#!/bin/bash
# SparkOS Setup Script
# Sets up a minimal rootfs with busybox and essential utilities
# Note: This script runs on the host system and uses bash for ${BASH_SOURCE}
# The target system uses busybox sh instead.

set -e

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
ROOTFS_DIR="$PROJECT_ROOT/rootfs"

echo "SparkOS Root Filesystem Setup"
echo "=============================="
echo ""

# Create directory structure
echo "Creating directory structure..."
mkdir -p "$ROOTFS_DIR"/{bin,sbin,etc,proc,sys,dev,tmp,usr/{bin,sbin,lib,lib64},var,root,home}
mkdir -p "$ROOTFS_DIR/etc"/{init.d,network}
mkdir -p "$ROOTFS_DIR/var"/{log,run}
mkdir -p "$ROOTFS_DIR/home/spark"
mkdir -p "$ROOTFS_DIR/etc/sudoers.d"

# Set permissions
chmod 1777 "$ROOTFS_DIR/tmp"
chmod 700 "$ROOTFS_DIR/root"
chmod 755 "$ROOTFS_DIR/home/spark"

# Create basic config files
echo "Creating configuration files..."

# /etc/hostname
echo "sparkos" > "$ROOTFS_DIR/etc/hostname"

# /etc/hosts
cat > "$ROOTFS_DIR/etc/hosts" << 'EOF'
127.0.0.1   localhost
127.0.1.1   sparkos
::1         localhost ip6-localhost ip6-loopback
EOF

# /etc/passwd
cat > "$ROOTFS_DIR/etc/passwd" << 'EOF'
root:x:0:0:root:/root:/bin/sh
spark:x:1000:1000:SparkOS User:/home/spark:/bin/sh
EOF

# /etc/group
cat > "$ROOTFS_DIR/etc/group" << 'EOF'
root:x:0:
spark:x:1000:
sudo:x:27:spark
EOF

# /etc/fstab
cat > "$ROOTFS_DIR/etc/fstab" << 'EOF'
# <file system> <mount point> <type> <options> <dump> <pass>
proc            /proc         proc    defaults          0 0
sysfs           /sys          sysfs   defaults          0 0
devtmpfs        /dev          devtmpfs defaults         0 0
tmpfs           /tmp          tmpfs   defaults          0 0
EOF

# /etc/resolv.conf - DNS configuration
cat > "$ROOTFS_DIR/etc/resolv.conf" << 'EOF'
# SparkOS DNS Configuration
# Fallback to public DNS servers for reliability
nameserver 8.8.8.8
nameserver 8.8.4.4
nameserver 1.1.1.1
nameserver 1.0.0.1
EOF

# /etc/sudoers - Sudo configuration
cat > "$ROOTFS_DIR/etc/sudoers" << 'EOF'
# SparkOS Sudoers Configuration
# Allow spark user to run any command without password

# Default settings
Defaults env_reset
Defaults secure_path="/bin:/sbin:/usr/bin:/usr/sbin"

# Root can run anything
root ALL=(ALL:ALL) ALL

# Spark user can run anything without password
spark ALL=(ALL:ALL) NOPASSWD: ALL

# Include sudoers.d directory
@includedir /etc/sudoers.d
EOF

chmod 0440 "$ROOTFS_DIR/etc/sudoers"

# /etc/network/interfaces - Wired network configuration
cat > "$ROOTFS_DIR/etc/network/interfaces" << 'EOF'
# SparkOS Network Configuration
# Wired networking only for bootstrapping

# Loopback interface
auto lo
iface lo inet loopback

# Primary wired interface (DHCP)
auto eth0
iface eth0 inet dhcp
EOF

# /etc/profile
cat > "$ROOTFS_DIR/etc/profile" << 'EOF'
# SparkOS System Profile

export PATH=/bin:/sbin:/usr/bin:/usr/sbin
export PS1='SparkOS:\w\$ '
export TERM=linux

