#!/bin/bash

# Particle-OS Unified Configuration
# This file provides consistent configuration for all Particle-OS scripts
# Source this file in other scripts: source /usr/local/etc/particle-config.sh

set -euo pipefail

# =============================================================================
# CORE CONFIGURATION
# =============================================================================

# Base directories
PARTICLE_ROOT="/var/lib/particle-os"
PARTICLE_CONFIG_DIR="/usr/local/etc/particle-os"
PARTICLE_LOG_DIR="/var/log/particle-os"
PARTICLE_CACHE_DIR="/var/cache/particle-os"

# Script locations
PARTICLE_SCRIPTS_DIR="/usr/local/bin"
COMPOSEFS_SCRIPT="$PARTICLE_SCRIPTS_DIR/composefs"
BOOTUPD_SCRIPT="$PARTICLE_SCRIPTS_DIR/bootupd"
APT_LAYER_SCRIPT="$PARTICLE_SCRIPTS_DIR/apt-layer"

# ComposeFS configuration
COMPOSEFS_DIR="/var/lib/composefs-alternative"
COMPOSEFS_IMAGES_DIR="$COMPOSEFS_DIR/images"
COMPOSEFS_LAYERS_DIR="$COMPOSEFS_DIR/layers"
COMPOSEFS_MOUNTS_DIR="$COMPOSEFS_DIR/mounts"

# Build and workspace directories
PARTICLE_BUILD_DIR="$PARTICLE_ROOT/build"
PARTICLE_WORKSPACE_DIR="$PARTICLE_ROOT/workspace"
PARTICLE_TEMP_DIR="$PARTICLE_ROOT/temp"

# Live overlay configuration
PARTICLE_LIVE_OVERLAY_DIR="$PARTICLE_ROOT/live-overlay"
PARTICLE_LIVE_UPPER_DIR="$PARTICLE_LIVE_OVERLAY_DIR/upper"
PARTICLE_LIVE_WORK_DIR="$PARTICLE_LIVE_OVERLAY_DIR/work"

# Transaction management
PARTICLE_TRANSACTION_LOG="$PARTICLE_LOG_DIR/transaction.log"
PARTICLE_TRANSACTION_STATE="$PARTICLE_ROOT/transaction.state"
PARTICLE_TRANSACTION_BACKUP_DIR="$PARTICLE_ROOT/backups"

# =============================================================================
# LOGGING CONFIGURATION
# =============================================================================

# Log levels: DEBUG, INFO, WARNING, ERROR
PARTICLE_LOG_LEVEL="${PARTICLE_LOG_LEVEL:-INFO}"

# Log file paths
PARTICLE_MAIN_LOG="$PARTICLE_LOG_DIR/particle.log"
COMPOSEFS_LOG="$PARTICLE_LOG_DIR/composefs.log"
BOOTUPD_LOG="$PARTICLE_LOG_DIR/bootupd.log"
APT_LAYER_LOG="$PARTICLE_LOG_DIR/apt-layer.log"

# Log rotation settings
PARTICLE_LOG_MAX_SIZE="100M"
PARTICLE_LOG_MAX_FILES=5
PARTICLE_LOG_COMPRESSION="${PARTICLE_LOG_COMPRESSION:-gzip}"
PARTICLE_LOG_FILES_PATTERN="${PARTICLE_LOG_FILES_PATTERN:-*.log}"

# =============================================================================
# SECURITY CONFIGURATION
# =============================================================================

# GPG key for signing
PARTICLE_SIGNING_KEY="${PARTICLE_SIGNING_KEY:-}"
PARTICLE_SIGNING_KEYRING="${PARTICLE_SIGNING_KEYRING:-/etc/apt/trusted.gpg}"

# Secure Boot configuration
PARTICLE_SECURE_BOOT_ENABLED="${PARTICLE_SECURE_BOOT_ENABLED:-false}"
PARTICLE_SB_KEYS_DIR="$PARTICLE_CONFIG_DIR/secure-boot"

