package service

import (
	"bytes"
	"context"
	"crypto/ecdh"
	"crypto/rand"
	"crypto/sha256"
	"crypto/x509"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"encoding/pem"
	"errors"
	"fmt"
	"io"
	"mime/multipart"
	stdnet "net"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"runtime"
	"strings"
	"sync"
	"time"

	"github.com/mhsanaei/3x-ui/v3/internal/amneziawgnet"
	"github.com/mhsanaei/3x-ui/v3/internal/config"
	"github.com/mhsanaei/3x-ui/v3/internal/database"
	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
	"github.com/mhsanaei/3x-ui/v3/internal/logger"
	"github.com/mhsanaei/3x-ui/v3/internal/util/common"
	"github.com/mhsanaei/3x-ui/v3/internal/util/sys"
	"github.com/mhsanaei/3x-ui/v3/internal/xray"

	"github.com/google/uuid"
	utls "github.com/refraction-networking/utls"
	"github.com/shirou/gopsutil/v4/cpu"
	"github.com/shirou/gopsutil/v4/disk"
	"github.com/shirou/gopsutil/v4/host"
	"github.com/shirou/gopsutil/v4/load"
	"github.com/shirou/gopsutil/v4/mem"
	"github.com/shirou/gopsutil/v4/net"
)

// ProcessState represents the current state of a system process.
type ProcessState string

// Process state constants
const (
	Running ProcessState = "running" // Process is running normally
	Stop    ProcessState = "stop"    // Process is stopped
	Error   ProcessState = "error"   // Process is in error state
)

// Status represents comprehensive system and application status information.
// It includes CPU, memory, disk, network statistics, and Xray process status.
type Status struct {
	T           time.Time `json:"-"`
	Cpu         float64   `json:"cpu"`
	CpuCores    int       `json:"cpuCores"`
	LogicalPro  int       `json:"logicalPro"`
	CpuSpeedMhz float64   `json:"cpuSpeedMhz"`
	Mem         struct {
		Current uint64 `json:"current"`
		Total   uint64 `json:"total"`
	} `json:"mem"`
	Swap struct {
		Current uint64 `json:"current"`
		Total   uint64 `json:"total"`
	} `json:"swap"`
	Disk struct {
		Current uint64 `json:"current"`
		Total   uint64 `json:"total"`
	} `json:"disk"`
	DiskIO struct {
		Read  uint64 `json:"read"`
		Write uint64 `json:"write"`
	} `json:"diskIO"`
	DiskTraffic struct {
		Read  uint64 `json:"read"`
		Write uint64 `json:"write"`
	} `json:"diskTraffic"`
	Xray struct {
		State    ProcessState `json:"state"`
		ErrorMsg string       `json:"errorMsg"`
		Version  string       `json:"version"`
	} `json:"xray"`
	// AmneziaWG gates the overview's AmneziaWG log view: Configured stays true
	// while an inbound exists but its embedded interface isn't up yet, which
	// is exactly when that view's event lines are worth reading.
	AmneziaWG struct {
		Configured bool `json:"configured"`
		Running    bool `json:"running"`
	} `json:"amneziawg"`
	PanelVersion string    `json:"panelVersion"`
	PanelGuid    string    `json:"panelGuid"`
	Uptime       uint64    `json:"uptime"`
	Loads        []float64 `json:"loads"`
	TcpCount     int       `json:"tcpCount"`
	UdpCount     int       `json:"udpCount"`
	NetIO        struct {
		Up      uint64 `json:"up"`
		Down    uint64 `json:"down"`
		PktUp   uint64 `json:"pktUp"`
		PktDown uint64 `json:"pktDown"`
	} `json:"netIO"`
	NetTraffic struct {
		Sent    uint64 `json:"sent"`
		Recv    uint64 `json:"recv"`
		PktSent uint64 `json:"pktSent"`
		PktRecv uint64 `json:"pktRecv"`
	} `json:"netTraffic"`
	PublicIP struct {
		IPv4 string `json:"ipv4"`
		IPv6 string `json:"ipv6"`
	} `json:"publicIP"`
	AppStats struct {
		Threads uint32 `json:"threads"`
		Mem     uint64 `json:"mem"`
		Uptime  uint64 `json:"uptime"`
	} `json:"appStats"`
}

// Release represents information about a software release from GitHub.
type Release struct {
	TagName         string `json:"tag_name"`         // The tag name of the release
	Body            string `json:"body"`             // The release notes; the dev channel reads its commit from here
	TargetCommitish string `json:"target_commitish"` // The branch/commit the tag points at
	Prerelease      bool   `json:"prerelease"`       // Whether this is a pre-release
}

// ServerService provides business logic for server monitoring and management.
// It handles system status collection, IP detection, and application statistics.
type ServerService struct {
	xrayService        XrayService
	inboundService     InboundService
	settingService     SettingService
	cachedIPv4         string
	cachedIPv6         string
	noIPv6             bool
	mu                 sync.Mutex
	lastCPUTimes       cpu.TimesStat
	hasLastCPUSample   bool
	hasNativeCPUSample bool
	emaCPU             float64
	cachedCpuSpeedMhz  float64
	lastCpuInfoAttempt time.Time

	lastStatusMu sync.RWMutex
	lastStatus   *Status

	versionsCacheMu sync.Mutex

	fail2banMu        sync.Mutex
	fail2banInstalled bool
	fail2banCheckedAt time.Time
}

// allowedHistoryBuckets is the bucket-second whitelist for time-series
// aggregation endpoints (server + node metrics). Restricting it prevents
// callers from triggering arbitrary aggregation work and keeps the
// frontend's bucket selector self-documenting.
var allowedHistoryBuckets = map[int]bool{
	2:     true, // 2m
	30:    true, // 30m
	60:    true, // 1h
	180:   true, // 3h
	360:   true, // 6h
	720:   true, // 12h
	1440:  true, // 24h
	2880:  true, // 2d
	10080: true, // 7d
}

// IsAllowedHistoryBucket reports whether a bucket-seconds value is in the
// whitelist used by the time-series aggregation endpoints
// (/server/history for the homepage overview, /nodes/history).
func IsAllowedHistoryBucket(bucketSeconds int) bool {
	return allowedHistoryBuckets[bucketSeconds]
}

// LastStatus returns the most recent Status snapshot collected by
// RefreshStatus. Safe for concurrent readers.
func (s *ServerService) LastStatus() *Status {
	s.lastStatusMu.RLock()
	defer s.lastStatusMu.RUnlock()
	return s.lastStatus
}

// Fail2banStatus tells the frontend whether the per-client IP limit can
// actually be enforced. Enforcement depends on fail2ban, so a limit set
// without it would silently do nothing.
type Fail2banStatus struct {
	Enabled   bool `json:"enabled"`
	Installed bool `json:"installed"`
	Usable    bool `json:"usable"`
	Windows   bool `json:"windows"`
}

const fail2banInstalledCacheTTL = 30 * time.Second

func (s *ServerService) GetFail2banStatus() Fail2banStatus {
	enabled := isFail2banEnabled()

	installed := false
	if enabled {
		installed = s.isFail2banInstalled()
	}

	return Fail2banStatus{
		Enabled:   enabled,
		Installed: installed,
		Usable:    enabled && installed,
		Windows:   runtime.GOOS == "windows",
	}
}

func isFail2banEnabled() bool {
	value, ok := os.LookupEnv("XUI_ENABLE_FAIL2BAN")
	return !ok || value == "true"
}

func (s *ServerService) isFail2banInstalled() bool {
	s.fail2banMu.Lock()
	defer s.fail2banMu.Unlock()

	if !s.fail2banCheckedAt.IsZero() && time.Since(s.fail2banCheckedAt) < fail2banInstalledCacheTTL {
		return s.fail2banInstalled
	}

	err := exec.CommandContext(context.Background(), "fail2ban-client", "-h").Run()
	s.fail2banInstalled = err == nil
	s.fail2banCheckedAt = time.Now()
	return s.fail2banInstalled
}

