path: root/home/zaread.nix

{ pkgs, lib, ... }:

let
  zareadScript = pkgs.writeShellScriptBin "zaread" ''
    # zaread cache path
    ZA_CACHE_DIR="''${XDG_CACHE_HOME:-"$HOME"/.cache}/zaread/"
    # zaread config path
    ZA_CONFIG="''${XDG_CONFIG_HOME:-"$HOME"/.config}/zaread/zareadrc"

    # Default reader, i.e. command, which script uses to open pdf, epub and converted files
    READER="${pkgs.zathura}/bin/zathura"
    # Default converters, i.e. commands, which script uses to convert files to pdf
    MOBI_CMD="${pkgs.calibre}/bin/ebook-convert"
    OFFICE_CMD="${pkgs.libreoffice-fresh}/bin/soffice"
    MD_CMD="${pkgs.md2pdf or pkgs.pandoc}/bin/${if pkgs ? md2pdf then "md2pdf" else "pandoc"}"
    TYPST_CMD="${pkgs.typst}/bin/typst"
    TYPST_ARG="compile" # Can be changed to "watch"
    MD_ARG=""
    MOBI_ARG=""
    OFFICE_ARG="--headless"
    # If you want to use other commands set these vars in $ZA_CONFIG. Some cli
    # arguments are hardcoded so some commands won't work. Check that first.

    # Sources the variables from config file if exists
    # shellcheck disable=1090
    [ -f "$ZA_CONFIG" ] && . "$ZA_CONFIG"

    # if $ZA_CACHE_DIR doesn't exist, we create it.
    [ ! -d "$ZA_CACHE_DIR" ] && mkdir -p "$ZA_CACHE_DIR"

    # Exit if called without arguments
    if [ "$#" = 0 ]; then
            echo "No files to open."
            exit
    fi

    if [ "$#" != 1 ]; then
            echo "More than one filename given. Closing."
            exit 1
    fi

    path="$1"

    if [ ! -f "$path" ]; then
            echo "File doesn't exist."
            exit 1
    fi

    if ! command -v "$READER" >/dev/null; then
        echo "$READER is not on the $PATH."
        echo "Closing."
        exit 1
    fi

    echo "\$READER='$READER' is in the \$PATH. Starting script..."

    ## create position and file variables ##

    # complete file name (path excluded):
    file="$(basename "$path")"
    echo "Filename: $file"
    case "$path" in
    # complete directory path:
    # if it has been inserted absolute path ($path starts with '/')
    /*)
            directory="$(dirname "$path")"
            ;;
    # else (relative path inserted)
    *)
            directory="''${PWD}/$(dirname "$path")"
            # directory="$(echo "$dir" | tr -s '/')"
            ;;
    esac

    echo "Directory: $directory/"
    echo "Path: $directory/$file"

    # get file type

    # if the file is itself a pdf, a djvu or an epub, or we already have a pdf converted version,
    # then we don't need a converter. But if it's an already converted document, then
    # file position is different: we must distinguish between original and converted files
    file_mt="$(file --mime-type "$directory/$file")"
    file_mt="''${file_mt#*: }"
    echo "Mime type: $file_mt"

    cd "$directory" || {
            echo "Couldn't cd into $directory"
            exit 1
    }

    # $pdffile is a string composed this way: CRC_BYTECOUNT_$filename.[pdf,epub]
    # if the converted file exists, then it's named like $pdffile
    pdffile="$(cksum "$file" | sed -E 's/^([0-9]+) ([0-9]+) (.*)$/\1_\2_\3.pdf/')"
    echo "Converted pdf filename: $pdffile"

    file_converter=""
    # If the converted file exists we can just open it.
    if [ -f "$ZA_CACHE_DIR/$pdffile" ]; then
            file_converter="none_converted"
    else
            case "$file_mt" in
            "application/pdf" | "image/vnd.djvu" | "application/epub+zip")
                    # If the file is a pdf, a djvu or an epub we don't need to convert it.
                    file_converter="none_original"
                    ;;
            "application/vnd.openxmlformats-officedocument.wordprocessingml.document" | \
                    "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" | \
                    "application/vnd.openxmlformats-officedocument.presentationml.presentation" | \
                    "application/msword" | \
                    "application/vnd.ms-excel" | \
                    "application/vnd.ms-powerpoint" | \
                    "application/vnd.oasis.opendocument.text" | \
                    "application/vnd.oasis.opendocument.spreadsheet" | \
                    "application/vnd.oasis.opendocument.presentation" | \
                    "text/rtf" | \
                    "text/csv")
                    # If the file is an office file (ooxml or the old format or an
                    # opendocument) we convert it using $OFFICE_CMD.
                    file_converter="$OFFICE_CMD"
                    ;;
            "application/octet-stream" | \
                    "application/x-mobipocket-ebook")

