package main

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"strings"
	"sync/atomic"
	"syscall"

	"github.com/spf13/cobra"

	"github.com/netsynth/netsynth/aggregate"
	"github.com/netsynth/netsynth/capture"
	"github.com/netsynth/netsynth/classify"
)

var (
	ifaceName  string
	listIfaces bool
	verbose    bool
)

func main() {
	rootCmd := &cobra.Command{
		Use:   "netsynth",
		Short: "Sonify live network traffic into ambient audio",
		Long:  "NetSynth captures network traffic, classifies it by protocol, and (in future phases) synthesizes an ambient MP3 soundscape.",
		RunE:  run,
	}

	rootCmd.Flags().StringVarP(&ifaceName, "interface", "i", "", "Network interface to capture on (required unless --list-interfaces)")
	rootCmd.Flags().BoolVar(&listIfaces, "list-interfaces", false, "List available network interfaces and exit")
	rootCmd.Flags().BoolVar(&verbose, "verbose", false, "Print per-window protocol activity to stderr")

	if err := rootCmd.Execute(); err != nil {
		os.Exit(1)
	}
}

func run(cmd *cobra.Command, args []string) error {
	// --list-interfaces mode (CAPT-02)
	if listIfaces {
		return runListInterfaces()
	}

	// Require -i flag
	if ifaceName == "" {
		return fmt.Errorf("interface required: use -i <interface> or --list-interfaces to see available interfaces")
	}

	// Set up signal handling (Ctrl+C)
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	// Stage 1: Capture (CAPT-01)
	fmt.Fprintf(os.Stderr, "Starting capture on %s... (press Ctrl+C to stop)\n", ifaceName)
	packets, droppedPtr, err := capture.StartCapture(ctx, ifaceName)
	if err != nil {
		return err // CAPT-04: permission error already has platform-specific message
	}

	// Stage 2: Classify (CLAS-01)
	classifier := classify.NewClassifier(classify.DefaultRules)
	classified := make(chan classify.ClassifiedPacket, 1024)
	go func() {
		defer close(classified)
		for pkt := range packets {
			classified <- classifier.Classify(pkt)
		}
	}()

	// Stage 3: Aggregate with optional verbose callback (CLAS-04)
	var onSnapshot func(classify.WindowSnapshot)
	if verbose {
		onSnapshot = func(snap classify.WindowSnapshot) {
			aggregate.PrintWindowLine(os.Stderr, snap) // CLAS-04: --verbose output
		}
	}
	snapshots := aggregate.Aggregate(ctx.Done(), classified, aggregate.DefaultWindowMs, onSnapshot)

	// Consume snapshots and accumulate totals
	totals := make(map[classify.TrafficClass]int64)
	for snap := range snapshots {
		aggregate.AccumulateTotals(totals, snap)
	}

	// Print exit summary (CLAS-03)
	dropped := atomic.LoadInt64(droppedPtr)
	if dropped > 0 {
		fmt.Fprintf(os.Stderr, "\nWarning: %d packets dropped (channel buffer full)\n", dropped)
	}
	aggregate.PrintSummary(os.Stderr, totals)

	return nil
}

func runListInterfaces() error {
	ifaces, err := capture.ListInterfaces()
	if err != nil {
		return fmt.Errorf("error listing interfaces: %w", err)
	}
	if len(ifaces) == 0 {
		fmt.Fprintln(os.Stderr, "No interfaces found. If interfaces are missing, run with sudo.")
		return nil
	}
	fmt.Fprintln(os.Stderr, "Available interfaces:")
	for _, iface := range ifaces {
		addrs, _ := iface.Addrs()
		addrStrs := make([]string, len(addrs))
		for i, a := range addrs {
			addrStrs[i] = a.String()
		}
		fmt.Fprintf(os.Stderr, "  %-15s  flags=%s  addrs=%s\n",
			iface.Name, iface.Flags, strings.Join(addrStrs, ", "))
	}
	return nil
}