package app

import (
	"archive/tar"
	"compress/gzip"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
	"strings"
	"time"
)

var supportBundleServices = []string{
	"bee-audit.service",
	"bee-web.service",
	"bee-network.service",
	"bee-nvidia.service",
	"bee-preflight.service",
	"bee-selfheal.service",
	"bee-selfheal.timer",
	"bee-sshsetup.service",
}

var supportBundleCommands = []struct {
	name string
	cmd  []string
}{
	{name: "system/uname.txt", cmd: []string{"uname", "-a"}},
	{name: "system/cmdline.txt", cmd: []string{"cat", "/proc/cmdline"}},
	{name: "system/lsmod.txt", cmd: []string{"lsmod"}},
	{name: "system/lspci-nn.txt", cmd: []string{"lspci", "-nn"}},
	{name: "system/lspci-vvv.txt", cmd: []string{"lspci", "-vvv"}},
	{name: "system/ip-addr.txt", cmd: []string{"ip", "addr"}},
	{name: "system/ip-link.txt", cmd: []string{"ip", "-details", "link", "show"}},
	{name: "system/ip-link-stats.txt", cmd: []string{"ip", "-s", "link", "show"}},
	{name: "system/ip-route.txt", cmd: []string{"ip", "route"}},
	{name: "system/mount.txt", cmd: []string{"mount"}},
	{name: "system/df-h.txt", cmd: []string{"df", "-h"}},
	{name: "system/dmesg.txt", cmd: []string{"dmesg"}},
	{name: "system/kernel-aer-nvidia.txt", cmd: []string{"sh", "-c", `
if command -v dmesg >/dev/null 2>&1; then
  dmesg | grep -iE 'AER|NVRM|Xid|pcieport|nvidia' || echo "no AER/NVRM/Xid kernel messages found"
else
  echo "dmesg not found"
fi
`}},
	{name: "system/nvidia-smi-q.txt", cmd: []string{"nvidia-smi", "-q"}},
	{name: "system/lspci-nvidia-bridges-vv.txt", cmd: []string{"sh", "-c", `
if ! command -v lspci >/dev/null 2>&1; then
  echo "lspci not found"
  exit 0
fi
found=0
for gpu in $(lspci -Dn | awk '$3 ~ /^10de:/ {print $1}'); do
  found=1
  echo "=== GPU $gpu ==="
  lspci -s "$gpu" -vv 2>&1 || true
  bridge=$(basename "$(readlink -f "/sys/bus/pci/devices/$gpu/.." 2>/dev/null)" 2>/dev/null)
  if [ -n "$bridge" ] && [ "$bridge" != "$gpu" ]; then
    echo
    echo "=== UPSTREAM $bridge for $gpu ==="
    lspci -s "$bridge" -vv 2>&1 || true
  fi
  echo
done
if [ "$found" -eq 0 ]; then
  echo "no NVIDIA PCI devices found"
fi
`}},
	{name: "system/pcie-nvidia-link.txt", cmd: []string{"sh", "-c", `
for d in /sys/bus/pci/devices/*/; do
  vendor=$(cat "$d/vendor" 2>/dev/null)
  [ "$vendor" = "0x10de" ] || continue
  dev=$(basename "$d")
  echo "=== $dev ==="
  for f in current_link_speed current_link_width max_link_speed max_link_width; do
    printf "  %-22s %s\n" "$f" "$(cat "$d/$f" 2>/dev/null)"
  done
done
`}},
	{name: "system/pcie-aer-sysfs.txt", cmd: []string{"sh", "-c", `
found=0
for dev in /sys/bus/pci/devices/*; do
  [ -e "$dev" ] || continue
  bdf=$(basename "$dev")
  block=""
  for f in aer_dev_correctable aer_dev_fatal aer_dev_nonfatal aer_rootport_total_err_cor aer_rootport_total_err_fatal aer_rootport_total_err_nonfatal; do
    if [ -r "$dev/$f" ]; then
      if [ -z "$block" ]; then
        block=1
        found=1
        echo "=== $bdf ==="
      fi
      printf "  %-30s %s\n" "$f" "$(cat "$dev/$f" 2>/dev/null)"
    fi
  done
  if [ -n "$block" ]; then
    echo
  fi
done
if [ "$found" -eq 0 ]; then
  echo "no PCIe AER sysfs counters found"
fi
`}},
	{name: "system/ethtool-info.txt", cmd: []string{"sh", "-c", `
if ! command -v ethtool >/dev/null 2>&1; then
  echo "ethtool not found"
  exit 0
fi
found=0
for path in /sys/class/net/*; do
  [ -e "$path" ] || continue
  iface=$(basename "$path")
  [ "$iface" = "lo" ] && continue
  found=1
  echo "=== $iface ==="
  ethtool -i "$iface" 2>&1 || true
  echo
done
if [ "$found" -eq 0 ]; then
  echo "no interfaces found"
fi
`}},
	{name: "system/ethtool-link.txt", cmd: []string{"sh", "-c", `
if ! command -v ethtool >/dev/null 2>&1; then
  echo "ethtool not found"
  exit 0
fi
found=0
for path in /sys/class/net/*; do
  [ -e "$path" ] || continue
  iface=$(basename "$path")
  [ "$iface" = "lo" ] && continue
  found=1
  echo "=== $iface ==="
  ethtool "$iface" 2>&1 || true
  echo
done
if [ "$found" -eq 0 ]; then
  echo "no interfaces found"
fi
`}},
	{name: "system/ethtool-module.txt", cmd: []string{"sh", "-c", `
if ! command -v ethtool >/dev/null 2>&1; then
  echo "ethtool not found"
  exit 0
fi
found=0
for path in /sys/class/net/*; do
  [ -e "$path" ] || continue
  iface=$(basename "$path")
  [ "$iface" = "lo" ] && continue
  found=1
  echo "=== $iface ==="
  ethtool -m "$iface" 2>&1 || true
  echo
done
if [ "$found" -eq 0 ]; then
  echo "no interfaces found"
fi
`}},
	{name: "system/mstflint-query.txt", cmd: []string{"sh", "-c", `
if ! command -v mstflint >/dev/null 2>&1; then
  echo "mstflint not found"
  exit 0
fi
found=0
for path in /sys/bus/pci/devices/*; do
  [ -e "$path/vendor" ] || continue
  vendor=$(cat "$path/vendor" 2>/dev/null)
  [ "$vendor" = "0x15b3" ] || continue
  bdf=$(basename "$path")
  found=1
  echo "=== $bdf ==="
  mstflint -d "$bdf" q 2>&1 || true
  echo
done
if [ "$found" -eq 0 ]; then
  echo "no Mellanox/NVIDIA networking devices found"
fi
`}},
}