# =============================================================================
# PERFORMANCE CONFIGURATION
# =============================================================================

# Parallel processing
PARTICLE_PARALLEL_JOBS="${PARTICLE_PARALLEL_JOBS:-$(nproc 2>/dev/null || echo 4)}"
PARTICLE_MAX_PARALLEL_JOBS=8

# Compression settings
PARTICLE_SQUASHFS_COMPRESSION="${PARTICLE_SQUASHFS_COMPRESSION:-xz}"
PARTICLE_SQUASHFS_BLOCK_SIZE="${PARTICLE_SQUASHFS_BLOCK_SIZE:-1M}"

# Cache settings
PARTICLE_APT_CACHE_DIR="$PARTICLE_CACHE_DIR/apt"
PARTICLE_CONTAINER_CACHE_DIR="$PARTICLE_CACHE_DIR/containers"

# =============================================================================
# CONTAINER CONFIGURATION
# =============================================================================

# Container runtime preference
PARTICLE_CONTAINER_RUNTIME="${PARTICLE_CONTAINER_RUNTIME:-podman}"

# Container registry settings
PARTICLE_REGISTRY_URL="${PARTICLE_REGISTRY_URL:-}"
PARTICLE_REGISTRY_USERNAME="${PARTICLE_REGISTRY_USERNAME:-}"
PARTICLE_REGISTRY_PASSWORD="${PARTICLE_REGISTRY_PASSWORD:-}"

# =============================================================================
# NETWORK CONFIGURATION
# =============================================================================

# Package repository mirrors
PARTICLE_APT_MIRRORS=(
    "http://archive.ubuntu.com/ubuntu/"
    "http://security.ubuntu.com/ubuntu/"
)

# Proxy settings (if needed)
PARTICLE_HTTP_PROXY="${PARTICLE_HTTP_PROXY:-}"
PARTICLE_HTTPS_PROXY="${PARTICLE_HTTPS_PROXY:-}"
PARTICLE_NO_PROXY="${PARTICLE_NO_PROXY:-localhost,127.0.0.1}"

# =============================================================================
# VALIDATION FUNCTIONS
# =============================================================================

# Validate configuration
validate_particle_config() {
    local errors=0
    
    # Check required directories
    for dir in "$PARTICLE_ROOT" "$PARTICLE_CONFIG_DIR" "$PARTICLE_LOG_DIR" "$PARTICLE_CACHE_DIR"; do
        if [[ ! -d "$dir" ]]; then
            echo "ERROR: Required directory does not exist: $dir" >&2
            errors=$((errors + 1))
        fi
    done
    
    # Check required scripts
    for script in "$COMPOSEFS_SCRIPT" "$BOOTUPD_SCRIPT" "$APT_LAYER_SCRIPT"; do
        if [[ ! -f "$script" ]]; then
            echo "WARNING: Script not found: $script" >&2
        elif [[ ! -x "$script" ]]; then
            echo "WARNING: Script not executable: $script" >&2
        fi
    done
    
    # Validate log level
    case "$PARTICLE_LOG_LEVEL" in
        DEBUG|INFO|WARNING|ERROR)
            ;;
        *)
            echo "ERROR: Invalid log level: $PARTICLE_LOG_LEVEL" >&2
            errors=$((errors + 1))
            ;;
    esac
    
    # Validate compression
    case "$PARTICLE_SQUASHFS_COMPRESSION" in
        gzip|lzo|xz|zstd)
            ;;
        *)
            echo "ERROR: Invalid compression: $PARTICLE_SQUASHFS_COMPRESSION" >&2
            errors=$((errors + 1))
            ;;
    esac
    
    # Validate container runtime
    if [[ -n "$PARTICLE_CONTAINER_RUNTIME" ]]; then
        if ! command -v "$PARTICLE_CONTAINER_RUNTIME" >/dev/null 2>&1; then
            echo "WARNING: Container runtime not found: $PARTICLE_CONTAINER_RUNTIME" >&2
        fi
    fi
    
    if [[ $errors -gt 0 ]]; then
        return 1
    fi
    
    return 0
}

# =============================================================================
# INITIALIZATION FUNCTIONS
# =============================================================================

