#!/bin/bash

set -euo pipefail

BIN_DIR="/usr/local/bin"
SOCKET_FILE="/etc/systemd/system/buildkitd.socket"
SERVICE_FILE="/etc/systemd/system/buildkitd.service"

_detect_arch() {
    ARCH=$(uname -m)
    case $ARCH in
        x86_64)
            echo "linux-amd64"
            ;;
        aarch64)
            echo "linux-arm64"
            ;;
        armv7l)
            echo "linux-arm-v7"
            ;;
        *)
            echo "Unsupported architecture: $ARCH"
            exit 1
            ;;
    esac
}

_install_buildkit() {
    local arch
    arch=$(_detect_arch)

    echo "Fetching latest BuildKit release..."
    local latest_url
    latest_url=$(curl -s https://api.github.com/repos/moby/buildkit/releases/latest | grep "browser_download_url" | grep "$arch.tar.gz" | cut -d '"' -f 4)
    if [[ -z $latest_url ]]; then
        echo "Failed to find a download URL for architecture $arch"
        exit 1
    fi

    echo "Downloading BuildKit binary from $latest_url..."
    local tmp_dir
    tmp_dir=$(mktemp -d)
    curl -L -o "$tmp_dir/buildkit.tar.gz" "$latest_url"

    echo "Installing BuildKit binary to $BIN_DIR..."
    tar -xzf "$tmp_dir/buildkit.tar.gz" -C "$tmp_dir"
    mv -f $tmp_dir/bin/* "$BIN_DIR/"

    rm -rf "$tmp_dir"
    echo "BuildKit installation complete!"
}

_setup_systemd() {
    echo "Creating $SOCKET_FILE..."
    cat <<EOF >"$SOCKET_FILE"
[Unit]
Description=Socket for BuildKit Daemon
Before=buildkitd.service

[Socket]
ListenStream=/run/buildkit/buildkitd.sock
SocketMode=0660
DirectoryMode=0755
ExecStartPre=-/bin/mkdir -p /run/buildkit
ExecStartPost=/bin/chmod 0660 /run/buildkit/buildkitd.sock

[Install]
WantedBy=sockets.target
EOF

    echo "Creating $SERVICE_FILE..."
    cat <<EOF >"$SERVICE_FILE"
[Unit]
Description=BuildKit Daemon
Requires=buildkitd.socket
After=buildkitd.socket

[Service]
ExecStart=$BIN_DIR/buildkitd
Restart=always
RestartSec=5s

[Install]
WantedBy=multi-user.target
EOF

    echo "Enabling and starting buildkitd.socket..."
    systemctl daemon-reload
    systemctl enable buildkitd.socket
    systemctl start buildkitd.socket

    echo "Systemd configuration complete!"
}

_install_buildkit
_setup_systemd