var supportBundleOptionalFiles = []struct {
	name string
	src  string
}{
	{name: "system/kern.log", src: "/var/log/kern.log"},
	{name: "system/syslog.txt", src: "/var/log/syslog"},
}

const supportBundleGlob = "bee-support-*.tar.gz"

func BuildSupportBundle(exportDir string) (string, error) {
	exportDir = strings.TrimSpace(exportDir)
	if exportDir == "" {
		exportDir = DefaultExportDir
	}
	if err := os.MkdirAll(exportDir, 0755); err != nil {
		return "", err
	}
	if err := cleanupOldSupportBundles(os.TempDir()); err != nil {
		return "", err
	}

	host := sanitizeFilename(hostnameOr("unknown"))
	ts := time.Now().UTC().Format("20060102-150405")
	stageRoot := filepath.Join(os.TempDir(), fmt.Sprintf("bee-support-%s-%s", host, ts))
	if err := os.MkdirAll(stageRoot, 0755); err != nil {
		return "", err
	}
	defer os.RemoveAll(stageRoot)

	if err := copyExportDirForSupportBundle(exportDir, filepath.Join(stageRoot, "export")); err != nil {
		return "", err
	}
	if err := writeJournalDump(filepath.Join(stageRoot, "systemd", "combined.journal.log")); err != nil {
		return "", err
	}
	for _, svc := range supportBundleServices {
		if err := writeCommandOutput(filepath.Join(stageRoot, "systemd", svc+".status.txt"), []string{"systemctl", "status", svc, "--no-pager"}); err != nil {
			return "", err
		}
		if err := writeCommandOutput(filepath.Join(stageRoot, "systemd", svc+".journal.log"), []string{"journalctl", "--no-pager", "-u", svc}); err != nil {
			return "", err
		}
	}
	for _, item := range supportBundleCommands {
		if err := writeCommandOutput(filepath.Join(stageRoot, item.name), item.cmd); err != nil {
			return "", err
		}
	}
	for _, item := range supportBundleOptionalFiles {
		_ = copyOptionalFile(item.src, filepath.Join(stageRoot, item.name))
	}
	if err := writeManifest(filepath.Join(stageRoot, "manifest.txt"), exportDir, stageRoot); err != nil {
		return "", err
	}

