#!/usr/bin/env nix-shell
#! nix-shell -I nixpkgs=../../../../.. -i bash -p coreutils curl jq moreutils nix nix-prefetch
# shellcheck shell=bash
# vim: ft=sh
#
# Update a terraform provider to the latest version advertised at the
# provider source address.
#
set -euo pipefail
shopt -s inherit_errexit

show_usage() {
  cat <<DOC
Usage: ./update-provider [--force] [--vendor] [<owner>/]<provider>

Update a single provider in the providers.json inventory file.

For example to update 'terraform-providers.aws' run:

    ./update-provider aws

If the provider is not in the list already, use the form '<owner>/<provider>'
to add the provider to the list:

    ./update-provider hetznercloud/hcloud

Options:

  * --force: Force the update even if the version matches.
  * --vendor: Switch from go package to go modules with vendor.
  * --vendor-sha256 <sha256>: Override the SHA256 or "null".
DOC
}

force=
provider=
vendor=
vendorSha256=

while [[ $# -gt 0 ]]; do
  case "$1" in
  -h | --help)
    show_usage
    exit
    ;;
  --force)
    force=1
    shift
    ;;
  --vendor)
    force=1
    vendor=1
    shift
    ;;
  --vendor-sha256)
    force=1
    vendorSha256=$2
    shift 2
    ;;
  *)
    if [[ -n ${provider} ]]; then
      echo "ERROR: provider name was passed two times: '${provider}' and '$1'"
      echo "Use --help for more info"
      exit 1
    fi
    provider=$1
    shift
    ;;
  esac
done

if [[ -z ${provider} ]]; then
  echo "ERROR: No providers specified!"
  echo
  show_usage
  exit 1
fi

provider_name=$(basename "${provider}")

# Usage: read_attr <key>
read_attr() {
  jq -r ".\"${provider_name}\".\"$1\"" providers.json
}

# Usage: update_attr <key> <value>
update_attr() {
  if [[ $2 == "null" ]]; then
    jq -S ".\"${provider_name}\".\"$1\" = null" providers.json | sponge providers.json
  else
    jq -S ".\"${provider_name}\".\"$1\" = \"$2\"" providers.json | sponge providers.json
  fi
}

prefetch_github() {
  # of a given owner, repo and rev, fetch the tarball and return the output of
  # `nix-prefetch-url`
  local owner=$1
  local repo=$2
  local rev=$3
  nix-prefetch-url --unpack "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz"
}

old_source_address="$(read_attr provider-source-address)"
old_vendor_sha256=$(read_attr vendorSha256)
old_version=$(read_attr version)

if [[ ${provider} =~ ^[^/]+/[^/]+$ ]]; then
  source_address=registry.terraform.io/${provider}
else
  source_address=${old_source_address}
fi
if [[ ${source_address} == "null" ]]; then
  echo "Could not find the source address for provider: ${provider}"
  exit 1
fi
update_attr "provider-source-address" "${source_address}"

# The provider source address (used inside Terraform `required_providers` block) is
# used to compute the registry API endpoint
#
# registry.terraform.io/hashicorp/aws (provider source address)
# registry.terraform.io/providers/hashicorp/aws (provider URL for the website)
# registry.terraform.io/v1/providers/hashicorp/aws (provider URL for the JSON API)
registry_response=$(curl -s https://"${source_address/\///v1/providers/}")

version="$(jq -r '.version' <<<"${registry_response}")"
if [[ ${old_version} == "${version}" && ${force} != 1 && -z ${vendorSha256} && ${old_vendor_sha256} != "${vendorSha256}" ]]; then
  echo "${provider_name} is already at version ${version}"
  exit
fi
update_attr version "${version}"

provider_source_url="$(jq -r '.source' <<<"${registry_response}")"

org="$(echo "${provider_source_url}" | cut -d '/' -f 4)"
update_attr owner "${org}"
repo="$(echo "${provider_source_url}" | cut -d '/' -f 5)"
update_attr repo "${repo}"
rev="$(jq -r '.tag' <<<"${registry_response}")"
update_attr rev "${rev}"
sha256=$(prefetch_github "${org}" "${repo}" "${rev}")
update_attr sha256 "${sha256}"

repo_root=$(git rev-parse --show-toplevel)

if [[ -z ${vendorSha256} ]]; then
  if [[ ${old_vendor_sha256} == null ]]; then
    vendorSha256=null
  elif [[ -n ${old_vendor_sha256} || ${vendor} == 1 ]]; then
    echo "=== Calculating vendorSha256 ==="
    vendorSha256=$(nix-prefetch "{ sha256 }: (import ../../../../.. {}).terraform-providers.${provider_name}.go-modules.overrideAttrs (_: { vendorSha256 = sha256; })")
    # Deal with nix unstable
    if [[ ${vendorSha256} == sha256-* ]]; then
      vendorSha256=$(nix --extra-experimental-features nix-command hash to-base32 "${vendorSha256}")
    fi
  fi
fi

if [[ -n ${vendorSha256} ]]; then
  update_attr vendorSha256 "${vendorSha256}"
fi

# Check that the provider builds
echo "=== Building terraform-providers.${provider_name} ==="
nix-build --no-out-link "${repo_root}" -A "terraform-providers.${provider_name}"