scripts/install_unity_mcp.sh

#!/usr/bin/env bash

set -euo pipefail

SCRIPT_NAME="$(basename "$0")"

RED="\033[31m"
YELLOW="\033[33m"
BLUE="\033[34m"
RESET="\033[0m"

info() {
	printf "%b[%s]%b %s\n" "$BLUE" "$SCRIPT_NAME" "$RESET" "$*"
}

warn() {
	printf "%b[%s]%b %s\n" "$YELLOW" "$SCRIPT_NAME" "$RESET" "$*" >&2
}

error() {
	printf "%b[%s]%b %s\n" "$RED" "$SCRIPT_NAME" "$RESET" "$*" >&2
}

require_command() {
	local cmd="$1"
	local package_hint="${2:-}"

	if ! command -v "$cmd" >/dev/null 2>&1; then
		if [[ -n "$package_hint" ]]; then
			error "Missing command '$cmd'. Try installing the package: $package_hint"
		else
			error "Missing command '$cmd'."
		fi
		exit 1
	fi
}

ensure_pacman_packages() {
	local packages=("python" "git" "curl" "jq" "code")
	local missing=()
	for pkg in "${packages[@]}"; do
		if ! pacman -Qi "$pkg" >/dev/null 2>&1; then
			missing+=("$pkg")
		fi
	done

	if (( ${#missing[@]} > 0 )); then
		info "Installing required packages with pacman: ${missing[*]}"
		sudo pacman -S --needed --noconfirm "${missing[@]}"
	else
		info "All required pacman packages are already installed."
	fi
}

install_uv() {
	if command -v uv >/dev/null 2>&1; then
		info "uv is already installed."
		return
	fi

	info "Installing uv toolchain manager via official installer."
	curl -LsSf https://astral.sh/uv/install.sh | sh

	local local_bin="$HOME/.local/bin"
	if [[ ":$PATH:" != *":$local_bin:"* ]]; then
		warn "Adding $local_bin to PATH in ~/.profile and ~/.zshrc. Open a new shell to apply."
		printf '\nexport PATH="$HOME/.local/bin:$PATH"\n' >> "$HOME/.profile"
		printf '\nexport PATH="$HOME/.local/bin:$PATH"\n' >> "$HOME/.zshrc"
	fi
}

ensure_unity_hub() {
	if command -v unityhub >/dev/null 2>&1; then
		info "Unity Hub already installed."
		return
	fi

	if command -v yay >/dev/null 2>&1; then
		info "Installing Unity Hub from AUR using yay."
		yay -S --needed --noconfirm unityhub
	elif command -v flatpak >/dev/null 2>&1; then
		warn "Unity Hub not found. Attempting Flatpak installation." 
		flatpak install -y com.unity.UnityHub || warn "Flatpak installation failed. Install Unity Hub manually via https://unity.com/download"
	else
		warn "Unity Hub not found and neither yay nor flatpak is available. Install Unity Hub manually from https://unity.com/download."
	fi
}

sync_unity_mcp_repo() {
	local data_home="${XDG_DATA_HOME:-$HOME/.local/share}"
	local unity_mcp_root="$data_home/UnityMCP"
	local repo_dir="$unity_mcp_root/unity-mcp-repo"
	local server_link="$unity_mcp_root/UnityMcpServer"
	local candidates=(
		"UnityMcpServer"
		"UnityMcpBridge/UnityMcpServer"
		"UnityMcpBridge/UnityMcpServer~"
	)
	local server_subdir=""

	mkdir -p "$unity_mcp_root"

	if [[ -d "$repo_dir/.git" ]]; then
		info "Updating existing unity-mcp repository."
		git -C "$repo_dir" pull --ff-only
	else
		info "Cloning unity-mcp repository."
		rm -rf "$repo_dir"
		git clone --depth=1 https://github.com/CoplayDev/unity-mcp.git "$repo_dir"
	fi

	for candidate in "${candidates[@]}"; do
		if [[ -d "$repo_dir/$candidate/src" ]]; then
			server_subdir="$candidate"
			break
		fi
	done

