#!/bin/bash

GEOFABRICK_SERVER=http://download.geofabrik.de/asia/taiwan-updates
PBF_FILE=$1

# get latest sequence number
echo Fetching latest sequence number
LATEST_SEQ=$(curl --silent http://download.geofabrik.de/asia/taiwan-updates/state.txt |\
             tail -1 | cut -d'=' -f2)

# get current sequence number
SEQ=$(osmium fileinfo $PBF_FILE |\
      grep osmosis_replication_sequence_number |\
      cut -d'=' -f2)

# while server has osc file with given sequence number,
# get it and do file update
while
    (( SEQ++ ))
    [ $SEQ -le $LATEST_SEQ ]
do
    mkdir -p changes
    CHANGE_URL=$GEOFABRICK_SERVER/000/$SEQ_PATH.osc.gz
    echo $CHANGE_URL
    curl -o changes/$SEQ.osc.gz $CHANGE_URL && \
    osmium apply-changes $PBF_FILE changes/$SEQ.osc.gz \
        --output-header=osmosis_replication_sequence_number=$SEQ \
        --overwrite \
        --output $SEQ.osm.pbf

    mv $PBF_FILE $((SEQ-1)).osm.pbf
    mv $SEQ.osm.pbf $PBF_FILE
done

echo
echo File sequence number is $((SEQ-1)), already the latest one on Geofrbrik