// RefreshStatus collects a new system snapshot and stores it as LastStatus.
// Returns the new snapshot (may be nil if collection failed). Called by the
// background ticker; the caller is responsible for any side effects
// (websocket broadcast). The realtime status served to the UI comes from
// this snapshot; the homepage overview ring is fed here too.
func (s *ServerService) RefreshStatus() *Status {
	next := s.GetStatus(s.LastStatus())
	if next == nil {
		return nil
	}
	s.lastStatusMu.Lock()
	s.lastStatus = next
	s.lastStatusMu.Unlock()
	s.AppendOverviewSample(time.Now(), next)
	return next
}

// AppendOverviewSample writes one tick of the homepage overview metrics —
// CPU, memory/swap/disk percents, network throughput (bytes/s) and TCP/UDP
// connection counts — into the memory-only overview ring. Called by
// RefreshStatus on the @2s status cadence, so all series stay aligned.
// Only the overview keys are kept; this is not the removed system-history
// sampler (no extra series, no persistence).
func (s *ServerService) AppendOverviewSample(t time.Time, status *Status) {
	if status == nil {
		return
	}
	overviewMetrics.append("cpu", t, status.Cpu)
	if status.Mem.Total > 0 {
		overviewMetrics.append("mem", t, float64(status.Mem.Current)*100.0/float64(status.Mem.Total))
	}
	if status.Swap.Total > 0 {
		overviewMetrics.append("swap", t, float64(status.Swap.Current)*100.0/float64(status.Swap.Total))
	} else {
		overviewMetrics.append("swap", t, 0)
	}
	overviewMetrics.append("netUp", t, float64(status.NetIO.Up))
	overviewMetrics.append("netDown", t, float64(status.NetIO.Down))
	if status.Disk.Total > 0 {
		overviewMetrics.append("diskUsage", t, float64(status.Disk.Current)*100.0/float64(status.Disk.Total))
	}
	overviewMetrics.append("tcpCount", t, float64(status.TcpCount))
	overviewMetrics.append("udpCount", t, float64(status.UdpCount))
}

// AggregateOverviewMetric returns up to maxPoints averaged buckets of size
// bucketSeconds for one overview metric (see OverviewMetricKeys). Output
// points have keys {"t": unixSec, "v": value}. It backs the seed fetch of
// the homepage overview curves; the ring behind it is memory-only, so
// shortly after a panel restart it legitimately returns few or no points.
func (s *ServerService) AggregateOverviewMetric(metric string, bucketSeconds int, maxPoints int) []map[string]any {
	return overviewMetrics.aggregate(metric, bucketSeconds, maxPoints)
}

func getPublicIP(url string) string {
	client := &http.Client{
		Timeout: 3 * time.Second,
	}

	req, reqErr := http.NewRequestWithContext(context.Background(), http.MethodGet, url, nil)
	if reqErr != nil {
		return "N/A"
	}
	resp, err := client.Do(req)
	if err != nil {
		return "N/A"
	}
	defer resp.Body.Close()

	// Don't retry if access is blocked or region-restricted
	if resp.StatusCode == http.StatusForbidden || resp.StatusCode == http.StatusUnavailableForLegalReasons {
		return "N/A"
	}
	if resp.StatusCode != http.StatusOK {
		return "N/A"
	}

	ip, err := io.ReadAll(resp.Body)
	if err != nil {
		return "N/A"
	}

	ipString := strings.TrimSpace(string(ip))
	if ipString == "" {
		return "N/A"
	}

	return ipString
}

var publicIPv4Services = []string{
	"https://api4.ipify.org",
	"https://ipv4.icanhazip.com",
	"https://v4.api.ipinfo.io/ip",
	"https://ipv4.myexternalip.com/raw",
	"https://4.ident.me",
	"https://check-host.net/ip",
}

var publicIPv6Services = []string{
	"https://api6.ipify.org",
	"https://ipv6.icanhazip.com",
	"https://v6.api.ipinfo.io/ip",
	"https://ipv6.myexternalip.com/raw",
	"https://6.ident.me",
}

// resolvePublicIPs caches the public IPv4/IPv6 addresses on first use. Guarded
// by s.mu because the bot's ServerService may call it from sendBackup while a
// status report runs concurrently.
func (s *ServerService) resolvePublicIPs() {
	s.mu.Lock()
	defer s.mu.Unlock()

	if s.cachedIPv4 == "" {
		for _, ip4Service := range publicIPv4Services {
			s.cachedIPv4 = getPublicIP(ip4Service)
			if s.cachedIPv4 != "N/A" {
				break
			}
		}
	}

	if s.cachedIPv6 == "" && !s.noIPv6 {
		for _, ip6Service := range publicIPv6Services {
			s.cachedIPv6 = getPublicIP(ip6Service)
			if s.cachedIPv6 != "N/A" {
				break
			}
		}
	}

	if s.cachedIPv6 == "N/A" {
		s.noIPv6 = true
	}
}

func (s *ServerService) GetStatus(lastStatus *Status) *Status {
	now := time.Now()
	status := &Status{
		T: now,
	}

	// CPU stats
	util, err := s.sampleCPUUtilization()
	if err != nil {
		logger.Warning("get cpu percent failed:", err)
	} else {
		status.Cpu = util
	}

	status.CpuCores, err = cpu.Counts(false)
	if err != nil {
		logger.Warning("get cpu cores count failed:", err)
	}

	status.LogicalPro = runtime.NumCPU()

	if status.CpuSpeedMhz = s.cachedCpuSpeedMhz; s.cachedCpuSpeedMhz == 0 && time.Since(s.lastCpuInfoAttempt) > 5*time.Minute {
		s.lastCpuInfoAttempt = time.Now()
		done := make(chan struct{})
		go func() {
			defer close(done)
			cpuInfos, err := cpu.Info()
			if err != nil {
				logger.Warning("get cpu info failed:", err)
				return
			}
			if len(cpuInfos) > 0 {
				s.cachedCpuSpeedMhz = cpuInfos[0].Mhz
				status.CpuSpeedMhz = s.cachedCpuSpeedMhz
			} else {
				logger.Warning("could not find cpu info")
			}
		}()
		select {
		case <-done:
		case <-time.After(1500 * time.Millisecond):
			logger.Warning("cpu info query timed out; will retry later")
		}
	} else if s.cachedCpuSpeedMhz != 0 {
		status.CpuSpeedMhz = s.cachedCpuSpeedMhz
	}

	// Uptime
	upTime, err := host.Uptime()
	if err != nil {
		logger.Warning("get uptime failed:", err)
	} else {
		status.Uptime = upTime
	}

	// Memory stats
	memInfo, err := mem.VirtualMemory()
	if err != nil {
		logger.Warning("get virtual memory failed:", err)
	} else {
		status.Mem.Current = memInfo.Used
		status.Mem.Total = memInfo.Total
	}

	swapInfo, err := mem.SwapMemory()
	if err != nil {
		logger.Warning("get swap memory failed:", err)
	} else {
		status.Swap.Current = swapInfo.Used
		status.Swap.Total = swapInfo.Total
	}