	archivePath := filepath.Join(os.TempDir(), fmt.Sprintf("bee-support-%s-%s.tar.gz", host, ts))
	if err := createSupportTarGz(archivePath, stageRoot); err != nil {
		return "", err
	}
	return archivePath, nil
}

func LatestSupportBundlePath() (string, error) {
	return latestSupportBundlePath(os.TempDir())
}

func cleanupOldSupportBundles(dir string) error {
	matches, err := filepath.Glob(filepath.Join(dir, supportBundleGlob))
	if err != nil {
		return err
	}
	entries := supportBundleEntries(matches)
	for path, mod := range entries {
		if time.Since(mod) > 24*time.Hour {
			_ = os.Remove(path)
			delete(entries, path)
		}
	}
	ordered := orderSupportBundles(entries)
	if len(ordered) > 3 {
		for _, old := range ordered[3:] {
			_ = os.Remove(old)
		}
	}
	return nil
}

func latestSupportBundlePath(dir string) (string, error) {
	matches, err := filepath.Glob(filepath.Join(dir, supportBundleGlob))
	if err != nil {
		return "", err
	}
	ordered := orderSupportBundles(supportBundleEntries(matches))
	if len(ordered) == 0 {
		return "", os.ErrNotExist
	}
	return ordered[0], nil
}

func supportBundleEntries(matches []string) map[string]time.Time {
	entries := make(map[string]time.Time, len(matches))
	for _, match := range matches {
		info, err := os.Stat(match)
		if err != nil {
			continue
		}
		entries[match] = info.ModTime()
	}
	return entries
}

func orderSupportBundles(entries map[string]time.Time) []string {
	ordered := make([]string, 0, len(entries))
	for path := range entries {
		ordered = append(ordered, path)
	}
	sort.Slice(ordered, func(i, j int) bool {
		return entries[ordered[i]].After(entries[ordered[j]])
	})
	return ordered
}

func writeJournalDump(dst string) error {
	args := []string{"--no-pager"}
	for _, svc := range supportBundleServices {
		args = append(args, "-u", svc)
	}
	raw, err := exec.Command("journalctl", args...).CombinedOutput()
	if len(raw) == 0 && err != nil {
		raw = []byte(err.Error() + "\n")
	}
	if len(raw) == 0 {
		raw = []byte("no journal output\n")
	}
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}
	return os.WriteFile(dst, raw, 0644)
}

func writeCommandOutput(dst string, cmd []string) error {
	if len(cmd) == 0 {
		return nil
	}
	raw, err := exec.Command(cmd[0], cmd[1:]...).CombinedOutput()
	if len(raw) == 0 {
		if err != nil {
			raw = []byte(err.Error() + "\n")
		} else {
			raw = []byte("no output\n")
		}
	}
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}
	return os.WriteFile(dst, raw, 0644)
}

func copyOptionalFile(src, dst string) error {
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}
	out, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer out.Close()
	_, err = io.Copy(out, in)
	return err
}

func writeManifest(dst, exportDir, stageRoot string) error {
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}
	var body strings.Builder
	fmt.Fprintf(&body, "bee_version=%s\n", buildVersion())
	fmt.Fprintf(&body, "host=%s\n", hostnameOr("unknown"))
	fmt.Fprintf(&body, "generated_at_utc=%s\n", time.Now().UTC().Format(time.RFC3339))
	fmt.Fprintf(&body, "export_dir=%s\n", exportDir)
	fmt.Fprintf(&body, "\nfiles:\n")

	var files []string
	if err := filepath.Walk(stageRoot, func(path string, info os.FileInfo, err error) error {
		if err != nil || info.IsDir() {
			return err
		}
		if filepath.Clean(path) == filepath.Clean(dst) {
			return nil
		}
		rel, err := filepath.Rel(stageRoot, path)
		if err != nil {
			return err
		}
		files = append(files, fmt.Sprintf("%s\t%d", rel, info.Size()))
		return nil
	}); err != nil {
		return err
	}
	sort.Strings(files)
	for _, line := range files {
		body.WriteString(line)
		body.WriteByte('\n')
	}
	return os.WriteFile(dst, []byte(body.String()), 0644)
}

