#!/usr/bin/env bash

set -Eeuo pipefail

function unapply_patches() {
  local -i exit_code=0
  quiet quilt pop -af 2>&1 || exit_code=$?
  case $exit_code in
    # Sucessfully unapplied.
    0) ;;
    # No more patches to unapply.
    2) ;;
    # Some error.
    *) return $exit_code ;;
  esac
}

function apply_patches() {
  local -i exit_code=0
  quiet quilt push -a 2>&1 || exit_code=$?
  case $exit_code in
    # Sucessfully applied.
    0) ;;
    # No more patches to apply.
    2) ;;
    # Some error.
    *) return $exit_code ;;
  esac
}

function update_vscode() {
  pushd lib/vscode
  if ! git checkout 2>&1 "$target_vscode_version" ; then
    echo "$target_vscode_version does not exist locally, fetching..."
    git fetch --all --prune --tags
    echo "Checking out $target_vscode_version again..."
    git checkout "$target_vscode_version"
  fi
  popd
}

function refresh_patches() {
  local -i exit_code=0
  while quiet quilt push 2>&1 ; ! (( exit_code=$? )) ; do
    quilt refresh 2>&1
  done
  case $exit_code in
    # No more patches to apply.
    2) ;;
    # Some error.
    *) return $exit_code ;;
  esac
}

function update_node() {
  local node_version
  node_version=$(cat .node-version)
  local target_node_version
  target_node_version=$(grep target lib/vscode/remote/.npmrc | awk -F= '{print $2}' | tr -d '"')
  if [[ $node_version == "$target_node_version" ]] ; then
    echo "Already set to $target_node_version"
  else
    echo "Updating from $node_version to $target_node_version..."
    echo "$target_node_version" > .node-version
  fi
}

function get-webview-script-hash() {
  local html
  html=$(<"$1")
  local start_tag='<script async type="module">'
  if [[ $file == */webWorkerExtensionHostIframe.html ]] ; then
    start_tag='<script>'
  fi
  local end_tag="</script>"
  html=${html##*"$start_tag"}
  html=${html%%"$end_tag"*}
  echo -n "$html" | openssl sha256 -binary | openssl base64
}

function delete_csp() {
  quilt delete csp-hashes.diff
}

function update_csp() {
  apply_patches

  local files=(
    ./lib/vscode/src/vs/workbench/contrib/webview/browser/pre/index.html
    ./lib/vscode/src/vs/workbench/services/extensions/worker/webWorkerExtensionHostIframe.html
  )

  quilt new csp-hashes.diff

  local file
  for file in "${files[@]}" ; do
    quilt add "$file"

    local hash
    hash=$(get-webview-script-hash "$file")
    echo "Calculated hash as $hash"
    # Use octothorpe as a delimiter since the hash may contain a slash.
    sed -i.bak "s#'sha256-[^']\+'#'sha256-$hash'#" "$file"
  done

  quilt refresh
}

function add_changelog() {
  local file=CHANGELOG.md
  if grep --quiet "Code $target_vscode_version" "$file" ; then
    echo "Changelog for $target_vscode_version already exists"
  else
    # TODO: This is not exactly robust.  In particular, it needs to handle if
    # there is already a "changed" section.
    sed -i.bak "s/## Unreleased/## Unreleased\n\nCode v$target_vscode_version\n\n### Changed\n\n- Update to Code $target_vscode_version/" "$file"
  fi
}

function main() {
  cd "$(dirname "${0}")/../.."

  source ./ci/lib.sh

  declare -a steps

  # Hashes are always regenerated to avoid having to resolve conflicts..
  steps+=("Revert CSP hashes" "delete_csp")

  # If version is not set, assume we are already at the target version and the
  # user is just trying to resolve conflics.
  local target_vscode_version
  if [[ ${VERSION-} ]] ; then
    # Removing patches only needs to be done locally; in CI we start from a
    # fresh clone each time.
    if [[ ! ${CI-} ]] ; then
      steps+=("Unapplying patches" "unapply_patches")
    fi
    target_vscode_version="${VERSION#v}"
    steps+=(
      "Update Code to $target_vscode_version" "update_vscode"
      "Refresh Code patches" "refresh_patches"
    )
  else
    target_vscode_version="$(git -C lib/vscode describe --tags --exact-match)"
    echo "Detected Code version $target_vscode_version"
  fi

  steps+=(
    "Update Node version" "update_node"
    "Regenerate CSP hashes" "update_csp"
    "Add changelog note" "add_changelog"
  )

  # Even if a step failed, still output the last checkmark.
  run-steps "${steps[@]}" || true

  # This step is always manual.
  echo "- [ ] Verify changelog" >> .cache/checklist
}

main "$@"