	// Disk stats
	diskInfo, err := disk.Usage("/")
	if err != nil {
		logger.Warning("get disk usage failed:", err)
	} else {
		status.Disk.Current = diskInfo.Used
		status.Disk.Total = diskInfo.Total
	}

	diskIOStats, err := disk.IOCounters()
	if err != nil {
		logger.Warning("get disk io counters failed:", err)
	} else {
		var totalRead, totalWrite uint64
		for _, counter := range diskIOStats {
			totalRead += counter.ReadBytes
			totalWrite += counter.WriteBytes
		}
		status.DiskTraffic.Read = totalRead
		status.DiskTraffic.Write = totalWrite

		if lastStatus != nil {
			duration := now.Sub(lastStatus.T)
			seconds := float64(duration) / float64(time.Second)
			if seconds > 0 && status.DiskTraffic.Read >= lastStatus.DiskTraffic.Read {
				status.DiskIO.Read = uint64(float64(status.DiskTraffic.Read-lastStatus.DiskTraffic.Read) / seconds)
			}
			if seconds > 0 && status.DiskTraffic.Write >= lastStatus.DiskTraffic.Write {
				status.DiskIO.Write = uint64(float64(status.DiskTraffic.Write-lastStatus.DiskTraffic.Write) / seconds)
			}
		}
	}

	// Load averages
	avgState, err := load.Avg()
	if err != nil {
		logger.Warning("get load avg failed:", err)
	} else {
		status.Loads = []float64{avgState.Load1, avgState.Load5, avgState.Load15}
	}

	// Network stats
	ioStats, err := net.IOCounters(true)
	if err != nil {
		logger.Warning("get io counters failed:", err)
	} else {
		var totalSent, totalRecv, totalPktSent, totalPktRecv uint64
		for _, iface := range ioStats {
			name := strings.ToLower(iface.Name)
			if isVirtualInterface(name) {
				continue
			}
			totalSent += iface.BytesSent
			totalRecv += iface.BytesRecv
			totalPktSent += iface.PacketsSent
			totalPktRecv += iface.PacketsRecv
		}
		status.NetTraffic.Sent = totalSent
		status.NetTraffic.Recv = totalRecv
		status.NetTraffic.PktSent = totalPktSent
		status.NetTraffic.PktRecv = totalPktRecv

		if lastStatus != nil {
			duration := now.Sub(lastStatus.T)
			seconds := float64(duration) / float64(time.Second)
			up := uint64(float64(status.NetTraffic.Sent-lastStatus.NetTraffic.Sent) / seconds)
			down := uint64(float64(status.NetTraffic.Recv-lastStatus.NetTraffic.Recv) / seconds)
			status.NetIO.Up = up
			status.NetIO.Down = down
			if seconds > 0 && status.NetTraffic.PktSent >= lastStatus.NetTraffic.PktSent {
				status.NetIO.PktUp = uint64(float64(status.NetTraffic.PktSent-lastStatus.NetTraffic.PktSent) / seconds)
			}
			if seconds > 0 && status.NetTraffic.PktRecv >= lastStatus.NetTraffic.PktRecv {
				status.NetIO.PktDown = uint64(float64(status.NetTraffic.PktRecv-lastStatus.NetTraffic.PktRecv) / seconds)
			}
		}
	}

	// TCP/UDP connections
	status.TcpCount, err = sys.GetTCPCount()
	if err != nil {
		logger.Warning("get tcp connections failed:", err)
	}

	status.UdpCount, err = sys.GetUDPCount()
	if err != nil {
		logger.Warning("get udp connections failed:", err)
	}

	s.resolvePublicIPs()
	status.PublicIP.IPv4 = s.cachedIPv4
	status.PublicIP.IPv6 = s.cachedIPv6

	// Xray status: the lite master runs no local core, so it always
	// reports stopped with no version.
	status.Xray.State = Stop
	status.Xray.ErrorMsg = ""
	status.Xray.Version = ""

	var amneziawgCount int64
	if err := database.GetDB().Model(model.Inbound{}).
		Where("protocol = ? AND enable = ? AND node_id IS NULL", model.AmneziaWG, true).
		Count(&amneziawgCount).Error; err != nil {
		logger.Warning("count amneziawg inbounds failed:", err)
	}
	status.AmneziaWG.Configured = amneziawgCount > 0
	status.AmneziaWG.Running = amneziawgnet.GetManager().HasRunning()

	status.PanelVersion = config.GetPanelVersion()
	if guid, err := s.settingService.GetPanelGuid(); err == nil {
		status.PanelGuid = guid
	}

	// Application stats
	if rss := sys.SelfRSS(); rss > 0 {
		status.AppStats.Mem = rss
	} else {
		var rtm runtime.MemStats
		runtime.ReadMemStats(&rtm)
		status.AppStats.Mem = rtm.Sys
	}
	status.AppStats.Threads = uint32(runtime.NumGoroutine())
	status.AppStats.Uptime = 0

	return status
}

func (s *ServerService) sampleCPUUtilization() (float64, error) {
	// Try native platform-specific CPU implementation first (Windows, Linux, macOS)
	if pct, err := sys.CPUPercentRaw(); err == nil {
		s.mu.Lock()
		// First call to native method returns 0 (initializes baseline)
		if !s.hasNativeCPUSample {
			s.hasNativeCPUSample = true
			s.mu.Unlock()
			return 0, nil
		}
		// Smooth with EMA
		const alpha = 0.3
		if s.emaCPU == 0 {
			s.emaCPU = pct
		} else {
			s.emaCPU = alpha*pct + (1-alpha)*s.emaCPU
		}
		val := s.emaCPU
		s.mu.Unlock()
		return val, nil
	}
	// If native call fails, fall back to gopsutil times
	// Read aggregate CPU times (all CPUs combined)
	times, err := cpu.Times(false)
	if err != nil {
		return 0, err
	}
	if len(times) == 0 {
		return 0, fmt.Errorf("no cpu times available")
	}

	cur := times[0]

	s.mu.Lock()
	defer s.mu.Unlock()

	// If this is the first sample, initialize and return current EMA (0 by default)
	if !s.hasLastCPUSample {
		s.lastCPUTimes = cur
		s.hasLastCPUSample = true
		return s.emaCPU, nil
	}

	// Compute busy and total deltas
	// Note: Guest and GuestNice times are already included in User and Nice respectively,
	// so we exclude them to avoid double-counting (Linux kernel accounting)
	idleDelta := cur.Idle - s.lastCPUTimes.Idle
	busyDelta := (cur.User - s.lastCPUTimes.User) +
		(cur.System - s.lastCPUTimes.System) +
		(cur.Nice - s.lastCPUTimes.Nice) +
		(cur.Iowait - s.lastCPUTimes.Iowait) +
		(cur.Irq - s.lastCPUTimes.Irq) +
		(cur.Softirq - s.lastCPUTimes.Softirq) +
		(cur.Steal - s.lastCPUTimes.Steal)

	totalDelta := busyDelta + idleDelta

	// Update last sample for next time
	s.lastCPUTimes = cur

	// Guard against division by zero or negative deltas (e.g., counter resets)
	if totalDelta <= 0 {
		return s.emaCPU, nil
	}

	raw := 100.0 * (busyDelta / totalDelta)
	if raw < 0 {
		raw = 0
	}
	if raw > 100 {
		raw = 100
	}

	// Exponential moving average to smooth spikes
	const alpha = 0.3 // smoothing factor (0<alpha<=1). Higher = more responsive, lower = smoother
	if s.emaCPU == 0 {
		// Initialize EMA with the first real reading to avoid long warm-up from zero
		s.emaCPU = raw
	} else {
		s.emaCPU = alpha*raw + (1-alpha)*s.emaCPU
	}

	return s.emaCPU, nil
}

// StopXrayService is a no-op on the lite master: there is no local core to
// stop. It stays so the DB import/restore flows keep their shape.
func (s *ServerService) StopXrayService() error {
	return nil
}

// RestartXrayService is a no-op on the lite master: there is no local core
// to restart. Agent nodes pick up changes on their next config pull.
func (s *ServerService) RestartXrayService() error {
	return nil
}

