#!/bin/bash

# Copyright (c) 2017 Simon Peter (@probonopd)
# Copyright (c) 2018 Kurt Pfeifle (@pdfkungfoo)
#
# License: MIT
#
# The purpose of this custom AppRun script is to enable symlinking the
# AppImage and invoking the corresponding binary depending on which
# symlink name was used to invoke the AppImage.
#
# At the same time it also allows to invoke the embedded binaries as
# 'sub-commands'. This is in the interest of saving users from
# creating extra symlinks (without preventing others from STILL using
# such, should they want or need these).
#
# It also provides some additional help parameters in order to allow
# faster familiarization with functionality embedded in this AppImage.
# For example it support the listing and viewing of embedded manpages,
# HTML files, PDF files, licenses and READMEs.
#
# Note, the AppImage can be renamed to anything what's 'legal' for an
# executable name under Linux or used via a symlink under any name and
# it should behave like 'qpdf' is expected to behave. If the symlink
# name is 'fix-qdf' or 'zlib-flate' it should behave like these...

HERE="$(dirname "$(readlink -f "${0}")")"

# Set APPDIR and ARGV0 when running directly from the AppDir.
# Running from the AppDir can be beneficial when debugging the
# AppImage (or give performance improvements):
if [ -z $APPDIR ]; then
    APPDIR="$HERE"
    ARGV0="$0"
fi

# This is a semi-secret environment variable which can be set for
# debugging the AppImage. For now it is only meant for temporary use
# and may be removed again in the near future once things have
# settled:
if [ "x$SET_BASH_X_FOR_APPRUN" == "xYeSS" ] ; then
   set -x
else
   set +x
fi

# Another semi-secret environment var:
if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
    env | less
fi

if [ "x$SET_SHOW_ENV_FOR_APPIMAGE" == "xYeSS" ] ; then
    env | grep --color -E '(APPIMAGE|APPDIR|APP|ARGV0|HERE)'
fi


function usage() {
echo "
 --------------------------------------------------------------------------
    All QPDF command line functionality inside an AppImage package.
 --------------------------------------------------------------------------

 (This package uses the AppImage software packaging technology for
 Linux ['One App == One File'] for easy availability of the newest
 QPDF releases across all major Linux distributions.)

 Usage:
 ------

   $ARGV0  --help
                # Show help screen of QPDF itself

   $ARGV0  --ai-usage
                # This message (it's only present in the AppImage
                # incarnation of QPDF)

   $ARGV0  qpdf|fix-qdf|zlib-flate
                # Run the named sub-command; not available if the AppImage
                # is invoked as one of the embedded executables

   $ARGV0  --list-exe
                # List all executables embedded in AppImage

   $ARGV0  --list-man
                # List available, embedded manual pages

   $ARGV0  --man qpdf|zlib-flate|fix-qdf
                # Display embedded manual page(s)

   $ARGV0  --list-html
                # List all HTML documents embedded in AppImage

   $ARGV0  --html <path/to/file>
                # Use browser to show HTML file embedded in AppImage
                # (for list of available HTML files see \"$ARGV0 --list-html\")

   $ARGV0  --list-pdf
                # List all PDF documents embedded in AppImage

   $ARGV0  --pdf <path/to/file>
                # Use system default PDF viewer to display embedded PDF
                # document(s)
                # (for list of available PDF files see \"$ARGV0 --list-pdf\")

   $ARGV0  --list-readme
                # List all READMEs embedded in AppImage

   $ARGV0  --readme <path/to/readme>
                # Show content of README embedded in AppImage
                # (for list of available READMEs see \"$ARGV0 --list-readme\")

   $ARGV0  --list-license
                # List all LICENSE files embedded in AppImage

   $ARGV0  --license <name-of-license>
                # Show content of LICENSE file embedded in AppImage
                # (piped thru 'less -N')

   $ARGV0  --show-apprun|--self-show|--selfshow
                # Show 'AppRun' invoked by 'less -N'; type '-N' to toggle
                # line number display

   $ARGV0  --appimage-help
                # Show AppImage options available for all 'type 2' AppImages

   $ARGV0  --help
                # Show help screen of QPDF itself

 ------------------------------------------------------------------------------
 NOTE: The execution of this AppImage is controlled by a custom AppRun
 script. The state of this script is experimental and preliminary.
 Hence it may not work as expected, or miss some functionality. You
 can hack on this script by unpacking this AppImage into a local
 subdirectory [currently named 'squashfs-root'] with this command:

