package metrics

import "time"

// HostSample is one point-in-time reading of whole-host resource usage.
// Every field is a pointer because a missing reading (a parser in parse.go
// returning nil) must stay distinguishable from a real zero all the way out
// to whatever renders or alerts on it.
type HostSample struct {
	CPUFrac  *float64 `json:"cpu"`
	Load1    *float64 `json:"load1"`
	Load5    *float64 `json:"load5"`
	Load15   *float64 `json:"load15"`
	MemFrac  *float64 `json:"mem"`
	DiskFrac *float64 `json:"disk"`
}

// UnitSample is one point-in-time reading for a single systemd unit's
// cgroup. ReadBytes and WriteBytes are cumulative counters (not deltas) —
// callers wanting a rate diff consecutive samples themselves.
type UnitSample struct {
	CPUFrac      *float64 `json:"cpu"`
	MemBytes     *int64   `json:"mem_bytes"`
	MemPeakBytes *int64   `json:"mem_peak_bytes"`
	ReadBytes    *int64   `json:"read_bytes"`  // cumulative
	WriteBytes   *int64   `json:"write_bytes"` // cumulative
}

// Sample is one point-in-time reading of a box: the host as a whole plus
// every monitored unit, keyed by unit name: systemd unit names (e.g.
// carlos-app@x.example.com.service) and delegated exec-child cgroup names
// (e.g. carlos-exec@x.example.com — no .service suffix; written by the
// sampler's exec-subtree scan since exec-child accounting).
type Sample struct {
	At    time.Time             `json:"at"`
	Host  HostSample            `json:"host"`
	Units map[string]UnitSample `json:"units"`
}

// RawChunk is an hour's worth of raw samples for one box, the unit of
// storage under metrics/boxes/<box>/raw/. V is the wire-shape version (1
// today); Hour is UTC, formatted 2006-01-02-15.
type RawChunk struct {
	V       int      `json:"v"` // 1
	Box     string   `json:"box"`
	Hour    string   `json:"hour"` // UTC, 2006-01-02-15
	Samples []Sample `json:"samples"`
}