#!/bin/bash
# ============================================================================
# MorphGuard - Ethereum Node Setup Script
# ============================================================================
# This script installs and configures a local Ethereum node (Geth) for 
# blockchain-based evidence logging. It uses Sepolia Testnet by default.
#
# Usage:
#   ./scripts/setup_ethereum_node.sh [--mainnet|--sepolia|--local]
#
# Options:
#   --sepolia   Connect to Ethereum Sepolia Testnet (default, free)
#   --mainnet   Connect to Ethereum Mainnet (requires ETH for gas)
#   --local     Start a local development chain (Ganache)
#
# Prerequisites:
#   - Ubuntu/Debian-based system
#   - sudo access
#   - ~50GB disk space for Sepolia, ~500GB for Mainnet
# ============================================================================

set -e

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

NETWORK="${1:-sepolia}"
GETH_DATA_DIR="${MORPHGUARD_GETH_DATA_DIR:-$HOME/.ethereum}"
MORPHGUARD_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"

echo -e "${BLUE}"
echo "╔══════════════════════════════════════════════════════════════════╗"
echo "║       MorphGuard - Ethereum Node Setup                           ║"
echo "║       Immutable Evidence Logging Infrastructure                  ║"
echo "╚══════════════════════════════════════════════════════════════════╝"
echo -e "${NC}"

# ============================================================================
# Helper Functions
# ============================================================================

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

log_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

check_disk_space() {
    local required_gb=$1
    local available_gb=$(df -BG "$HOME" | awk 'NR==2 {print $4}' | tr -d 'G')
    
    if [ "$available_gb" -lt "$required_gb" ]; then
        log_error "Insufficient disk space. Need ${required_gb}GB, have ${available_gb}GB."
        exit 1
    fi
    log_info "Disk space check passed (${available_gb}GB available)"
}

# ============================================================================
# Install Geth (Go Ethereum)
# ============================================================================

install_geth() {
    if command -v geth &> /dev/null; then
        local version=$(geth version | head -n1)
        log_info "Geth already installed: $version"
        return 0
    fi

    log_info "Installing Geth (Go Ethereum Client)..."
    
    # Add Ethereum PPA
    sudo add-apt-repository -y ppa:ethereum/ethereum
    sudo apt-get update
    
    # Install Geth
    sudo apt-get install -y ethereum
    
    if command -v geth &> /dev/null; then
        log_info "Geth installed successfully: $(geth version | head -n1)"
    else
        log_error "Geth installation failed."
        exit 1
    fi
}

# ============================================================================
# Install Ganache (Local Development Chain)
# ============================================================================

install_ganache() {
    if command -v ganache &> /dev/null; then
        log_info "Ganache already installed."
        return 0
    fi

    log_info "Installing Ganache (Local Development Blockchain)..."
    
    # Check for npm
    if ! command -v npm &> /dev/null; then
        log_warn "npm not found. Installing Node.js..."
        curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash -
        sudo apt-get install -y nodejs
    fi
    
    # Install Ganache globally
    sudo npm install -g ganache
    
    if command -v ganache &> /dev/null; then
        log_info "Ganache installed successfully."
    else
        log_error "Ganache installation failed."
        exit 1
    fi
}

# ============================================================================
# Generate Wallet (if needed)
# ============================================================================

generate_wallet() {
    local keystore_dir="$GETH_DATA_DIR/keystore"
    
    if [ -d "$keystore_dir" ] && [ "$(ls -A $keystore_dir 2>/dev/null)" ]; then
        log_info "Existing wallet found in $keystore_dir"
        return 0
    fi

    log_info "Generating new Ethereum wallet..."
    
    # Create a new account with a random password
    local password=$(openssl rand -base64 32)
    echo "$password" > "$MORPHGUARD_DIR/.eth_wallet_password"
    chmod 600 "$MORPHGUARD_DIR/.eth_wallet_password"
    
    mkdir -p "$keystore_dir"
    
    geth account new --datadir "$GETH_DATA_DIR" --password "$MORPHGUARD_DIR/.eth_wallet_password"
    
    # Extract wallet address
    local wallet_file=$(ls "$keystore_dir" | head -n1)
    local wallet_address="0x$(echo "$wallet_file" | grep -oP '(?<=--)[a-fA-F0-9]{40}')"
    
    log_info "Wallet generated: $wallet_address"
    echo "$wallet_address" > "$MORPHGUARD_DIR/.eth_wallet_address"
    
    log_warn "IMPORTANT: Fund this wallet with Sepolia ETH from a faucet:"
    echo "  https://sepoliafaucet.com/"
    echo "  https://faucet.sepolia.dev/"
}

# ============================================================================
# Configure Environment
# ============================================================================

configure_env() {
    local endpoint=$1
    local network=$2
    
    log_info "Configuring MorphGuard environment for $network..."
    