       $ARGV0 --appimage-extract

 After you're done with your hacks, repackage the AppImage again with
 this command:

       appimagetool [/path/to/]squashfs-root [/path/to/]QPDF-*.AppImage

 Latest versions of tools provided by AppImageKit are always available from
   * https://github.com/AppImage/AppImageKit/releases/     and
   * https://github.com/AppImage/AppImageUpdate/releases/  and
   * https://github.com/AppImage/zsync2/releases           and
   * https://github.com/probonopd/linuxdeployqt/releases/
 ------------------------------------------------------------------------------
"
}


function mimetype() {
case "$#" in
    1)
        # 'file --mime-type some-foo-file.ext' usually returns: 'some-foo-file.ext: major/minor', on stderr...
        # However, we want to get back only 'major/minor', on stdout!
        file --mime-type "$1" 2>&1 | sed 's#'"$1"':##;s# ##'
        ;;
    0)
        echo ""                                                                     1>&2
        echo " #  This is a Bash function, named \"$FUNCNAME\"."                    1>&2
        echo " #  You cannot run it without an argument. If you run it with a"      1>&2
        echo " #  [path to a] file as a single argument, it simply returns the"     1>&2
        echo " #  'major/minor' MIME type. If you add multiple [paths to] files"    1>&2
        echo " #  as arguments, it returns a list of 'major/minor' MIME types with" 1>&2
        echo " #  the respective file names prepended. Example usage:"              1>&2
        echo " #"                                                                   1>&2
        echo " #         $> $FUNCNAME /path/to/a.pdf"                               1>&2
        echo " #"                                                                   1>&2
        echo " #         $> $FUNCNAME /path/to/a.txt ./myscript.sh ../some.txt"     1>&2
        echo " #"                                                                   1>&2
        echo " #  This Bash function's source code is this:"                        1>&2
        echo ""                                                                     1>&2
        typeset -f "${FUNCNAME}"                                                    1>&2
        echo ""                                                                     1>&2
        ;;
    *)
        file --mime-type "$@"
        ;;
esac
}


if [ x"$1" == "xshow-apprun" -o \
     x"$1" == "x--show-apprun" -o \
     x"$1" == "x--apprunshow" -o \
     x"$1" == "x--apprun-show" -o \
     x"$1" == "xselfshow" -o \
     x"$1" == "x--selfshow" -o \
     x"$1" == "xself-show" -o \
     x"$1" == "x--self-show" -o \
     x"$1" == "x--show-self" -o \
     x"$1" == "x--showself" -o \
     x"$1" == "xshow-self" -o \
     x"$1" == "xshowself" ] ; then
    cd "$HERE"
    less -N AppRun
    exit $?
fi


if [ x"$1" == "xlistlicense" -o \
      x"$1" == "x--listlicense" -o  \
      x"$1" == "xlist-license" -o \
      x"$1" == "x--list-license" -o \
      x"$1" == "x--licenselist" -o \
      x"$1" == "x--license-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This will then display the respective license file:"
    echo ""
    find . -type f -name "*LICENSE*" -o -name "*license*" | sed 's#^./#  --license #'
    echo ""
    exit $?
fi


if [ x"$1" == "xai-usage" -o \
     x"$1" == "x--aiusage" -o \
     x"$1" == "x--ai-usage" ]; then
    usage | less
    #usage
    exit $?
fi


if [ x"$1" == "xlistman" -o \
     x"$1" == "x--listman" -o \
     x"$1" == "xlist-man" -o \
     x"$1" == "x--list-man" -o \
     x"$1" == "x--manlist" -o \
     x"$1" == "x--man-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This will then open the respective manual page:"
    echo ""
    find usr/share/man* -type f | sed 's#^#  --man #'
    echo ""
    exit $?
fi


if [ x"$1" == "xlistexe" -o \
     x"$1" == "x--listexe" -o \
     x"$1" == "xlist-exe" -o \
     x"$1" == "x--list-exe" -o \
     x"$1" == "x--exelist" -o \
     x"$1" == "x--exe-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This would run the respective exe as a 'sub-command':"
    echo ""
    find . \( \( -type f -o -type l -o -type s -o -type p \) -a -executable \) | grep '/bin/' | grep -v qpdf | sed 's#./usr/bin/#  #' | sort -V | grep -v ".sh$"
    echo ""
    find . \( \( -type f -o -type l -o -type s -o -type p \) -a -executable \) | grep '/bin/' | grep -v qpdf | sed 's#./usr/bin/#  #' | sort -V | grep    ".sh$"
    echo ""
    exit $?
fi


if [ x"$1" == "xlistreadme" -o \
     x"$1" == "x--listreadme" -o \
     x"$1" == "xlist-readme" -o \
     x"$1" == "x--list-readme" -o \
     x"$1" == "x--readmelist" -o \
     x"$1" == "x--readme-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This will then display the respective README file:"
    echo ""
    find . -type f -iname "*README*" -o -iname "*.txt" -o -iname "*.md" -o -iname "*copyright*" -o -iname "*changelog*" -o -iname "*todo*" | sed 's#^./#  --readme #'
    echo ""
    exit $?
fi


