#!/bin/bash

# Service-specific NFS mount for tinsnip services
# Implements DEPLOYMENT_STRATEGY.md conventions

set -euo pipefail

# Required parameters
TIN_SERVICE_NAME="${1:-}"
TIN_SERVICE_ENVIRONMENT="${2:-}"
NAS_SERVER="${3:-}"

# Get script directory and source lib
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/lib.sh"

log() {
    echo "[NFS Mount] $*"
}

error() {
    log "ERROR: $*" >&2
    exit 1
}

usage() {
    echo "Usage: $0 <service_name> <service_env> <nas_server>"
    echo "  service_name: tinsnip, gazette, etc."
    echo "  service_env:  prod, test"
    echo "  nas_server:   NAS hostname or IP"
    echo ""
    echo "Example: $0 tinsnip test DS412plus"
    exit 1
}

# calculate_service_uid is now provided by lib.sh


install_nfs_dependencies() {
    log "Installing NFS dependencies..."
    
    if sudo apt-get update -qq >/dev/null 2>&1; then
        log "  Package lists updated"
    else
        error "Failed to update package lists"
    fi
    
    if sudo apt-get install -y nfs-common >/dev/null 2>&1; then
        log "  NFS utilities installed"
    else
        error "Failed to install NFS dependencies"
    fi
}

create_service_user() {
    local service_user="$1"
    local service_uid="$2"
    
    if ! id "$service_user" &>/dev/null; then
        log "Creating service user: $service_user (UID: $service_uid)"
        sudo useradd -u "$service_uid" -s /bin/bash -m "$service_user"
    else
        log "Service user $service_user already exists"
    fi
}

show_nfs_setup_instructions() {
    local service_name="$1"
    local service_env="$2"
    local nas_server="$3"
    local namespace="$4"
    local service_uid="$5"
    
    local nfs_export="/volume1/${namespace}/${service_name}/${service_env}"
    local client_host=$(hostname -f 2>/dev/null || hostname)
    
    echo
    echo "============================================================"
    echo "NFS EXPORT SETUP REQUIRED"
    echo "============================================================"
    echo
    echo "Before mounting, you need to configure NFS exports on your NAS."
    echo "SSH into your NAS ($nas_server) and run these commands:"
    echo
    echo "# 1. Create directory and set ownership"
    echo "sudo mkdir -p $nfs_export"
    echo "sudo chown ${service_uid}:${service_uid} $nfs_export"
    echo
    echo "# 2. Add this line to /etc/exports (use TAB between path and options):"
    echo "${nfs_export}	${client_host}(rw,async,no_subtree_check,all_squash,anonuid=${service_uid},anongid=${service_uid})"
    echo
    echo "# 3. Reload NFS exports"
    echo "sudo exportfs -ra"
    echo "sudo exportfs -v  # Verify export is active"
    echo
    echo "============================================================"
    echo
    
    # Wait for user confirmation
    while true; do
        read -p "Have you completed the NFS export setup on $nas_server? (y/n): " confirm
        case $confirm in
            [Yy]* ) 
                log "Proceeding with NFS mount..."
                break
                ;;
            [Nn]* ) 
                echo "Please complete the NFS export setup before continuing."
                echo "You can also use: ./machine/scripts/generate_nfs_exports.sh $service_name $service_env $namespace $client_host"
                ;;
            * ) 
                echo "Please answer yes or no."
                ;;
        esac
    done
}

mount_nfs_share() {
    local service_name="$1"
    local service_env="$2"
    local nas_server="$3"
    local mount_point="/mnt/${service_name}-${service_env}"
    
    local namespace
    namespace=$(get_namespace)
    local nfs_export="/volume1/${namespace}/${service_name}/${service_env}"
    
    # Calculate service UID for NFS setup instructions
    local service_uid
    service_uid=$(calculate_service_uid "$service_name" "$service_env")
    
    log "Mounting NFS:"
    log "  Export: ${nas_server}:${nfs_export}"
    log "   Mount: ${mount_point}"
    
