#!/bin/sh

# Copyright (c) 2010 - 2011 Vasileios Porpodas 
# 
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#                                                                              
#    The above copyright notice and this permission notice shall be            
#    included in all copies or substantial portions of the Software.           
#                                                                              
#    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,           
#    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES           
#    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND                  
#    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT               
#    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,              
#    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING              
#    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR             
#    OTHER DEALINGS IN THE SOFTWARE.                                           
#                                                                              
# This software is licensed under GPL 3 License. http://gplv3.fsf.org/

# ABOUT
# Slack-desc is a script that generates the slack-desc files for
# Slackware linux packages (http://www.slackware.org). 
# It supports two modes of operation: 
#   o the argument-based one 
#   o the interactive one which guides you thourgh the process.
# The output is printed on the screen.


# EXAMPLE
# a. argument-based:
# ./slack-desc-gen "slack-desc" "0.01" "slackware slack-desc generator
#  script" "Slack-desc is a script that generates the slack-desc files
#  for slackware linux packages. It supports two modes of operation: the
#  argument-based one and the interactive one." "http://slack-desc-gen
#  .sourceforge.net"
#
# b. interactive:
# ./slack-desc-gen -i
#
# 


# Read from stdin until newline or LIMIT
# Usage: SIMPLEINPUT LIMIT
simpleinput()
{
    local limit=$1
    read -a IN -n $limit
    $ECHO ${IN[@]}
}


# Read stdin until the special characters are typed in.
# or until charecter LIMIT is reached. Return the input string up
# to the LIMIT.
# Usage: GETINPUT LIMIT
getinput()
{
    local limit=$1
    local i=2
    while [ "${ALL[i-2]}" != ";" ]||[ "${ALL[i-1]}" != ";" ] ;do 
	if [ $i -gt $limit ];then
	    $ECHO "Warning: Character limit of $limit exceeded." 1>&2
	    $ECHO -e $str
	    exit -1
	fi
	read -a IN -n 1
        #convert newlines into spaces
	if [ "$IN" == "" ]; then IN=" "; fi
	ALL[i]=$IN
	str+=$IN
	i=$(($i+1))
    done
    local max=$(($i - 4))
    local str=`$ECHO $str|head -c $max`
    $ECHO -e $str
}

# Format the given STRING in slack-desc format using PKGNAME prefix.
# Make sure that it takes up to LINES lines.
# Usage: FORMAT PKGNAME "STRING" LINES
format() 
{
    # LINES
    local max_lines=$3

    local lines=1
    local out=""
    local wordlist=( )
    local i=0

    # STRING
    for word in $2; do
	wordlist[$i]=$word
	i=$(($i + 1))
    done
    local max=${#wordlist[@]}

    # "PKGNAME: "
    local fmted_pname="$1: "
    local linebuffer="${fmted_pname}"
    i=0;
    while [ $i -le $max ]; do
	if [ $lines -le $max_lines ] ; then
	    local linebuffer_chars=`get_length "$linebuffer"`
	    local next_word=${wordlist[$i]}
	    local next_word_chars=$((`get_length $next_word`))
	    # Test if adding the next word will overflow the screen width.
	    local test_chars=$(($linebuffer_chars + $next_word_chars + 1)) 
	    if [ $test_chars -lt $screen_width ]; then
		linebuffer+="$next_word "
	    else
		lines=$(($lines + 1))
		# commit linbuffer to the output buffer
		out+="$linebuffer\n"
		linebuffer="${fmted_pname}"
		# redo the last one.
		i=$(($i - 1))
	    fi
	else
	    if [ $i -lt $((max)) ]; then
		OVERFLOW="Y"
		break
	    fi
	fi
	i=$(($i + 1))
    done
    if [ $lines -le $max_lines ]; then
	out+="$linebuffer\n"
    fi

    #This is a hack. all other checks are done in sanity_check()
    if [ "$OVERFLOW" == "Y" ]; then
    	if [ ! "$DISABLED_CHECKS" == "N" ]; then
            # FORCE EXIT ON ERROR
    	    check_size "$description" $description_limit "FORCE"
    	fi
    fi


    # line padding: add lines until we reach max_lines
    for ((i=lines; i < max_lines; i++ )); do
	out+="${fmted_pname}\n"
    done
    $PRINTF "$out"
    if [ "$OUTFILE" != "" ]; then
	$ECHO -e $out >> $OUTFILE
    fi

}

# Print help message.
# Usage HELP_MESSAGE
help_message()
{
$ECHO -e "Usage: $PKGNAME \"<package name>\" \"<version>\" \"<Short description>\" \"<Long description>\" \"<http://homepage>\" [ -r ] [ -n ]\n\
 OR\n\
Usage: $PKGNAME -i [ -r ] [ -n ]  // Interactive wizard (beta)\n\
\n\
Example: $PKGNAME \"slackdesc\" \"0.01\" \"slackware slack-desc generator tool\" \"$PKGNAME is a tool that generates the slack-desc files for Slackware linux packages. It supports two modes of operation: the argument-based one and the interactive one.\" \"http://slack-desc.sourceforge.net\" \n\
\n\
Arguments description\n\
-i                   Launch interactive wizard\n\
<package name>       Single word; The name of the package (application name)\n\
<version>            The application version\n\
<short description>  A short description that fits one line\n\
<long description>   A description up to 7 lines long\n\
<http://homepage>    The project homepage. Should fit in 1 line\n\
-r                   Show handy ruler on top\n\
-n                   Disable sanity checks\n\
"
}