if [ x"$1" == "xlisthtml" -o \
     x"$1" == "x--listhtml" -o  \
     x"$1" == "xlist-html" -o \
     x"$1" == "x--list-html" -o \
     x"$1" == "x--htmllist" -o \
     x"$1" == "x--html-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This will then open the respective HTML file in your preferred browser:"
    echo ""
    find . -type f -name "*.html" | sed 's#^./#  --html #'
    echo ""
    exit $?
fi


if [ x"$1" == "xlistpdf" -o \
     x"$1" == "x--listpdf" -o \
     x"$1" == "xlist-pdf" -o \
     x"$1" == "x--list-pdf" -o \
     x"$1" == "x--pdflist" -o \
     x"$1" == "x--pdf-list" ] ; then
    cd "$HERE"
    echo ""
    echo "You may invoke \"$ARGV0\" with one of the following additional arguments."
    echo "This will then open the respective PDF file in your preferred viewer program:"
    echo ""
    find . -type f -name "*.pdf" | sed 's#^./#  --pdf #'
    echo ""
    exit $?
fi


if [ x"$1" == "xreadme" -o \
     x"$1" == "x--readme" ] ; then
    cd "$HERE"
    shift
    echo ""
    if [ x"$1" == "x" ] ; then
        echo " You must give a path to the README you want to open."
        echo "   For available READMEs run \"$ARGV0 --listreadme\"."
    else
        readmefile=$( find . -type f -iname "*README*" -o -iname "*.txt" -o -iname "*.md" -o -iname "*copyright*" -o -iname "*changelog*" | grep "${1}" | sort -rV | head -n 1 )
        MIME=$(mimetype $readmefile)
        case $MIME in
            text/html|application/pdf|application/epub*)
                xdg-open "$readmefile"
                sleep 3  # sleep to allow slow xdg-open do its job
             ;;
            inode/x-empty)
                echo ""
                echo " Sorry, this file, \"$readmefile\", is empty and has no content."
                echo ""
             ;;
            text/*)
                less -N "$readmefile"
             ;;
        esac
        sleep 0
    fi
    echo ""
   exit $?
fi


if [ x"$1" == "xlicense" -o \
     x"$1" == "x--license" ] ; then
    cd "$HERE"
    shift
    echo ""
    if [ x"$1" == "x" ] ; then
        echo " You must give a path to the LICENSE you want to open."
        echo "   For available LICENSE run \"$ARGV0 --list-license\"."
    else
        licensefile=$( find . -type f -iname "*LICENSE*" | grep "${1}" | sort -rV | head -n 1 )
        #if PDF or EPUB or HTML ; then xdg-open $licensefile ; else
        MIME=$(mimetype $licensefile)
        case $MIME in
            text/html|application/pdf|application/epub*)
                xdg-open "$licensefile"
                sleep 3  # sleep to allow slow xdg-open do its job
             ;;
            inode/x-empty)
                echo ""
                echo " Sorry, this file, \"$licensefile\", is empty and has no content."
                echo ""
             ;;
            text/*)
                less -N "$licensefile"
             ;;
        esac
        sleep 0
    fi
    echo ""
   exit $?
fi


if [ x"$1" == "xman"  -o  x"$1" == "x--man" ] ; then
    export MANPATH="$HERE/usr/share/man:$MANPATH"
    shift
    exec man "$@" || man $(basename $1)
fi


if [ x"$1" == "xpdf" -o x"$1" == "x--pdf" ] ; then
    cd "$HERE"
    shift
    echo ""
    if [ x"$1" == "x" ] ; then
        echo ""
        echo " You must give a path to the PDF file you want to open."
        echo "   For available PDFs run \"$ARGV0 --list-pdf\""
        echo ""
    else
        pdffile=$( find . -type f -name "*.pdf" | grep "${1/.pdf/}.pdf" | sort -rV | head -n 1 )
        xdg-open "$pdffile"
        sleep 5
    fi
    echo ""
    exit $?
fi


if [ x"$1" == "xhtml" -o x"$1" == "x--html" ] ; then
    cd "$HERE"
    shift
    if [ x"$1" == "x" ] ; then
        echo ""
        echo " You must give a path to the HTML file you want to open."
        echo "   For available HTMLs run \"$ARGV0 --list-html\""
        echo ""
    else
        htmlfile=$( find . -type f -name "*.html" | grep "${1}" | sort -rV | head -n 1 )
        xdg-open "$htmlfile"
        sleep 5
    fi
    exit $?
fi


