#!/bin/bash

set -e
set -u

APPSH_HOME=$(cd $(dirname "$0")/.. && pwd)

. $APPSH_HOME/lib/common
# HEADER END

usage_text() {
  echo "usage: $usage_app init -r <repo> <maven url>"
  echo "usage: $usage_app resolve-version"
  echo "usage: $usage_app download-version -v <version> -f <download target>"
}

slash() {
  echo $1 | sed "s,\.,/,g"
}

# TODO: support file:// repositories
# TODO: look in the local repository first
get() {
  local url=$1; shift
  local file=$1; shift

  if [[ $url == file://* ]]
  then
    get_file "$url" "$file"
  else
    get_http "$url" "$file"
  fi
}

get_file() {
  url=${1:7}

  cp "$url" "$2"
}

get_http() {
  curl -o $file $url -D curl.tmp

  exit=`grep "^HTTP/[0-9]\.[0-9] 200 .*" curl.tmp >/dev/null; echo $?`
  head=`head -n 1 curl.tmp`
  rm -f curl.tmp
  if [ "$exit" != 0 ]
  then
    echo "Unable to download $url: $head" >&2
    exit 1
  fi
}

download_artifact() {
  local file="$1"; shift
  local url="$1"; shift

  echo "Downloading $url.md5"
  get $url.md5 $file.md5
  local expected_md5="`cat $file.md5`"

  if [ -r $file ]
  then
    if [ "$expected_md5" == "`calculate_md5 $file`" ]
    then
      echo "Artifact already downloaded."
    else
      rm -f "$file"
    fi
    return 0
  fi
  echo "Downloading artifact: $url"
  get $url $file

  local actual_md5="`calculate_md5 $file`"
  if [ "$expected_md5" == "$actual_md5" ]
  then
    echo "Artifact downloaded."
  else
    echo "Invalid checksum. Expected $expected_md5, got $actual_md5" >&2
    exit 1
  fi
}

resolve_version() {
  local group_id=`app-conf get maven.group_id`
  local artifact_id=`app-conf get maven.artifact_id`
  local version=`app-conf get maven.version`

  repo=`app-conf get maven.repo`

  if [[ ! $version == *-SNAPSHOT ]]
  then
    app-conf set app.resolved_version "$version"
    exit 0
  fi

  echo "Resolving version $version..."
  resolve_snapshot $group_id $artifact_id $version
}

resolve_snapshot() {
  local group_id=$1; shift
  local artifact_id=$1; shift
  local version=$1; shift

  repo=`app-conf get maven.repo`

  local group_id_slash=`slash $group_id`

  local base_path=$group_id_slash/$artifact_id/$version

  mkdir -p .app/cache/$base_path

  local l=.app/cache/$base_path/maven-metadata.xml
  local r=$repo/$base_path/maven-metadata.xml

  get $r $l
  x=$(xmlstarlet sel -t -m '/metadata/versioning/snapshot' -v timestamp -o ' ' -v buildNumber $l)
  set -- $x

  if [[ $# != 2 ]]
  then
    fatal "Unable extract a useful timestamp from maven-metadata.xml."
  fi

  snapshot_version="$1-$2"

  if [[ $snapshot_version == "" ]]
  then
    echo "Unable to resolve SNAPSHOT version for $group_id:$artifact_id:$version"
    exit 1
  fi

  app-conf set maven.snapshotVersion "$snapshot_version"
  app-conf set app.resolved_version "${version%-SNAPSHOT}-$snapshot_version"
}

download_version() {
  resolved_version=""
  target=""
  while getopts "v:f:" opt
  do
    case $opt in
      v)
        resolved_version="$OPTARG"
        ;;
      f)
        target="$OPTARG"
        ;;
      *)
        usage "Invalid option: $OPTARG" 
        ;;
    esac
  done

  if [[ $resolved_version == "" || $target == "" ]]
  then
    usage
  fi

  repo=`app-conf get maven.repo`
  group_id=`app-conf get maven.group_id`
  artifact_id=`app-conf get maven.artifact_id`
  version=`app-conf get maven.version`

  group_id_slash=`slash $group_id`
  base_path=$group_id_slash/$artifact_id/$version

  mkdir -p .app/cache/$base_path

  l=.app/cache/$base_path/$artifact_id-$resolved_version.zip
  r=$repo/$base_path/$artifact_id-$resolved_version.zip

  echo "Downloading $group_id:$artifact_id:$resolved_version..."
  get $r $l

  ln -s "`pwd`/$l" "$target"
}

init() {
  while getopts "r:" opt
  do
    case $opt in
      r)
        app-conf set maven.repo "$OPTARG"
        shift 2
        OPTIND=1
        ;;
      *)
        usage "Invalid option: $OPTARG" 
        ;;
    esac
  done

  local coordinates=${1-}
  x=${coordinates}
  x=${x//:/ }
  set -- $x

  if [[ $# != 3 || $1 == "" || $2 == "" || $3 == "" ]]
  then
    usage "Invalid Maven coordinates: $coordinates"
  fi

  group_id=$1
  artifact_id=$2
  version=$3

  app-conf set maven.group_id "$group_id"
  app-conf set maven.artifact_id "$artifact_id"
  app-conf set maven.version "$version"
}

command="$1"; shift

case "$command" in
  init)
    init "$@"
    ;;
  resolve-version)
    resolve_version
    ;;
  download-version)
    download_version "$@"
    ;;
  *)
    usage
    ;;
esac

exit 0