// Package main is mavenclient — maven's reference client.
//
// Per DESIGN.md § Voice pipeline (STT / TTS): capture lives on the client;
// the server transcribes + synthesises on demand. The PC client runs the
// wake-word / VAD gate (cmd/mavwaked) and ships ONE clean audio blob per
// utterance on activation. The server never owns a mic.
//
// This binary is the floor reference: there is NO wake-word / VAD here
// (production PC client libraries); it ships ONE wav file from disk per
// invocation, posts it via voice.PushToTalk, and writes the reply audio to
// a wav file (or stdout). The point is to round-trip the daemon's reactive
// path end-to-end with the real TCP wire, not to be the production client.
//
//	usage:
//	  mavenclient -in audio.wav -out reply.wav
//	  mavenclient -in audio.wav         # reply written to ./reply.wav
//	  mavenclient -addr 127.0.0.1:9100  # default; production = wg-tunnel addr
//
// -listen mode keeps the conn open and writes incoming Push frames
// (proactive nudge audio) to disk sequentially — exercise proactive
// delivery end-to-end. The reference for "the most-recently-active client
// plays it": run one, fire a tick, see the file appear.
//
//	mavenclient -listen -out-prefix /tmp/maven-nudge-
//	# then trigger a tick; /tmp/maven-nudge-1.wav, -2.wav ... appear
package main

import (
	"context"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"log"
	"net"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"syscall"
	"time"

	"github.com/kami/maven/internal/audio"
	"github.com/kami/maven/internal/voice"
)

func main() {
	if err := run(os.Args[1:]); err != nil {
		fmt.Fprintln(os.Stderr, "mavenclient:", err)
		os.Exit(1)
	}
}

func run(args []string) error {
	addr := flag.String("addr", "127.0.0.1:9100", "mavend voice address (TCP; inside wg tunnel in prod)")
	inPath := flag.String("in", "", "input WAV (canonical 16k mono int16); required for one-shot")
	outPath := flag.String("out", "", "output WAV (default ./reply.wav or nudge-N.wav for -listen)")
	lang := flag.String("lang", "ru", "BCP-47 lang hint for stt ('ru' | 'en' | 'mixed')")
	listen := flag.Bool("listen", false, "stay open + write incoming Push frames to disk")
	outPrefix := flag.String("out-prefix", "", "-listen: prefix for received-nudge wav files (default ./nudge-)")
	flag.CommandLine.Parse(args)

	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
	defer stop()

	c := voice.Dial(*addr)
	defer c.Close()

	if *listen {
		return runListen(ctx, c, *outPrefix)
	}
	if *inPath == "" {
		flag.Usage()
		return errors.New("-in is required for one-shot mode (or use -listen)")
	}
	return runOneShot(ctx, c, *inPath, *outPath, *lang)
}

func runOneShot(ctx context.Context, c *voice.Client, inPath, outPath, lang string) error {
	wav, err := os.ReadFile(inPath)
	if err != nil {
		return fmt.Errorf("read input: %w", err)
	}
	format, pcm, err := audio.PCMFromWAV(wav)
	if err != nil {
		return err
	}
	log.Printf("mavenclient: loaded %s (%.2fs, %+v)", inPath, float64(len(pcm))/float64(format.SampleRate)/float64(format.SampleBits/8), format)

	resp, err := c.PushToTalk(ctx, audio.Audio{Format: format, Bytes: pcm}, lang)
	if err != nil {
		return fmt.Errorf("voice round-trip: %w", err)
	}
	if outPath == "" {
		outPath = "reply.wav"
	}
	if err := writeWAV(outPath, resp.ReplyAudio); err != nil {
		return err
	}
	log.Printf("mavenclient: reply (%.2fs, %q) -> %s", resp.ReplyAudio.Duration(), resp.ReplyText, outPath)
	if len(resp.RoutedChannels) > 0 {
		log.Printf("mavenclient: also routed to: %v", resp.RoutedChannels)
	}
	return nil
}

func runListen(ctx context.Context, c *voice.Client, prefix string) error {
	if prefix == "" {
		prefix = "nudge-"
	}
	h := &filePushHandler{prefix: prefix, counter: 0}
	log.Printf("mavenclient: listening for server pushes; writing to %s*.wav", prefix)
	return c.RunPushReceiver(ctx, h)
}

type filePushHandler struct {
	prefix  string
	counter int
}

func (h *filePushHandler) OnPush(p voice.Push) {
	switch p.Kind {
	case voice.PushKindAudioNudge:
		var ap voice.AudioNudgePush
		if err := jsonUnmarshal(p.Params, &ap); err != nil {
			log.Printf("mavenclient: bad audio_nudge push: %v", err)
			return
		}
		h.counter++
		name := fmt.Sprintf("%s%d.wav", h.prefix, h.counter)
		if err := writeWAV(name, ap.Audio); err != nil {
			log.Printf("mavenclient: write %s: %v", name, err)
			return
		}
		log.Printf("mavenclient: nudge %q (sev %d) -> %s (%.2fs) %q", ap.RuleName, ap.Severity, name, ap.Audio.Duration(), ap.Text)
	case voice.PushKindPing:
		// liveness; ignore.
	default:
		log.Printf("mavenclient: unknown push kind %q", p.Kind)
	}
}

func writeWAV(path string, a audio.Audio) error {
	if err := os.MkdirAll(filepath.Dir(path), 0o755); filepath.Dir(path) != "" && err != nil {
		return err
	}
	wav, err := audio.WAVFromPCM(a.Format, a.Bytes)
	if err != nil {
		return err
	}
	return os.WriteFile(path, wav, 0o644)
}

// jsonUnmarshal — kept local rather than pulling encoding/json into main.go
// top-level space.
func jsonUnmarshal(b []byte, v any) error { return json.Unmarshal(b, v) }

// keep strconv + io + net + time alive for future duration/size helpers.
var _ = strconv.Atoi
var _ io.Reader = (io.Reader)(nil)
var _ = net.IPv4
var _ = time.Second