#!/bin/bash
# vi:set ts=8 sw=4 et sta:
#
# Author : Clark J. Wang <dearvoid at gmail.com>
# License: GPLv2
# 
# $Date$
# $Author$
# $HeadURL$
# $Revision$
#
#--------------------------------------------------------------------#

{
    # global variables
    declare g_progname=$(basename $0)
    declare g_man g_ps2pdf g_groff
    declare g_secs g_all g_verbose g_showonly g_topics
    declare g_errno=0
    declare ESC=$'\033'
}

#--------------------------------------------------------------------#

debug()
{
    if [ "$g_verbose" = yes ]; then
        echo "[debug] $1"
    fi
}

#--------------------------------------------------------------------#

error()
{
    echo "[$ESC[0;31merror$ESC[0m] $1"
}

#--------------------------------------------------------------------#

usage()
{
    cat << HELP
Usage: $g_progname [-h] [-a | -s <secs>] [-v] [-w] topic ...

    -a          Search all manual sections.
    -h          Help
    -s <secs>   <secs> is a colon separated list of manual sections to
                search.
    -v          Verbose
    -w          Do not create PDF. Only show which file to use.

Report bugs to $ESC[1;35mClark J. Wang$ESC[0m <dearvoid at gmail.com>
HELP

    exit $1
}

#--------------------------------------------------------------------#

getargs()
{
    declare option

    OPTIND=1
    OPTERR=0
    while getopts ":ahs:vw" option "$@"; do
        case $option in
            a)  g_all=yes ;;

            h|:|'?')
                [ $option = h ] && usage 0 || usage 1 ;;

            s)  g_secs=$OPTARG ;;
            v)  g_verbose=yes ;;
            w)  g_showonly=yes ;;
        esac
    done
    shift $((OPTIND - 1))

    if [ "$g_all" = yes -a "$g_secs" ]; then
        usage 1
    fi

    g_topics=( "$@" )
    if [ ${#g_topics[@]} = 0 ]; then
        usage 1
    fi
}

#--------------------------------------------------------------------#

findcmd()
{
    declare cmd exe

    for cmd in "$@"; do
        exe=$(type -P "$cmd" 2> /dev/null)
        if [ "$exe" ]; then
            echo "$exe"
            return
        fi
    done
}

#--------------------------------------------------------------------#

findcmds()
{
    g_man=$(findcmd man)
    if [ "$g_man" ]; then
        debug "MAN: $g_man"
    else
        error "Man not found"
        exit 1
    fi

    g_groff=$(findcmd groff)
    if [ "$g_groff" ]; then
        debug "GROFF: $g_groff"
    else
        error "Groff not found"
        exit 1
    fi

    g_ps2pdf=$(findcmd ps2pdf14 ps2pdf13 ps2pdf12 ps2pdf pstopdf)
    if [ "$g_ps2pdf" ]; then
        debug "PS2PDF: $g_ps2pdf"
    else
        error "Ps2pdf not found"
        exit 1
    fi
}

#--------------------------------------------------------------------#

runcmd()
{
    declare cmd=$1

    debug "$cmd"
    if [ "$g_verbose" = yes ]; then
        eval "$cmd"
    else
        eval "$cmd" >& /dev/null
    fi
    g_errno=$?
    if [ $g_errno -gt 0 ]; then
        debug "Command exited: $g_errno"
    fi
}

#--------------------------------------------------------------------#

man2pdf()
{
    declare topic man_w tmpdir cmd manfile basename found=0

    topic=$1
    man_w="$g_man -w"
    tmpdir=/tmp

    if [ ! "$topic" ]; then
        return 1
    fi

    if [ "$g_all" = yes ]; then
        man_w="$man_w -a"
    elif [ "$g_secs" ]; then
        man_w="$man_w -a -S$g_secs"
    fi

    #
    # On Mac OS X (Darwin), "man -w" may output like this:
    #
    # $ man -w ls
    # /usr/share/man/cat1/ls.1.gz (source: /usr/share/man/man1/ls.1)
    #

    #
    # On Gentoo, "man -w" may output like this:
    #
    # $ man -w emerge
    # /var/cache/man/cat1/emerge.1.bz2 (<-- /usr/share/man/man1/emerge.1.gz)
    #
    while read manfile; do
        found=1

        if [ -f "$manfile" ]; then
            debug "File: $manfile"
        else
            error "File '$manfile' not found"
            continue
        fi

        if [ "$g_showonly" = yes ]; then
            echo "$topic: $manfile"
            continue
        fi

        # copy to $tmpdir
        basename=$(basename $manfile)
        if [[ $basename == *.gz ]]; then
            basename=${basename%.gz}
            cmd="gzip -dc $manfile > $tmpdir/$basename"
        elif [[ $basename == *.bz2 ]]; then
            basename=${basename%.bz2}
            cmd="bzip2 -dc $manfile > $tmpdir/$basename"
        else
            cmd="cp -f $manfile $tmpdir"
        fi
        runcmd "$cmd"
        if [ $g_errno -gt 0 ]; then
            continue
        fi

        # groff
        cmd="$g_groff -t -e -mandoc -Tps $tmpdir/$basename > $tmpdir/$basename.ps"
        runcmd "$cmd"
        if [ $g_errno -gt 0 ]; then
            continue
        fi

        # ps2pdf
        if [[ $g_ps2pdf == *pstopdf ]]; then
            # On Mac OS X, 'pstopdf' by default puts the new PDF file in
            # the same directory as the PS file.
            cmd="$g_ps2pdf -o ./$basename.pdf $tmpdir/$basename.ps"
        else
            cmd="$g_ps2pdf $tmpdir/$basename.ps"
        fi
        runcmd "$cmd"
        if [ $g_errno -gt 0 ]; then
            continue
        fi

        if [ -f $basename.pdf ]; then
            echo "Created: $basename.pdf"
        else
            error "Failed to create '$basename.pdf'"
        fi

        cmd="rm -f $tmpdir/$basename $tmpdir/$basename.ps"
        runcmd "$cmd"
    done < <( $man_w -- $topic 2> /dev/null                  \
              | sed -e 's@^[[:blank:]]\+\|[[:blank:]]\+$@@g' \
                    -e 's@ (source:.*@@'                     \
                    -e 's@.*(<-- \(.*\))@\1@')

    if ((! found)); then
        error "Man page for '$topic' not found"
        return 1
    fi
}

#--------------------------------------------------------------------#

mans2pdfs()
{
    declare topic

    for topic in "${g_topics[@]}"; do
        man2pdf "$topic"
    done
}

#--------------------------------------------------------------------#

{
    getargs "$@"

    findcmds

    mans2pdfs
}