package poller

import (
	"context"
	"log"
	"sync"
	"time"

	"supply-intelligence/internal/discovery"
)

// DiscoveryRuntime runs periodic discovery scans for all registered platforms.
type DiscoveryRuntime struct {
	scheduler *discovery.DiscoveryScheduler
	interval  time.Duration
	cancel    context.CancelFunc
	wg        sync.WaitGroup
}

// NewDiscoveryRuntime creates a discovery runtime with the given scheduler and interval.
func NewDiscoveryRuntime(scheduler *discovery.DiscoveryScheduler, interval time.Duration) *DiscoveryRuntime {
	return &DiscoveryRuntime{scheduler: scheduler, interval: interval}
}

// Start begins periodic discovery scanning. Does nothing if already started.
func (r *DiscoveryRuntime) Start(parent context.Context) bool {
	if r == nil || r.scheduler == nil || r.cancel != nil {
		return false
	}
	ctx, cancel := context.WithCancel(parent)
	r.cancel = cancel
	r.wg.Add(1)
	go func() {
		defer r.wg.Done()
		// Run an immediate first scan
		r.runScan(context.Background())
		ticker := time.NewTicker(r.interval)
		defer ticker.Stop()
		for {
			select {
			case <-ticker.C:
				r.runScan(context.Background())
			case <-ctx.Done():
				log.Println("[discovery-runtime] stopped")
				return
			}
		}
	}()
	log.Printf("[discovery-runtime] started with interval=%v", r.interval)
	return true
}

// Stop halts periodic scanning.
func (r *DiscoveryRuntime) Stop() {
	if r == nil || r.cancel == nil {
		return
	}
	r.cancel()
	r.wg.Wait()
}

func (r *DiscoveryRuntime) runScan(ctx context.Context) {
	results, err := r.scheduler.ScanAllPlatforms(ctx)
	if err != nil {
		log.Printf("[discovery-runtime] scan error: %v", err)
		return
	}
	for _, res := range results {
		if len(res.Errors) > 0 {
			log.Printf("[discovery-runtime] platform=%s errors=%v", res.Platform, res.Errors)
		} else if res.NewModels > 0 {
			log.Printf("[discovery-runtime] platform=%s new_models=%d", res.Platform, res.NewModels)
		}
	}
}