package host

import (
	"context"
	"time"
)

// RawSource is the narrow read-only boundary implemented by an authenticated
// agent or another approved host telemetry source. It returns one bounded
// source snapshot; it cannot execute arbitrary host commands.
type RawSource interface {
	Snapshot(context.Context) (RawSnapshot, error)
}

type Adapter struct {
	Source RawSource
	Limits Limits
	Policy Policy
	Now    func() time.Time
}

func (a Adapter) Snapshot(ctx context.Context) (Snapshot, error) {
	if err := ctx.Err(); err != nil {
		return Snapshot{}, err
	}
	if a.Source == nil {
		return UnknownSnapshot(time.Now().UTC(), "host", "agent", "source_unavailable"), nil
	}
	raw, err := a.Source.Snapshot(ctx)
	if err != nil {
		return Snapshot{}, err
	}
	now := time.Now().UTC()
	if a.Now != nil {
		now = a.Now()
	}
	return Normalize(raw, now, a.Limits, a.Policy)
}