package main

import (
	"context"
	"log"
	"time"

	"github.com/livekit/protocol/livekit"
	"github.com/livekit/egress-sdk-go/egress"
)

func main() {
	// Initialize the egress client (fill with your values)
	egressAPIKey := "YOUR_EGRESS_API_KEY"
	egressAPISecret := "YOUR_EGRESS_API_SECRET"
	egressURL := "https://egress.livekit.example" // replace with your egress endpoint

	client, err := egress.NewClient(egressURL, egressAPIKey, egressAPISecret)
	if err != nil {
		log.Fatalf("failed to create egress client: %v", err)
	}

	// Room and output target
	roomName := "my-room"
	outputFile := "mixed_audio.mp4" // container supporting stereo audio
	bucket := "your-bucket-name"
	region := "us-west-2"
	accessKey := "AWS_ACCESS_KEY"
	secret := "AWS_SECRET_KEY"

	// Composite layout with audio mapping:
	// - We request stereo output (2 channels).
	// - Left channel will contain the customer's audio, right channel the AI agent.
	// The layout JSON below is illustrative — adjust participant sources/track names to match your room.
	layout := &livekit.RoomLayout{
		Base: &livekit.Layout{
			Width:  1920,
			Height: 1080,
			// Request stereo audio; LiveKit will mix according to audio mapping below.
			Audio: &livekit.LayoutAudio{
				// set to stereo (2 channels). If the SDK exposes channel count directly, set it; otherwise stereo is default for composite.
			},
		},
		// Add regions/layers specifying which participant maps to which audio channel.
		// Note: exact field names for channel mapping may vary; ensure you map participant audio tracks to left/right in your egress layout.
		Layers: []*livekit.LayoutLayer{
			{
				Name: "customer_audio",
				// Source could be participant identity or track name; use what identifies the customer's track.
				Source: &livekit.LayoutLayer_SourceParticipant{
					SourceParticipant: &livekit.LayoutLayer_Participant{
						Identity: "customer-identity",
					},
				},
				// For audio-only layers you can set position/size to zero or ignore visual parameters.
			},
			{
				Name: "agent_audio",
				Source: &livekit.LayoutLayer_SourceParticipant{
					SourceParticipant: &livekit.LayoutLayer_Participant{
						Identity: "ai-agent-identity",
					},
				},
			},
		},
	}

	// Build RoomCompositeEgressRequest
	req := &livekit.RoomCompositeEgressRequest{
		RoomName: roomName,
		// Specify output formats & S3 upload config
		Output: &livekit.EncodedFileOutput{
			File: &livekit.EncodedFileOutput_File{
				File: &livekit.EncodedFileOutput_File_S3{
					S3: &livekit.S3Upload{
						AccessKey: accessKey,
						Secret:    secret,
						Bucket:    bucket,
						Region:    region,
						Key:       outputFile,
					},
				},
			},
		},
		// Set the desired file format; mp4 is used here to carry stereo audio.
		// If the SDK requires explicit format field, set it to "mp4" or another supported container.
		Layout: layout,
		// Optionally set audio bitrate/sample rate if the API supports it
		Audio: &livekit.RoomCompositeEgressRequest_AudioEncodingOptions{
			// Example fields; exact names may vary in SDK:
			Codec:       livekit.AudioCodec_AAC, // choose a codec supported by the container
			Bitrate:     128000,
			SampleRateHz: 44100,
			Channels:    2,
		},
		// Set a timeout or other request-level options
	}

	// Start the egress
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()

	res, err := client.StartRoomCompositeEgress(ctx, req)
	if err != nil {
		log.Fatalf("failed to start room composite egress: %v", err)
	}

	log.Printf("egress started: id=%s, file=%s", res.EgressId, outputFile)
}