#!/usr/bin/env bash

# Install `mold` official binaries from GitHub Releases.
#
# Adapted from the official rui314/setup-mold@v1 action to:
# * use environment variables instead of action inputs
# * remove make-default support
# * use curl instead of wget
# * support doas for sudo
# * support redhat systems
# See: https://github.com/rui314/setup-mold/blob/main/action.yml

set -euo pipefail

MOLD_VERSION="2.34.0"

if [ "$(uname -s)" != "Linux" ]; then
    echo "Error: This script is intended for Linux systems only."
    exit 1
elif [ -e /usr/local/bin/mold ]; then
    echo "Warning: existing mold found at /usr/local/bin/mold. Skipping installation."
    exit 0
fi

if [ "$(whoami)" = root ]; then SUDO=; else SUDO="$(command -v sudo || command -v doas || true)"; fi

MOLD_REPO="${MOLD_REPO:-https://github.com/rui314/mold}"
MOLD_URL="${MOLD_URL:-$MOLD_REPO}/releases/download/v$MOLD_VERSION/mold-$MOLD_VERSION-$(uname -m)-linux.tar.gz"

echo "Downloading from $MOLD_URL"
curl -fsSL --output - "$MOLD_URL" \
    | $SUDO tar -C /usr/local --strip-components=1 --no-overwrite-dir -xzf -

# Note this binary depends on the system libatomic.so.1 which is usually
# provided as a dependency of gcc so it should be available on most systems.

cat <<EOF
Mold is installed to /usr/local/bin/mold

To make it your default, add or merge these lines into your ~/.cargo/config.toml:

[target.'cfg(target_os = "linux")']
linker = "clang"
rustflags = ["-C", "link-arg=-fuse-ld=mold"]
EOF
