// Package scheduler enthält den Display-Zeitplan-Scheduler.
// Er prüft jede Minute ob ein Screen ein- oder ausgeschaltet werden soll.
package scheduler

import (
	"context"
	"log/slog"
	"time"

	"git.az-it.net/az/morz-infoboard/server/backend/internal/store"
)

// DisplayCommander sendet einen Display-Befehl per MQTT.
type DisplayCommander interface {
	SendDisplayCommand(screenSlug, action string) error
}

// ScreenSlugGetter lädt den Slug für eine Screen-ID.
type ScreenSlugGetter interface {
	GetByID(ctx context.Context, id string) (*store.Screen, error)
}

// Run startet den Scheduler-Loop. Blockiert bis ctx abgebrochen wird.
func Run(ctx context.Context, schedules *store.ScreenScheduleStore, screens ScreenSlugGetter, notifier DisplayCommander) {
	ticker := time.NewTicker(1 * time.Minute)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			check(ctx, schedules, screens, notifier)
		case <-ctx.Done():
			return
		}
	}
}

// check prüft alle aktiven Zeitpläne und sendet ggf. Befehle.
func check(ctx context.Context, schedules *store.ScreenScheduleStore, screens ScreenSlugGetter, notifier DisplayCommander) {
	// Uses process-local timezone — ensure TZ env var is set in the container (e.g. Europe/Berlin).
	now := time.Now().Format("15:04")

	enabled, err := schedules.ListEnabled(ctx)
	if err != nil {
		slog.Error("scheduler: list enabled schedules failed", "err", err)
		return
	}

	for _, sc := range enabled {
		screen, err := screens.GetByID(ctx, sc.ScreenID)
		if err != nil {
			slog.Warn("scheduler: screen not found", "screen_id", sc.ScreenID, "err", err)
			continue
		}

		var action string
		if sc.PowerOnTime != "" && sc.PowerOnTime == now {
			action = "display_on"
		} else if sc.PowerOffTime != "" && sc.PowerOffTime == now {
			action = "display_off"
		}

		if action == "" {
			continue
		}

		if err := notifier.SendDisplayCommand(screen.Slug, action); err != nil {
			slog.Error("scheduler: send command failed", "screen_id", sc.ScreenID, "action", action, "err", err)
		} else {
			slog.Info("scheduler: display command sent", "screen_id", sc.ScreenID, "slug", screen.Slug, "action", action)
		}
	}
}