    # Create mount point
    sudo mkdir -p "$mount_point"
    
    # Unmount if already mounted
    if mountpoint -q "$mount_point" 2>/dev/null; then
        log "          Unmounting old $mount_point first"
        sudo umount "$mount_point"
    fi
    
    # Mount NFS share
    if ! sudo mount -t nfs "${nas_server}:${nfs_export}" "$mount_point"; then
        echo
        echo "❌ NFS mount failed!"
        echo "Common issues:"
        echo "1. NFS export not configured correctly on NAS"
        echo "2. Wrong hostname/IP for NAS server" 
        echo "3. Directory doesn't exist or has wrong ownership on NAS"
        echo "4. Firewall blocking NFS traffic (ports 111, 2049)"
        echo "5. NFS service not running on NAS"
        echo
        echo "To troubleshoot:"
        echo "1. Verify export exists: ssh $nas_server sudo exportfs -v"
        echo "2. Test basic NFS: sudo mount -t nfs $nas_server:/volume1 /tmp/test"
        echo "3. Check NAS logs for errors"
        echo
        error "Cannot mount NFS export ${nas_server}:${nfs_export}"
    fi
    
    # Verify mount
    if ! mountpoint -q "$mount_point"; then
        error "Mount point verification failed"
    fi
    
    log "  NFS mount successful"
}

get_namespace() {
    # Use namespace from environment, file, or default
    if [[ -n "${TIN_NAMESPACE:-}" ]]; then
        echo "$TIN_NAMESPACE"
    elif [[ -f "/etc/tinsnip-namespace" ]]; then
        cat "/etc/tinsnip-namespace"
    else
        echo "dynamicalsystem"
    fi
}

# Check if NFS export exists and is accessible
check_nfs_exists() {
    local nas_server="$1"
    local nfs_export="$2"
    
    # First try using showmount if available
    if command -v showmount >/dev/null 2>&1; then
        if showmount -e "$nas_server" 2>/dev/null | grep -q "^${nfs_export}[[:space:]]"; then
            log "NFS export found via showmount"
            return 0
        fi
    fi
    
    # Try temporary mount to check NFS export
    local temp_mount="/tmp/nfs-check-$$"
    mkdir -p "$temp_mount"
    
    # Increased timeout and retries for better detection
    if sudo mount -t nfs -o ro,soft,timeo=10,retry=3 "${nas_server}:${nfs_export}" "$temp_mount" 2>/dev/null; then
        sudo umount "$temp_mount" 2>/dev/null || true
        rmdir "$temp_mount" 2>/dev/null || true
        return 0  # NFS export exists and is accessible
    else
        # Log why it failed for debugging
        log "  ❌ Mount test failed: ${nas_server}:${nfs_export}"
        rmdir "$temp_mount" 2>/dev/null || true
        return 1  # NFS export doesn't exist or can't mount
    fi
}

# Guide user through NFS export creation using generate_nfs_exports.sh
guide_nfs_export_creation() {
    local service_name="$1"
    local service_env="$2"
    local nas_server="$3"
    local namespace
    namespace=$(get_namespace)
    
    log "  📝 Generating $service_name-$service_env NFS export instructions..."
    
    # Use generate_nfs_exports.sh to show exact commands needed
    if ! NAS_HOST="$nas_server" "$SCRIPT_DIR/generate_nfs_exports.sh" "$service_name" "$service_env" "$namespace" "$(hostname)"; then
        error "Failed to generate NFS export instructions"
    fi
    
    echo
    log "Press Enter when you've completed the NFS export setup:"
    read -p "  $nas_server..."
    
    # Build NFS export path for verification
    local nfs_export="/volume1/${namespace}/${service_name}/${service_env}"
    
    # Verify it's now accessible
    if ! check_nfs_exists "$nas_server" "$nfs_export"; then
        error "NFS export still not accessible: ${nas_server}:${nfs_export}. Please verify the setup."
    fi
    
    log "NFS export verified successfully"
}

# Set up service environment with NFS .env file and shell integration
setup_service_environment() {
    local service_name="$1"
    local service_env="$2"
    local service_uid="$3"
    local service_user="${service_name}-${service_env}"
    local mount_point="/mnt/${service_name}-${service_env}"
    
    log "Setting up service environment for $service_user"
    