// isVirtualInterface returns true for loopback and virtual/tunnel interfaces
// that should be excluded from network traffic statistics.
func isVirtualInterface(name string) bool {
	// Exact matches
	if name == "lo" || name == "lo0" {
		return true
	}
	// Prefix matches for virtual/tunnel interfaces
	virtualPrefixes := []string{
		"loopback",
		"docker",
		"br-",
		"veth",
		"virbr",
		"tun",
		"tap",
		"wg",
		"tailscale",
		"zt",
	}
	for _, prefix := range virtualPrefixes {
		if strings.HasPrefix(name, prefix) {
			return true
		}
	}
	return false
}

// GetConfigJson returns the stored xray template as JSON. The lite master
// builds no local config (there is no local core to run one), so this is
// the template itself — the same document the settings page edits.
func (s *ServerService) GetConfigJson() (any, error) {
	template, err := s.settingService.GetXrayConfigTemplate()
	if err != nil {
		return nil, err
	}

	var jsonData any
	if err := json.Unmarshal([]byte(template), &jsonData); err != nil {
		return nil, err
	}

	return jsonData, nil
}

func (s *ServerService) GetDb() ([]byte, error) {
	if database.IsPostgres() {
		return s.exportPostgresDB()
	}
	backupPath, cleanup, err := s.backupSQLite()
	if err != nil {
		return nil, err
	}
	defer cleanup()
	return os.ReadFile(backupPath)
}

func (s *ServerService) backupSQLite() (string, func(), error) {
	backupDir, err := os.MkdirTemp(filepath.Dir(config.GetDBPath()), ".x-ui-backup-")
	if err != nil {
		return "", nil, err
	}
	cleanup := func() { _ = os.RemoveAll(backupDir) }
	backupPath := filepath.Join(backupDir, "backup.db")
	if err := database.BackupSQLite(backupPath); err != nil {
		cleanup()
		return "", nil, err
	}
	return backupPath, cleanup, nil
}

// BackupFilename returns the filename for a database backup, named after the
// panel's address so a downloaded or Telegram-sent backup identifies the server
// it came from, followed by the current date and time (_YYYY-MM-DD_HHMMSS) so
// files accumulated in Telegram chat history group by server then sort
// chronologically and same-day backups stay distinct. requestHost is the
// browser's address: the getDb handler passes c.Request.Host so a panel download
// is named after whatever address the user reached the panel with, no Listen
// Domain needed. The Telegram bot has no request and passes "", falling back to
// the configured Listen Domain (webDomain) and then the public IP. The extension
// is .dump on PostgreSQL and .db on SQLite; the base falls back to "x-ui" when
// no address is known.
func (s *ServerService) BackupFilename(requestHost string) string {
	ext := ".db"
	if database.IsPostgres() {
		ext = ".dump"
	}
	return s.backupHost(requestHost) + backupDateSuffix(time.Now()) + ext
}

// backupDateSuffix returns the _YYYY-MM-DD_HHMMSS chronological suffix appended
// after the host in backup filenames. Uses server-local time for consistency
// with the timestamp printed in the Telegram backup message body.
func backupDateSuffix(now time.Time) string {
	return "_" + now.Format("2006-01-02_150405")
}

// backupHost picks the address used to name backup files: the browser's request
// host (port stripped) when available, otherwise the configured Listen Domain
// (webDomain) and then the resolved public IP (IPv4 before IPv6), reduced to safe
// filename characters. The public IP is resolved directly rather than read from
// LastStatus so callers whose ServerService never runs the status ticker —
// notably the Telegram bot — still get a real address instead of the "x-ui"
// fallback.
func (s *ServerService) backupHost(requestHost string) string {
	host := extractHostname(strings.TrimSpace(requestHost))
	if host == "" {
		if domain, err := s.settingService.GetWebDomain(); err == nil {
			host = strings.TrimSpace(domain)
		}
	}
	if host == "" {
		s.resolvePublicIPs()
		if ip := s.cachedIPv4; ip != "" && ip != "N/A" {
			host = ip
		} else if ip := s.cachedIPv6; ip != "" && ip != "N/A" {
			host = ip
		}
	}
	return sanitizeBackupHost(host)
}

// sanitizeBackupHost reduces a host to characters safe in a download filename
// (the getDb handler enforces ^[a-zA-Z0-9_\-.]+$). IPv6 brackets are stripped
// and any other character — such as the colons in an IPv6 address — becomes a
// hyphen. Returns "x-ui" when nothing usable remains.
func sanitizeBackupHost(host string) string {
	host = strings.Trim(host, "[]")
	var b strings.Builder
	for _, r := range host {
		switch {
		case r >= 'a' && r <= 'z', r >= 'A' && r <= 'Z', r >= '0' && r <= '9', r == '.', r == '-', r == '_':
			b.WriteRune(r)
		default:
			b.WriteRune('-')
		}
	}
	out := strings.Trim(b.String(), ".-")
	if out == "" {
		return "x-ui"
	}
	return out
}

// GetMigration produces a cross-engine migration file plus its filename: on a
// SQLite panel it returns a portable .dump (SQL text), and on a PostgreSQL panel
// it returns a .db SQLite database built from the live data. Either output can
// then seed a panel running on the other backend.
func (s *ServerService) GetMigration() ([]byte, string, error) {
	if database.IsPostgres() {
		tmp, err := os.CreateTemp("", "x-ui-migration-*.db")
		if err != nil {
			return nil, "", err
		}
		tmpPath := tmp.Name()
		tmp.Close()
		defer os.Remove(tmpPath)

		if err := database.ExportPostgresToSQLite(config.GetDBDSN(), tmpPath); err != nil {
			return nil, "", err
		}
		data, err := os.ReadFile(tmpPath)
		if err != nil {
			return nil, "", err
		}
		return data, "x-ui.db", nil
	}

	backupPath, cleanup, err := s.backupSQLite()
	if err != nil {
		return nil, "", err
	}
	defer cleanup()
	data, err := database.DumpSQLiteToBytes(backupPath)
	if err != nil {
		return nil, "", err
	}
	return data, "x-ui.dump", nil
}

// hostBoundSettingKeys are the settings that describe *this* machine rather
// than the configuration being carried: where the panel and the subscription
// service listen, the certificates they present, and the identity this panel
// uses towards its nodes. An import that overwrites them leaves the
// destination unreachable on its own address, or impersonating the source.
var hostBoundSettingKeys = []string{
	"webListen", "webDomain", "webPort", "webCertFile", "webKeyFile", "webBasePath",
	"subListen", "subDomain", "subPort", "subCertFile", "subKeyFile", "subURI", "subJsonURI",
	"secret", "panelGuid",
	"nodeMtlsCaCertPem", "nodeMtlsCaKeyPem", "nodeMtlsClientCertPem",
	"nodeMtlsClientKeyPem", "nodeMtlsClientCertSha256", "nodeMtlsClientCAPem",
}

