#!/usr/bin/env bash
set -euo pipefail

GVFS_ROOT=${GVFS_ROOT:-"/run/user/$(id -u)/gvfs"}
FUJIFILM_DEST=${FUJIFILM_DEST:-"$HOME/Documents/Inbox/Fujifilm"}
SUPERNOTE_DEST=${SUPERNOTE_DEST:-"$HOME/Documents/Inbox/Note"}
SUPERNOTE_PDF_DEST=${SUPERNOTE_PDF_DEST:-"$HOME/Documents/Supernote"}
SUPERNOTE_BACKUP_DEST=${SUPERNOTE_BACKUP_DEST:-"$HOME/Books/journals/Supernote"}
SUPERNOTE_BACKUP_TIMEOUT=${SUPERNOTE_BACKUP_TIMEOUT:-20s}

TOTAL_FOUND=0
TOTAL_COPIED=0
TOTAL_SKIPPED=0
TOTAL_FAILED=0
TOTAL_CONVERTED=0
TOTAL_CONVERT_SKIPPED=0
TOTAL_BACKED_UP=0
TOTAL_BACKUP_SKIPPED=0
TOTAL_BACKUP_FAILED=0

log() {
  printf '%s\n' "$*"
}

usage() {
  cat <<EOF_USAGE
Usage: ${0##*/} [auto|fujifilm|fuji|camera|supernote|nomad] [destination]

Import files from supported USB devices mounted through GVFS.

Modes:
  auto       Import from the single supported device currently connected.
  fujifilm   Copy only JPEG files from a Fuji/Fujifilm camera.
  supernote  Copy only the Note folder from a Supernote Nomad, then convert .note files to PDF.

Default destinations:
  Fujifilm JPEGs:        $FUJIFILM_DEST
  Supernote Note files:  $SUPERNOTE_DEST
  Supernote PDF files:   $SUPERNOTE_PDF_DEST
  Optional backup mirror: $SUPERNOTE_BACKUP_DEST

Environment overrides:
  FUJIFILM_DEST=/path/to/dir
  SUPERNOTE_DEST=/path/to/dir
  SUPERNOTE_PDF_DEST=/path/to/dir
  SUPERNOTE_BACKUP_DEST=/path/to/dir
  SUPERNOTE_BACKUP_TIMEOUT=20s
  GVFS_ROOT=/run/user/UID/gvfs
EOF_USAGE
}

require_gio() {
  if ! command -v gio >/dev/null 2>&1; then
    log "gio is required but was not found in PATH." >&2
    return 1
  fi
}

find_fujifilm_root() {
  local root
  shopt -s nullglob
  for root in "$GVFS_ROOT"/gphoto2:*; do
    if gio info "$root" >/dev/null 2>&1; then
      printf '%s\n' "$root"
      shopt -u nullglob
      return 0
    fi
  done
  shopt -u nullglob
  return 1
}

find_supernote_root() {
  local root storage
  shopt -s nullglob
  for root in "$GVFS_ROOT"/mtp:*Supernote* "$GVFS_ROOT"/mtp:*supernote*; do
    [[ -e "$root" ]] || continue
    storage="$root/Internal shared storage"
    if gio info "$storage" >/dev/null 2>&1; then
      printf '%s\n' "$storage"
      shopt -u nullglob
      return 0
    fi
    if gio info "$root" >/dev/null 2>&1; then
      printf '%s\n' "$root"
      shopt -u nullglob
      return 0
    fi
  done
  shopt -u nullglob
  return 1
}

copy_fujifilm_jpegs_from_dir() {
  local dir=$1 dest_root=$2
  local name type src dest

  while IFS=$'\t' read -r name _ type _; do
    [[ -n ${name:-} ]] || continue
    src="$dir/$name"

    case "$type" in
      *directory*)
        copy_fujifilm_jpegs_from_dir "$src" "$dest_root"
        ;;
      *regular*)
        case "$name" in
          *.[Jj][Pp][Gg]|*.[Jj][Pp][Ee][Gg])
            TOTAL_FOUND=$((TOTAL_FOUND + 1))
            dest="$dest_root/$name"
            if [[ -e "$dest" ]]; then
              log "skip existing: $name"
              TOTAL_SKIPPED=$((TOTAL_SKIPPED + 1))
              continue
            fi

