package evaluation

import (
	"context"
	"errors"

	"github.com/google/uuid"
	"gorm.io/gorm"
)

var ErrEventNotFound = errors.New("事件不存在")

type EventResults struct {
	Evaluations []Evaluation `json:"evaluations"`
	Alerts      []AlertLink  `json:"alerts"`
}

type AlertLink struct {
	ID       string `json:"id"`
	Summary  string `json:"summary"`
	Status   string `json:"status"`
	Severity string `json:"severity"`
	Location string `json:"location"`
}

type Service struct{ DB *gorm.DB }

func NewService(db *gorm.DB) Service { return Service{DB: db} }

func (s Service) ForEvent(ctx context.Context, eventID string) (EventResults, error) {
	if _, err := uuid.Parse(eventID); err != nil {
		return EventResults{}, ErrEventNotFound
	}
	var count int64
	if err := s.DB.WithContext(ctx).Table("bell_events").Where("id = ?", eventID).Count(&count).Error; err != nil {
		return EventResults{}, err
	}
	if count == 0 {
		return EventResults{}, ErrEventNotFound
	}
	result := EventResults{Evaluations: make([]Evaluation, 0), Alerts: make([]AlertLink, 0)}
	if err := s.DB.WithContext(ctx).Where("event_id = ?", eventID).Order("evaluated_at, rule_id").Find(&result.Evaluations).Error; err != nil {
		return EventResults{}, err
	}
	err := s.DB.WithContext(ctx).Table("bell_alerts a").
		Select("a.id, a.summary, a.status, a.severity, a.location").
		Joins("JOIN bell_alert_events ae ON ae.alert_id = a.id").
		Where("ae.event_id = ?", eventID).Order("a.created_at, a.id").Scan(&result.Alerts).Error
	return result, err
}