// hostBoundSnapshot records this machine's values, and just as importantly
// which keys it had no row for: an absent row means the built-in default is in
// force, and leaving the imported row in place would silently adopt the source
// machine's certificate path or listen address.
type hostBoundSnapshot struct {
	values  map[string]string
	present map[string]struct{}
	taken   bool
}

func captureHostBoundSettings() hostBoundSnapshot {
	db := database.GetDB()
	if db == nil {
		return hostBoundSnapshot{}
	}
	var rows []model.Setting
	if err := db.Model(&model.Setting{}).Where("key IN ?", hostBoundSettingKeys).Find(&rows).Error; err != nil {
		logger.Warningf("Import: could not read this machine's settings, they will come from the uploaded file: %v", err)
		return hostBoundSnapshot{}
	}
	snap := hostBoundSnapshot{
		values:  make(map[string]string, len(rows)),
		present: make(map[string]struct{}, len(rows)),
		taken:   true,
	}
	for _, row := range rows {
		snap.values[row.Key] = row.Value
		snap.present[row.Key] = struct{}{}
	}
	return snap
}

func restoreHostBoundSettings(snap hostBoundSnapshot) {
	if !snap.taken {
		return
	}
	db := database.GetDB()
	if db == nil {
		return
	}
	settingSvc := &SettingService{}
	for _, key := range hostBoundSettingKeys {
		if _, had := snap.present[key]; !had {
			// Absent because it is minted on demand, not because a default applied:
			// the imported copy is the only one that exists, so keep it (#6227).
			if lazilyMintedSettingKeys[key] {
				continue
			}
			if err := db.Where("key = ?", key).Delete(&model.Setting{}).Error; err != nil {
				logger.Warningf("Import: could not drop imported setting %q: %v", key, err)
			}
			continue
		}
		// saveSetting rather than Assign(struct): GORM drops zero-valued fields from
		// the assignment map, so an empty local value never overwrote the import.
		if err := settingSvc.saveSetting(key, snap.values[key]); err != nil {
			logger.Warningf("Import: could not restore setting %q for this machine: %v", key, err)
		}
	}
}

// Minted on demand, so a fresh install has no row: dropping the imported copy
// would destroy the only one that exists, CA private key included.
var lazilyMintedSettingKeys = map[string]bool{
	"nodeMtlsCaCertPem":     true,
	"nodeMtlsCaKeyPem":      true,
	"nodeMtlsClientCertPem": true,
	"nodeMtlsClientKeyPem":  true,
	"nodeMtlsClientCAPem":   true,
}

func (s *ServerService) ImportDB(file multipart.File, keepHostSettings bool) error {
	if database.IsPostgres() {
		return s.importPostgresDB(file, keepHostSettings)
	}
	kind, err := sniffUploadKind(file)
	if err != nil {
		return common.NewErrorf("Error reading uploaded file: %v", err)
	}
	switch kind {
	case importKindSQLiteDB, importKindSQLiteDump:
	case importKindPgDump:
		return common.NewError("This file is a PostgreSQL backup; it can only be restored on a panel running PostgreSQL")
	default:
		return common.NewError("Invalid file: expected a SQLite database (.db) from Back Up or a SQLite migration dump (.dump)")
	}

	tempPath := fmt.Sprintf("%s.temp", config.GetDBPath())

	if _, err := os.Stat(tempPath); err == nil {
		if errRemove := os.Remove(tempPath); errRemove != nil {
			return common.NewErrorf("Error removing existing temporary db file: %v", errRemove)
		}
	}
	defer func() {
		if _, err := os.Stat(tempPath); err == nil {
			if rerr := os.Remove(tempPath); rerr != nil {
				logger.Warningf("Warning: failed to remove temp file: %v", rerr)
			}
		}
	}()

	if err := stageSQLiteUpload(file, kind, tempPath); err != nil {
		return err
	}

	if err = database.ValidateSQLiteDB(tempPath); err != nil {
		return common.NewErrorf("Invalid or corrupt db file: %v", err)
	}
	if err = database.PrepareSQLiteForMigration(tempPath); err != nil {
		return common.NewErrorf("This file cannot be imported: %v", err)
	}

	xrayStopped := true
	defer func() {
		if xrayStopped {
			if errR := s.RestartXrayService(); errR != nil {
				logger.Warningf("Failed to restart Xray after DB import error: %v", errR)
			}
		}
	}()
	if errStop := s.StopXrayService(); errStop != nil {
		logger.Warningf("Failed to stop Xray before DB import: %v", errStop)
	}

	var keptSettings hostBoundSnapshot
	if keepHostSettings {
		keptSettings = captureHostBoundSettings()
	}

	if errClose := database.CloseDB(); errClose != nil {
		logger.Warningf("Failed to close existing DB before replacement: %v", errClose)
	}

	// Registered after the xray-restart defer so it runs first (LIFO): every
	// error return below leaves a database file at the configured path, and the
	// restart needs an open pool to build the xray config from it.
	dbReopened := false
	defer func() {
		if dbReopened {
			return
		}
		if errReopen := database.InitDB(config.GetDBPath()); errReopen != nil {
			logger.Warningf("Failed to reopen the database after import error: %v", errReopen)
		}
	}()

	// Backup the current database for fallback
	fallbackPath := fmt.Sprintf("%s.backup", config.GetDBPath())

	// Remove the existing fallback file (if any)
	if _, err := os.Stat(fallbackPath); err == nil {
		if errRemove := os.Remove(fallbackPath); errRemove != nil {
			return common.NewErrorf("Error removing existing fallback db file: %v", errRemove)
		}
	}

	// Move the current database to the fallback location
	if err = os.Rename(config.GetDBPath(), fallbackPath); err != nil {
		return common.NewErrorf("Error backing up current db file: %v", err)
	}

	// Move temp to DB path
	if err = os.Rename(tempPath, config.GetDBPath()); err != nil {
		// Restore from fallback
		if errRename := os.Rename(fallbackPath, config.GetDBPath()); errRename != nil {
			return common.NewErrorf("Error moving db file and restoring fallback: %v", errRename)
		}
		return common.NewErrorf("Error moving db file: %v", err)
	}

	// Open & migrate new DB
	if err = database.InitDB(config.GetDBPath()); err != nil {
		// A failed InitDB still holds the imported file open; close before the
		// rename or Windows refuses to replace it.
		if errClose := database.CloseDB(); errClose != nil {
			logger.Warningf("Failed to close the imported DB before restoring fallback: %v", errClose)
		}
		if errRename := os.Rename(fallbackPath, config.GetDBPath()); errRename != nil {
			return common.NewErrorf("Error migrating db and restoring fallback: %v", errRename)
		}
		return common.NewErrorf("Error migrating db: %v", err)
	}
	dbReopened = true

	restoreHostBoundSettings(keptSettings)

	s.inboundService.MigrateDB()

	xrayStopped = false
	if err = s.RestartXrayService(); err != nil {
		return common.NewErrorf("Imported DB but failed to start Xray: %v; the previous database was kept at %s", err, fallbackPath)
	}

	if _, err := os.Stat(fallbackPath); err == nil {
		if rerr := os.Remove(fallbackPath); rerr != nil {
			logger.Warningf("Warning: failed to remove fallback file: %v", rerr)
		}
	}
	return nil
}

// pgConnEnv turns the configured PostgreSQL DSN into the PG* environment used by
// pg_dump/pg_restore, keeping the password out of the process argument list.
func pgConnEnv(dsn string) (env []string, dbname string, err error) {
	u, err := url.Parse(strings.TrimSpace(dsn))
	if err != nil {
		return nil, "", err
	}
	if u.Scheme != "postgres" && u.Scheme != "postgresql" {
		return nil, "", common.NewErrorf("unsupported DSN scheme %q", u.Scheme)
	}
	dbname = strings.TrimPrefix(u.Path, "/")
	if dbname == "" {
		return nil, "", common.NewError("PostgreSQL DSN is missing a database name")
	}
	host := u.Hostname()
	if host == "" {
		host = "127.0.0.1"
	}
	port := u.Port()
	if port == "" {
		port = "5432"
	}
	env = append(os.Environ(), "PGHOST="+host, "PGPORT="+port, "PGDATABASE="+dbname)
	if user := u.User.Username(); user != "" {
		env = append(env, "PGUSER="+user)
	}
	if pass, ok := u.User.Password(); ok {
		env = append(env, "PGPASSWORD="+pass)
	}
	if sslmode := u.Query().Get("sslmode"); sslmode != "" {
		env = append(env, "PGSSLMODE="+sslmode)
	}
	return env, dbname, nil
}

