#!/usr/bin/env bash
# Install one of my Rust binaries from GitHub.
#
# This was originally written to pull just my Rust binaries, but it
# turns out it can work reasonably well for other projects.  This allows
# me to bypass Homebrew, which is generally nicer.
#
# For my CLI tools written in Rust, I use a GitHub Action [1]
# to compile binaries and add them to a release on GitHub.
#
# These are the "canonical" versions, rather than recompiling on
# each machine and having slightly different versions because I
# was using different checkouts of the code.
#
# This script gets the latest version of a binary from GitHub and
# adds it to my $PATH.
#
# This script isn't meant to be run directly (hence the underscore) --
# I have other scripts that invoke it (e.g. install-vfd), so I can find
# those scripts with autocomplete in my shell, even on a new machine.
#
# TODO: I publish macOS/Windows/Linux binaries, but this script only
# fetches the macOS binary.  In theory, it could detect which OS it's
# running on and pick the right binary.
#
# [1]: https://github.com/taiki-e/upload-rust-binary-action

set -o errexit
set -o nounset

if (( "$#" != 1 ))
then
  echo "Usage: _install-rust-bin <REPO_NAME>"
fi

REPO_NAME="$1"

RELEASES_API_URL="https://api.github.com/repos/$REPO_NAME/releases/latest"

# Fetch the asset URL using the GitHub Releases API [2].
#
# For the purposes of this script, these are the interesting bits of the
# API response that we want to pay attention to:
#
#     {
#       "assets": [
#         {
#           "name": "vfd-x86_64-apple-darwin.tar.gz",
#           "url": "https://api.github.com/repos/alexwlchan/books.alexwlchan.net/releases/assets/64229966",
#           ...
#         },
#         {
#           "name": "vfd-x86_64-pc-windows-msvc.zip",
#           "url": "https://api.github.com/repos/alexwlchan/books.alexwlchan.net/releases/assets/64229889",
#           ...
#         },
#         {
#           "name": "vfd-x86_64-unknown-linux-gnu.tar.gz",
#           "url": "https://api.github.com/repos/alexwlchan/books.alexwlchan.net/releases/assets/64229611",
#           ...
#         }
#       ],
#     }
#
# [2]: https://docs.github.com/en/rest/releases/releases#get-the-latest-release
#
# Note: this will filter out ARM binaries because I'm not running on
# Apple Silicon yet; this will need updating eventually.
#
ASSET_URL=$(curl --silent "$RELEASES_API_URL" \
  | jq -r '.assets | .[] | select(.name | contains("darwin")) | select(.name | contains("arm") | not) | select(.name | contains("aarch64") | not) | .url' \
  | grep -v arm64
)

if [[ "$ASSET_URL" == "" ]]
then
  echo "No macOS download available for the latest version! Is it still building?" >&2
  exit 1
fi

# Download and unpack the asset using the GitHub Release Assets API [3].
#
# We supply the headers required by the GitHub API, and the `--location`
# flag caused curl to follow redirects.
#
# Note: this assumes the binary is packaged as a tar.gz.  The Windows
# binaries are zipped instead of tar.gz-ed, so if you want to support
# Windows, inspect the "content_type" field in the Releases API response.
#
# [3]: https://docs.github.com/en/rest/releases/assets#get-a-release-asset

cd $(mktemp -d)

curl \
  --header "Accept: application/octet-stream" \
  --location \
  --silent \
  "$ASSET_URL" > "asset.tar.gz"

# Identify the name of the binary, which may be different from the repo name.
#
# We list all the files in the asset package, which should contain a single
# file, and assume that's the name of the binary.
ASSET_FILES=$(tar --list --file "asset.tar.gz")

if [[ "$REPO_NAME" == "BurntSushi/ripgrep" ]]
then
  BINARY_PATH=$(echo "$ASSET_FILES" | grep "/rg$")
  BINARY_NAME="rg"
else
  if (( $(echo "$ASSET_FILES" | wc -l) != 1 ))
  then
    echo "Release asset doesn't contain exactly 1 file; not sure what to do:" >&2
    echo "$ASSET_FILES" >&2
    exit 1
  fi

  BINARY_PATH="$(echo "$ASSET_FILES" | head -n 1)"
  BINARY_NAME="$BINARY_PATH"
fi

# Now actually extract the binary, make it executable, and add it to the PATH.
tar --extract --gunzip --file "asset.tar.gz"

chmod +x "$BINARY_PATH"
sudo mv "$BINARY_PATH" /usr/local/bin

which "$BINARY_NAME"
"$BINARY_NAME" --version