func buildVersion() string {
	raw, err := exec.Command("bee", "version").CombinedOutput()
	if err != nil {
		return "unknown"
	}
	return strings.TrimSpace(string(raw))
}

func copyDirContents(srcDir, dstDir string) error {
	entries, err := os.ReadDir(srcDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	for _, entry := range entries {
		src := filepath.Join(srcDir, entry.Name())
		dst := filepath.Join(dstDir, entry.Name())
		if err := copyPath(src, dst); err != nil {
			return err
		}
	}
	return nil
}

func copyExportDirForSupportBundle(srcDir, dstDir string) error {
	if err := copyDirContentsFiltered(srcDir, dstDir, func(rel string, info os.FileInfo) bool {
		cleanRel := filepath.ToSlash(strings.TrimPrefix(filepath.Clean(rel), "./"))
		if cleanRel == "" {
			return true
		}
		if strings.HasPrefix(cleanRel, "bee-sat/") && strings.HasSuffix(cleanRel, ".tar.gz") {
			return false
		}
		if strings.HasPrefix(filepath.Base(cleanRel), "bee-support-") && strings.HasSuffix(cleanRel, ".tar.gz") {
			return false
		}
		return true
	}); err != nil {
		return err
	}
	return normalizeSupportBundleAuditJSON(filepath.Join(dstDir, "bee-audit.json"))
}

func normalizeSupportBundleAuditJSON(path string) error {
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	normalized, err := ApplySATOverlay(data)
	if err != nil {
		return nil
	}
	return os.WriteFile(path, normalized, 0644)
}

func copyDirContentsFiltered(srcDir, dstDir string, keep func(rel string, info os.FileInfo) bool) error {
	entries, err := os.ReadDir(srcDir)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	for _, entry := range entries {
		src := filepath.Join(srcDir, entry.Name())
		dst := filepath.Join(dstDir, entry.Name())
		if err := copyPathFiltered(srcDir, src, dst, keep); err != nil {
			return err
		}
	}
	return nil
}

func copyPath(src, dst string) error {
	info, err := os.Stat(src)
	if err != nil {
		return err
	}
	if info.IsDir() {
		if err := os.MkdirAll(dst, info.Mode().Perm()); err != nil {
			return err
		}
		entries, err := os.ReadDir(src)
		if err != nil {
			return err
		}
		for _, entry := range entries {
			if err := copyPath(filepath.Join(src, entry.Name()), filepath.Join(dst, entry.Name())); err != nil {
				return err
			}
		}
		return nil
	}

	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return err
	}
	in, err := os.Open(src)
	if err != nil {
		return err
	}
	defer in.Close()

	out, err := os.OpenFile(dst, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, info.Mode().Perm())
	if err != nil {
		return err
	}
	defer out.Close()

	_, err = io.Copy(out, in)
	return err
}

func copyPathFiltered(rootSrc, src, dst string, keep func(rel string, info os.FileInfo) bool) error {
	info, err := os.Stat(src)
	if err != nil {
		return err
	}
	rel, err := filepath.Rel(rootSrc, src)
	if err != nil {
		return err
	}
	if keep != nil && !keep(rel, info) {
		return nil
	}
	if info.IsDir() {
		if err := os.MkdirAll(dst, info.Mode().Perm()); err != nil {
			return err
		}
		entries, err := os.ReadDir(src)
		if err != nil {
			return err
		}
		for _, entry := range entries {
			if err := copyPathFiltered(rootSrc, filepath.Join(src, entry.Name()), filepath.Join(dst, entry.Name()), keep); err != nil {
				return err
			}
		}
		return nil
	}
	return copyPath(src, dst)
}

func createSupportTarGz(dst, srcDir string) error {
	file, err := os.Create(dst)
	if err != nil {
		return err
	}
	defer file.Close()

	gz := gzip.NewWriter(file)
	defer gz.Close()

	tw := tar.NewWriter(gz)
	defer tw.Close()

	base := filepath.Dir(srcDir)
	return filepath.Walk(srcDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			return nil
		}

		header, err := tar.FileInfoHeader(info, "")
		if err != nil {
			return err
		}
		header.Name, err = filepath.Rel(base, path)
		if err != nil {
			return err
		}
		if err := tw.WriteHeader(header); err != nil {
			return err
		}

		f, err := os.Open(path)
		if err != nil {
			return err
		}
		defer f.Close()

		_, err = io.Copy(tw, f)
		return err
	})
}