func (s *ServerService) exportPostgresDB() ([]byte, error) {
	bin, err := exec.LookPath("pg_dump")
	if err != nil {
		return nil, common.NewError("pg_dump not found on the server; install the postgresql-client package to back up a PostgreSQL database")
	}
	env, dbname, err := pgConnEnv(config.GetDBDSN())
	if err != nil {
		return nil, common.NewErrorf("invalid PostgreSQL DSN: %v", err)
	}
	cmd := exec.CommandContext(context.Background(), bin, "--format=custom", "--no-owner", "--no-privileges", "--dbname", dbname)
	cmd.Env = env
	var out, stderr bytes.Buffer
	cmd.Stdout = &out
	cmd.Stderr = &stderr
	if err := cmd.Run(); err != nil {
		return nil, common.NewErrorf("pg_dump failed: %v: %s", err, strings.TrimSpace(stderr.String()))
	}
	return out.Bytes(), nil
}

var (
	pgUnsupportedDumpVersionPattern = regexp.MustCompile(`unsupported version \((\d+\.\d+)\) in file header`)
	pgToolVersionPattern            = regexp.MustCompile(`\d+(?:\.\d+)+`)
)

var pgArchiveVersionIntroducedIn = map[string]int{
	"1.15": 16,
	"1.16": 17,
}

// checkPgRestoreCanRead probes the dump with pg_restore --list (reads only the
// TOC, no database connection) so an unreadable file fails before Xray is stopped.
func checkPgRestoreCanRead(bin, dumpPath string) error {
	cmd := exec.CommandContext(context.Background(), bin, "--list", dumpPath)
	cmd.Stdout = io.Discard
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	if cmd.Run() == nil {
		return nil
	}
	return pgRestoreReadFailureError(strings.TrimSpace(stderr.String()), pgRestoreVersion(bin))
}

func pgRestoreReadFailureError(probeOutput, localVersion string) error {
	m := pgUnsupportedDumpVersionPattern.FindStringSubmatch(probeOutput)
	if m == nil {
		return common.NewErrorf("pg_restore cannot read this dump file: %s", probeOutput)
	}
	if localVersion == "" {
		localVersion = "unknown"
	}
	if major, known := pgArchiveVersionIntroducedIn[m[1]]; known {
		return common.NewErrorf("This backup was created by pg_dump from PostgreSQL %d or newer, but the server's pg_restore is version %s and cannot read it; run 'x-ui pgclient %d' on the server (or upgrade the postgresql-client package to version %d or newer), then retry the import", major, localVersion, major, major)
	}
	return common.NewErrorf("This backup was created by a newer pg_dump than the server's pg_restore (version %s) can read; upgrade the postgresql-client package and retry the import", localVersion)
}

func pgRestoreVersion(bin string) string {
	out, err := exec.CommandContext(context.Background(), bin, "--version").Output()
	if err != nil {
		return ""
	}
	return parsePgToolVersion(string(out))
}

func parsePgToolVersion(versionOutput string) string {
	return pgToolVersionPattern.FindString(versionOutput)
}

const (
	importKindUnknown = iota
	importKindPgDump
	importKindSQLiteDB
	importKindSQLiteDump
)

// sniffImportKind classifies an uploaded restore file by its leading bytes:
// a pg_dump custom archive, a raw SQLite database, or a SQLite SQL text dump.
func sniffImportKind(header []byte) int {
	if bytes.HasPrefix(header, []byte("PGDMP")) {
		return importKindPgDump
	}
	if bytes.HasPrefix(header, []byte("SQLite format 3\x00")) {
		return importKindSQLiteDB
	}
	text := bytes.TrimLeft(bytes.TrimPrefix(header, []byte("\xef\xbb\xbf")), " \t\r\n")
	if bytes.HasPrefix(text, []byte("PRAGMA")) || bytes.HasPrefix(text, []byte("BEGIN TRANSACTION")) {
		return importKindSQLiteDump
	}
	return importKindUnknown
}

func sniffUploadKind(file multipart.File) (int, error) {
	header := make([]byte, 64)
	n, err := file.ReadAt(header, 0)
	if err != nil && !errors.Is(err, io.EOF) {
		return importKindUnknown, err
	}
	if _, err := file.Seek(0, 0); err != nil {
		return importKindUnknown, err
	}
	return sniffImportKind(header[:n]), nil
}

func (s *ServerService) importPostgresDB(file multipart.File, keepHostSettings bool) error {
	kind, err := sniffUploadKind(file)
	if err != nil {
		return common.NewErrorf("Error reading uploaded file: %v", err)
	}
	switch kind {
	case importKindPgDump:
		return s.restorePostgresDump(file, keepHostSettings)
	case importKindSQLiteDB:
		return s.migrateSQLiteIntoPostgres(file, false)
	case importKindSQLiteDump:
		return s.migrateSQLiteIntoPostgres(file, true)
	default:
		return common.NewError("Invalid file: expected a PostgreSQL custom-format dump (.dump) from this panel's Back Up, a SQLite database (.db), or a SQLite migration dump")
	}
}

func (s *ServerService) restorePostgresDump(file multipart.File, keepHostSettings bool) error {
	bin, err := exec.LookPath("pg_restore")
	if err != nil {
		return common.NewError("pg_restore not found on the server; install the postgresql-client package to restore a PostgreSQL database")
	}
	env, dbname, err := pgConnEnv(config.GetDBDSN())
	if err != nil {
		return common.NewErrorf("invalid PostgreSQL DSN: %v", err)
	}

	tempFile, err := os.CreateTemp("", "x-ui-pg-restore-*.dump")
	if err != nil {
		return common.NewErrorf("Error creating temporary dump file: %v", err)
	}
	tempPath := tempFile.Name()
	defer os.Remove(tempPath)
	if _, err := io.Copy(tempFile, file); err != nil {
		tempFile.Close()
		return common.NewErrorf("Error saving dump: %v", err)
	}
	if err := tempFile.Close(); err != nil {
		return common.NewErrorf("Error closing temporary dump file: %v", err)
	}

	if err := checkPgRestoreCanRead(bin, tempPath); err != nil {
		return err
	}

	xrayStopped := true
	defer func() {
		if xrayStopped {
			if errR := s.RestartXrayService(); errR != nil {
				logger.Warningf("Failed to restart Xray after DB restore error: %v", errR)
			}
		}
	}()
	if errStop := s.StopXrayService(); errStop != nil {
		logger.Warningf("Failed to stop Xray before DB restore: %v", errStop)
	}

	var keptSettings hostBoundSnapshot
	if keepHostSettings {
		keptSettings = captureHostBoundSettings()
	}

	if errClose := database.CloseDB(); errClose != nil {
		logger.Warningf("Failed to close existing DB before restore: %v", errClose)
	}

	cmd := exec.CommandContext(context.Background(), bin,
		"--clean", "--if-exists", "--no-owner", "--no-privileges",
		"--single-transaction", "--dbname", dbname, tempPath,
	)
	cmd.Env = env
	var stderr bytes.Buffer
	cmd.Stderr = &stderr
	runErr := cmd.Run()

	if errInit := database.InitDB(config.GetDBPath()); errInit != nil {
		return common.NewErrorf("Restore finished but reopening the database failed: %v", errInit)
	}
	restoreHostBoundSettings(keptSettings)

	s.inboundService.MigrateDB()

	if runErr != nil {
		return common.NewErrorf("pg_restore failed (database left unchanged): %v: %s", runErr, strings.TrimSpace(stderr.String()))
	}

	xrayStopped = false
	if err := s.RestartXrayService(); err != nil {
		return common.NewErrorf("Restored DB but failed to start Xray: %v", err)
	}
	return nil
}

func (s *ServerService) migrateSQLiteIntoPostgres(file multipart.File, isSQLDump bool) error {
	tempDir, err := os.MkdirTemp("", "x-ui-pg-migrate-*")
	if err != nil {
		return common.NewErrorf("Error creating temporary folder: %v", err)
	}
	defer os.RemoveAll(tempDir)

