#!/bin/bash

# Simplified rootless Docker installation for tinsnip
# Eliminates complex systemd detection and environment management

set -euo pipefail

SERVICE_USER="${1:-}"

log() {
    echo "[Docker Install] $*"
}

error() {
    log "ERROR: $*" >&2
    exit 1
}

usage() {
    echo "Usage: $0 <service_user>"
    echo "  service_user: User to install rootless Docker for (e.g., gateway-prod)"
    exit 1
}

install_dependencies() {
    log "Installing rootless Docker dependencies..."
    
    sudo apt-get update -qq >/dev/null 2>&1 || error "Failed to update package lists"
    sudo apt-get install -y uidmap dbus-user-session fuse-overlayfs slirp4netns >/dev/null 2>&1 || error "Failed to install Docker dependencies"
    
    log "Dependencies installed"
}

install_rootless_docker() {
    local username="$1"
    
    log "Installing rootless Docker for user: $username"
    
    # Check if already installed
    if sudo -u "$username" -i bash -c "command -v docker &>/dev/null"; then
        log "Docker already installed for $username"
        return 0
    fi
    
    # Install rootless Docker
    sudo -u "$username" -i bash << 'EOF'
# Download and install rootless Docker
curl -fsSL https://get.docker.com/rootless | sh

# Add Docker to PATH in .bashrc (simple approach)
if ! grep -q 'export PATH=$HOME/bin:$PATH' ~/.bashrc 2>/dev/null; then
    echo 'export PATH=$HOME/bin:$PATH' >> ~/.bashrc
fi

# Source the new PATH
export PATH=$HOME/bin:$PATH

# Test Docker installation
if command -v docker >/dev/null 2>&1; then
    echo "Docker binary installed successfully"
else
    echo "ERROR: Docker binary not found after installation"
    exit 1
fi
EOF

    if [[ $? -ne 0 ]]; then
        error "Failed to install Docker for $username"
    fi
    
    log "Rootless Docker installation completed for $username"
}

setup_docker_environment() {
    local username="$1"
    
    log "Setting up Docker environment for $username"
    
    # Create Docker runtime directory
    sudo -u "$username" -i bash -c 'mkdir -p "$HOME/.docker/run"'
    
    # Create simple Docker configuration
    sudo -u "$username" tee "/home/$username/.docker/daemon.json" > /dev/null << 'EOF'
{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  },
  "storage-driver": "overlay2"
}
EOF

    # Set up environment variables in service .env file
    local service_env_file="/mnt/$username/.env"
    
    if [[ -f "$service_env_file" ]]; then
        log "Adding Docker environment to service .env file"
        
        # Remove existing Docker variables
        sudo -u "$username" bash -c "grep -v '^XDG_RUNTIME_DIR=\|^DOCKER_HOST=\|^PATH=' '$service_env_file' > '${service_env_file}.tmp' 2>/dev/null || touch '${service_env_file}.tmp'"
        sudo -u "$username" bash -c "mv '${service_env_file}.tmp' '$service_env_file'"
        
        # Add Docker environment variables
        sudo -u "$username" bash -c "cat >> '$service_env_file' << 'DOCKER_EOF'

# Docker rootless environment
XDG_RUNTIME_DIR=/home/$username/.docker/run
DOCKER_HOST=unix:///home/$username/.docker/run/docker.sock  
PATH=/home/$username/bin:\$PATH
DOCKER_EOF"
        
        log "Docker environment added to $service_env_file"
    else
        log "WARNING: Service .env file not found at $service_env_file"
    fi
}

start_docker_daemon() {
    local username="$1"
    
    log "Starting Docker daemon for $username"
    
    sudo -u "$username" -i bash << 'EOF'
# Set up environment
export XDG_RUNTIME_DIR="$HOME/.docker/run"
export DOCKER_HOST="unix://$XDG_RUNTIME_DIR/docker.sock"
export PATH="$HOME/bin:$PATH"

# Kill any existing dockerd processes
pkill -f dockerd-rootless || true
sleep 2

# Start Docker daemon
nohup dockerd-rootless.sh > "$HOME/.docker/docker.log" 2>&1 &
sleep 5

# Wait for socket
for i in {1..10}; do
    if [[ -S "$XDG_RUNTIME_DIR/docker.sock" ]]; then
        echo "Docker socket created successfully"
        break
    fi
    echo "Waiting for Docker socket... ($i/10)"
    sleep 2
done

# Test Docker
if docker version >/dev/null 2>&1; then
    echo "Docker daemon started successfully"
else
    echo "ERROR: Docker daemon failed to start properly"
    cat "$HOME/.docker/docker.log" 2>/dev/null || echo "No log file found"
    exit 1
fi
EOF

    if [[ $? -ne 0 ]]; then
        error "Failed to start Docker daemon for $username"
    fi
    
    log "Docker daemon started successfully"
}

verify_installation() {
    local username="$1"
    
    log "Verifying Docker installation for $username..."
    
    local service_env_file="/mnt/$username/.env"
    
    if sudo -u "$username" bash -c "source '$service_env_file' 2>/dev/null && docker version >/dev/null 2>&1"; then
        log "Docker verification successful!"
        local docker_version
        docker_version=$(sudo -u "$username" bash -c "source '$service_env_file' 2>/dev/null && docker --version")
        log "Installed: $docker_version"
    else
        error "Docker verification failed for $username"
    fi
}

main() {
    # Validate parameters
    if [[ -z "$SERVICE_USER" ]]; then
        usage
    fi
    
    # Check if user exists
    if ! id "$SERVICE_USER" &>/dev/null; then
        error "User $SERVICE_USER does not exist. Create the user first."
    fi
    
    log "Installing rootless Docker for service user: $SERVICE_USER"
    
    # Install dependencies
    install_dependencies
    
    # Install rootless Docker
    install_rootless_docker "$SERVICE_USER"
    
    # Setup Docker environment
    setup_docker_environment "$SERVICE_USER"
    
    # Start Docker daemon
    start_docker_daemon "$SERVICE_USER"
    
    # Verify installation
    verify_installation "$SERVICE_USER"
    
    log ""
    log "Rootless Docker installation complete!"
    log "User: $SERVICE_USER"
    log "To test: sudo -u $SERVICE_USER bash -c 'source /mnt/$SERVICE_USER/.env && docker run hello-world'"
}

main "$@"