package appconfig

import (
	"errors"
	"fmt"
	"strings"
	"unicode"

	"hyapp-admin-server/internal/model"
	"hyapp-admin-server/internal/repository"
)

const h5LinkGroup = "h5-links"

var h5LinkDefinitions = []H5LinkDefinition{
	{Key: "host-center", Label: "Host Center"},
	{Key: "bd-center", Label: "BD Center"},
	{Key: "bd-leader-center", Label: "BD Leader Center"},
	{Key: "agency-center", Label: "Agency Center"},
	{Key: "invite-user", Label: "Invite User"},
}

type AppConfigService struct {
	store *repository.Store
}

type H5LinkDefinition struct {
	Key   string `json:"key"`
	Label string `json:"label"`
}

type H5Link struct {
	Key         string `json:"key"`
	Label       string `json:"label"`
	URL         string `json:"url"`
	UpdatedAtMs int64  `json:"updatedAtMs"`
}

func NewService(store *repository.Store) *AppConfigService {
	return &AppConfigService{store: store}
}

func (s *AppConfigService) ListH5Links() ([]H5Link, error) {
	configs, err := s.store.ListAppConfigs(h5LinkGroup)
	if err != nil {
		return nil, err
	}

	configByKey := make(map[string]model.AppConfig, len(configs))
	for _, config := range configs {
		configByKey[config.Key] = config
	}

	items := make([]H5Link, 0, len(h5LinkDefinitions))
	for _, definition := range h5LinkDefinitions {
		item := H5Link{
			Key:   definition.Key,
			Label: definition.Label,
		}
		if config, ok := configByKey[definition.Key]; ok {
			item.URL = config.Value
			item.UpdatedAtMs = config.UpdatedAt.UnixMilli()
		}
		items = append(items, item)
	}
	return items, nil
}

func (s *AppConfigService) UpdateH5Links(request updateH5LinksRequest) ([]H5Link, error) {
	if len(request.Items) == 0 {
		return nil, errors.New("items are required")
	}

	allowed := h5LinkDefinitionSet()
	items := make([]model.AppConfig, 0, len(request.Items))
	seen := make(map[string]struct{}, len(request.Items))
	for _, item := range request.Items {
		key := strings.TrimSpace(item.Key)
		if _, ok := allowed[key]; !ok {
			return nil, fmt.Errorf("invalid h5 link key: %s", key)
		}
		if _, ok := seen[key]; ok {
			return nil, fmt.Errorf("duplicate h5 link key: %s", key)
		}
		seen[key] = struct{}{}

		link := strings.TrimSpace(item.URL)
		if err := validateH5URL(link); err != nil {
			return nil, err
		}
		items = append(items, model.AppConfig{
			Group:       h5LinkGroup,
			Key:         key,
			Value:       link,
			Description: allowed[key],
		})
	}

	if err := s.store.UpsertAppConfigs(items); err != nil {
		return nil, err
	}
	return s.ListH5Links()
}

func h5LinkDefinitionSet() map[string]string {
	out := make(map[string]string, len(h5LinkDefinitions))
	for _, definition := range h5LinkDefinitions {
		out[definition.Key] = definition.Label
	}
	return out
}

func validateH5URL(value string) error {
	if value == "" {
		return nil
	}
	if len(value) > 2048 {
		return errors.New("h5 link is too long")
	}
	for _, char := range value {
		if unicode.IsSpace(char) {
			return errors.New("h5 link cannot contain whitespace")
		}
	}
	return nil
}