#!/bin/bash
# Shared library functions for tinsnip machine setup

# Color constants
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

# Shared logging functions with customizable prefix
log_with_prefix() {
    local prefix="$1"
    shift
    echo -e "${GREEN}[$prefix]${NC} $*"
}

error_with_prefix() {
    local prefix="$1"
    shift
    echo -e "${RED}[ERROR]${NC} $*" >&2
    exit 1
}

warn_with_prefix() {
    local prefix="$1"
    shift
    echo -e "${YELLOW}[WARNING]${NC} $*"
}

# Get namespace number from namespace name (1-9 range)
# Uses deterministic hash that maps "dynamicalsystem" to 1 for backward compatibility
get_namespace_number() {
    local namespace="${1:-dynamicalsystem}"
    
    # Hash namespace to 1-9 range
    echo "$namespace" | md5sum | cut -c1-1 | {
        read hex
        printf "%d\n" "0x$hex" | awk '{n=($1 % 9) + 1; print n}'
    }
}

# Find the next available service number from a registry file
find_next_service_number() {
    local registry_path="$1"
    
    if [[ ! -f "$registry_path" ]]; then
        echo "1"
        return
    fi
    
    # Extract all service numbers from registry, find the highest
    local max_num=0
    while IFS='=' read -r service_name service_num; do
        # Skip comments and empty lines
        [[ "$service_name" =~ ^#.*$ ]] || [[ -z "$service_name" ]] && continue
        
        if [[ "$service_num" =~ ^[0-9]+$ ]] && [[ "$service_num" -gt "$max_num" ]]; then
            max_num="$service_num"
        fi
    done < "$registry_path"
    
    # Return next available number (max + 1)
    echo $((max_num + 1))
}

# Calculate service UID using TNSEP convention
# T=1 (Docker), N=namespace number, S=service, E=environment, P=0
calculate_service_uid() {
    local service_name="$1"
    local service_env="$2"
    
    # Get namespace from environment or file
    local namespace="${TIN_NAMESPACE:-}"
    if [[ -z "$namespace" ]] && [[ -f "/etc/tinsnip-namespace" ]]; then
        namespace=$(cat /etc/tinsnip-namespace)
    fi
    namespace="${namespace:-dynamicalsystem}"
    
    # Get namespace number (1-9)
    local namespace_num=$(get_namespace_number "$namespace")
    
    # Service number mapping
    local service_num
    
    # Special case for station (namespace infrastructure)
    if [[ "$service_name" == "station" ]]; then
        service_num=0
    else
        # Try to read from service registry
        local registry_path="/volume1/${namespace}/station/prod/service-registry"
        if [[ -f "$registry_path" ]]; then
            service_num=$(grep "^${service_name}=" "$registry_path" | cut -d= -f2)
            if [[ -z "$service_num" ]]; then
                # Service not in registry - auto-assign next available number
                service_num=$(find_next_service_number "$registry_path")
                warn_with_prefix "UID Calculation" "Service '$service_name' not in registry, auto-assigning service number $service_num"
            fi
        else
            # Registry doesn't exist - use fallback mapping or auto-assign
            case "$service_name" in
                gazette) service_num=1 ;;
                lldap) service_num=2 ;;
                gateway) service_num=3 ;;
                *) 
                    # Auto-assign starting from service number 4
                    service_num=4
                    warn_with_prefix "UID Calculation" "No registry found, auto-assigning service number $service_num for '$service_name'"
                    ;;
            esac
        fi
    fi
    
    # Environment number mapping  
    local env_num
    case "$service_env" in
        prod) env_num=0 ;;
        test) env_num=1 ;;
        *)
            echo "ERROR: Unknown environment: $service_env" >&2
            return 1
            ;;
    esac
    
    # Return TNSEP UID
    echo "1${namespace_num}${service_num}${env_num}0"
}

# Calculate service ports based on UID
calculate_service_ports() {
    local service_uid="$1"
    local port_count="${2:-3}"
    
    local base_port=$service_uid
    for ((i=0; i<port_count; i++)); do
        echo $((base_port + i))
    done
}

# Update shell configuration files (.bashrc or .profile) with environment variables
# Usage: update_shell_config username config_file "VAR1=value1" "VAR2=value2" ...
update_shell_config() {
    local username="$1"
    local config_file="$2"
    shift 2
    local env_vars=("$@")
    
    sudo -u "$username" -i bash << EOF
# Remove any existing environment variables to avoid duplicates
grep -v "$(printf "%s\\\\|" "${env_vars[@]}" | sed 's/=.*/=/g' | sed 's/\\\\|$//')" ~/$config_file > ~/${config_file}.tmp 2>/dev/null && mv ~/${config_file}.tmp ~/$config_file || touch ~/$config_file

# Add environment variables
cat >> ~/$config_file << 'CONFIG_EOF'

# Environment variables managed by tinsnip
$(printf "export %s\n" "${env_vars[@]}")
CONFIG_EOF
EOF
}

# Create service environment file on NFS mount with all variables needed by service
create_service_env_file() {
    local service_name="$1"
    local service_env="$2"
    local service_uid="$3"
    local mount_point="/mnt/${service_name}-${service_env}"
    local namespace="${TIN_NAMESPACE:-dynamicalsystem}"
    
    local env_file="$mount_point/.env"
    
    log_with_prefix "Service Env" "Creating $env_file"
    
    # Create the .env file with all service variables
    sudo -u "${service_name}-${service_env}" tee "$env_file" > /dev/null << EOF
# Tinsnip service environment variables
# Generated automatically - do not edit manually
TIN_SERVICE_NAME=$service_name
TIN_SERVICE_ENVIRONMENT=$service_env
TIN_SERVICE_UID=$service_uid
TIN_NAMESPACE=$namespace

# XDG Base Directory variables (NFS-backed)
XDG_DATA_HOME=$mount_point/data
XDG_CONFIG_HOME=$mount_point/config
XDG_STATE_HOME=$mount_point/state
XDG_CACHE_HOME=$mount_point/cache

# Docker environment (set by install_docker.sh if applicable)
# These will be added by Docker setup process
EOF

    log_with_prefix "Service Env" "Created service environment file"
}

# Generate shell environment loading code for .bashrc/.profile
# This creates the code that loads service env with cache fallback
generate_service_env_loader() {
    cat << 'EOF'
# Tinsnip service environment loading with NFS resilience
# Set XDG_CACHE_HOME first (host-based, not NFS)
export XDG_CACHE_HOME="${XDG_CACHE_HOME:-$HOME/.cache}"

# Load service environment variables
if [[ "\$(whoami)" =~ ^[^-]+-[^-]+\$ ]]; then
    # This is a service user (format: service-environment)
    SERVICE_ENV_FILE="/mnt/\$(whoami)/.env"
    TIN_SERVICE_ENV_CACHE="\$XDG_CACHE_HOME/tinsnip/\$(whoami).env"
    
    if [[ -f "$SERVICE_ENV_FILE" ]]; then
        # NFS available - source primary file and update cache
        source "$SERVICE_ENV_FILE"
        mkdir -p "$(dirname "$TIN_SERVICE_ENV_CACHE")"
        cp "$SERVICE_ENV_FILE" "$TIN_SERVICE_ENV_CACHE" 2>/dev/null || true
    elif [[ -f "$TIN_SERVICE_ENV_CACHE" ]]; then
        # NFS unavailable - use cached version
        source "$TIN_SERVICE_ENV_CACHE"
    fi
fi
EOF
}