#!/bin/bash

# AutoLaTeX - Re-run a LaTeX file and reload the output
# Copyright (c) 2008 Alan Briolat <alan@codescape.net>
#
# Wait for modifications to any of the files specified as arguments.  When an
# event is caught, run the BUILD program with the first file as its argument.
# If the build is successful, run the SHOW program with OUTFILE as the argument.
#
# Requires inotify-tools (more specifically, inotifywait).

# Various tools
BUILD="pdflatex -halt-on-error"
SHOW="evince"
WAIT="inotifywait -qq"

# Check that the bare minimum has been done to run this
if [ ! -n "$1" ] ; then
    echo "Usage: `basename $0` file1 [file2 ...]"
    exit
elif [ ! -e "$1" ] ; then
    echo "Cannot watch non-existent file: $1"
    exit
fi

# Get the main input file and output file names
TEXFILE="$1"
OUTFILE="${1/.tex/.pdf}"

# Drop the first argument
shift 1

# Wait on the input file (obviously)
WAITFILES="$TEXFILE"

# Add the remaining files to the wait list
if [ -n "$*" ] ; then
    for F in "$*" ; do
        if [ ! -e "$F" ] ; then
            echo "--- Dropping non-existent watch file: $F"
        else
            WAITFILES+=" $F"
        fi
    done
fi

echo "--- Watching: $WAITFILES"

while [ 1 ] ; do
    # Wait until the source file is modified
    $WAIT $WAITFILES
    # Because sometimes the file "disappears" for a fraction of a second...
    sleep "0.25"
    # Build the file once
    $BUILD "$TEXFILE"
    # If that failed, then go back to waiting
    if [ $? != 0 ] ; then
        echo -e "\033[1;31m!!! ERROR PROCESSING $TEXFILE\033[0m"
        continue
    fi
    # Build it a second time (resolve those table-of-contents things etc)
    $BUILD "$TEXFILE"
    echo -e "\033[1;32m+++ Processed $TEXFILE\033[0m"
    # Just in case it doesn't exist, check!
    if [ -e "$OUTFILE" ] ; then
        $SHOW "$OUTFILE"
    fi
done