package appconfig

import (
	"encoding/json"
	"errors"
	"fmt"

	"hyapp-admin-server/internal/appctx"
	"hyapp-admin-server/internal/model"

	"gorm.io/gorm"
)

const (
	giftConfigGroup                = "room-gift"
	giftQuantityPresetsKey         = "quantity-presets"
	giftQuantityPresetMaxCount     = 8
	giftQuantityPresetMaxValue     = 9_999
	giftQuantityPresetsDescription = "语音房送礼数量档位，严格递增且每档为 1-9999"
)

var defaultGiftQuantityPresets = []int32{1, 9, 99, 999}

type giftConfigRequest struct {
	QuantityPresets []int32 `json:"quantityPresets"`
}

// GiftConfig 是当前 App 的语音房送礼配置；缺少持久化行时仍返回兼容旧客户端的默认档位。
type GiftConfig struct {
	AppCode         string  `json:"appCode"`
	QuantityPresets []int32 `json:"quantityPresets"`
	UpdatedAtMS     int64   `json:"updatedAtMs"`
}

func (s *AppConfigService) GetGiftConfig(appCode string) (GiftConfig, error) {
	appCode = appctx.Normalize(appCode)
	item, err := s.store.GetOwnedAppConfig(appCode, giftConfigGroup, giftQuantityPresetsKey)
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return GiftConfig{
			AppCode:         appCode,
			QuantityPresets: cloneGiftQuantityPresets(defaultGiftQuantityPresets),
		}, nil
	}
	if err != nil {
		return GiftConfig{}, err
	}
	return giftConfigFromModel(item)
}

func (s *AppConfigService) UpdateGiftConfig(appCode string, request giftConfigRequest) (GiftConfig, error) {
	appCode = appctx.Normalize(appCode)
	presets, err := normalizeGiftQuantityPresets(request.QuantityPresets)
	if err != nil {
		return GiftConfig{}, err
	}
	raw, err := json.Marshal(presets)
	if err != nil {
		return GiftConfig{}, err
	}
	// App 作用域只取鉴权上下文；请求体没有 app_code，保存 Lalu 时不会覆盖 Fami 或其他 App。
	if err := s.store.UpsertScopedAppConfigs(appCode, []model.AppConfig{{
		AppCode:     appCode,
		Group:       giftConfigGroup,
		Key:         giftQuantityPresetsKey,
		Value:       string(raw),
		Description: giftQuantityPresetsDescription,
	}}); err != nil {
		return GiftConfig{}, err
	}
	return s.GetGiftConfig(appCode)
}

func giftConfigFromModel(item model.AppConfig) (GiftConfig, error) {
	var presets []int32
	if err := json.Unmarshal([]byte(item.Value), &presets); err != nil {
		return GiftConfig{}, fmt.Errorf("送礼数量档位配置格式不正确: %w", err)
	}
	presets, err := normalizeGiftQuantityPresets(presets)
	if err != nil {
		return GiftConfig{}, err
	}
	return GiftConfig{
		AppCode:         appctx.Normalize(item.AppCode),
		QuantityPresets: presets,
		UpdatedAtMS:     item.UpdatedAtMS,
	}, nil
}

func normalizeGiftQuantityPresets(values []int32) ([]int32, error) {
	if len(values) == 0 || len(values) > giftQuantityPresetMaxCount {
		return nil, fmt.Errorf("送礼数量档位必须配置 1-%d 个", giftQuantityPresetMaxCount)
	}
	normalized := make([]int32, len(values))
	var previous int32
	for index, value := range values {
		if value < 1 || value > giftQuantityPresetMaxValue {
			return nil, fmt.Errorf("送礼数量档位必须在 1-%d 之间", giftQuantityPresetMaxValue)
		}
		if index > 0 && value <= previous {
			return nil, errors.New("送礼数量档位必须严格递增且不能重复")
		}
		normalized[index] = value
		previous = value
	}
	return normalized, nil
}

func cloneGiftQuantityPresets(values []int32) []int32 {
	return append([]int32(nil), values...)
}