if [ x"$1" == "x--appimage-help" ] ; then
    cd "$HERE"
    shift
    if [ x"$APPIMAGE" == "x" ] ; then
        echo ""
        echo " The parameter '--appimage-help' does not work if you run this application from an AppDir (as you do)."
        echo " To create an AppImage from your AppDir run this command:"
        echo ""
        echo "    appimagetool -n $APPDIR qpdf.AppImage"
        echo ""
        echo " You can download the latest version of 'appimagetool' (as an AppImage) from here:"
        echo ""
        echo "    https://github.com/AppImage/AppImageKit/releases"
        echo ""
    fi
    exit $?
fi


if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
    echo APPIMAGE=$APPIMAGE     1>&2  # Don't leak strings into output of qpdf|fix-qdf|zlib-flate which goes to stdout!
    echo ARGV0=$ARGV0           1>&2  # Don't leak strings into output of qpdf|fix-qdf|zlib-flate which goes to stdout!
    echo dollar0=$0             1>&2  # Don't leak strings into output of qpdf|fix-qdf|zlib-flate which goes to stdout!
    echo dollar1=$1             1>&2  # Don't leak strings into output of qpdf|fix-qdf|zlib-flate which goes to stdout!
    echo dollar_at="$@"         1>&2  # Don't leak strings into output of qpdf|fix-qdf|zlib-flate which goes to stdout!
fi


### Main stuff happens from here:
if [ ! -z $APPIMAGE ] ; then
    # We run as an AppImage
    BINARY_NAME=$(basename "$ARGV0")
    APPIMAGE=$APPIMAGE
    CALLED_SUBCMD=$( basename $1 2>/dev/null )
    if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
        # We have the (hidden) env var for debugging stuff set
        echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into output of qpdf|fix-pdf|zlib-flate going to stdout!
        echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into output of qpdf|fix-pdf|zlib-flate going to stdout!
        echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into output of qpdf|fix-pdf|zlib-flate going to stdout!
    fi

    if [ -x "$HERE/usr/bin/$BINARY_NAME" ] && [ x"$BINARY_NAME" != "x" ] ; then
        # We are invoked from a symlink (like 'fix-qdf' or 'zlib-flate')
        if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
            # We have the (hidden) env var for debugging stuff set
            echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        fi
        shift
        exec "$HERE/usr/bin/$BINARY_NAME" "$@"

    else
        if [ -x "$HERE/usr/bin/$CALLED_SUBCMD" ] && [ x"$CALLED_SUBCMD" != "x" ] ; then
            # We are invoked by a (currently not yet known future) binary name which may be located in ./usr/bin/ ...
            BINARY_NAME=$1
            if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
                # We have the (hidden) env var for debugging stuff set
                echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
                echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
                echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            fi
            shift
            exec "$HERE/usr/bin/$BINARY_NAME" "$@"
        elif [ -x "$HERE/$CALLED_SUBCMD" ] && [ x"$CALLED_SUBCMD" != "x" ] ; then
            # We are invoked by a (currently not yet known future) binary name which may be located in our root AppDir ...
            BINARY_NAME=$CALLED_SUBCMD
            if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
                # We have the (hidden) env var for debugging stuff set
                echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
                echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
                echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            fi
            shift
            exec "$HERE/$BINARY_NAME" "$@"
        else
            # this clause may not be necessary...
            exec "$HERE/usr/bin/qpdf" "$@"
        fi
    fi

else
    # Most likely we run from an AppDir, not as an AppImage:
    BINARY_NAME=$(basename "$ARGV0")
    APPIMAGE=$APPIMAGE
    CALLED_SUBCMD=$( basename $1 2>/dev/null )
    if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
        # We have the (hidden) env var for debugging stuff set
        echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
    fi

    if [ -x "$HERE/usr/bin/$CALLED_SUBCMD" ] && [ "x$CALLED_SUBCMD" != "x" ]; then
        #echo before shift dollar_at=$@
        if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
            # We have the (hidden) env var for debugging stuff set
            echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        fi
        shift
        #echo after shift dollar_at=$@
        #echo CALLED_SUBCMD=$CALLED_SUBCMD
        exec "$HERE/usr/bin/$CALLED_SUBCMD" "$@"

    elif [ -x "$HERE/usr/bin/$BINARY_NAME" ] && [ "x$BINARY_NAME" != "x" ] ; then
        if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
            # We have the (hidden) env var for debugging stuff set
            echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        fi
        shift
        exec "$HERE/usr/bin/$BINARY_NAME" "$@"

    else
        if [ "x$SET_SHOW_ENV_FOR_APPRUN" == "xYeSS" ] ; then
            # We have the (hidden) env var for debugging stuff set
            echo BINARY_NAME=$BINARY_NAME       1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo APPIMAGE=$APPIMAGE             1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
            echo CALLED_SUBCMD=$CALLED_SUBCMD   1>&2  # Don't leak strings into qpdf|fix-pdf|zlib-flate output going to stdout!
        fi
        exec "$HERE/usr/bin/qpdf" "$@"
    fi

fi