# Get a string's length (count of characters)
# Usage: GET_LENGTH STRING
get_length() {	
    string="$@"
    # don't use $ECHO because it inserts extra newline chars, destroys count
    local length=`$PRINTF "$string"|$WC -c`
    $ECHO $length
}

# Parse the command line arguments
# Usage PARSE_INPUT [ARG1] [ARG2] ...
parse_input(){

    if [ "$1" == "" ]||[ "$1" == "--help" ] || [ "$1" == "-help" ] || [ $# -eq 0 ]; then
	help_message
	exit -1
    fi;
    SHOW_RULER="N"
    local INTERACTIVE="N"
    if [ "$1" == "-i" ] || [ "$1" == "--interactive" ] || [ "$1" == "-interactive" ]; then
	INTERACTIVE="Y"
	if [ "$2" == "-r" ]; then
	    SHOW_RULER="Y"
	fi
    fi
    if [ "$6" == "-r" ]||[ "$7" == "-r" ]; then
	SHOW_RULER="Y"
    fi

    DISABLE_CHECKS="N"
    if [ "$6" == "-n" ]||[ "$7" == "-n" ]; then
	DISABLE_CHECKS="Y"
    fi
    

    package_name_limit=$(($screen_width-10))
    version_limit=20

    if [ "$INTERACTIVE" == "Y" ]; then
	$ECHO -e "\nEnter package name"
	local package_name="`simpleinput $package_name_limit`"
	local name_width=`get_length "${package_name} :"`
	homepage_limit=$(($screen_width - $name_width))

	$ECHO -e "\nEnter application version"
	local version="`simpleinput $version_limit`"
	local version_width=`get_length "$version"`
	local package_name_width=`get_length "$package_name"`
	summary_limit=$(($screen_width - $name_width - $version_width - $package_name_width))
	description_limit=$(($summary_limit * $desc_lines))

	$ECHO -e "\nEnter package summary"
	local summary="`simpleinput $summary_limit`"

	$ECHO -e "\nEnter package description --> USE \";;\" TO END INPUT <--" 
	local description="`getinput $description_limit`"

	$ECHO -e "\nEnter application's homepage"
	local homepage="`simpleinput $homepage_limit`"

    else
	package_name="$1"
	version="$2"
	summary="$3"
	description="$4"
	homepage="$5"

	local name_width=`get_length "${package_name}: "`
	homepage_limit=$(($screen_width - $name_width))
	local version_width=`get_length "$version"`
	local package_name_width=`get_length "$package_name"`
	summary_limit=$(($screen_width - $name_width - $version_width - $package_name_width))
	description_limit=$(($(($screen_width - $name_width -1)) * $desc_lines))

    fi
}


# Check whether the STRING's size is less than or equal to MAX_LENGTH
# If FORCE_ERROR is "FORCE" then ignore the check and fail.
# Usage: CHECK_SIZE STRING MAX_LENGTH [FORCE_ERROR]
check_size() 
{
    local string="$1"
    local length=$2
    local FORCE_ERROR=$3
    local chars=`get_length "$string"`
    if [ $chars -ge ${length} ]||[ "$FORCE_ERROR" == "FORCE" ]; then
	$ECHO "ERROR! string: "+${string} +" too big!"
	exit -1
    fi
}

# Sanity checks about input's character lengths
# Usage: SANITY_CHECKS 
sanity_checks(){
    if [ ! "DISABLE_CHECKS" == "Y" ]; then
	check_size "$package_name" $package_name_limit
	check_size "$version" $version_limit
	check_size "$package_name: $package_name $version" $(($screen_width))
	check_size "$summary" $summary_limit
	check_size "$package_name: $package_name $version $summary" $(($screen_width))
	check_size "$homepage" $homepage_limit
	check_size "$description" $description_limit
    fi
}

# Print the |----habndy-ruler----...--|
# Usage: HANDY_RULER
handy_ruler()
{
    if [ "$SHOW_RULER" == "Y" ]; then
#	$ECHO "appname|-----handy-ruler------------------------------------------------------|"
	local HANDY_RULER="${package_name}|-----handy-ruler--"
	check_size "$HANDY_RULER" $screen_width
	local chars=`get_length "$HANDY_RULER"`
	while [ $chars -lt $screen_width ]; do
	    HANDY_RULER+="-"
	    chars=`get_length "${HANDY_RULER}-"`
	done
	HANDY_RULER+="|"
	$ECHO "$HANDY_RULER"
    fi
}

# Print the slack-desc output
# Usage: PRINT_OUTPUT
print_output()
{
    handy_ruler
    sanity_checks
    format ${package_name} "$package_name $version $summary" $summ_lines 
    format ${package_name} "" $empty_line
    format ${package_name} "$description" $desc_lines
    format ${package_name} "$homepage" $homepage_lines

}


# Entry point
# Usage: MAIN [ARG1] [ARG2] ...
main() 
    {
	parse_input "$1" "$2" "$3" "$4" "$5" "$6" "$7"
	print_output
    }


# GENERAL CONFIGURATION
# paths to programs used
WC=wc
PRINTF=printf
ECHO=echo

PKGNAME="slackdesc"

summ_lines=1
empty_line=1
desc_lines=8
homepage_lines=1
screen_width=80

main "$1" "$2" "$3" "$4" "$5" "$6" "$7"