# Set HOME based on user
if [ "$(id -u)" = "0" ]; then
    export HOME=/root
else
    export HOME=/home/$(whoami)
fi

# Welcome message
echo "Welcome to SparkOS!"
echo "Type 'help' for available commands"
echo ""
EOF

# Create .profile for root (busybox uses .profile instead of .bashrc)
cat > "$ROOTFS_DIR/root/.profile" << 'EOF'
# SparkOS Root Shell Configuration

# Set prompt
PS1='SparkOS:\w# '

# Aliases
alias ll='ls -lah'
alias ..='cd ..'

# Environment
export EDITOR=vi
export PAGER=less
EOF

# Create .profile for spark user
cat > "$ROOTFS_DIR/home/spark/.profile" << 'EOF'
# SparkOS User Shell Configuration

# Set prompt
PS1='SparkOS:\w\$ '

# Aliases
alias ll='ls -lah'
alias ..='cd ..'

# Environment
export EDITOR=vi
export PAGER=less
EOF

# Create clone-sparkos.sh script for spark user
cat > "$ROOTFS_DIR/home/spark/clone-sparkos.sh" << 'EOF'
#!/bin/sh
# SparkOS CLI Installation Script
# This script clones the SparkOS CLI repository

echo "SparkOS CLI Installation"
echo "========================"
echo ""

SPARK_REPO="https://github.com/johndoe6345789/spark-cli.git"
INSTALL_DIR="$HOME/spark-cli"

echo "This script will clone the SparkOS CLI to: $INSTALL_DIR"
echo ""

# Check if git is available
if ! command -v git >/dev/null 2>&1; then
    echo "Error: git is not installed"
    echo "Please install git to continue"
    exit 1
fi

# Check if directory already exists
if [ -d "$INSTALL_DIR" ]; then
    echo "Warning: $INSTALL_DIR already exists"
    echo -n "Do you want to remove it and re-clone? (y/N): "
    read answer
    if [ "$answer" = "y" ] || [ "$answer" = "Y" ]; then
        rm -rf "$INSTALL_DIR"
    else
        echo "Installation cancelled"
        exit 0
    fi
fi

# Clone the repository
echo "Cloning spark CLI repository..."
if git clone "$SPARK_REPO" "$INSTALL_DIR"; then
    echo ""
    echo "SparkOS CLI cloned successfully!"
    echo ""
    echo "Next steps:"
    echo "  1. cd $INSTALL_DIR"
    echo "  2. Follow the installation instructions in the repository"
    echo ""
else
    echo ""
    echo "Error: Failed to clone repository"
    echo "Please check your network connection and try again"
    exit 1
fi
EOF

chmod +x "$ROOTFS_DIR/home/spark/clone-sparkos.sh"

# Create a simple help script
cat > "$ROOTFS_DIR/bin/sparkos-help" << 'EOF'
#!/bin/sh
cat << 'HELP'
SparkOS - Minimal Linux Distribution
====================================

Default Packages:
  - Kernel (Linux)
  - Init system (custom)
  - Busybox (shell and utilities)
  - Git (for installing spark CLI)
  - Sudo (privilege elevation)

Default User:
  Username: spark
  Home: /home/spark
  Privileges: Full sudo access (no password required)
  
  To run commands as root: sudo <command>
  To become root: sudo -i

Available commands:
  ls, cd, pwd      - Navigate filesystem
  cat, less        - View files
  mkdir, rm, cp    - File operations
  mount, umount    - Mount filesystems
  ip, ifconfig     - Network configuration
  ping, wget       - Network testing
  git              - Version control
  sudo             - Run commands as root
  poweroff, reboot - System control
  help             - Show this help

Network:
  Wired networking (eth0) configured via DHCP
  DNS: 8.8.8.8, 1.1.1.1 (Google and Cloudflare)
  To check network: ping 8.8.8.8
  To test DNS: ping google.com

Next Steps:
  1. Install spark CLI: ~/clone-sparkos.sh
  2. Use spark CLI to configure WiFi and system
  3. Install additional packages as needed

For more information: https://github.com/johndoe6345789/SparkOS
HELP
EOF

chmod +x "$ROOTFS_DIR/bin/sparkos-help"
ln -sf sparkos-help "$ROOTFS_DIR/bin/help"

# Create network initialization script
cat > "$ROOTFS_DIR/sbin/init-network" << 'EOF'
#!/bin/sh
# SparkOS Network Initialization
# Brings up wired networking for system bootstrap

echo "Initializing network..."

