package notification

import (
	"context"
	"fmt"
	"log/slog"

	"github.com/google/uuid"
)

// Router dispatches an OutboundMessage to the channel-appropriate sender.
// The notifier worker holds one Router and stays oblivious to whether the
// concrete backend is SES, Twilio, or a logger stub.
type Router struct {
	email Sender
	sms   Sender
}

func NewRouter(email, sms Sender) *Router {
	return &Router{email: email, sms: sms}
}

func (r *Router) Send(ctx context.Context, msg OutboundMessage) (string, error) {
	switch msg.Channel {
	case ChannelEmail:
		if r.email == nil {
			return "", fmt.Errorf("no email sender configured")
		}
		return r.email.Send(ctx, msg)
	case ChannelSMS:
		if r.sms == nil {
			return "", fmt.Errorf("no sms sender configured")
		}
		return r.sms.Send(ctx, msg)
	}
	return "", fmt.Errorf("router: unknown channel %q", msg.Channel)
}

// LogGuestEmailDispatcher is the dev-mode dispatcher that renders the
// templated email and logs both bodies. Useful for local docker-compose
// before SES is configured — gives engineers the rendered output without
// needing a real inbox.
type LogGuestEmailDispatcher struct {
	logger *slog.Logger
	tpls   *Templates
}

func NewLogGuestEmailDispatcher(logger *slog.Logger, tpls *Templates) *LogGuestEmailDispatcher {
	return &LogGuestEmailDispatcher{logger: logger, tpls: tpls}
}

func (d *LogGuestEmailDispatcher) SendGuest(_ context.Context, to, subject string, name TemplateName, data map[string]any) (string, error) {
	if data == nil {
		data = map[string]any{}
	}
	data["Subject"] = subject
	_, text, err := d.tpls.Render(name, data)
	if err != nil {
		return "", err
	}
	id := "log:" + uuid.NewString()
	d.logger.Info("guest email (stub)",
		"to", to,
		"subject", subject,
		"template", string(name),
		"provider_message_id", id,
		"text_body", text,
	)
	return id, nil
}