package main

import (
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"sort"
	"strconv"
	"strings"
	"sync"
	"time"
)

type ProxmoxTask struct {
	UPID      string `json:"upid"`
	Node      string `json:"node"`
	Type      string `json:"type"`
	ID        string `json:"id"`
	User      string `json:"user"`
	Status    string `json:"status"`
	StartTime int64  `json:"starttime"`
	EndTime   int64  `json:"endtime"`
	Duration  int64  `json:"duration"`
}
type GuestSnapshot struct {
	VMID        int     `json:"vmid"`
	GuestName   string  `json:"guestName"`
	GuestType   string  `json:"guestType"`
	Name        string  `json:"name"`
	Description string  `json:"description"`
	CreatedAt   int64   `json:"createdAt"`
	Running     bool    `json:"running"`
	Parent      string  `json:"parent,omitempty"`
	SizeBytes   *uint64 `json:"sizeBytes,omitempty"`
	AgeSeconds  int64   `json:"ageSeconds"`
}
type ProxmoxActivity struct {
	Available bool            `json:"available"`
	Tasks     []ProxmoxTask   `json:"tasks"`
	Snapshots []GuestSnapshot `json:"snapshots"`
	CheckedAt int64           `json:"checkedAt"`
}
type activityCollector struct {
	mu         sync.RWMutex
	value      ProxmoxActivity
	refreshing bool
}

func newActivityCollector() *activityCollector {
	c := &activityCollector{refreshing: true}
	go c.refresh()
	return c
}
func (c *activityCollector) collect(guests GuestsMetrics) ProxmoxActivity {
	c.mu.RLock()
	value := c.value
	c.mu.RUnlock()
	c.mu.Lock()
	if !c.refreshing && time.Since(time.Unix(value.CheckedAt, 0)) > 15*time.Second {
		c.refreshing = true
		go c.refreshWithGuests(guests)
	}
	c.mu.Unlock()
	return value
}
func (c *activityCollector) refresh() { c.refreshWithGuests(readGuests()) }
func (c *activityCollector) refreshWithGuests(guests GuestsMetrics) {
	value := readProxmoxActivity(guests)
	c.mu.Lock()
	c.value = value
	c.refreshing = false
	c.mu.Unlock()
}
func readProxmoxActivity(guests GuestsMetrics) ProxmoxActivity {
	result := ProxmoxActivity{CheckedAt: time.Now().Unix()}
	if _, err := exec.LookPath("pvesh"); err != nil {
		return result
	}
	node, err := os.Hostname()
	if err != nil {
		return result
	}
	result.Available = true
	out := commandOutput(8*time.Second, "pvesh", "get", "/nodes/"+node+"/tasks", "--limit", "100", "--output-format", "json")
	if out != "" && json.Unmarshal([]byte(out), &result.Tasks) == nil {
		for i := range result.Tasks {
			if result.Tasks[i].EndTime > result.Tasks[i].StartTime {
				result.Tasks[i].Duration = result.Tasks[i].EndTime - result.Tasks[i].StartTime
			}
		}
	}
	for _, guest := range guests.Guests {
		if guest.Template != 0 {
			continue
		}
		kind := "qemu"
		label := "VM"
		if guest.Type != "qemu" {
			kind = "lxc"
			label = "LXC"
		}
		out := commandOutput(5*time.Second, "pvesh", "get", fmt.Sprintf("/nodes/%s/%s/%d/snapshot", guest.Node, kind, guest.VMID), "--output-format", "json")
		if out == "" {
			continue
		}
		var raw []struct {
			Name        string `json:"name"`
			Description string `json:"description"`
			SnapTime    int64  `json:"snaptime"`
			Running     int    `json:"running"`
			Parent      string `json:"parent"`
			VMState     any    `json:"vmstate"`
		}
		if json.Unmarshal([]byte(out), &raw) != nil {
			continue
		}
		for _, s := range raw {
			if s.Name == "current" {
				continue
			}
			item := GuestSnapshot{VMID: guest.VMID, GuestName: guest.Name, GuestType: label, Name: s.Name, Description: s.Description, CreatedAt: s.SnapTime, Running: s.Running != 0, Parent: s.Parent}
			if item.CreatedAt > 0 {
				item.AgeSeconds = time.Now().Unix() - item.CreatedAt
			}
			if size := uintValue(s.VMState); size > 1 {
				item.SizeBytes = &size
			}
			result.Snapshots = append(result.Snapshots, item)
		}
	}
	sort.Slice(result.Snapshots, func(i, j int) bool { return result.Snapshots[i].CreatedAt > result.Snapshots[j].CreatedAt })
	return result
}
func uintValue(v any) uint64 {
	switch n := v.(type) {
	case float64:
		return uint64(n)
	case string:
		value, _ := strconv.ParseUint(n, 10, 64)
		return value
	}
	return 0
}

type BackupCheckResult struct {
	OK        bool   `json:"ok"`
	Level     string `json:"level"`
	Message   string `json:"message"`
	CheckedAt int64  `json:"checkedAt"`
}

func verifyBackup(volid string) BackupCheckResult {
	result := BackupCheckResult{CheckedAt: time.Now().Unix(), Level: "metadata"}
	if volid == "" || strings.ContainsAny(volid, "\r\n") {
		result.Message = "Некорректный идентификатор backup"
		return result
	}
	out, err := exec.Command("pvesm", "path", volid).CombinedOutput()
	if err != nil {
		result.Message = "Backup не найден в подключённом storage: " + strings.TrimSpace(string(out))
		return result
	}
	path := strings.TrimSpace(string(out))
	if strings.HasPrefix(path, "pbs://") {
		ctxOutput := commandOutput(20*time.Second, "pvesm", "extractconfig", volid)
		if ctxOutput == "" {
			result.Message = "Snapshot найден в PBS, но конфигурацию для тестового чтения получить не удалось"
			return result
		}
		result.OK = true
		result.Level = "pbs-metadata"
		result.Message = "PBS snapshot и его конфигурация успешно прочитаны. Полное восстановление VM не запускалось."
		return result
	}
	info, err := os.Stat(path)
	if err != nil {
		result.Message = "Метаданные доступны, но локальный файл не открыт: " + err.Error()
		return result
	}
	if info.Size() == 0 {
		result.Message = "Файл backup пуст"
		return result
	}
	result.OK = true
	result.Level = "readability"
	result.Message = fmt.Sprintf("Файл доступен для чтения, размер %d байт. Полное тестовое восстановление не запускалось.", info.Size())
	return result
}