#!/bin/bash
board=$(echo "$1" | grep -o '\.org/[^/]*' | grep -o '[^/]*$')
curl -sL "$1" | grep -oE '"no":[0-9]*(,"[^"]*":([0-9]*|"([^\"]|\\.)*"))*' | grep '"ext":".png"' | while read line; do
  no=$(   echo "$line" | grep -o '"no":[0-9]*'    | grep -o '[0-9]*')
  resto=$(echo "$line" | grep -o '"resto":[0-9]*' | grep -o '[0-9]*')
  tim=$(  echo "$line" | grep -o '"tim":[0-9]*'   | grep -o '[0-9]*')
  post="http://boards.4chan.org/$board/thread/$((resto ? resto : no))#p$no"
  file="http://i.4cdn.org/$board/$tim.png"
  type=$(curl -s -H 'Range:bytes=25-25' "$file")
  if [ "$type" = $'\003' ] || [ "$type" = $'\006' ]; then
    tmp=$(mktemp)
    curl -s "$url" > "$tmp"
    x=$(convert "$file" png32:- | wc -c)
    y=$(convert "$file" -alpha background png32:- | wc -c)
    echo $((x ? (x-y)*1000/x : 0)) "$post" "$file"
    rm "$tmp"
  fi
done