package apppopup

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"strings"
	"time"

	"chatapp3-golang/internal/model"
	"chatapp3-golang/internal/utils"

	"gorm.io/gorm"
)

// PageAdminConfigs 返回后台首页弹窗配置分页。
func (s *Service) PageAdminConfigs(ctx context.Context, sysOrigin, scene, popupKey string, cursor, limit int) (*AdminConfigPageResponse, error) {
	if s == nil || s.db == nil {
		return nil, NewAppError(http.StatusServiceUnavailable, "app_popup_unavailable", "app popup service is unavailable")
	}
	sysOrigin = normalizeSysOrigin(sysOrigin)
	scene = normalizeScene(scene)
	cursor = normalizePageCursor(cursor)
	limit = normalizePageLimit(limit)

	query := s.db.WithContext(ctx).
		Model(&model.AppPopupConfig{}).
		Where("sys_origin = ? AND scene = ?", sysOrigin, scene)
	if key := normalizePopupKey(popupKey); key != "" {
		query = query.Where("popup_key LIKE ?", "%"+key+"%")
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		return nil, err
	}

	var rows []model.AppPopupConfig
	if err := query.
		Order("priority DESC").
		Order("id ASC").
		Limit(limit).
		Offset((cursor - 1) * limit).
		Find(&rows).Error; err != nil {
		return nil, err
	}

	items := make([]AdminConfigItem, 0, len(rows))
	for _, row := range rows {
		items = append(items, adminItemFromModel(row))
	}
	return &AdminConfigPageResponse{
		Records: items,
		Total:   total,
		Current: cursor,
		Size:    limit,
	}, nil
}

// SaveAdminConfig 创建或更新后台首页弹窗配置。
func (s *Service) SaveAdminConfig(ctx context.Context, req SaveAdminConfigRequest) (*AdminConfigItem, error) {
	if s == nil || s.db == nil {
		return nil, NewAppError(http.StatusServiceUnavailable, "app_popup_unavailable", "app popup service is unavailable")
	}
	sysOrigin := normalizeSysOrigin(req.SysOrigin)
	scene := normalizeScene(req.Scene)
	popupKey := normalizePopupKey(req.PopupKey)
	if popupKey == "" {
		return nil, NewAppError(http.StatusBadRequest, "popup_key_required", "popupKey is required")
	}
	if req.LimitDays < 0 {
		return nil, NewAppError(http.StatusBadRequest, "invalid_limit_days", "limitDays must be greater than or equal to 0")
	}

	var savedID int64
	if err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		var row model.AppPopupConfig
		requestID := req.ID.Int64()
		if requestID > 0 {
			err := tx.Where("id = ?", requestID).First(&row).Error
			if errors.Is(err, gorm.ErrRecordNotFound) {
				return NewAppError(http.StatusNotFound, "app_popup_config_not_found", "config not found")
			}
			if err != nil {
				return err
			}
		} else {
			id, err := utils.NextID()
			if err != nil {
				return err
			}
			row.ID = id
			row.CreateTime = time.Now()
		}

		var duplicate model.AppPopupConfig
		err := tx.Where("sys_origin = ? AND scene = ? AND popup_key = ? AND id <> ?", sysOrigin, scene, popupKey, row.ID).
			First(&duplicate).Error
		if err == nil {
			return NewAppError(http.StatusConflict, "duplicate_popup_key", "popupKey already exists")
		}
		if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
			return err
		}

		now := time.Now()
		row.SysOrigin = sysOrigin
		row.Scene = scene
		row.PopupKey = popupKey
		row.Name = defaultIfBlank(req.Name, popupKey)
		row.Enabled = req.Enabled
		row.LimitDays = req.LimitDays
		row.Priority = req.Priority
		row.Version = normalizeVersion(req.Version)
		row.ContentJSON = mustContentJSON(req.Title, req.Image)
		row.JumpType = strings.TrimSpace(req.JumpType)
		row.JumpURL = strings.TrimSpace(req.JumpURL)
		row.Remark = strings.TrimSpace(req.Description)
		row.PlatformsJSON = normalizeJSONField(req.PlatformsJSON)
		row.MinAppVersion = strings.TrimSpace(req.MinAppVersion)
		row.MaxAppVersion = strings.TrimSpace(req.MaxAppVersion)
		row.UserScopeType = "ALL"
		if strings.TrimSpace(row.UserScopeJSON) == "" {
			row.UserScopeJSON = "{}"
		}
		row.UpdateTime = now
		if row.CreateTime.IsZero() {
			row.CreateTime = now
		}

		if err := tx.Save(&row).Error; err != nil {
			return err
		}
		savedID = row.ID
		return nil
	}); err != nil {
		return nil, err
	}

	s.ClearConfigCache(ctx, sysOrigin, scene)
	var saved model.AppPopupConfig
	if err := s.db.WithContext(ctx).Where("id = ?", savedID).First(&saved).Error; err != nil {
		return nil, err
	}
	item := adminItemFromModel(saved)
	return &item, nil
}

// DeleteAdminConfig 删除后台首页弹窗配置。
func (s *Service) DeleteAdminConfig(ctx context.Context, id int64) error {
	if s == nil || s.db == nil {
		return NewAppError(http.StatusServiceUnavailable, "app_popup_unavailable", "app popup service is unavailable")
	}
	if id <= 0 {
		return NewAppError(http.StatusBadRequest, "invalid_id", "id is required")
	}
	var row model.AppPopupConfig
	if err := s.db.WithContext(ctx).Where("id = ?", id).First(&row).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return NewAppError(http.StatusNotFound, "app_popup_config_not_found", "config not found")
		}
		return err
	}
	if err := s.db.WithContext(ctx).Delete(&row).Error; err != nil {
		return err
	}
	s.ClearConfigCache(ctx, row.SysOrigin, row.Scene)
	return nil
}

// ClearConfigCache 清理指定场景的配置缓存，供后台配置保存后调用。
func (s *Service) ClearConfigCache(ctx context.Context, sysOrigin, scene string) {
	if s == nil || s.cache == nil {
		return
	}
	_ = s.cache.Del(ctx, appPopupConfigCacheKey(sysOrigin, scene)).Err()
}

func normalizePageCursor(cursor int) int {
	if cursor <= 0 {
		return 1
	}
	return cursor
}

func normalizePageLimit(limit int) int {
	if limit <= 0 {
		return 20
	}
	if limit > 100 {
		return 100
	}
	return limit
}

func defaultIfBlank(value, fallback string) string {
	value = strings.TrimSpace(value)
	if value != "" {
		return value
	}
	return strings.TrimSpace(fallback)
}

func mustContentJSON(title, image string) string {
	payload := map[string]any{}
	if title = strings.TrimSpace(title); title != "" {
		payload["title"] = title
	}
	if image = strings.TrimSpace(image); image != "" {
		payload["image"] = image
	}
	if len(payload) == 0 {
		return "{}"
	}
	raw, err := json.Marshal(payload)
	if err != nil {
		return ""
	}
	return string(raw)
}

func normalizeJSONField(raw string) string {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return "null"
	}
	var value any
	if err := json.Unmarshal([]byte(raw), &value); err != nil {
		return "null"
	}
	encoded, err := json.Marshal(value)
	if err != nil {
		return "null"
	}
	return string(encoded)
}