#!/usr/bin/env bash

set -euo pipefail

# Ensure we're in a flakes-enabled environment with required tools
if ! command -v nix &> /dev/null; then
    echo "❌ Nix is not installed. Please install Nix first:"
    echo "curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install"
    exit 1
fi

# Check if we need to enter a new shell
if [ -z "${INSIDE_NIX_SHELL+x}" ]; then
    export NIX_CONFIG="experimental-features = nix-command flakes"
    export INSIDE_NIX_SHELL=1
    exec nix shell nixpkgs#git nixpkgs#jq --command bash "$0"
fi

get_current_version() {
    local version_file=$1
    if [ -f "$version_file" ]; then
        jq -r '.version' "$version_file"
    else
        echo "0.0.0"
    fi
}

get_latest_version() {
    local LATEST_VERSION

    latest_version=$(curl -s "https://code.m3tam3re.com/api/v1/repos/m3tam3re/self-host-playbook/tags" | jq -r '.[] | select(.name | startswith("v")) | .name' | sort -V | tail -n1)

    if [ -z "$latest_version" ]; then
        echo "❌ Error: Could not fetch latest version from repository"
        exit 1
    fi

    # Remove 'v' prefix if present and return
    echo "${latest_version#v}"
}

check_compatibility() {
    local current_version=$1
    local target_version=$2
    local version_file=$3

    # Special case for initial install
    if [ "$current_version" = "0.0.0" ]; then
        echo "ℹ️ First time upgrade detected - proceeding with upgrade"
        return 0
    fi

    local min_compatible_version
    min_compatible_version=$(curl -s "https://code.m3tam3re.com/m3tam3re/self-host-playbook/raw/branch/develop/v${target_version}/$version_file" | jq -r '.minCompatibleVersion')

    if version_lt "$current_version" "$min_compatible_version"; then
        echo "❌ Your current version ($current_version) is too old for direct upgrade."
        echo "Please upgrade to version $min_compatible_version first."
        return 1
    fi
    return 0
}

# Show changelog - modified to use version file parameter
show_changelog() {
    local current_version=$1
    local target_version=$2
    local version_file=$3

    echo "📋 Changelog from $current_version to $target_version:"
    echo "------------------------------------------------"

    local changelog
    changelog=$(curl -s "https://code.m3tam3re.com/m3tam3re/self-host-playbook/raw/branch/develop/v${target_version}/$version_file" | jq -r '.changelog')

    # Process each version once, then all its changes
    echo "$changelog" | jq -r --arg cv "$current_version" --arg tv "$target_version" '
        to_entries[]
        | select(.key > $cv and .key <= $tv)
        | "\(.key):\n" + (.value | map("  - " + .) | join("\n"))
    ' 2>/dev/null

    echo "------------------------------------------------"
}

perform_update() {
    local target_version=$1
    local backup_dir=$2
    echo "⬇️ Downloading version $target_version..."

    TEMP_DIR=$(mktemp -d)
    trap 'rm -rf "$TEMP_DIR"' EXIT

    # Create a subdirectory for the clone
    CLONE_DIR="${TEMP_DIR}/clone"
    mkdir -p "$CLONE_DIR"

    # Clone to temporary directory with --quiet flag
    if ! nix flake clone --quiet "git+https://code.m3tam3re.com/m3tam3re/self-host-playbook?ref=v${target_version}" --dest "$CLONE_DIR" 2>/dev/null; then
        echo "❌ Failed to clone repository"
        return 1
    fi

    # Remove current directory contents except backup
    echo "🗑️ Cleaning current directory..."
    find . -maxdepth 1 ! -name "." ! -name ".." ! -name "$backup_dir" -exec rm -rf {} +

    # Copy new version from clone
    echo "📋 Installing new version..."
    cp -r "$CLONE_DIR"/* .

    # Restore configuration files from backup
    echo "🔄 Restoring configuration files..."
    cp -r "${backup_dir}/config.json" \
          "${backup_dir}/env" . 2>/dev/null || true


    return 0
}

setup_ssh_config() {
    local username=$1
    local ip_address=$2
    local ssh_config_dir="$HOME/.ssh"
    local ssh_config_file="$ssh_config_dir/config"
    local ssh_key_file="$ssh_config_dir/self-host-playbook"

    # Create .ssh directory if it doesn't exist
    mkdir -p "$ssh_config_dir"
    chmod 700 "$ssh_config_dir"

    # Create or append to SSH config
    local config_entry="Host self-host-playbook
    HostName $ip_address
    User $username
    Port 2222
    IdentityFile $ssh_key_file"

