#!/usr/bin/env nix-shell
#! nix-shell -i bash -p coreutils curl jq
# shellcheck shell=bash
#
# Update a terraform provider to the latest version advertised at
# the provider source address.
set -euo pipefail

USAGE=$(cat<<DOC
Specify the terraform provider name to update.

Example:
To update nixpkgs.terraform-providers.aws run:
./update-provider aws
DOC
)

provider_name="${1:-}"
if [ -z "$provider_name" ]; then
  echo "No providers specified!"
  echo
  echo "$USAGE"
  exit 1
fi

provider_source_address="$(jq -r ".$provider_name.\"provider-source-address\"" providers.json)"

if [ "$provider_source_address" == "null" ]; then
  echo "No provider source address specified with provider: $provider_name"
  exit 1
fi

# 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=$(curl -s https://"${provider_source_address/\///v1/providers/}")

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"
}

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

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

sha256=$(prefetch_github "$org" "$repo" "$rev")

version="$(jq -r '.version' <<< "$registry_response")"

updated_provider="$(mktemp)"
cat <<EOF >> "$updated_provider"
{
  "$provider_name": {
    "owner": "$org",
    "repo": "$repo",
    "rev": "$rev",
    "sha256": "$sha256",
    "version": "$version",
    "provider-source-address": "$provider_source_address"
  }
}
EOF

original_provider_list="$(mktemp)"
cat providers.json > "$original_provider_list"

jq --sort-keys --slurp '.[0] * .[1]' "$original_provider_list" "$updated_provider" > providers.json