# Initialize Particle-OS environment
init_particle_environment() {
    # Create required directories
    mkdir -p "$PARTICLE_ROOT" "$PARTICLE_CONFIG_DIR" "$PARTICLE_LOG_DIR" "$PARTICLE_CACHE_DIR"
    mkdir -p "$PARTICLE_BUILD_DIR" "$PARTICLE_WORKSPACE_DIR" "$PARTICLE_TEMP_DIR"
    mkdir -p "$PARTICLE_LIVE_OVERLAY_DIR" "$PARTICLE_LIVE_UPPER_DIR" "$PARTICLE_LIVE_WORK_DIR"
    mkdir -p "$PARTICLE_TRANSACTION_BACKUP_DIR"
    mkdir -p "$PARTICLE_APT_CACHE_DIR" "$PARTICLE_CONTAINER_CACHE_DIR"
    
    # Set proper permissions
    chmod 755 "$PARTICLE_ROOT" "$PARTICLE_CONFIG_DIR" "$PARTICLE_LOG_DIR" "$PARTICLE_CACHE_DIR"
    chmod 700 "$PARTICLE_TRANSACTION_BACKUP_DIR"
    
    # Initialize log files if they don't exist
    for log_file in "$PARTICLE_MAIN_LOG" "$COMPOSEFS_LOG" "$BOOTUPD_LOG" "$APT_LAYER_LOG"; do
        if [[ ! -f "$log_file" ]]; then
            touch "$log_file"
            chmod 644 "$log_file"
        fi
    done
    
    # Validate configuration
    if ! validate_particle_config; then
        echo "WARNING: Configuration validation failed" >&2
    fi
}

# =============================================================================
# LOGGING FUNCTIONS
# =============================================================================

# Log levels
PARTICLE_LOG_DEBUG=0
PARTICLE_LOG_INFO=1
PARTICLE_LOG_WARNING=2
PARTICLE_LOG_ERROR=3

# Get numeric log level
get_log_level() {
    case "$PARTICLE_LOG_LEVEL" in
        DEBUG) echo $PARTICLE_LOG_DEBUG ;;
        INFO) echo $PARTICLE_LOG_INFO ;;
        WARNING) echo $PARTICLE_LOG_WARNING ;;
        ERROR) echo $PARTICLE_LOG_ERROR ;;
        *) echo $PARTICLE_LOG_INFO ;;
    esac
}

# Check if should log at given level
should_log() {
    local level="$1"
    local current_level
    current_level=$(get_log_level)
    
    case "$level" in
        DEBUG) [[ $current_level -le $PARTICLE_LOG_DEBUG ]] ;;
        INFO) [[ $current_level -le $PARTICLE_LOG_INFO ]] ;;
        WARNING) [[ $current_level -le $PARTICLE_LOG_WARNING ]] ;;
        ERROR) [[ $current_level -le $PARTICLE_LOG_ERROR ]] ;;
        *) false ;;
    esac
}

# Unified logging function
particle_log() {
    local level="$1"
    local message="$2"
    local script_name="${3:-$(basename "${BASH_SOURCE[1]:-unknown}")}"
    local timestamp
    timestamp=$(date '+%Y-%m-%d %H:%M:%S')
    
    if should_log "$level"; then
        echo "[$timestamp] [$level] [$script_name] $message" | tee -a "$PARTICLE_MAIN_LOG"
    fi
}

# Convenience logging functions
log_debug() { particle_log "DEBUG" "$1" "$2"; }
log_info() { particle_log "INFO" "$1" "$2"; }
log_warning() { particle_log "WARNING" "$1" "$2"; }
log_error() { particle_log "ERROR" "$1" "$2"; }

