package service

import (
	"context"
	"sync"
	"time"
)

type Probe func(context.Context) error

type Component struct {
	Status string `json:"status"`
}
type Health struct {
	Status     string               `json:"status"`
	CheckedAt  time.Time            `json:"checked_at"`
	Components map[string]Component `json:"components"`
}
type HealthService struct{ postgres, redis Probe }

func NewHealthService(postgres, redis Probe) *HealthService {
	return &HealthService{postgres: postgres, redis: redis}
}

func (s *HealthService) Check(ctx context.Context) Health {
	ctx, cancel := context.WithTimeout(ctx, 2*time.Second)
	defer cancel()
	result := Health{Status: "ready", CheckedAt: time.Now().UTC(), Components: map[string]Component{}}
	var mu sync.Mutex
	var wg sync.WaitGroup
	for name, probe := range map[string]Probe{"postgresql": s.postgres, "redis": s.redis} {
		wg.Go(func() {
			status := "unavailable"
			if probe == nil {
				status = "not_configured"
			} else if probe(ctx) == nil {
				status = "ready"
			}
			mu.Lock()
			defer mu.Unlock()
			result.Components[name] = Component{Status: status}
			if status != "ready" {
				result.Status = "not_ready"
			}
		})
	}
	wg.Wait()
	return result
}