#!/usr/bin/env bash

# guri - Get HTTP URIs from the Web
# Usage: ./guri <httpuri>
# License: GPL 2; share and enjoy!
# Author: Sean B. Palmer, inamidst.com
# Requirements: 
#    @@ curl
#    http://inamidst.com/util/uriquote
# Todo: @@ --help and usage 

curl=$(which curl)
if [ $? != 0 ]; then
   echo "Couldn't find curl." >&2
   exit 1
fi
uri=$1

# Test that it's an HTTP URI
case $uri in
   http://*) path=${uri#http://};;
   *) echo "Invalid HTTP URI: $uri" >&2; exit 1;;
esac
path=$(uriquote $path)

# Split the path into directory and filename
dir=${path%/*}
fn=${path##*/}
fn=${fn:-'index'}

if [ ! "$GURI_OUTDIR" ]; then 
   echo 'Sorry, you must set $GURI_OUTDIR first.' >&2
   echo 'For example: export GURI_OUTDIR=~/http' >&2
   exit 1
fi

output=$GURI_OUTDIR/$dir/$fn

if [ -f $output ]; then
   echo "@@ Already downloaded $uri" >&2

   # @@ need to check mtime
   mtime=$(stat -c %Y $output)
   lastmod=$(curl -I -A 'Mozilla/5.0 (guri)' $uri | egrep '^Last-Modified')
   if [ $? != 0 ]; then
      echo "Couldn't get the Last-Modified date." >&2
      exit 1
   fi

   lastmod=$(date -d "${lastmod#*: }" +%s)
   if [ $? != 0 ]; then exit 1; fi

   echo Last-Modified: $lastmod
   if (("$lastmod" < "$mtime" )); then
      echo "Local file is more recent! Strange." >&2
   elif (("$lastmod" > "$mtime")); then
      echo "Remote file is more recent. @@ Offer update." >&2
   else
      echo "File modification time hasn't changed anyway." >&2
   fi
   exit 1
fi

if [ ! -d $GURI_OUTDIR/$dir ]; then
   mkdir -p $GURI_OUTDIR/$dir
fi

echo "Downloading using curl..." >&2
curl -R -A 'Mozilla/5.0 (guri)' -o $output $uri
echo $output