# =============================================================================
# UTILITY FUNCTIONS
# =============================================================================

# Get Ubuntu version
get_ubuntu_version() {
    lsb_release -rs 2>/dev/null || echo "unknown"
}

# Get Ubuntu codename
get_ubuntu_codename() {
    lsb_release -cs 2>/dev/null || echo "unknown"
}

# Check if running as root
check_root() {
    if [[ $EUID -ne 0 ]]; then
        log_error "This operation requires root privileges" "config"
        return 1
    fi
    return 0
}

# Get system architecture
get_architecture() {
    uname -m
}

# Check if system supports Secure Boot
check_secure_boot() {
    if [[ -d "/sys/firmware/efi" ]] && [[ -f "/sys/kernel/security/efi_test" ]]; then
        return 0
    else
        return 1
    fi
}

# =============================================================================
# EXPORT CONFIGURATION
# =============================================================================

# Export all configuration variables
export PARTICLE_ROOT PARTICLE_CONFIG_DIR PARTICLE_LOG_DIR PARTICLE_CACHE_DIR
export PARTICLE_SCRIPTS_DIR COMPOSEFS_SCRIPT BOOTUPD_SCRIPT APT_LAYER_SCRIPT
export COMPOSEFS_DIR COMPOSEFS_IMAGES_DIR COMPOSEFS_LAYERS_DIR COMPOSEFS_MOUNTS_DIR
export PARTICLE_BUILD_DIR PARTICLE_WORKSPACE_DIR PARTICLE_TEMP_DIR
export PARTICLE_LIVE_OVERLAY_DIR PARTICLE_LIVE_UPPER_DIR PARTICLE_LIVE_WORK_DIR
export PARTICLE_TRANSACTION_LOG PARTICLE_TRANSACTION_STATE PARTICLE_TRANSACTION_BACKUP_DIR
export PARTICLE_LOG_LEVEL PARTICLE_MAIN_LOG COMPOSEFS_LOG BOOTUPD_LOG APT_LAYER_LOG
export PARTICLE_LOG_MAX_SIZE PARTICLE_LOG_MAX_FILES PARTICLE_LOG_COMPRESSION PARTICLE_LOG_FILES_PATTERN
export PARTICLE_SIGNING_KEY PARTICLE_SIGNING_KEYRING
export PARTICLE_SECURE_BOOT_ENABLED PARTICLE_SB_KEYS_DIR
export PARTICLE_PARALLEL_JOBS PARTICLE_MAX_PARALLEL_JOBS
export PARTICLE_SQUASHFS_COMPRESSION PARTICLE_SQUASHFS_BLOCK_SIZE
export PARTICLE_APT_CACHE_DIR PARTICLE_CONTAINER_CACHE_DIR
export PARTICLE_CONTAINER_RUNTIME
export PARTICLE_REGISTRY_URL PARTICLE_REGISTRY_USERNAME PARTICLE_REGISTRY_PASSWORD
export PARTICLE_HTTP_PROXY PARTICLE_HTTPS_PROXY PARTICLE_NO_PROXY

# Export functions
export -f validate_particle_config init_particle_environment
export -f get_log_level should_log particle_log
export -f log_debug log_info log_warning log_error
export -f get_ubuntu_version get_ubuntu_codename check_root get_architecture check_secure_boot

# =============================================================================
# AUTO-INITIALIZATION
# =============================================================================

# Auto-initialize if this file is sourced
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    # This file is being executed directly
    echo "Particle-OS Configuration"
    echo "========================="
    echo "Root directory: $PARTICLE_ROOT"
    echo "Config directory: $PARTICLE_CONFIG_DIR"
    echo "Log directory: $PARTICLE_LOG_DIR"
    echo "Log level: $PARTICLE_LOG_LEVEL"
    echo ""
    
    if init_particle_environment; then
        echo "Environment initialized successfully"
    else
        echo "Environment initialization failed"
        exit 1
    fi
else
    # This file is being sourced
    init_particle_environment
fi