	uploadPath := filepath.Join(tempDir, "upload.db")
	if isSQLDump {
		uploadPath = filepath.Join(tempDir, "upload.dump")
	}
	if err := saveUploadedFile(file, uploadPath); err != nil {
		return common.NewErrorf("Error saving uploaded file: %v", err)
	}

	dbPath := uploadPath
	if isSQLDump {
		dbPath = filepath.Join(tempDir, "restored.db")
		if err := database.RestoreSQLite(uploadPath, dbPath); err != nil {
			return common.NewErrorf("Error rebuilding a SQLite database from the migration dump: %v", err)
		}
	}
	if err := database.ValidateSQLiteDB(dbPath); err != nil {
		return common.NewErrorf("Invalid or corrupt db file: %v", err)
	}
	if err := database.PrepareSQLiteForMigration(dbPath); err != nil {
		return common.NewErrorf("This file cannot be imported: %v", err)
	}

	xrayStopped := true
	defer func() {
		if xrayStopped {
			if errR := s.RestartXrayService(); errR != nil {
				logger.Warningf("Failed to restart Xray after DB restore error: %v", errR)
			}
		}
	}()
	if errStop := s.StopXrayService(); errStop != nil {
		logger.Warningf("Failed to stop Xray before DB restore: %v", errStop)
	}

	if errClose := database.CloseDB(); errClose != nil {
		logger.Warningf("Failed to close existing DB before restore: %v", errClose)
	}

	migrateErr := database.MigrateData(dbPath, config.GetDBDSN())

	if errInit := database.InitDB(config.GetDBPath()); errInit != nil {
		return common.NewErrorf("Restore finished but reopening the database failed: %v", errInit)
	}
	s.inboundService.MigrateDB()

	if migrateErr != nil {
		return common.NewErrorf("Importing the SQLite data into PostgreSQL failed: %v; the import runs in a single transaction, so the database was left unchanged", migrateErr)
	}

	xrayStopped = false
	if err := s.RestartXrayService(); err != nil {
		return common.NewErrorf("Restored DB but failed to start Xray: %v", err)
	}
	return nil
}

func saveUploadedFile(file multipart.File, dstPath string) error {
	dst, err := os.Create(dstPath)
	if err != nil {
		return err
	}
	if _, err := io.Copy(dst, file); err != nil {
		dst.Close()
		return err
	}
	return dst.Close()
}

func stageSQLiteUpload(file multipart.File, kind int, tempPath string) error {
	if kind == importKindSQLiteDump {
		dumpPath := tempPath + ".dump"
		defer os.Remove(dumpPath)
		if err := saveUploadedFile(file, dumpPath); err != nil {
			return common.NewErrorf("Error saving migration dump: %v", err)
		}
		if err := database.RestoreSQLite(dumpPath, tempPath); err != nil {
			return common.NewErrorf("Error rebuilding a SQLite database from the migration dump: %v", err)
		}
		return nil
	}
	if err := saveUploadedFile(file, tempPath); err != nil {
		return common.NewErrorf("Error saving db: %v", err)
	}
	return nil
}

// parseXrayKeyPairOutput reads the two-line "Label: value" output that xray's
// key-generation subcommands (x25519, mldsa65, mlkem768) print and returns the
// two values. Short or label-less output yields an error instead of panicking
// on an out-of-range slice index, so a future xray version that changes the
// format degrades to a 500 with a message rather than a crash.
func parseXrayKeyPairOutput(output string) (string, string, error) {
	lines := strings.Split(output, "\n")
	if len(lines) < 2 {
		return "", "", common.NewError("unexpected key generator output")
	}
	first := strings.Split(lines[0], ":")
	second := strings.Split(lines[1], ":")
	if len(first) < 2 || len(second) < 2 {
		return "", "", common.NewError("unexpected key generator output")
	}
	return strings.TrimSpace(first[1]), strings.TrimSpace(second[1]), nil
}

// generateX25519KeyPair returns a fresh X25519 key pair in the exact format
// `xray x25519` prints (base64 RawURLEncoding of the raw 32-byte keys), but
// generated in-process: a control-plane-only panel has no xray binary to shell
// out to, and shelling out made Reality inbound creation fail there.
func generateX25519KeyPair() (privateKey string, publicKey string, err error) {
	priv, err := ecdh.X25519().GenerateKey(rand.Reader)
	if err != nil {
		return "", "", err
	}
	return base64.RawURLEncoding.EncodeToString(priv.Bytes()),
		base64.RawURLEncoding.EncodeToString(priv.PublicKey().Bytes()), nil
}

func (s *ServerService) GetNewX25519Cert() (any, error) {
	privateKey, publicKey, err := generateX25519KeyPair()
	if err != nil {
		return nil, err
	}

	keyPair := map[string]any{
		"privateKey": privateKey,
		"publicKey":  publicKey,
	}

	return keyPair, nil
}

func (s *ServerService) GetNewmldsa65() (any, error) {
	// Run the command
	cmd := exec.CommandContext(context.Background(), xray.GetBinaryPath(), "mldsa65")
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		return nil, err
	}

	seed, verify, err := parseXrayKeyPairOutput(out.String())
	if err != nil {
		return nil, err
	}

	keyPair := map[string]any{
		"seed":   seed,
		"verify": verify,
	}

	return keyPair, nil
}

// GetCertHash parses a certificate (from a file path or inline PEM/DER content)
// and returns the hex-encoded SHA-256 over each certificate's raw DER — the
// value xray-core's pinnedPeerCertSha256 (pcs) expects. Lets the panel fill the
// pinned-cert field from the inbound's own certificate without the user
// computing the hash by hand.
func (s *ServerService) GetCertHash(certFile string, certContent string) ([]string, error) {
	var certBytes []byte
	if path := strings.TrimSpace(certFile); path != "" {
		// Guard against path traversal: only hash certificate files the panel
		// already references in its own configuration (an inbound's TLS
		// certificateFile or the panel's own web cert). The path handed to
		// os.ReadFile comes from that allow-list, never directly from the
		// caller-supplied value.
		known, ok := s.resolveKnownCertFile(path)
		if !ok {
			return nil, common.NewError("certificate file is not referenced by any inbound or panel setting")
		}
		b, err := os.ReadFile(known)
		if err != nil {
			return nil, err
		}
		certBytes = b
	} else if strings.TrimSpace(certContent) != "" {
		certBytes = []byte(certContent)
	} else {
		return nil, common.NewError("no certificate provided")
	}

	var certs []*x509.Certificate
	if bytes.Contains(certBytes, []byte("BEGIN")) {
		rest := certBytes
		for {
			block, remain := pem.Decode(rest)
			if block == nil {
				break
			}
			cert, err := x509.ParseCertificate(block.Bytes)
			if err != nil {
				return nil, common.NewError("unable to decode certificate: ", err)
			}
			certs = append(certs, cert)
			rest = remain
		}
	} else {
		parsed, err := x509.ParseCertificates(certBytes)
		if err != nil {
			return nil, common.NewError("unable to parse certificates: ", err)
		}
		certs = parsed
	}

	if len(certs) == 0 {
		return nil, common.NewError("no certificates found")
	}

	hashes := make([]string, 0, len(certs))
	for _, cert := range certs {
		sum := sha256.Sum256(cert.Raw)
		hashes = append(hashes, hex.EncodeToString(sum[:]))
	}
	return hashes, nil
}

// resolveKnownCertFile checks the caller-supplied certificate path against the
// set of certificate files the panel already references (inbound TLS configs
// plus the panel's own web cert) and, on a match, returns the path taken from
// that configuration — not the caller's value. This both confines reads to
// known certificates and breaks the user-input-to-filesystem taint flow.
func (s *ServerService) resolveKnownCertFile(certFile string) (string, bool) {
	want := filepath.Clean(certFile)
	for _, known := range s.knownCertFiles() {
		if filepath.Clean(known) == want {
			return known, true
		}
	}
	return "", false
}

