				item = strings.TrimSpace(item)
				if item != "" {
					out = append(out, item)
				}
			}
			if len(out) > 0 {
				return out
			}
			continue
		}
		var s string
		if err := json.Unmarshal(raw, &s); err != nil {
			continue
		}
		s = strings.TrimSpace(s)
		if s == "" {
			continue
		}
		parts := strings.Split(s, ",")
		out := make([]string, 0, len(parts))
		for _, p := range parts {
			p = strings.TrimSpace(p)
			if p != "" {
				out = append(out, p)
			}
		}
		if len(out) > 0 {
			return out
		}
	}
	return nil
}