package aggregate

import (
	"fmt"
	"io"
	"sort"

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

// PrintSummary writes a per-protocol packet count summary to w (typically os.Stderr).
// Output format matches tcpdump conventions (CLAS-03): per-protocol counts with
// percentages and a TOTAL line, sorted alphabetically for stable output.
func PrintSummary(w io.Writer, totals map[classify.TrafficClass]int64) {
	var totalPackets int64
	for _, count := range totals {
		totalPackets += count
	}

	fmt.Fprintln(w, "\n--- Protocol Summary ---")

	// Sort classes for stable output.
	classes := make([]string, 0, len(totals))
	for c := range totals {
		classes = append(classes, string(c))
	}
	sort.Strings(classes)

	for _, className := range classes {
		c := classify.TrafficClass(className)
		count := totals[c]
		pct := 0.0
		if totalPackets > 0 {
			pct = float64(count) / float64(totalPackets) * 100.0
		}
		fmt.Fprintf(w, "  %-15s %8d packets (%5.1f%%)\n", c, count, pct)
	}
	fmt.Fprintf(w, "  %-15s %8d packets\n", "TOTAL", totalPackets)
}

// PrintWindowLine writes a single verbose per-window activity line to w (CLAS-04).
// Format: [window N] CLASS:count CLASS:count ... (total: N)
// Classes with zero counts are omitted. Output is sorted for deterministic display.
func PrintWindowLine(w io.Writer, snap classify.WindowSnapshot) {
	fmt.Fprintf(w, "[window %d]", snap.WindowIndex)

	// Sort for stable output.
	classes := make([]string, 0, len(snap.Counts))
	for c := range snap.Counts {
		classes = append(classes, string(c))
	}
	sort.Strings(classes)

	for _, className := range classes {
		c := classify.TrafficClass(className)
		if snap.Counts[c] > 0 {
			fmt.Fprintf(w, " %s:%d", c, snap.Counts[c])
		}
	}
	fmt.Fprintf(w, " (total: %d)\n", snap.TotalPackets)
}

// AccumulateTotals merges a WindowSnapshot's counts into cumulative totals.
// This is used to build the final summary passed to PrintSummary.
func AccumulateTotals(totals map[classify.TrafficClass]int64, snap classify.WindowSnapshot) {
	for class, count := range snap.Counts {
		totals[class] += count
	}
}