package main

import (
	"fmt"
	"sort"
	"strings"
	"time"

	"github.com/novox/mesh-controller/internal/inventory"
)

// machineLines is what a machine said it is made of (novox/hq issue 160), as `node` shows it: every fact in
// one block with its age, the architecture and kernel the profile always carried among them, and each fact
// the machine could not determine said as unknown with its why — never as a zero, and never left out.
func machineLines(a inventory.MachineAccount, had bool, now time.Time) []string {
	if !had {
		return []string{"  what it is made of: never said — this machine has not reported a profile"}
	}
	m := a.Machine
	if m == nil {
		return []string{
			"  what it is made of: not said — its node-engine is older than the one that says it",
			"    " + factLine("architecture", orUnsaid(a.Architecture)),
			"    " + factLine("kernel", orUnsaid(a.Kernel)),
		}
	}
	age := roughly(now.Sub(m.ObservedAt)) + " ago"
	if m.ObservedAt.IsZero() {
		// Said with no time: its age is not known, and is never read as two thousand years.
		age = "at a time it did not say (age unknown)"
	}
	out := []string{fmt.Sprintf("  what it is made of, as it said %s:", age)}
	add := func(name, value string) { out = append(out, "    "+factLine(name, value)) }
	unknown := map[string]string{}
	for k, v := range m.Unknown {
		unknown[k] = v
	}
	// said is the value, or the fact's own reason it is unknown; a fact neither said nor unknown is a
	// node-engine that broke its own rule, and is said so rather than shown blank.
	said := func(fact, value string) string {
		if value != "" {
			delete(unknown, fact)
			return value
		}
		if why, ok := unknown[fact]; ok {
			delete(unknown, fact)
			return "unknown: " + why
		}
		return "unknown: the machine said neither it nor why"
	}

	add("architecture", orUnsaid(a.Architecture))
	release := said("kernel release", m.KernelRelease)
	if m.KernelRelease == "" {
		release = "(release " + release + ")"
	}
	add("kernel", orUnsaid(a.Kernel)+" "+release)
	dist := said("distribution", m.Distribution)
	if m.Distribution != "" {
		dist += " " + said("version", m.Version)
	}
	add("distribution", dist)
	add("processor", said("processor", m.Processor))
	add("cores", said("cores", countWords(m.Cores)))
	add("threads", said("threads", countWords(m.Threads)))
	add("memory", said("memory", bytesWords(m.MemoryBytes)))
	add("virtual", said("virtual or physical", m.Virtual))
	up := ""
	if m.BootedAt != nil {
		up = fmt.Sprintf("%s, since %s", roughly(now.Sub(*m.BootedAt)), m.BootedAt.Local().Format("2006-01-02 15:04"))
	}
	add("up", said("uptime", up))
	add("timezone", said("timezone", m.Timezone))
	if len(m.Filesystems) == 0 {
		add("filesystems", said("filesystems", ""))
	} else {
		for i, f := range m.Filesystems {
			name := ""
			if i == 0 {
				name = "filesystems"
			}
			add(name, fmt.Sprintf("%s  %s, %s free (%s %s)", f.Mount, bytesWords(f.SizeBytes),
				bytesWords(f.FreeBytes), f.Type, f.Device))
		}
		if why, ok := unknown["filesystems"]; ok {
			add("", "and some unknown: "+why)
			delete(unknown, "filesystems")
		}
	}
	add("public address", said("public address", ""))
	// Any other fact a newer node-engine named unknown, so nothing it said is dropped.
	rest := make([]string, 0, len(unknown))
	for k := range unknown {
		rest = append(rest, k)
	}
	sort.Strings(rest)
	for _, k := range rest {
		add(k, "unknown: "+unknown[k])
	}
	return out
}

func factLine(name, value string) string { return fmt.Sprintf("%-15s %s", name, value) }

func orUnsaid(s string) string {
	if strings.TrimSpace(s) == "" {
		return "not said"
	}
	return s
}

// countWords is a number a machine said, or nothing when it said none (its unknown says why).
func countWords(n int) string {
	if n <= 0 {
		return ""
	}
	return fmt.Sprint(n)
}

// bytesWords is an amount of bytes a person reads, in binary units; nothing when none was said.
func bytesWords(n int64) string {
	if n <= 0 {
		return ""
	}
	units := []string{"B", "KiB", "MiB", "GiB", "TiB", "PiB"}
	v, u := float64(n), 0
	for v >= 1024 && u < len(units)-1 {
		v /= 1024
		u++
	}
	if u == 0 {
		return fmt.Sprintf("%d B", n)
	}
	return fmt.Sprintf("%.1f %s", v, units[u])
}