#!/bin/bash

#

# Might want to drop this in ~/bin/ and chmod u+x it

#

#  Initial Author: Karanbir Singh <kbsingh@centos.org>

#         Updates:

#                  Mike McLean <mikem@redhat.com>

#                  Pat Riehecky <riehecky@fnal.gov>

#                  Tyler Parsons <tparsons@fnal.gov>

#                  Tuomo Soini <tis@foobar.fi>

#####################################################################

usage() {

    echo ''                                               >&2

    echo "$0 [-hcq] [-b branch] [--surl url]"             >&2

    echo ''                                               >&2

    echo 'Script to parse the non-text sources metadata file'   >&2

    echo ' and download the required files from the lookaside'  >&2

    echo ' cache.'                                              >&2

    echo ''                                                     >&2

    echo 'PLEASE NOTE: this script is non-destructive, it wont' >&2

    echo ' replace files that already exist, regardless of'     >&2

    echo ' their state, allowing you to have work-in-progress'  >&2

    echo ' content that wont get overwritten.'                  >&2

    echo ''                                                     >&2

    echo 'You need to run this from inside a sources git repo'  >&2

    echo ''                                               >&2

    echo ' -h: This help message'                         >&2

    echo ''                                               >&2

    echo "  $0 -b c7"                                     >&2

    echo "  $0 -q -b c7"                                  >&2

    echo "  $0 -c -b remotes/origin/c7"                   >&2

    echo "  $0 -c -b c7 --surl '$SURL'"                   >&2

    echo "  $0"                                           >&2

    exit 1

}

#####################################################################

SURL="https://git.centos.org/sources"

QUIET=0

BRANCH=''

CHECK=0

# for setting any overrides, such as SURL, default BRANCH, or force CHECK

if [ -f /etc/centos-git-common ]; then

  . /etc/centos-git-common

fi

#####################################################################

# setup args in the right order for making getopt evaluation

# nice and easy.  You'll need to read the manpages for more info

# utilizing 'while' construct rather than 'for arg' to avoid unnecessary

# shifting of program args

args=$(getopt -o hcqb: -l surl: -- "$@")

eval set -- "$args"

while [[ 0 -eq 0 ]]; do

    case $1 in

        -- )

            # end of getopt args, shift off the -- and get out of the loop

            shift

            break

           ;;

         -c )

            # verify the sha1sum of the downloaded file

            CHECK=1

            shift

           ;;

         -q )

            # suppress warnings

            QUIET=1

            shift

           ;;

         -b )

            # Check this particular branch 

            BRANCH=$2

            shift

            shift

           ;;

         --surl )

            # override sources url

            SURL=$2

            shift

            shift

           ;;

         -h )

            # get help

            usage

           ;;

    esac

done

# set curl options this way so defaults can be set in /etc/centos-git-common

# across multiple scripts

if [[ ${QUIET} -eq 1 ]]; then

    QUIET='--silent'

else

    QUIET=''

fi

which git >/dev/null 2>&1

if [[ $? -ne 0 ]]; then

    echo 'You need git in PATH' >&2

    exit 1

fi

which curl >/dev/null 2>&1

if [[ $? -ne 0 ]]; then

    echo 'You need curl in PATH' >&2

    exit 1

fi

# should go into a function section at some point

weakHashDetection () {

  strHash=${1};

  case $((`echo ${strHash}|wc -m` - 1 )) in

    128)

      hashBin='sha512sum'

      ;;

    64)

      hashBin='sha256sum'

      ;;

    40)

      hashBin='sha1sum'

      ;;

    32)

      hashBin='md5sum'

      ;;

    *)

      hashBin='unknown'

      ;;

  esac

  echo ${hashBin};

}

# check metadata file and extract package name

shopt -s nullglob

set -- .*.metadata

if (( $# == 0 ))

then

    echo 'Missing metadata. Please run from inside a sources git repo' >&2

    exit 1

elif (( $# > 1 ))

then

    echo "Warning: multiple metadata files found. Using $1"

fi

meta=$1

pn=${meta%.metadata}

pn=${pn#.}

if [ ! -d .git ] || [ ! -d SPECS ]; then

  echo 'You need to run this from inside a sources git repo' >&2

  exit 1

fi

mkdir -p SOURCES

# sort out our branch

if [ -n "$BRANCH" ]

then

  branches=("$BRANCH")

else

  # generate a list of all branches containing current HEAD

  branches=()

  while IFS='' read -r line

  do

    # input from: git branch --contains HEAD

    branch="${line:2}"

    if [[ "$branch" =~ "detached from" ]]

    then

      # ignore detached heads

      continue

    fi

    if [ ".${line:0:1}" = ".*" ]

    then

      # current branch, put it first

      branches=("$branch" "${branches[@]}")

    else

      branches=("${branches[@]}" "$branch")

    fi

  done <<< "$(git branch --contains HEAD)"

fi

while read -r fsha fname ; do

  if [ ".${fsha}" = ".da39a3ee5e6b4b0d3255bfef95601890afd80709" ]; then

    # zero byte file

    touch ${fname}

  else

    if [ ${CHECK} -eq 1 ]; then

      hashType=$(weakHashDetection ${fsha})

      if [ "${hashType}" == "unknown" ]; then

        echo 'Failure: Hash type unknown.' >&2

        exit 1;

      else

        which ${hashType} >/dev/null 2>&1

        if [[ $? -ne 0 ]]; then

          echo "Failure: You need ${hashType} in PATH." >&2

          exit 1;

        fi

      fi

    fi

    if [ -e ${fname} -a ${CHECK} -eq 1 ]; then

	# check hash sum and force download if wrong

        downsum=$(${hashType} ${fname} | awk '{print $1}')

        if [ "${fsha}" != "${downsum}" ]; then

            rm -f ${fname}

        fi

    fi

    if [ ! -e "${fname}" ]; then

      for br in "${branches[@]}"

      do

        br=$(echo ${br}| sed -e s'|remotes/origin/||')

        url="${SURL}/${pn}/${br}/${fsha}"

        echo "Retrieving ${url}"

        curl -L ${QUIET} -f "${url}" -o "${fname}" && break

      done

    else

      echo "${fname} exists. skipping"

    fi

    if [ ${CHECK} -eq 1 ]; then

        downsum=$(${hashType} ${fname} | awk '{print $1}')

        if [ "${fsha}" != "${downsum}" ]; then

            rm -f ${fname}

            echo "Failure: ${fname} hash does not match hash from the .metadata file" >&2

            exit 1;

        fi

    fi

  fi

done < "${meta}"