    local env_file="$MORPHGUARD_DIR/.env"
    
    # Read wallet address
    local wallet_address=""
    if [ -f "$MORPHGUARD_DIR/.eth_wallet_address" ]; then
        wallet_address=$(cat "$MORPHGUARD_DIR/.eth_wallet_address")
    fi
    
    # Append or update blockchain settings
    if [ -f "$env_file" ]; then
        # Remove old blockchain settings
        sed -i '/^BLOCKCHAIN_/d' "$env_file"
        sed -i '/^MORPHGUARD_ETH_/d' "$env_file"
    fi
    
    cat >> "$env_file" << EOF

# ============================================================================
# Blockchain Configuration (Auto-generated by setup_ethereum_node.sh)
# ============================================================================
BLOCKCHAIN_ENABLED=true
BLOCKCHAIN_NETWORK=$network
BLOCKCHAIN_ENDPOINT=$endpoint
MORPHGUARD_ETH_WALLET_ADDRESS=$wallet_address
MORPHGUARD_ETH_KEYSTORE_DIR=$GETH_DATA_DIR/keystore
EOF

    log_info "Environment configured in $env_file"
}

# ============================================================================
# Create Systemd Service (for production)
# ============================================================================

create_systemd_service() {
    local network=$1
    
    log_info "Creating systemd service for Geth..."
    
    sudo tee /etc/systemd/system/morphguard-geth.service > /dev/null << EOF
[Unit]
Description=MorphGuard Ethereum Node (Geth)
After=network.target

[Service]
Type=simple
User=$USER
ExecStart=/usr/bin/geth --$network --http --http.addr 0.0.0.0 --http.port 8545 --http.api eth,net,web3,personal --http.corsdomain "*" --datadir $GETH_DATA_DIR --syncmode snap
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
EOF

    sudo systemctl daemon-reload
    log_info "Systemd service created: morphguard-geth.service"
}

# ============================================================================
# Main Setup Logic
# ============================================================================

case "$NETWORK" in
    --sepolia|sepolia)
        log_info "Setting up Ethereum Sepolia Testnet..."
        check_disk_space 50
        install_geth
        generate_wallet
        create_systemd_service "sepolia"
        configure_env "http://localhost:8545" "ethereum-sepolia"
        
        echo ""
        echo -e "${GREEN}Setup Complete!${NC}"
        echo ""
        echo "To start the Ethereum node:"
        echo "  sudo systemctl start morphguard-geth"
        echo "  sudo systemctl enable morphguard-geth  # Auto-start on boot"
        echo ""
        echo "To check sync status:"
        echo "  geth attach http://localhost:8545 --exec 'eth.syncing'"
        echo ""
        log_warn "Initial sync may take 2-6 hours depending on network speed."
        ;;
        
    --mainnet|mainnet)
        log_info "Setting up Ethereum Mainnet..."
        log_warn "Mainnet requires real ETH for gas fees!"
        check_disk_space 500
        install_geth
        generate_wallet
        create_systemd_service "mainnet"
        configure_env "http://localhost:8545" "ethereum-mainnet"
        
        echo ""
        echo -e "${GREEN}Setup Complete!${NC}"
        echo ""
        log_warn "Mainnet sync can take 1-3 days and requires 500GB+ storage."
        ;;
        
    --local|local)
        log_info "Setting up Local Development Chain (Ganache)..."
        install_ganache
        
        # Start Ganache in background
        log_info "Starting Ganache..."
        ganache --detach --port 8545 --mnemonic "morphguard test mnemonic do not use in production" > /dev/null 2>&1 &
        
        # Use pre-funded test account from Ganache
        local test_wallet="0x90F8bf6A479f320ead074411a4B0e7944Ea8c9C1"
        echo "$test_wallet" > "$MORPHGUARD_DIR/.eth_wallet_address"
        
        configure_env "http://localhost:8545" "local-ganache"
        
        echo ""
        echo -e "${GREEN}Setup Complete!${NC}"
        echo ""
        echo "Ganache is running on http://localhost:8545"
        echo "Test accounts are pre-funded with 1000 ETH each."
        echo ""
        echo "To restart Ganache:"
        echo "  ganache --port 8545"
        ;;
        
    *)
        echo "Usage: $0 [--sepolia|--mainnet|--local]"
        echo ""
        echo "Options:"
        echo "  --sepolia   Ethereum Sepolia Testnet (default, free)"
        echo "  --mainnet   Ethereum Mainnet (requires ETH)"
        echo "  --local     Local Ganache development chain"
        exit 1
        ;;
esac

echo ""
echo -e "${BLUE}Next Steps:${NC}"
echo "1. Start MorphGuard: ./start_morphguard.sh"
echo "2. Enable blockchain logging in Admin Panel > Forensic Evidence"
echo "3. Check connection status in the UI"
echo ""