    # Create the directories on the NFS mount
    sudo -u "$service_user" mkdir -p "$mount_point"/{data,config,state,cache}
    
    # Create service .env file on NFS mount (source of truth)
    create_service_env_file "$service_name" "$service_env" "$service_uid"
    
    # Update shell configs to load from NFS .env with cache fallback
    local env_loader_code
    env_loader_code=$(generate_service_env_loader)
    
    sudo -u "$service_user" -i bash << 'SETUP_EOF'
# Clear any existing environment loading code (more comprehensive cleanup)
for config_file in ~/.bashrc ~/.profile; do
    if [[ -f "$config_file" ]]; then
        # Remove all tinsnip-related environment code
        grep -v -E "(Tinsnip service environment|SERVICE_ENV_FILE|TIN_SERVICE_ENV_CACHE|XDG_.*_HOME.*=|export XDG_)" "$config_file" > "${config_file}.tmp" 2>/dev/null && mv "${config_file}.tmp" "$config_file" || touch "$config_file"
    else
        touch "$config_file"
    fi
done
SETUP_EOF

    # Add environment loading code to both files using printf
    printf '%s\n' "$env_loader_code" | sudo -u "$service_user" tee -a /home/"$service_user"/.bashrc > /dev/null
    printf '%s\n' "$env_loader_code" | sudo -u "$service_user" tee -a /home/"$service_user"/.profile > /dev/null
    
    log "Service environment configured:"
    log "  Primary: $mount_point/.env"
    log "  Cache: \$XDG_CACHE_HOME/tinsnip/$service_user.env"
    log "  Shell integration: .bashrc and .profile updated"
}

main() {
    # Validate parameters
    if [[ -z "$TIN_SERVICE_NAME" || -z "$TIN_SERVICE_ENVIRONMENT" || -z "$NAS_SERVER" ]]; then
        usage
    fi
    
    # Calculate service UID using convention
    TIN_SERVICE_UID=$(calculate_service_uid "$TIN_SERVICE_NAME" "$TIN_SERVICE_ENVIRONMENT")
    SERVICE_USER="${TIN_SERVICE_NAME}-${TIN_SERVICE_ENVIRONMENT}"
    
    log "Setting up NFS mount:"
    log "  Service: $TIN_SERVICE_NAME"
    log "  Environment: $TIN_SERVICE_ENVIRONMENT"
    log "  Service user: $SERVICE_USER (UID: $TIN_SERVICE_UID)"
    log "  NAS server: $NAS_SERVER"
    
    # Install dependencies
    install_nfs_dependencies
    
    # Create service user with calculated UID
    create_service_user "$SERVICE_USER" "$TIN_SERVICE_UID"
    
    # Check if NFS export exists, guide creation if needed
    local namespace
    namespace=$(get_namespace)
    local nfs_export="/volume1/${namespace}/${TIN_SERVICE_NAME}/${TIN_SERVICE_ENVIRONMENT}"
    
    log "Checking NFS export..."
    if ! check_nfs_exists "$NAS_SERVER" "$nfs_export"; then
        log "  ❌ ${NAS_SERVER}:${nfs_export}"
        log "NFS export not found, guiding setup..."
        guide_nfs_export_creation "$TIN_SERVICE_NAME" "$TIN_SERVICE_ENVIRONMENT" "$NAS_SERVER"
    else
        log "  ${NAS_SERVER}:${nfs_export}"
    fi
    
    # Mount the NFS share
    mount_nfs_share "$TIN_SERVICE_NAME" "$TIN_SERVICE_ENVIRONMENT" "$NAS_SERVER"
    
    # Set up service environment (.env file and shell integration)
    setup_service_environment "$TIN_SERVICE_NAME" "$TIN_SERVICE_ENVIRONMENT" "$TIN_SERVICE_UID"
    
    log "NFS mount setup complete!"
    log "Mount point: /mnt/${TIN_SERVICE_NAME}-${TIN_SERVICE_ENVIRONMENT}"
    log "Service user: $SERVICE_USER"
}

main "$@"