package service

import "sort"

// RegionDiseaseEntry 区域发病条目（trace_records 联查 rooms 得到）
type RegionDiseaseEntry struct {
	Region  string
	Disease string
}

// RegionStat 区域发病统计
type RegionStat struct {
	Region   string         `json:"region"`
	Total    int            `json:"total"`
	Diseases map[string]int `json:"diseases"`
}

// AggregateRegionStats 按区域分组统计发病数与病种分布（空区域剔除，按总数降序）
func AggregateRegionStats(entries []RegionDiseaseEntry) []RegionStat {
	byRegion := make(map[string]*RegionStat)
	for _, e := range entries {
		if e.Region == "" {
			continue
		}
		s, ok := byRegion[e.Region]
		if !ok {
			s = &RegionStat{Region: e.Region, Diseases: map[string]int{}}
			byRegion[e.Region] = s
		}
		s.Total++
		s.Diseases[e.Disease]++
	}
	result := make([]RegionStat, 0, len(byRegion))
	for _, s := range byRegion {
		result = append(result, *s)
	}
	sort.Slice(result, func(i, j int) bool {
		if result[i].Total != result[j].Total {
			return result[i].Total > result[j].Total
		}
		return result[i].Region < result[j].Region
	})
	return result
}