// knownCertFiles collects every certificate file path the panel legitimately
// references: the certificateFile of each inbound's TLS settings and the
// panel's own web TLS certificate.
func (s *ServerService) knownCertFiles() []string {
	var files []string
	if cert, err := s.settingService.GetCertFile(); err == nil {
		if cert = strings.TrimSpace(cert); cert != "" {
			files = append(files, cert)
		}
	}
	if inbounds, err := s.inboundService.GetAllInbounds(); err == nil {
		for _, inbound := range inbounds {
			files = collectCertFiles(inbound.StreamSettings, files)
		}
	}
	return files
}

// collectCertFiles walks a stream-settings JSON document and appends the value
// of every "certificateFile" field it finds (TLS settings may nest them under
// several keys depending on the security type).
func collectCertFiles(streamSettings string, out []string) []string {
	streamSettings = strings.TrimSpace(streamSettings)
	if streamSettings == "" {
		return out
	}
	var parsed any
	if err := json.Unmarshal([]byte(streamSettings), &parsed); err != nil {
		return out
	}
	return walkCertFiles(parsed, out)
}

func walkCertFiles(node any, out []string) []string {
	switch v := node.(type) {
	case map[string]any:
		for key, val := range v {
			if key == "certificateFile" {
				if path, ok := val.(string); ok {
					if path = strings.TrimSpace(path); path != "" {
						out = append(out, path)
					}
				}
			}
			out = walkCertFiles(val, out)
		}
	case []any:
		for _, item := range v {
			out = walkCertFiles(item, out)
		}
	}
	return out
}

// GetRemoteCertHash opens a uTLS (Chrome fingerprint) handshake to a remote
// endpoint and returns the hex-encoded SHA-256 of its leaf certificate — the
// value to put in pinnedPeerCertSha256 (pcs) when pinning a server whose
// certificate file you don't hold (a CDN front, a REALITY dest, an external
// proxy). A native handshake replaces the old `xray tls ping` subprocess so the
// real dial/handshake failure (connection refused, timeout, …) surfaces
// verbatim. `server` may be host or host:port; the port defaults to 443.
func (s *ServerService) GetRemoteCertHash(server string) ([]string, error) {
	server = strings.TrimSpace(server)
	if server == "" {
		return nil, common.NewError("no server provided")
	}

	host, port := server, "443"
	if h, p, err := stdnet.SplitHostPort(server); err == nil {
		host, port = h, p
	}

	dialer := stdnet.Dialer{Timeout: 10 * time.Second}
	tcpConn, err := dialer.Dial("tcp", stdnet.JoinHostPort(host, port))
	if err != nil {
		return nil, common.NewErrorf("failed to dial %s: %s", stdnet.JoinHostPort(host, port), err)
	}
	defer tcpConn.Close()
	_ = tcpConn.SetDeadline(time.Now().Add(15 * time.Second))

	tlsConn := utls.UClient(tcpConn, &utls.Config{
		ServerName:         host,
		InsecureSkipVerify: true,
		NextProtos:         []string{"h2", "http/1.1"},
	}, utls.HelloChrome_Auto)
	defer tlsConn.Close()
	if err := tlsConn.Handshake(); err != nil {
		return nil, common.NewErrorf("tls handshake with %s failed: %s", host, err)
	}

	certs := tlsConn.ConnectionState().PeerCertificates
	if len(certs) == 0 {
		return nil, common.NewError("no certificate returned by ", host)
	}
	// PeerCertificates[0] is always the leaf the connection verifies against —
	// robust for IP-only self-signed certs that carry no DNS SANs.
	sum := sha256.Sum256(certs[0].Raw)
	return []string{hex.EncodeToString(sum[:])}, nil
}

func (s *ServerService) GetNewEchCert(sni string) (any, error) {
	// Run the command
	cmd := exec.CommandContext(context.Background(), xray.GetBinaryPath(), "tls", "ech", "--serverName", sni)
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		return nil, err
	}

	lines := strings.Split(out.String(), "\n")
	if len(lines) < 4 {
		return nil, common.NewError("invalid ech cert")
	}

	configList := lines[1]
	serverKeys := lines[3]

	return map[string]any{
		"echServerKeys": serverKeys,
		"echConfigList": configList,
	}, nil
}

func (s *ServerService) GetNewVlessEnc() (any, error) {
	cmd := exec.CommandContext(context.Background(), xray.GetBinaryPath(), "vlessenc")
	var out bytes.Buffer
	cmd.Stdout = &out
	if err := cmd.Run(); err != nil {
		return nil, err
	}

	auths := parseVlessEncAuths(out.String())
	auths = append(auths, deriveVlessEncModes(auths)...)

	return map[string]any{
		"auths": auths,
	}, nil
}

func deriveVlessEncModes(auths []map[string]string) []map[string]string {
	var extra []map[string]string
	for _, a := range auths {
		for _, mode := range []string{"xorpub", "random"} {
			dec := strings.Replace(a["decryption"], ".native.", "."+mode+".", 1)
			enc := strings.Replace(a["encryption"], ".native.", "."+mode+".", 1)
			if dec == a["decryption"] && enc == a["encryption"] {
				continue
			}
			extra = append(extra, map[string]string{
				"id":         a["id"] + "_" + mode,
				"label":      a["label"] + " (" + mode + ")",
				"decryption": dec,
				"encryption": enc,
			})
		}
	}
	return extra
}

func parseVlessEncAuths(output string) []map[string]string {
	lines := strings.Split(output, "\n")
	var auths []map[string]string
	var current map[string]string

	for _, line := range lines {
		line = strings.TrimSpace(line)
		if strings.HasPrefix(line, "Authentication:") {
			if current != nil {
				auths = append(auths, current)
			}
			label := strings.TrimSpace(strings.TrimPrefix(line, "Authentication:"))
			current = map[string]string{
				"id":    vlessEncAuthID(label),
				"label": label,
			}
		} else if strings.HasPrefix(line, `"decryption"`) || strings.HasPrefix(line, `"encryption"`) {
			parts := strings.SplitN(line, ":", 2)
			if len(parts) == 2 && current != nil {
				key := strings.Trim(parts[0], `" `)
				val := strings.TrimSpace(parts[1])
				val = strings.TrimSuffix(val, ",")
				val = strings.Trim(val, `" `)
				current[key] = val
			}
		}
	}

	if current != nil {
		auths = append(auths, current)
	}

	return auths
}

func vlessEncAuthID(label string) string {
	normalized := strings.NewReplacer("-", "", "_", "", " ", "").Replace(strings.ToLower(label))
	switch {
	case strings.Contains(normalized, "mlkem768"):
		return "mlkem768"
	case strings.Contains(normalized, "x25519"):
		return "x25519"
	default:
		return normalized
	}
}

func (s *ServerService) GetNewUUID() (map[string]string, error) {
	newUUID, err := uuid.NewRandom()
	if err != nil {
		return nil, fmt.Errorf("failed to generate UUID: %w", err)
	}

	return map[string]string{
		"uuid": newUUID.String(),
	}, nil
}

func (s *ServerService) GetNewmlkem768() (any, error) {
	// Run the command
	cmd := exec.CommandContext(context.Background(), xray.GetBinaryPath(), "mlkem768")
	var out bytes.Buffer
	cmd.Stdout = &out
	err := cmd.Run()
	if err != nil {
		return nil, err
	}

	seed, client, err := parseXrayKeyPairOutput(out.String())
	if err != nil {
		return nil, err
	}

	keyPair := map[string]any{
		"seed":   seed,
		"client": client,
	}

	return keyPair, nil
}