package main

import (
	"fmt"
	"time"

	"node-lookup/internal/puppet"
)

// formatWhen renders the "last report" column for a node lookup result. It
// handles the lookup error, the unknown-node, and the never-reported cases so
// the output always has a value in every column.
func formatWhen(node *puppet.Node, lookupErr error, relative bool, loc *time.Location, now time.Time) string {
	if lookupErr != nil {
		return "error: " + lookupErr.Error()
	}
	if node == nil {
		return "unknown node"
	}
	if node.ReportTimestamp == "" {
		return "no report"
	}
	ts, err := time.Parse(time.RFC3339Nano, node.ReportTimestamp)
	if err != nil {
		return node.ReportTimestamp // fall back to the raw value
	}
	if relative {
		return humanizeSince(now, ts)
	}
	return ts.In(loc).Format("2006-01-02 15:04:05 MST")
}

// humanizeSince renders the gap between now and ts as a coarse relative string
// ("42s ago", "9m ago", "3h ago", "5d ago"). Future timestamps (clock skew)
// render as "in <d>".
func humanizeSince(now, ts time.Time) string {
	d := now.Sub(ts)
	suffix := "ago"
	if d < 0 {
		d = -d
		suffix = "from now"
	}
	switch {
	case d < time.Minute:
		return fmt.Sprintf("%ds %s", int(d.Seconds()), suffix)
	case d < time.Hour:
		return fmt.Sprintf("%dm %s", int(d.Minutes()), suffix)
	case d < 24*time.Hour:
		return fmt.Sprintf("%dh %s", int(d.Hours()), suffix)
	default:
		return fmt.Sprintf("%dd %s", int(d.Hours()/24), suffix)
	}
}