// backend/internal/refresh.go
package internal

import (
	"io"
	"log"
	"net/http"
	"os"
	"strings"
	"sync"
	"time"
)

// Debounce refresh calls so a burst of uploads/renames/deletes only triggers one scan.
var (
	refreshMu    sync.Mutex
	refreshTimer *time.Timer
)

// RefreshLibrary triggers a Jellyfin library scan.
// - Prefers JELLYFIN_API_KEY (admin key). Falls back to userToken if no key.
// - Debounced: calls within 2s are coalesced to a single scan.
func (j *Jellyfin) RefreshLibrary(userToken string) {
	refreshMu.Lock()
	defer refreshMu.Unlock()

	if refreshTimer != nil {
		// push the timer out a bit if more events arrive
		refreshTimer.Reset(2 * time.Second)
		return
	}

	refreshTimer = time.AfterFunc(2*time.Second, func() {
		base := strings.TrimRight(os.Getenv("JELLYFIN_URL"), "/")
		if base == "" {
			log.Printf("jellyfin refresh: JELLYFIN_URL missing; skipping")
			safeClearTimer()
			return
		}
		token := os.Getenv("JELLYFIN_API_KEY")
		if token == "" {
			token = userToken // last resort (may fail if user is not admin)
		}
		if token == "" {
			log.Printf("jellyfin refresh: no token; skipping")
			safeClearTimer()
			return
		}

		req, _ := http.NewRequest(http.MethodPost, base+"/Library/Refresh", nil)
		// Jellyfin/Emby accept API key via header or query; header is cleanest.
		// Either X-Emby-Token or X-MediaBrowser-Token are accepted; we use X-Emby-Token.
		req.Header.Set("X-Emby-Token", token)

		client := j.Client
		if client == nil {
			client = &http.Client{Timeout: 20 * time.Second}
		}
		resp, err := client.Do(req)
		if err != nil {
			log.Printf("jellyfin refresh: request error: %v", err)
			safeClearTimer()
			return
		}
		_, _ = io.Copy(io.Discard, resp.Body)
		_ = resp.Body.Close()

		if resp.StatusCode >= 300 {
			log.Printf("jellyfin refresh: HTTP %s", resp.Status)
		} else {
			log.Printf("jellyfin refresh: triggered")
		}

		safeClearTimer()
	})
}

func safeClearTimer() {
	refreshMu.Lock()
	defer refreshMu.Unlock()
	refreshTimer = nil
}