#!/bin/bash
# =============================================
# Debian Distribution Upgrade Script
# Upgrades Debian to the next stable release
# =============================================
# Configuration
LOG_FILE="/var/log/debian_upgrade.log"
BACKUP_DIR="/root/debian_upgrade_backup_$(date +%Y%m%d_%H%M%S)"

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[1;34m'
NC='\033[0m' # No Color
MAX_LOG_SIZE_KB=1024  # 1MB

# Função de Log (modificada para usar logger)
log() {
    local message="$1"
    local timestamp=$(date '+%Y-%m-%d %H:%M:%S')

    # Escreve no ficheiro de log
    echo -e "$timestamp: $message" | tee -a "$LOG_FILE"

    # Envia para o syslog (opcional)
    logger -t "debian_upgrade" "$message"
}

# Função para limitar o tamanho do log
limit_log_size() {
    local log_file="$1"
    local max_size_kb="$2"
    local max_size_bytes=$((max_size_kb * 1024))

    if [ -f "$log_file" ]; then
        local current_size=$(stat -c %s "$log_file" 2>/dev/null || wc -c < "$log_file" 2>/dev/null)

        if [ "$current_size" -gt "$max_size_bytes" ]; then
            log "Aviso: Ficheiro de log $log_file excedeu $max_size_kb KB. A truncar..."
            tail -n 500 "$log_file" > "${log_file}.tmp" && mv "${log_file}.tmp" "$log_file"
            log "Ficheiro de log truncado. As últimas 500 linhas foram mantidas."
        fi
    fi
}

# Function to ask for confirmation
ask_confirmation() {
    local message="$1"
    local default="$2"  # "y" or "n"
    while true; do
        if [ "$default" = "y" ]; then
            read -p "$message [Y/n]: " choice < /dev/tty
        else
            read -p "$message [y/N]: " choice < /dev/tty
        fi
        # Default choice if user just presses Enter
        if [ -z "$choice" ]; then
            choice="$default"
        fi
        case "$choice" in
            y|Y|yes|Yes|YES)
                return 0
                ;;
            n|N|no|No|NO)
                return 1
                ;;
            *)
                echo "Please answer yes or no."
                ;;
        esac
    done
}

# Function to check if running on Raspberry Pi
is_raspberry_pi() {
    if [ -f /proc/device-tree/model ] && grep -q "Raspberry Pi" /proc/device-tree/model; then
        return 0
    else
        return 1
    fi
}

# Function to validate if curl is installed
check_curl() {
    if ! command -v curl >/dev/null 2>&1; then
        log "Installing curl..."
        if ! apt install -y curl; then
            log "${RED}Failed to install curl${NC}"
            return 1
        fi
    fi
    return 0
}

# Function to get current Debian version
get_current_version() {
    CURRENT_VERSION=$(cat /etc/debian_version | cut -d'.' -f1)
    CURRENT_CODENAME=$(grep -oP '(?<=VERSION_CODENAME=).*' /etc/os-release)
    log "Current Debian version: $CURRENT_CODENAME (Debian $CURRENT_VERSION)"
}

# Function to get next Debian stable version
get_next_version() {
    if ! check_curl; then
        return 1
    fi

    NEXT_CODENAME=$(curl -s "http://ftp.debian.org/debian/dists/stable/Release" | grep -oP '(?<=Codename: ).*' | head -n 1)
    if [ -z "$NEXT_CODENAME" ]; then
        log "${RED}Failed to fetch next Debian version${NC}"
        return 1
    fi

    NEXT_VERSION=$(curl -s "http://ftp.debian.org/debian/dists/${NEXT_CODENAME}/Release" | grep -oP '(?<=Version: ).*' | cut -d'.' -f1)
    log "Next Debian version available: $NEXT_CODENAME (Debian $NEXT_VERSION)"
    return 0
}

# Function to backup important configurations
backup_configs() {
    log "Creating backup of important configurations in $BACKUP_DIR..."
    mkdir -p "$BACKUP_DIR" || {
        log "${RED}Failed to create backup directory${NC}"
        return 1
    }

    # Backup APT sources
    cp -a /etc/apt/sources.list "$BACKUP_DIR/" || {
        log "${RED}Failed to backup /etc/apt/sources.list${NC}"
        return 1
    }
    cp -a /etc/apt/sources.list.d/ "$BACKUP_DIR/" 2>/dev/null || true

    # Backup installed packages
    dpkg --get-selections > "$BACKUP_DIR/installed_packages.txt" || {
        log "${RED}Failed to backup installed packages${NC}"
        return 1
    }

