#!/usr/bin/env bash

set -euo pipefail

usage() {
  echo "$(
    tput bold
    tput setaf 74
  )$0 [-h|--help] [-a|--arch arch] [-p|--platform platform] [--pull] [docker_args --] [args...]$(tput sgr0)

cargo-docker: run a shell in a docker image with cargo set up correctly.

Takes the same args you would pass to cargo.

Without arguments runs an interactive shell.

OPTIONS:

--arch: build for a different arch to the current one ($(uname -m)), e.g. amd64 or arm64
--pull: pull the image before running
--platform: build for a different platform to the current one (linux/$(uname -m)), e.g. linux/amd64 or linux/arm64

EXAMPLES:

\`meta/cargo-docker cargo build\` builds in debug.
\`meta/cargo-docker cargo test --release\` tests in release mode.
\`meta/cargo-docker --arch=amd64\` puts you in a shell in an Intel image.
\`meta/cargo-docker --arch=arm64 -- cargo build\` runs cargo build in an arm64 image
\`meta/cargo-docker --arch=arm64 -it -- cargo build\` runs cargo build in an interactive arm64 image
"
}

main() {
  parse_args "$@"

  : "${arch:="$(uname -m)"}" # returns x86_64/arm64 on Darwin, x86_64/aarch64 on Linux.

  # Convert user-specified arch to docker arch.
  case $arch in
    x86_64 | amd64 | intel | linux/amd64) docker_arch=amd64 rust_arch=x86_64 ;;
    arm64 | aarch64 | arm | linux/arm64) docker_arch=arm64 rust_arch=aarch64 ;;
    *) error "Unknown architecture '$arch'" ;;
  esac
  unset arch

  # Interactive shell means interactive
  if [[ "${#build_args[@]}" == 0 ]]; then
    docker_args+=(-it)
  fi

  image=clux/muslrust:stable

  if [[ -n $pull_image ]]; then
    set -x
    docker pull $image
    { set +x; } 2>/dev/null
  fi

  set -x
  # shellcheck disable=SC2086 # We want tty_flag to expand to nothing if not set.
  # https://docs.rs/cc/latest/cc/#external-configuration-via-environment-variables
  docker run --rm "${docker_args[@]}" \
    --platform="linux/$docker_arch" \
    -e CC=musl-gcc \
    -e AR=ar \
    -e RANLIB=ranlib \
    -e CARGO_BUILD_TARGET="${rust_arch}-unknown-linux-musl" \
    -v "${CARGO_HOME:-$HOME/.cargo}"/registry:/root/.cargo/registry \
    -v "$PWD":/code \
    -v "$HOME"/.netrc:/root/.netrc \
    -w /code \
    "$image" \
    "${build_args[@]}"
}

parse_args() {
  docker_args=()
  build_args=()
  pull_image=

  while [[ $# != 0 ]]; do
    [[ ${1:-} =~ ^(--help|-h)$ ]] && {
      usage
      exit
    }

    [[ ${1:-} =~ ^(--arch|-a)$ ]] && {
      arch=$2
      shift 2
      continue
    }

    [[ ${1:-} =~ ^(--platform|-p)$ ]] && {
      arch=$2
      shift 2
      continue
    }

    [[ ${1:-} =~ ^(--pull)$ ]] && {
      pull_image=true
      shift
      continue
    }

    [[ $1 == "--" ]] && {
      shift
      docker_args=("${build_args[@]}")
      build_args=("${@}")
      shift "$#"
      return
    }

    [[ $# != 0 ]] && {
      build_args+=("$1")
      shift 1
      continue
    }
  done
}

# Usage: exit message [rc]
error() {
  local RED='\033[0;31m' NC='\033[0m'
  echo -e "${RED}Error:${NC} $1"
  exit "${2:-1}"
}

main "$@"

# vim: filetype=bash