	if [[ -z "$server_subdir" ]]; then
		error "UnityMcpServer src directory not found. Checked candidates: ${candidates[*]}"
		error "Repository layout may have changed. Inspect $repo_dir for the new server location."
		exit 1
	fi

	ln -sfn "$repo_dir/$server_subdir" "$server_link"
	info "UnityMcpServer synchronized at $server_link (source: $server_subdir)"
}

configure_vscode_mcp() {
	local data_home="${XDG_DATA_HOME:-$HOME/.local/share}"
	local server_src="$data_home/UnityMCP/UnityMcpServer/src"
	local mcp_config_dir="$HOME/.config/Code/User"
	local mcp_config="$mcp_config_dir/mcp.json"
	local tmp

	if [[ ! -d "$server_src" ]]; then
		error "Server source directory $server_src is missing."
		exit 1
	fi

	mkdir -p "$mcp_config_dir"

	if [[ ! -f "$mcp_config" ]]; then
		info "Creating new VS Code MCP configuration at $mcp_config"
		echo '{}' > "$mcp_config"
	else
		info "Updating existing VS Code MCP configuration at $mcp_config"
	fi

	tmp="$(mktemp)"

	if ! jq '.' "$mcp_config" >/dev/null 2>&1; then
		error "Existing $mcp_config is not valid JSON. Please fix it before running this script again."
		exit 1
	fi

	jq \
		--arg path "$server_src" \
		'(.servers //= {}) |
		 .servers.unityMCP = {
			 command: "uv",
			 args: ["--directory", $path, "run", "server.py"],
			 type: "stdio"
		 }' \
		"$mcp_config" > "$tmp"

	mv "$tmp" "$mcp_config"
	info "VS Code MCP server configuration updated for UnityMCP."
}

verify_python_version() {
	require_command python "python"
	local version
	version="$(python - <<'PY'
import sys
print("%d.%d.%d" % sys.version_info[:3])
PY
)"
	local major minor
	IFS='.' read -r major minor _ <<< "$version"
	if (( major < 3 || (major == 3 && minor < 12) )); then
		error "Python 3.12+ is required. Detected version $version. Upgrade python before continuing."
		exit 1
	fi
	info "Python version $version satisfies requirement (>= 3.12)."
}

print_next_steps() {
	cat <<'EOT'

Next steps:
	1. Launch Unity Hub and install a Unity Editor version 2021.3 LTS or newer.
	2. Open your Unity project and add the MCP for Unity Bridge package via:
			 Window > Package Manager > + > Add package from git URL...
			 https://github.com/CoplayDev/unity-mcp.git?path=/UnityMcpBridge
	3. In Unity, open Window > MCP for Unity and run Auto-Setup. Confirm the status shows Connected ✓.
	4. Open Visual Studio Code. The MCP server entry "unityMCP" is now configured. Reload if prompted.
	5. In VS Code, open the MCP client (e.g., Copilot / Claude Code) and issue a request such as "Create a tic-tac-toe game in 3D". The Unity MCP server should respond by operating inside your Unity project.

Optional (Roslyn strict validation):
	- Install NuGetForUnity and add Microsoft.CodeAnalysis + SQLitePCLRaw packages, then define USE_ROSLYN, OR
	- Manually place Roslyn DLLs into Assets/Plugins and add USE_ROSLYN to Scripting Define Symbols.

Troubleshooting tips:
	- If VS Code cannot launch the server, ensure `uv` is on PATH and that ~/.local/bin is exported in your shell.
	- To run the server manually: `uv --directory ~/.local/share/UnityMCP/UnityMcpServer/src run server.py`
	- Verify the directory path in ~/.config/Code/User/mcp.json matches your installation.

EOT
}

main() {
	if [[ ! -f /etc/arch-release ]]; then
		error "This script is intended for Arch Linux."
		exit 1
	fi

	info "Ensuring base dependencies are installed."
	require_command sudo "sudo"
	require_command pacman "pacman"
	ensure_pacman_packages
	verify_python_version
	install_uv
	ensure_unity_hub
	sync_unity_mcp_repo
	configure_vscode_mcp
	print_next_steps
	info "Setup complete. Follow the next steps above to finish configuration inside Unity."
}

main "$@"