package notify

import (
	"encoding/json"
	"fmt"
	"log/slog"

	webpush "github.com/SherClockHolmes/webpush-go"
	"github.com/thepeterstone/claudomator/internal/storage"
)

// PushSubscriptionStore is the minimal storage interface needed by WebPushNotifier.
type PushSubscriptionStore interface {
	ListPushSubscriptions() ([]storage.PushSubscription, error)
}

// WebPushNotifier sends web push notifications to all registered subscribers.
type WebPushNotifier struct {
	Store           PushSubscriptionStore
	VAPIDPublicKey  string
	VAPIDPrivateKey string
	VAPIDEmail      string
	Logger          *slog.Logger
}

// notificationContent derives urgency, title, body, and tag from a notify Event.
// Exported only for tests; use lowercase in production code via this same file.
func notificationContent(ev Event) (urgency, title, body, tag string) {
	tag = "task-" + ev.TaskID
	switch ev.Status {
	case "BLOCKED":
		urgency = "urgent"
		title = "Needs input"
		body = fmt.Sprintf("%s is waiting for your response", ev.TaskName)
	case "FAILED", "BUDGET_EXCEEDED", "TIMED_OUT":
		urgency = "high"
		title = "Task failed"
		if ev.Error != "" {
			body = fmt.Sprintf("%s failed: %s", ev.TaskName, ev.Error)
		} else {
			body = fmt.Sprintf("%s failed", ev.TaskName)
		}
	case "COMPLETED":
		urgency = "low"
		title = "Task done"
		body = fmt.Sprintf("%s completed ($%.2f)", ev.TaskName, ev.CostUSD)
	default:
		urgency = "normal"
		title = "Task update"
		body = fmt.Sprintf("%s: %s", ev.TaskName, ev.Status)
	}
	return
}

// Notify sends a web push notification to all registered subscribers.
func (n *WebPushNotifier) Notify(ev Event) error {
	subs, err := n.Store.ListPushSubscriptions()
	if err != nil {
		return fmt.Errorf("listing push subscriptions: %w", err)
	}
	if len(subs) == 0 {
		return nil
	}

	urgency, title, body, tag := notificationContent(ev)

	payload := map[string]string{
		"title": title,
		"body":  body,
		"tag":   tag,
	}
	data, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("marshaling push payload: %w", err)
	}

	opts := &webpush.Options{
		Subscriber:      n.VAPIDEmail,
		VAPIDPublicKey:  n.VAPIDPublicKey,
		VAPIDPrivateKey: n.VAPIDPrivateKey,
		Urgency:         webpush.Urgency(urgency),
		TTL:             86400,
	}

	var lastErr error
	for _, sub := range subs {
		wSub := &webpush.Subscription{
			Endpoint: sub.Endpoint,
			Keys: webpush.Keys{
				P256dh: sub.P256DHKey,
				Auth:   sub.AuthKey,
			},
		}
		resp, sendErr := webpush.SendNotification(data, wSub, opts)
		if sendErr != nil {
			n.Logger.Error("webpush send failed", "endpoint", sub.Endpoint, "error", sendErr)
			lastErr = sendErr
			continue
		}
		resp.Body.Close()
		if resp.StatusCode >= 400 {
			n.Logger.Warn("webpush returned error status", "endpoint", sub.Endpoint, "status", resp.StatusCode)
		}
	}
	return lastErr
}