#!/usr/bin/env bash
#
# Log viewer for email_tunnel systemd service

set -euo pipefail

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

SERVICE_NAME="email_tunnel.service"

# Check if systemctl is available
if ! command -v systemctl &> /dev/null; then
    echo -e "${RED}Error: systemctl not found${NC}"
    echo "This script requires systemd."
    exit 1
fi

# Check if journalctl is available
if ! command -v journalctl &> /dev/null; then
    echo -e "${RED}Error: journalctl not found${NC}"
    echo "This script requires journalctl."
    exit 1
fi

# Function to show help
show_help() {
    cat << EOF
${GREEN}email_tunnel Log Viewer${NC}

Usage: $0 [OPTION]

Options:
  -f, --follow          Follow logs in real-time (like tail -f)
  -n, --lines NUMBER    Show last N lines (default: 50)
  -t, --today           Show logs from today only
  -h, --hour            Show logs from the last hour
  -b, --boot            Show logs since last boot
  -a, --all             Show all logs (no limit)
  -s, --status          Show service status
  -e, --errors          Show only error messages
  -v, --verbose         Show verbose output (all log levels)
  --help                Show this help message

Examples:
  $0                    Show last 50 log lines
  $0 -f                 Follow logs in real-time
  $0 -n 100             Show last 100 lines
  $0 -t                 Show today's logs
  $0 -e                 Show only errors
  $0 -s                 Show service status

EOF
}

# Function to show status
show_status() {
    echo -e "${BLUE}=== Service Status ===${NC}"
    systemctl status "$SERVICE_NAME" --no-pager -l || true
    echo ""
    echo -e "${BLUE}=== Recent Runs ===${NC}"
    journalctl -u "$SERVICE_NAME" -n 5 --no-pager -o short-precise
}

# Parse command line arguments
FOLLOW=false
LINES=50
SINCE=""
PRIORITY=""
SHOW_ALL=false
SHOW_STATUS=false

if [ $# -eq 0 ]; then
    :
else
    while [[ $# -gt 0 ]]; do
        case $1 in
            -f|--follow)
                FOLLOW=true
                shift
                ;;
            -n|--lines)
                LINES="$2"
                shift 2
                ;;
            -t|--today)
                SINCE="today"
                shift
                ;;
            -h|--hour)
                SINCE="1 hour ago"
                shift
                ;;
            -b|--boot)
                SINCE="boot"
                shift
                ;;
            -a|--all)
                SHOW_ALL=true
                shift
                ;;
            -s|--status)
                SHOW_STATUS=true
                shift
                ;;
            -e|--errors)
                PRIORITY="err"
                shift
                ;;
            -v|--verbose)
                PRIORITY=""
                shift
                ;;
            --help)
                show_help
                exit 0
                ;;
            *)
                echo -e "${RED}Error: Unknown option: $1${NC}"
                echo "Use --help for usage information"
                exit 1
                ;;
        esac
    done
fi

# Check if service exists
if ! systemctl list-unit-files | grep -q "$SERVICE_NAME"; then
    echo -e "${YELLOW}Warning: $SERVICE_NAME is not installed${NC}"
    echo "Install the service first with: ./install_email_tunnel.sh"
    exit 1
fi

# Show status if requested
if [ "$SHOW_STATUS" = true ]; then
    show_status
    exit 0
fi

# Build journalctl command
CMD="journalctl -u $SERVICE_NAME"

# Add follow flag
if [ "$FOLLOW" = true ]; then
    CMD="$CMD -f"
fi

# Add line limit
if [ "$SHOW_ALL" = false ] && [ "$FOLLOW" = false ]; then
    CMD="$CMD -n $LINES"
fi

# Add time filter
if [ -n "$SINCE" ]; then
    if [ "$SINCE" = "boot" ]; then
        CMD="$CMD -b"
    else
        CMD="$CMD --since \"$SINCE\""
    fi
fi

# Add priority filter
if [ -n "$PRIORITY" ]; then
    CMD="$CMD -p $PRIORITY"
fi

# Add no-pager for non-follow mode
if [ "$FOLLOW" = false ]; then
    CMD="$CMD --no-pager"
fi

# Show what we're doing
if [ "$FOLLOW" = true ]; then
    echo -e "${GREEN}Following logs for $SERVICE_NAME...${NC}"
    echo "Press Ctrl+C to stop"
    echo ""
elif [ -n "$SINCE" ]; then
    echo -e "${GREEN}Showing logs since $SINCE...${NC}"
    echo ""
elif [ "$SHOW_ALL" = true ]; then
    echo -e "${GREEN}Showing all logs for $SERVICE_NAME...${NC}"
    echo ""
else
    echo -e "${GREEN}Showing last $LINES log lines for $SERVICE_NAME...${NC}"
    echo ""
fi

# Execute the command
eval "$CMD"