#!/usr/bin/env bash

# Enumerates the list of expected downloadable files, loads the SHAs for each file, then
# dumps the result to //rust:known_shas.bzl

export LC_ALL=C

# Detect workspace root
if [[ -z "${BUILD_WORKSPACE_DIRECTORY}" ]]; then
    SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
    BUILD_WORKSPACE_DIRECTORY="$( dirname "${SCRIPT_DIR}")"
fi

TOOLS="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_TOOLS.txt")"
HOST_TOOLS="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_HOST_TOOLS.txt")"
TARGETS="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_TARGETS.txt")"
VERSIONS="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_VERSIONS.txt")"
BETA_ISO_DATES="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_BETA_ISO_DATES.txt")"
NIGHTLY_ISO_DATES="$(cat "${BUILD_WORKSPACE_DIRECTORY}/util/fetch_shas_NIGHTLY_ISO_DATES.txt")"

EXTENSIONS=(
   tar.gz
   tar.xz
)

function enumerate_keys() {
  for TOOL in $TOOLS
  do
    for TARGET in $TARGETS
    do
      for VERSION in $VERSIONS
      do
        echo "$TOOL-$VERSION-$TARGET"
      done

      for ISO_DATE in $BETA_ISO_DATES
      do
        echo "$ISO_DATE/$TOOL-beta-$TARGET"
      done

      for ISO_DATE in $NIGHTLY_ISO_DATES
      do
        echo "$ISO_DATE/$TOOL-nightly-$TARGET"
      done
    done
  done

  for HOST_TOOL in $HOST_TOOLS
  do
    for VERSION in $VERSIONS
    do
      echo "$HOST_TOOL-$VERSION"
    done
  done
}

function emit_bzl_file_contents() {
  local out_dir="${TMPDIR}/outs"
  mkdir "${out_dir}"

  echo "--parallel" >> "${TMPDIR}/curl_config"
  echo "--fail" >> "${TMPDIR}/curl_config"
  echo "--silent" >> "${TMPDIR}/curl_config"
  echo "--create-dirs" >> "${TMPDIR}/curl_config"
  for key in "$@"; do
    for ext in "${EXTENSIONS[@]}"; do
      echo "--output ${out_dir}/${key}.${ext}" >> "${TMPDIR}/curl_config"
      echo "--url https://static.rust-lang.org/dist/${key}.${ext}.sha256" >> "${TMPDIR}/curl_config"
    done
  done
  curl --config "${TMPDIR}/curl_config"

  pushd "${out_dir}" > /dev/null
  for file in $(find . -type f)
  do
    echo "$(echo ${file} | sed 's|./||') $(cat ${file} | awk '{ print $1 }')" >> "${TMPDIR}/shas.txt"
  done
  
  popd > /dev/null

  echo "\"\"\"A module containing a mapping of Rust tools to checksums"
  echo ""
  echo "This is a generated file -- see //util:fetch_shas"
  echo "\"\"\""
  echo ""
  echo "FILE_KEY_TO_SHA = {"
  cat "${TMPDIR}/shas.txt" | sed '/^[[:space:]]*$/d' | sort | awk '{print "    \"" $1 "\": \"" $2 "\","}'
  echo "}"
}

export TMPDIR="$(mktemp -d -t bazel_reload_shas_shalists.XXXXXXXXXX)"
echo "Fetching known shas..."
echo "$(emit_bzl_file_contents $(enumerate_keys))" > "${BUILD_WORKSPACE_DIRECTORY}/rust/known_shas.bzl"
echo "Done"
rm -rf "${TMPDIR}"