            log "copy: $src -> $dest"
            if gio copy -- "$src" "$dest"; then
              TOTAL_COPIED=$((TOTAL_COPIED + 1))
            else
              TOTAL_FAILED=$((TOTAL_FAILED + 1))
            fi
            ;;
        esac
        ;;
    esac
  done < <(gio list -a standard::name,standard::type "$dir")
}

copy_supernote_files_from_dir() {
  local src_dir=$1 dest_dir=$2 rel_dir=${3:-}
  local name size type src dest rel_path src_mtime dest_size dest_mtime

  mkdir -p "$dest_dir"

  while IFS=$'\t' read -r name size type _; do
    [[ -n ${name:-} ]] || continue
    src="$src_dir/$name"
    dest="$dest_dir/$name"
    rel_path="${rel_dir:+$rel_dir/}$name"

    case "$type" in
      *directory*)
        copy_supernote_files_from_dir "$src" "$dest" "$rel_path"
        ;;
      *regular*)
        TOTAL_FOUND=$((TOTAL_FOUND + 1))
        if [[ -e "$dest" ]]; then
          src_mtime=$(gio info -a time::modified "$src" 2>/dev/null | awk -F': ' '/time::modified:/ {print $2; exit}')
          dest_size=$(stat -c '%s' "$dest")
          dest_mtime=$(stat -c '%Y' "$dest")
          if [[ -n "$src_mtime" && "$size" == "$dest_size" && "$src_mtime" == "$dest_mtime" ]]; then
            log "skip unchanged: $rel_path"
            TOTAL_SKIPPED=$((TOTAL_SKIPPED + 1))
            continue
          fi
          rm -f -- "$dest"
        fi

        log "copy: $rel_path"
        if gio copy -- "$src" "$dest"; then
          TOTAL_COPIED=$((TOTAL_COPIED + 1))
        else
          TOTAL_FAILED=$((TOTAL_FAILED + 1))
        fi
        ;;
    esac
  done < <(gio list -a standard::name,standard::type,standard::size "$src_dir")
}

copy_if_changed() {
  local src=$1 dest=$2 label=$3
  local src_size dest_size src_mtime dest_mtime

  mkdir -p "$(dirname "$dest")"
  if [[ -e "$dest" ]]; then
    src_size=$(stat -c '%s' "$src")
    dest_size=$(stat -c '%s' "$dest")
    src_mtime=$(stat -c '%Y' "$src")
    dest_mtime=$(stat -c '%Y' "$dest")
    if [[ "$src_size" == "$dest_size" && "$src_mtime" == "$dest_mtime" ]]; then
      log "skip existing $label: ${dest#"$HOME"/}"
      return 1
    fi
  fi

  if timeout "$SUPERNOTE_BACKUP_TIMEOUT" cp -pf -- "$src" "$dest"; then
    log "copy $label: ${dest#"$HOME"/}"
    return 0
  fi

  log "backup copy timed out or failed: ${dest#"$HOME"/}" >&2
  return 2
}

note_signature() {
  local note=$1

  printf 'size=%s\nmtime=%s\n' "$(stat -c '%s' "$note")" "$(stat -c '%Y' "$note")"
}

pdf_is_current_for_note() {
  local note=$1 pdf=$2 meta=$3
  local current recorded

  [[ -e "$pdf" && -e "$meta" ]] || return 1
  current=$(note_signature "$note")
  recorded=$(cat "$meta")
  [[ "$current" == "$recorded" ]]
}

convert_supernote_notes_to_pdfs() {
  local notes_dir=$1 pdf_dir=$2
  local note rel pdf meta status_dir todo converted_log failed_log converted_count failed_count

  if ! command -v supernote-tool >/dev/null 2>&1; then
    log "supernote-tool is required to convert .note files to PDF but was not found in PATH." >&2
    TOTAL_FAILED=$((TOTAL_FAILED + 1))
    return 1
  fi

  mkdir -p "$pdf_dir"
  find "$pdf_dir" -type f -name '*.pdf.tmp.*' -delete
  status_dir=$(mktemp -d)
  todo="$status_dir/todo"
  converted_log="$status_dir/converted"
  failed_log="$status_dir/failed"

  while IFS= read -r -d '' note; do
    rel=${note#"$notes_dir"/}
    pdf="$pdf_dir/${rel%.note}.pdf"
    meta="${pdf}.note-meta"
    mkdir -p "$(dirname "$pdf")"

