package cluster

import (
	"errors"
	"fmt"
	"math"
	"strings"

	"pxmon/internal/history"
)

type InterfaceP95Snapshot struct {
	ClusterName string                    `json:"cluster"`
	ClusterID   string                    `json:"cluster_id"`
	Interface   string                    `json:"interface"`
	Range       history.RangeShortcut     `json:"range"`
	Samples     int                       `json:"samples"`
	P95Mbps     float64                   `json:"p95_mbps"`
	AvgMbps     float64                   `json:"avg_mbps"`
	MaxMbps     float64                   `json:"max_mbps"`
	Series      []history.NodeSamplePoint `json:"series,omitempty"`
}

func (s *Service) CollectInterfaceP95(selector, iface string, rng history.RangeShortcut) (InterfaceP95Snapshot, error) {
	iface = strings.TrimSpace(iface)
	if iface == "" {
		return InterfaceP95Snapshot{}, errors.New("interface is required")
	}
	c, err := s.Get(selector)
	if err != nil {
		return InterfaceP95Snapshot{}, err
	}
	store := s.NetworkStore()
	if store == nil {
		return InterfaceP95Snapshot{}, errors.New("history store not configured")
	}
	snaps, err := store.Load(c.ID, rng.Since(s.now()))
	if err != nil {
		return InterfaceP95Snapshot{}, err
	}
	series := history.AggregateNodeSeries(snaps, iface)
	out := InterfaceP95Snapshot{
		ClusterName: c.Name,
		ClusterID:   c.ID,
		Interface:   iface,
		Range:       rng,
		Samples:     len(series),
		P95Mbps:     history.PercentileMbps(series, 95),
		Series:      series,
	}
	if len(series) == 0 {
		return out, nil
	}
	var sum, maxV float64
	for _, p := range series {
		sum += p.TotalMbps
		if p.TotalMbps > maxV {
			maxV = p.TotalMbps
		}
	}
	out.AvgMbps = sum / float64(len(series))
	out.MaxMbps = maxV
	return out, nil
}

func (s *Service) RenderInterfaceP95GraphPNG(snap InterfaceP95Snapshot) ([]byte, error) {
	if len(snap.Series) == 0 {
		return history.RenderNodeNetworkPNG([]history.NodeSamplePoint{}, history.ChartOptions{
			Title:    fmt.Sprintf("%s: %s", snap.ClusterName, snap.Interface),
			Subtitle: "No samples",
		})
	}
	subtitle := fmt.Sprintf("P95 %.1f Mbps | max %.1f Mbps | avg %.1f Mbps", snap.P95Mbps, snap.MaxMbps, snap.AvgMbps)
	if math.IsNaN(snap.P95Mbps) {
		subtitle = "No samples"
	}
	return history.RenderNodeNetworkPNG(snap.Series, history.ChartOptions{
		Title:      fmt.Sprintf("%s: %s", snap.ClusterName, snap.Interface),
		Subtitle:   subtitle,
		Percentile: 95,
	})
}