#!/usr/bin/env bash
# author: joe.zheng
# version: 24.07.11

set -e

SELF="$(basename $0)"
SELF_VERSION="$(sed -n '1,4s/# version: \(.*\)/\1/p' $0)"

SUDO=""
if [[ $(id -u) != "0" ]]; then
  SUDO="sudo"
fi

DIR_CHARTS="${DIR_CHARTS:-$(dirname $0)/charts}"
NO_CLOBBER="${NO_CLOBBER:-n}"

USE_MIRROR="${USE_MIRROR:-n}"
MIRROR_URL="${MIRROR_URL:-https://ghps.cc}"

SVC_NAME="${SVC_NAME:-$SELF}" # container name
SVC_PORT="${SVC_PORT:-9080}"  # port number

function usage() {
  cat <<EOF
Usage: $SELF [command] [args]
  Mirror and serve Helm charts

Commands:
  list <repo>      list all the charts in the repository
  pull [<url>...]  pull the charts, read from stdin if no url
  serve            serve the local Helm charts

Environment variables:
  DRY_RUN:     print out information only if it is "y"
  DIR_CHARTS:  dir to save charts or load from, default: $DIR_CHARTS
  NO_CLOBBER:  do not overwrite existing files, default: $NO_CLOBBER
  USE_MIRROR:  use mirror to pull chart or not, default: $USE_MIRROR
  MIRROR_URL:  mirror to speedup chart pulling, default: $MIRROR_URL
  SVC_NAME:    container name to use: default: $SVC_NAME
  SVC_PORT:    port number to listen: default: $SVC_PORT

Examples:

  1. List and pull Helm charts
    $SELF list https://helm.releases.hashicorp.com | $SELF pull

  2. Start web server to serve local repo
    $SELF serve

  3. Use the local repo
    $SELF list http://localhost:$SVC_PORT
    helm repo add local http://localhost:$SVC_PORT
    helm repo update
    helm search repo local

Version: $SELF_VERSION
EOF
}

function msg {
  echo "> $@"
}

function err {
  echo "> $@" >&2
}

function list_chart_url {
  curl -sL "$1/index.yaml" \
  | perl -ne 'if (/^(\s+)urls:/../$1\s*-\s+/) { s/^\s+(?:urls:|-)\s*//; print if $_ }' \
  | sort
}

function pull_chart {
  url="$1"
  if [[ "$USE_MIRROR" == 'y' ]]; then
    url="$MIRROR_URL/$url"
  fi
  msg "pulling $url"
  file="${url##*/}"
  msg "saving $file"

  if [[ "$NO_CLOBBER" == 'y' ]]; then
    if [[ -e "$file" ]]; then
      msg "file exists, skip"
      return
    fi
  fi
  if [[ "$DRY_RUN" != 'y' ]]; then
    wget -q -c $url
  fi
}

if [[ -z "$1" || "$1" == "-h" ]]; then
  usage && exit
else
  cmd="$1"
  shift
fi

mkdir -p $DIR_CHARTS

if [[ "$cmd" == "list" ]]; then
  if [[ -z "$1" ]]; then
    err "no repository is provided"
    exit 1
  fi
  list_chart_url "$1" && exit
elif [[ "$cmd" == "pull" ]]; then
  if [[ -t 0 ]]; then
    # pass args into stdin
    exec < <(printf '%s\n' "$@")
  fi
  while IFS= read -r url; do
    if [[ "$url" != *.tgz ]]; then
      msg "ingore $url" && continue
    fi
    msg "processing $url"
    (cd $DIR_CHARTS && pull_chart "$url")
  done
elif [[ "$cmd" == "serve" ]]; then
  if $SUDO docker container inspect -f '{{.ID}}' $SVC_NAME >/dev/null; then
    msg "stop and delete the old container: $SVC_NAME"
    $SUDO docker rm -f $SVC_NAME
  fi
  msg "clean the index cache"
  rm -f $DIR_CHARTS/index-cache.yaml
  msg "create container $SVC_NAME"
  $SUDO docker create --name $SVC_NAME \
    -v $(cd $DIR_CHARTS && pwd):/charts \
    -p $SVC_PORT:8080 --restart unless-stopped \
    -e STORAGE=local -e STORAGE_LOCAL_ROOTDIR=/charts \
    chartmuseum/chartmuseum:edge
  msg "start container $SVC_NAME"
  $SUDO docker start $SVC_NAME
  cat <<EOF
# now you can try to list all the charts in local repo by cmd:
  $SELF list http://localhost:$SVC_PORT
EOF
else
  err "not supported cmd: $cmd"
  exit 1
fi

msg "done"