    if pdf_is_current_for_note "$note" "$pdf" "$meta"; then
      log "skip current PDF: ${pdf#"$HOME"/}"
      TOTAL_CONVERT_SKIPPED=$((TOTAL_CONVERT_SKIPPED + 1))
      continue
    fi

    printf '%s\0' "$note" >>"$todo"
  done < <(find "$notes_dir" -type f -iname '*.note' -print0)

  if [[ -s "$todo" ]]; then
    export NOTES_DIR=$notes_dir
    export PDF_DIR=$pdf_dir
    export CONVERTED_LOG=$converted_log
    export FAILED_LOG=$failed_log

    # Worker variables are intentionally expanded inside bash -c.
    # shellcheck disable=SC2016
    xargs -0 -r -n 1 -P 3 bash -c '
        set -euo pipefail
        note=$1
        rel=${note#"$NOTES_DIR"/}
        pdf="$PDF_DIR/${rel%.note}.pdf"
        meta="${pdf}.note-meta"
        tmp="${pdf}.tmp.$$"

        mkdir -p "$(dirname "$pdf")"
        printf "convert: %s -> %s\n" "$rel" "${pdf#"$HOME"/}"
        if supernote-tool convert -a -t pdf "$note" "$tmp" >/dev/null; then
          mv -f -- "$tmp" "$pdf"
          {
            printf "size=%s\n" "$(stat -c "%s" "$note")"
            printf "mtime=%s\n" "$(stat -c "%Y" "$note")"
          } >"$meta"
          printf "%s\n" "$rel" >>"$CONVERTED_LOG"
        else
          printf "failed to convert: %s\n" "$rel" >&2
          rm -f -- "$tmp"
          printf "%s\n" "$rel" >>"$FAILED_LOG"
        fi
      ' _ <"$todo"
  fi

  converted_count=0
  failed_count=0
  [[ -f "$converted_log" ]] && converted_count=$(wc -l <"$converted_log")
  [[ -f "$failed_log" ]] && failed_count=$(wc -l <"$failed_log")
  TOTAL_CONVERTED=$((TOTAL_CONVERTED + converted_count))
  TOTAL_FAILED=$((TOTAL_FAILED + failed_count))
  rm -rf -- "$status_dir"

  log "Conversion summary: converted=$TOTAL_CONVERTED skipped=$TOTAL_CONVERT_SKIPPED"
}

backup_supernote_notes_and_pdfs() {
  local notes_dir=$1 pdf_dir=$2 backup_dir=$3
  local src rel dest rc

  if [[ ! -d "$backup_dir" ]]; then
    log "Backup directory not found; skipping backup mirror: $backup_dir"
    return 0
  fi

  while IFS= read -r -d '' src; do
    rel=${src#"$notes_dir"/}
    dest="$backup_dir/$rel"
    if copy_if_changed "$src" "$dest" "backup note"; then
      TOTAL_BACKED_UP=$((TOTAL_BACKED_UP + 1))
    else
      rc=$?
      if [[ $rc -eq 1 ]]; then
        TOTAL_BACKUP_SKIPPED=$((TOTAL_BACKUP_SKIPPED + 1))
      else
        TOTAL_BACKUP_FAILED=$((TOTAL_BACKUP_FAILED + 1))
      fi
    fi
  done < <(find "$notes_dir" -type f -iname '*.note' -print0)

  if [[ -d "$pdf_dir" ]]; then
    while IFS= read -r -d '' src; do
      rel=${src#"$pdf_dir"/}
      dest="$backup_dir/$rel"
      if copy_if_changed "$src" "$dest" "backup PDF"; then
        TOTAL_BACKED_UP=$((TOTAL_BACKED_UP + 1))
      else
        rc=$?
        if [[ $rc -eq 1 ]]; then
          TOTAL_BACKUP_SKIPPED=$((TOTAL_BACKUP_SKIPPED + 1))
        else
          TOTAL_BACKUP_FAILED=$((TOTAL_BACKUP_FAILED + 1))
        fi
      fi
    done < <(find "$pdf_dir" -type f -iname '*.pdf' -print0)
  fi

