// ABOUTME: Emits a RunSummary as a structured log entry via slog.
// ABOUTME: Follows the same slog pattern as internal/output/logger.go for consistency.
package summary

import (
	"io"
	"log/slog"
)

// SummaryWriter outputs a RunSummary using structured logging
type SummaryWriter struct {
	logger *slog.Logger
}

// NewSummaryWriter creates a writer that emits summaries to the given output in the given format
func NewSummaryWriter(output io.Writer, format string) *SummaryWriter {
	opts := &slog.HandlerOptions{Level: slog.LevelInfo}

	var handler slog.Handler
	switch format {
	case "text":
		handler = slog.NewTextHandler(output, opts)
	default:
		handler = slog.NewJSONHandler(output, opts)
	}

	return &SummaryWriter{
		logger: slog.New(handler),
	}
}

// Write emits the run summary as a single structured log entry
func (w *SummaryWriter) Write(s *RunSummary) {
	if s == nil {
		return
	}

	w.logger.Info("run_summary",
		slog.Time("start_time", s.StartTime),
		slog.Time("end_time", s.EndTime),
		slog.Float64("duration_seconds", s.DurationSeconds),
		slog.Int("sample_count", s.SampleCount),
		slog.Group("cpu_total_percent",
			slog.Float64("peak", s.CPUTotal.Peak),
			slog.Float64("avg", s.CPUTotal.Avg),
			slog.Float64("p95", s.CPUTotal.P95),
		),
		slog.Group("mem_used_bytes",
			slog.Float64("peak", s.MemUsedBytes.Peak),
			slog.Float64("avg", s.MemUsedBytes.Avg),
			slog.Float64("p95", s.MemUsedBytes.P95),
		),
		slog.Group("mem_used_percent",
			slog.Float64("peak", s.MemUsedPercent.Peak),
			slog.Float64("avg", s.MemUsedPercent.Avg),
			slog.Float64("p95", s.MemUsedPercent.P95),
		),
		slog.Any("top_cpu_processes", s.TopCPUProcesses),
		slog.Any("top_mem_processes", s.TopMemProcesses),
	)
}