                    case "$file" in
                    *.mobi)
                            # If the file is a mobi ebook we convert it using $MOBI_CMD.
                            file_converter="$MOBI_CMD"
                            ;;
                    esac
                    ;;
            "text/plain" | \
                    "text/x-c" | \
                    "text/x-objective-c" | \
                    "text/x-script.python" )
                    case "$file" in
                    *.md)
                            # If the file is a markdown we convert it using $MD_CMD.
                            file_converter="$MD_CMD"
                            ;;
                    *.typ)
                            file_converter="$TYPST_CMD"
                            ;;
                    esac
                    ;;
            esac
    fi

    case "$file_converter" in
    "")
            echo "The file format is unsupported."
            exit 2
            ;;
    "none_original")
            echo "The file is already in PDF format. We just open it."
            eval "$READER" \""$directory/$file"\"
            ;;
    "none_converted")
            echo "We already converted this file. We just open it."
            eval "$READER" \""$ZA_CACHE_DIR/$pdffile"\"
            ;;
    *)
            # So the file is not a pdf or an epub, and a converted version
            # doesn't exist, but its format may be convertible
            if command -v "$file_converter" >/dev/null; then
                    echo "We are starting to convert the file \"$file\" using $file_converter"
                    # If converter tools are changed in $ZA_CONFIG check calling
                    # commands bellow. They may need to be called with different
                    # arguments and format.
                    case "$file_converter" in
                    "$OFFICE_CMD")
                            eval "$OFFICE_CMD" "$OFFICE_ARG" --convert-to pdf \""$directory/$file"\" --outdir \""$ZA_CACHE_DIR"\"
                            # We need to handle cases where file starts with a . and
                            # that's the only one . in filename, i.e. filename hasn't
                            # got extension
                            case "$file" in
                            .*.*)
                                    # If it has one more . after the first character
                                    # which is a ., we'll consider that as an
                                    # extension, so we can use parameter expansion,
                                    # and we need this case for the next one to work.
                                    tmpfile="''${file%.*}.pdf"
                                    ;;
                            .*)
                                    # If this case was the first it would also match cases with 2 .'s in the filename.
                                    # If the filename starts with a . and it hasn't got an
                                    # extension, we just add .pdf to the filename to get
                                    # tmpfilename
                                    tmpfile="$file.pdf"
                                    ;;
                            *)
                                    # In the rest of cases we can use parameter expansion
                                    tmpfile="''${file%.*}.pdf"
                                    ;;
                            esac
                            mv "$ZA_CACHE_DIR/$tmpfile" "$ZA_CACHE_DIR/$pdffile"
                            ;;
                    "$MOBI_CMD")
                            eval "$MOBI_CMD" "$MOBI_ARG" \""$directory/$file"\" \""$ZA_CACHE_DIR/$pdffile"\"
                            ;;
                    "$MD_CMD")
                            if [ "$MD_CMD" = "${pkgs.pandoc}/bin/pandoc" ]; then
                                eval "$MD_CMD" "$MD_ARG" \""$directory/$file"\" -o \""$ZA_CACHE_DIR/$pdffile"\"
                            else
                                eval "$MD_CMD" "$MD_ARG" \""$directory/$file"\" -o \""$ZA_CACHE_DIR/$pdffile"\"
                            fi
                            ;;
                    "$TYPST_CMD")
                            eval "$TYPST_CMD" "$TYPST_ARG" \""$directory/$file"\" \""$ZA_CACHE_DIR/$pdffile"\" --open "$READER"
                            exit
                            ;;
                    esac
            else
                    echo "The command we need to convert '$file_converter' is not in \$PATH."
                    exit 4
            fi
            echo "Now we can open the file $ZA_CACHE_DIR/$pdffile"
            # ...and after the conversion we open the file
            eval "$READER" \""$ZA_CACHE_DIR/$pdffile"\"
            ;;
    esac
  '';
in
{
  home.packages = [ zareadScript ];

  xdg.desktopEntries.zaread = {
    name = "zaread";
    exec = "${zareadScript}/bin/zaread %f";
    icon = "org.pwmt.zathura";
    comment = "Lightweight ebook and office document reader";
    terminal = false;
    noDisplay = true;
    categories = [
      "Office"
      "Viewer"
    ];
    mimeType = [
      "application/pdf"
      "image/vnd.djvu"
      "application/epub+zip"
      "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
      "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
      "application/vnd.openxmlformats-officedocument.presentationml.presentation"
      "application/msword"
      "application/vnd.ms-excel"
      "application/vnd.ms-powerpoint"
      "application/vnd.oasis.opendocument.text"
      "application/vnd.oasis.opendocument.spreadsheet"
      "application/vnd.oasis.opendocument.presentation"
      "text/rtf"
      "text/csv"
      "application/x-mobipocket-ebook"
      "text/plain"
    ];
  };
}