  log "Backup summary: copied=$TOTAL_BACKED_UP skipped=$TOTAL_BACKUP_SKIPPED failed=$TOTAL_BACKUP_FAILED destination=$backup_dir"
}

finish_import() {
  local dest=$1

  log "Summary: found=$TOTAL_FOUND copied=$TOTAL_COPIED skipped=$TOTAL_SKIPPED failed=$TOTAL_FAILED"
  if [[ $TOTAL_BACKUP_FAILED -gt 0 ]]; then
    log "Optional backup failures: $TOTAL_BACKUP_FAILED" >&2
  fi
  if [[ $TOTAL_FAILED -eq 0 ]]; then
    log "Flushing copied files to disk..."
    sync
    log "Imported files to: $dest"
    log "Import complete. It is safe to unplug the USB device."
    return 0
  fi

  log "Imported files to: $dest" >&2
  log "Import finished with failures. It is safe to unplug the USB device, but some files were not copied or converted." >&2
  return 1
}

import_fujifilm() {
  local dest=${1:-$FUJIFILM_DEST}
  local root

  root=$(find_fujifilm_root) || {
    log "No GVFS Fuji/Fujifilm camera mount found under $GVFS_ROOT" >&2
    log "Open the camera in your file manager first, then rerun ${0##*/} fujifilm." >&2
    return 1
  }

  mkdir -p "$dest"
  log "Device: Fujifilm camera"
  log "Source: $root"
  log "Destination: $dest"
  log "Importing JPEG files only; RAW files are ignored."
  copy_fujifilm_jpegs_from_dir "$root" "$dest"
  finish_import "$dest"
}

import_supernote() {
  local dest=${1:-$SUPERNOTE_DEST}
  local root note_root

  root=$(find_supernote_root) || {
    log "No GVFS Supernote mount found under $GVFS_ROOT" >&2
    log "Open the Supernote in your file manager first, then rerun ${0##*/} supernote." >&2
    return 1
  }
  note_root="$root/Note"

  if ! gio info "$note_root" >/dev/null 2>&1; then
    log "Supernote is mounted, but its Note folder was not found at: $note_root" >&2
    return 1
  fi

  mkdir -p "$dest"
  log "Device: Supernote Nomad"
  log "Source: $note_root"
  log "Destination: $dest"
  log "PDF destination: $SUPERNOTE_PDF_DEST"
  log "Optional backup destination: $SUPERNOTE_BACKUP_DEST"
  log "Importing only the Supernote Note folder."
  copy_supernote_files_from_dir "$note_root" "$dest"
  log "Supernote note files are copied locally. It is safe to unplug the Supernote now if you eject/unmount it safely."
  convert_supernote_notes_to_pdfs "$dest" "$SUPERNOTE_PDF_DEST"
  backup_supernote_notes_and_pdfs "$dest" "$SUPERNOTE_PDF_DEST" "$SUPERNOTE_BACKUP_DEST"
  finish_import "$dest"
}

import_auto() {
  local has_supernote=0 detected=0

  if find_fujifilm_root >/dev/null; then
    detected=$((detected + 1))
  fi
  if find_supernote_root >/dev/null; then
    has_supernote=1
    detected=$((detected + 1))
  fi

  case "$detected" in
    0)
      log "No supported USB device found under $GVFS_ROOT." >&2
      log "Supported devices: Fujifilm cameras, Supernote Nomad." >&2
      return 1
      ;;
    1)
      if [[ $has_supernote -eq 1 ]]; then
        import_supernote "$@"
      else
        import_fujifilm "$@"
      fi
      ;;
    *)
      log "Multiple supported devices are connected." >&2
      log "Run one of these explicitly:" >&2
      log "  ${0##*/} fujifilm" >&2
      log "  ${0##*/} supernote" >&2
      return 2
      ;;
  esac
}

main() {
  local mode=${1:-auto}
  local dest=${2:-}

  case "$mode" in
    -h|--help)
      usage
      return 0
      ;;
    auto)
      require_gio
      import_auto "$dest"
      ;;
    fujifilm|fuji|camera)
      require_gio
      import_fujifilm "$dest"
      ;;
    supernote|nomad)
      require_gio
      import_supernote "$dest"
      ;;
    -* )
      log "Unknown option: $mode" >&2
      usage >&2
      return 2
      ;;
    *)
      require_gio
      import_auto "$mode"
      ;;
  esac
}

main "$@"