    # Backup important system configs
    cp -a /etc/network/interfaces "$BACKUP_DIR/" 2>/dev/null || true
    cp -a /etc/resolv.conf "$BACKUP_DIR/" 2>/dev/null || true
    cp -a /etc/ssh/sshd_config "$BACKUP_DIR/" 2>/dev/null || true

    log "${GREEN}Backup completed successfully${NC}"
    return 0
}

# Function to update APT repositories
update_repositories() {
    log "Updating APT repositories to $NEXT_CODENAME..."
    sed -i "s/$CURRENT_CODENAME/$NEXT_CODENAME/g" /etc/apt/sources.list || {
        log "${RED}Failed to update /etc/apt/sources.list${NC}"
        return 1
    }

    if [ -d /etc/apt/sources.list.d/ ]; then
        find /etc/apt/sources.list.d/ -type f -name "*.list" -exec sed -i "s/$CURRENT_CODENAME/$NEXT_CODENAME/g" {} \; || {
            log "${RED}Failed to update repositories in /etc/apt/sources.list.d/${NC}"
            return 1
        }
    fi

    return 0
}

# Function to perform the upgrade
perform_upgrade() {
    log "Updating package lists..."
    if ! apt update; then
        log "${RED}Failed to update package lists${NC}"
        return 1
    fi

    log "Performing full upgrade..."
    if ! apt full-upgrade -y; then
        log "${RED}Failed to perform full upgrade${NC}"
        return 1
    fi

    log "Performing distribution upgrade to $NEXT_CODENAME..."
    if ! apt dist-upgrade -y; then
        log "${RED}Failed to perform distribution upgrade${NC}"
        return 1
    fi

    return 0
}

# Function to clean up after upgrade
cleanup() {
    log "Cleaning up..."
    apt autoremove -y || log "${YELLOW}Warning: Failed to autoremove packages${NC}"
    apt clean || log "${YELLOW}Warning: Failed to clean APT cache${NC}"
    return 0
}

# Function to verify upgrade
verify_upgrade() {
    NEW_CODENAME=$(grep -oP '(?<=VERSION_CODENAME=).*' /etc/os-release)
    if [ "$NEW_CODENAME" != "$NEXT_CODENAME" ]; then
        log "${RED}Upgrade verification failed. Current codename is still $NEW_CODENAME${NC}"
        return 1
    fi
    log "${GREEN}Successfully upgraded to $NEXT_CODENAME (Debian $NEXT_VERSION)${NC}"
    return 0
}

# Main function
main() {
    # Check if running as root
    if [ "$(id -u)" -ne 0 ]; then
        log "${RED}This script must be run as root. Use 'sudo'.${NC}"
        exit 1
    fi

    mkdir -p "$(dirname "$LOG_FILE")"
    limit_log_size "$LOG_FILE" "$MAX_LOG_SIZE_KB"  # Verifica o tamanho do log no início


    # Check if this is a Debian system
    if [ ! -f /etc/debian_version ]; then
        log "${RED}This script is only for Debian-based systems.${NC}"
        exit 1
    fi

    # Check if running on Raspberry Pi
    if is_raspberry_pi; then
        log "${RED}WARNING: This is a Raspberry Pi device.${NC}"
        log "${RED}Upgrading the Debian distribution may break compatibility with Raspberry Pi OS.${NC}"
        if ! ask_confirmation "Are you sure you want to continue?" "n"; then
            log "${YELLOW}Aborting Debian distribution upgrade${NC}"
            exit 0
        fi
    fi

    # Get current and next Debian versions
    get_current_version
    if ! get_next_version; then
        exit 1
    fi

    # Check if upgrade is needed
    if [ "$CURRENT_CODENAME" == "$NEXT_CODENAME" ]; then
        log "No new Debian stable version available. Current version: $CURRENT_CODENAME"
        exit 0
    fi

    # Ask for confirmation
    if ! ask_confirmation "Do you want to upgrade from $CURRENT_CODENAME to $NEXT_CODENAME?" "n"; then
        log "${YELLOW}Skipping Debian distribution upgrade${NC}"
        exit 0
    fi

    # Backup configurations
    if ! backup_configs; then
        exit 1
    fi

    # Update repositories
    if ! update_repositories; then
        exit 1
    fi

    # Perform upgrade
    if ! perform_upgrade; then
        exit 1
    fi

    # Clean up
    cleanup

    # Verify upgrade
    if ! verify_upgrade; then
        exit 1
    fi

    log "${YELLOW}Please reboot the system to complete the upgrade${NC}"
    exit 0
}

# Call main function
main