# Bring up loopback
ip link set lo up 2>/dev/null || ifconfig lo up 2>/dev/null

# Bring up primary wired interface with DHCP
# Try eth0 first, then other common interface names
for iface in eth0 enp0s3 enp0s8 ens33; do
    if ip link show "$iface" >/dev/null 2>&1; then
        echo "Bringing up $iface..."
        
        # Bring up the interface
        if ip link set "$iface" up 2>/dev/null || ifconfig "$iface" up 2>/dev/null; then
            # Try to get IP via DHCP using busybox udhcpc
            if command -v udhcpc >/dev/null 2>&1; then
                # Run udhcpc in background, it will daemonize itself
                udhcpc -i "$iface" -b -t 5 2>/dev/null
            fi
        else
            echo "Warning: Failed to bring up $iface"
        fi
        break
    fi
done

echo "Network initialization complete"
EOF

chmod +x "$ROOTFS_DIR/sbin/init-network"

# Create README
cat > "$ROOTFS_DIR/README.txt" << 'EOF'
SparkOS Root Filesystem
=======================

This is the root filesystem for SparkOS, a minimal Linux distribution.

Minimal System Packages:
  - Linux Kernel (with networking support)
  - SparkOS Init System (custom)
  - Busybox (shell, utilities, networking)
  - Git (for installing spark CLI)
  - Sudo (privilege elevation)

Directory Structure:
  /bin, /sbin       - Essential binaries
  /etc              - Configuration files
  /proc, /sys, /dev - Kernel interfaces
  /tmp              - Temporary files
  /usr              - User programs
  /var              - Variable data
  /root             - Root home directory
  /home/spark       - Default user home directory

Default User:
  Username: spark (UID 1000)
  Home: /home/spark
  Sudo: Full access without password
  Scripts: ~/clone-sparkos.sh for installing spark CLI

Network Configuration:
  /etc/network/interfaces - Wired network (DHCP)
  /etc/resolv.conf        - DNS configuration (8.8.8.8, 1.1.1.1)
  /sbin/init-network      - Network initialization script

Bootstrap Process:
  1. System boots as 'spark' user with wired networking (DHCP)
  2. Run ~/clone-sparkos.sh to install spark CLI
  3. Use spark CLI to configure WiFi and system
  4. Install additional packages via spark CLI
  5. Use 'sudo' for any root-level operations

Note: This is a minimal system. You'll need to populate /bin and /usr/bin
with actual binaries (busybox, git, sudo) from a proper Linux system
or by cross-compiling.
EOF

echo ""
echo "Root filesystem structure created at: $ROOTFS_DIR"
echo ""
echo "User configuration:"
echo "  - Default user: spark (UID 1000)"
echo "  - Home directory: /home/spark"
echo "  - Sudo access: Enabled (no password required)"
echo "  - Clone script: /home/spark/clone-sparkos.sh"
echo ""
echo "Network configuration:"
echo "  - Wired networking (DHCP) configured for eth0"
echo "  - DNS: 8.8.8.8, 1.1.1.1, 8.8.4.4, 1.0.0.1"
echo "  - Network init script: /sbin/init-network"
echo ""
echo "Next steps:"
echo "  1. Build init: make init"
echo "  2. Install init: make install"
echo "  3. Copy busybox, git, and sudo binaries to rootfs/bin/"
echo "  4. Create busybox symlinks"
echo "  5. Create bootable image: sudo make image"
echo ""
echo "Minimum required binaries:"
echo "  - busybox (provides shell, networking, utilities)"
echo "  - git (for installing spark CLI)"
echo "  - sudo (for privilege elevation)"
echo ""
echo "Note: Busybox should be compiled with networking support"
echo "      (CONFIG_UDHCPC, CONFIG_IFCONFIG, CONFIG_IP, CONFIG_PING, CONFIG_WGET)"