    # Check if entry already exists
    if ! grep -q "Host self-host-playbook" "$ssh_config_file" 2>/dev/null; then
        echo -e "\n$config_entry" >> "$ssh_config_file"
        echo "✅ Added SSH config entry"
    else
        # Update existing entry
        sed -i.bak "/Host self-host-playbook/,/IdentityFile.*/{
            s/HostName.*/HostName $ip_address/
            s/User.*/User $username/
        }" "$ssh_config_file"
        echo "✅ Updated existing SSH config entry"
    fi

    # Set appropriate permissions
    chmod 600 "$ssh_config_file"
}

update_config_json() {
    local ip_address=$1
    local config_file="config.json"

    # Read existing config
    local config
    config=$(cat "$config_file")

    # Update or add ipAddress field
    if jq -e '.ipAddress' "$config_file" >/dev/null 2>&1; then
        config=$(echo "$config" | jq --arg ip "$ip_address" '.ipAddress = $ip')
    else
        config=$(echo "$config" | jq --arg ip "$ip_address" '. + {ipAddress: $ip}')
    fi

    # Write back to file
    echo "$config" | jq '.' > "$config_file"
    echo "✅ Updated IP address in config.json"
}

install_deploy_rs() {
    echo "🔧 Installing deploy-rs to user environment..."

    # Check if deploy is already installed
    if command -v deploy >/dev/null 2>&1; then
        echo "ℹ️ deploy-rs is already installed"
        return 0
    fi

    # Install deploy-rs using nix profile
    if nix profile install 'github:serokell/deploy-rs'; then
        echo "✅ deploy-rs installed successfully"
    else
        echo "❌ Failed to install deploy-rs"
        return 1
    fi
}


# Main script
echo "🔄 Self-Host Playbook Update Assistant"
echo "======================================"

# Check if we're in the right directory
if [ ! -f "config.json" ]; then
    echo "❌ Error: config.json not found. Please run this script in your self-host-playbook directory."
    exit 1
fi

USERNAME=$(jq -r '.username' config.json)
IP_ADDRESS=$(jq -r '.ipAddress // empty' config.json)

if [ -z "$USERNAME" ]; then
    echo "❌ Error: Could not read username from config.json"
    exit 1
fi

# If IP address is not in config.json, prompt for it
if [ -z "$IP_ADDRESS" ]; then
    echo "ℹ️ No IP address found in config.json"
    read -p "Enter the IP address of your server: " IP_ADDRESS

    # Validate IP address format
    if ! [[ $IP_ADDRESS =~ ^[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
        echo "❌ Error: Invalid IP address format"
        exit 1
    fi

    # Update config.json with the new IP address
    update_config_json "$IP_ADDRESS"
fi

VERSION_FILE="version.json"
CURRENT_VERSION=$(get_current_version "$VERSION_FILE")
LATEST_VERSION=$(get_latest_version)

echo "Current version: $CURRENT_VERSION"
echo "Latest version:  $LATEST_VERSION"
echo

if [ "$CURRENT_VERSION" = "$LATEST_VERSION" ]; then
    echo "✅ You are already on the latest version!"
    exit 0
fi

if ! check_compatibility "$CURRENT_VERSION" "$LATEST_VERSION" "$VERSION_FILE"; then
    exit 1
fi

show_changelog "$CURRENT_VERSION" "$LATEST_VERSION" "$VERSION_FILE"

echo
read -p "Do you want to update to version $LATEST_VERSION? (y/N) " -n 1 -r
echo

if [[ $REPLY =~ ^[Yy]$ ]]; then
    # Create backup
    backup_dir="backup_${CURRENT_VERSION}_$(date +%Y%m%d_%H%M%S)"
    echo "📑 Creating backup in $backup_dir..."
    mkdir -p "$backup_dir"
    find . -maxdepth 1 ! -name "." ! -name ".." ! -name "$backup_dir" -exec cp -r {} "$backup_dir/" \;


    # Perform update
    if perform_update "$LATEST_VERSION" "$backup_dir"; then
        echo
        echo "✅ Update completed successfully!"
        # Setup SSH configuration
        echo
        echo "🔧 Setting up SSH configuration..."
        setup_ssh_config "$USERNAME" "$IP_ADDRESS"
        echo
        install_deploy_rs
        echo "🚀 Applying the update to your system..."
        echo
        echo "If you encounter any issues, your backup is available in $backup_dir"
    else
        echo "❌ Update failed. Your backup is available in $backup_dir"
        exit 1
    fi
else
    echo "Update cancelled."
    exit 1
fi