package pgmonitor

import (
	"context"
	"log"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

// StartScheduler runs periodic PostgreSQL analyzer snapshots until ctx is cancelled.
func StartScheduler(ctx context.Context, pool *pgxpool.Pool) {
	if pool == nil {
		return
	}
	go func() {
		t5 := time.NewTicker(5 * time.Minute)
		t15 := time.NewTicker(15 * time.Minute)
		defer t5.Stop()
		defer t15.Stop()
		s := NewService(pool)
		runLight := func() {
			c, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
			defer cancel()
			if err := s.RefreshMetricsSnapshot(c); err != nil {
				log.Printf("pgmonitor: metrics refresh: %v", err)
			}
			if err := s.DetectAutovacuumLag(c); err != nil {
				log.Printf("pgmonitor: autovacuum lag: %v", err)
			}
		}
		runHeavy := func() {
			c, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
			defer cancel()
			if err := s.AggregateSlowQueries(c, 30); err != nil {
				log.Printf("pgmonitor: slow queries snapshot: %v", err)
			}
			if err := s.EstimateTableBloat(c); err != nil {
				log.Printf("pgmonitor: bloat: %v", err)
			}
			if err := s.AnalyzeIndexUsage(c); err != nil {
				log.Printf("pgmonitor: index usage: %v", err)
			}
		}
		runLight()
		runHeavy()
		for {
			select {
			case <-ctx.Done():
				return
			case <-t5.C:
				runLight()
			case <-t15.C:
				runHeavy()
			}
		}
	}()
	log.Printf("pgmonitor: scheduler started (5m light / 15m heavy)")
}